Toxoplasmosis gondii and schizophrenia: a case control study in a low Toxoplasma gondii seroprevalence Mexican population

USDA-ARS?s Scientific Manuscript database

There are conflicting reports concerning the association of T. gondii infection and schizophrenia. Therefore, we determined such association in a Mexican population of Mestizo ethnicity. Through a case-control study design, 50 schizophrenic patients and 150 control subjects matched by gender, age, r...

A matched case-control study of convenience store robbery risk factors.

PubMed

Hendricks, S A; Landsittel, D P; Amandus, H E; Malcan, J; Bell, J

1999-11-01

Convenience store clerks have been shown to be at high risk for assault and homicide, mostly owing to robbery or robbery attempts. Although the literature consistently indicates that at least some environmental designs are effective deterrents of robbery, the significance of individual interventions and policies has differed across past studies. To address these issues, a matched case-control study of 400 convenience store robberies in three metropolitan areas of Virginia was conducted. Conditional logistic regression was implemented to evaluate the significance of various environmental designs and other factors possibly related to convenience store robbery. Findings indicate that numerous characteristics of the surrounding environment and population were significantly associated with convenience store robbery. Results also showed that, on a univariate level, most crime prevention factors were significantly associated with a lower risk for robbery. Using a forward selection process, a multivariate model, which included cash handling policy, bullet-resistant shielding, and numerous characteristics of the surrounding area and population, was identified. This study addressed numerous limitations of the previous literature by prospectively collecting extensive data on a large sample of diverse convenience stores and directly addressing the current theory on the robbers' selection of a target store through a matched case-control design.

Importance of relationship context in HIV transmission: results from a qualitative case-control study in Rakai, Uganda.

PubMed

Higgins, Jenny A; Mathur, Sanyukta; Eckel, Elizabeth; Kelley, Laura; Kelly, Laura; Nakyanjo, Neema; Sekamwa, Richard; Namatovu, Josephine; Ddaaki, William; Nakubulwa, Rosette; Namakula, Sylvia; Nalugoda, Fred; Santelli, John S

2014-04-01

We present results from life history interviews with 60 young adults from southern Uganda. Using a novel qualitative case-control design, we compared newly HIV-positive cases with HIV-negative controls matched on age, gender, marital status, and place of residence. Relationship context was the most salient theme differentiating cases from controls. Compared with HIV-negative respondents, recent seroconverters described relationships marked by poorer communication, greater suspicion and mistrust, and larger and more transitory sexual networks. Results highlight the importance of dyadic approaches to HIV and possibly of couple-based interventions. Using HIV-matched pairs allowed additional understanding of the factors influencing transmission. This hybrid methodological approach holds promise for future studies of sexual health.

Importance of Relationship Context in HIV Transmission: Results From a Qualitative Case-Control Study in Rakai, Uganda

PubMed Central

Mathur, Sanyukta; Eckel, Elizabeth; Kelly, Laura; Nakyanjo, Neema; Sekamwa, Richard; Namatovu, Josephine; Ddaaki, William; Nakubulwa, Rosette; Namakula, Sylvia; Nalugoda, Fred; Santelli, John S.

2014-01-01

We present results from life history interviews with 60 young adults from southern Uganda. Using a novel qualitative case-control design, we compared newly HIV-positive cases with HIV-negative controls matched on age, gender, marital status, and place of residence. Relationship context was the most salient theme differentiating cases from controls. Compared with HIV-negative respondents, recent seroconverters described relationships marked by poorer communication, greater suspicion and mistrust, and larger and more transitory sexual networks. Results highlight the importance of dyadic approaches to HIV and possibly of couple-based interventions. Using HIV-matched pairs allowed additional understanding of the factors influencing transmission. This hybrid methodological approach holds promise for future studies of sexual health. PMID:24524490

Comments on: blood product transfusion in emergency department patients: a case control study of practice patterns and impact on outcome.

PubMed

Karami, Manoochehr; Khazaei, Salman

2017-12-06

Clinical decision makings according studies result require the valid and correct data collection, andanalysis. However, there are some common methodological and statistical issues which may ignore by authors. In individual matched case- control design bias arising from the unconditional analysis instead of conditional analysis. Using an unconditional logistic for matched data causes the imposition of a large number of nuisance parameters which may result in seriously biased estimates.

Role of matching in case-control studies of antimicrobial resistance.

PubMed

Cerceo, Elizabeth; Lautenbach, Ebbing; Linkin, Darren R; Bilker, Warren B; Lee, Ingi

2009-05-01

Of 57 case-control studies of antimicrobial resistance, matching was used in 23 (40%). Matched variables differed substantially across studies. Of these 23 matched case-control studies, 12 (52%) justified the use of matching, and 9 (39%) noted the strengths or limitations of this approach. Analysis that accounted for matching was performed in only 52% of the case-control studies.

User-only design to assess drug effectiveness in clinical practice: application to bisphosphonates and secondary prevention of fractures.

PubMed

Corrao, Giovanni; Ghirardi, Arianna; Segafredo, Giulia; Zambon, Antonella; Della Vedova, Gianluca; Lapi, Francesco; Cipriani, Francesco; Caputi, Achille; Vaccheri, Alberto; Gregori, Dario; Gesuita, Rosaria; Vestri, Annarita; Staniscia, Tommaso; Mazzaglia, Giampiero; Di Bari, Mauro

2014-08-01

Different strategies applicable to control for confounding by indication in observational studies were compared in a large population-based study regarding the effect of bisphosphonates (BPs) for secondary prevention of fractures. The cohort was drawn from healthcare utilization databases of 13 Italian territorial units. Patients aged 55 years or more who were hospitalized for fracture during 2003-2005 entered into the cohort. A nested case-control design was used to compare BPs use in cohort members who did (cases) and who did not experience (controls) a new fracture until 2007 (outcome). Three designs were employed: conventional-matching (D1 ), propensity score-matching (D2 ), and user-only (D3 ) designs. They differed for (i) cohort composition, restricted to patients who received BPs straight after cohort entry (D3 ); (ii) using propensity score for case-control matching (D2 ); and (iii) compared groups of BPs users versus no users (D1 and D2 ) and long-term versus short-term users (D3 ). Bisphosphonate users had odds ratios (95% confidence interval) of 1.20 (1.01 to 1.44) and 0.95 (0.74 to 1.24) by applying D1 and D2 designs, respectively. Statistical evidence that long-term BPs use protects the outcome onset with respect to short-term use was observed for user-only design (D3 ) being the corresponding odds ratio (95% confidence interval) 0.64 (0.44 to 0.93). User-only design yielded closer results to those seen in RCTs. This approach is one possible strategy to account for confounding by indication. Copyright © 2014 John Wiley & Sons, Ltd.

Methodologic considerations in the design and analysis of nested case-control studies: association between cytokines and postoperative delirium.

PubMed

Ngo, Long H; Inouye, Sharon K; Jones, Richard N; Travison, Thomas G; Libermann, Towia A; Dillon, Simon T; Kuchel, George A; Vasunilashorn, Sarinnapha M; Alsop, David C; Marcantonio, Edward R

2017-06-06

The nested case-control study (NCC) design within a prospective cohort study is used when outcome data are available for all subjects, but the exposure of interest has not been collected, and is difficult or prohibitively expensive to obtain for all subjects. A NCC analysis with good matching procedures yields estimates that are as efficient and unbiased as estimates from the full cohort study. We present methodological considerations in a matched NCC design and analysis, which include the choice of match algorithms, analysis methods to evaluate the association of exposures of interest with outcomes, and consideration of overmatching. Matched, NCC design within a longitudinal observational prospective cohort study in the setting of two academic hospitals. Study participants are patients aged over 70 years who underwent scheduled major non-cardiac surgery. The primary outcome was postoperative delirium from in-hospital interviews and medical record review. The main exposure was IL-6 concentration (pg/ml) from blood sampled at three time points before delirium occurred. We used nonparametric signed ranked test to test for the median of the paired differences. We used conditional logistic regression to model the risk of IL-6 on delirium incidence. Simulation was used to generate a sample of cohort data on which unconditional multivariable logistic regression was used, and the results were compared to those of the conditional logistic regression. Partial R-square was used to assess the level of overmatching. We found that the optimal match algorithm yielded more matched pairs than the greedy algorithm. The choice of analytic strategy-whether to consider measured cytokine levels as the predictor or outcome-- yielded inferences that have different clinical interpretations but similar levels of statistical significance. Estimation results from NCC design using conditional logistic regression, and from simulated cohort design using unconditional logistic regression, were similar. We found minimal evidence for overmatching. Using a matched NCC approach introduces methodological challenges into the study design and data analysis. Nonetheless, with careful selection of the match algorithm, match factors, and analysis methods, this design is cost effective and, for our study, yields estimates that are similar to those from a prospective cohort study design.

Delinquency and Recidivism: A Multicohort, Matched-Control Study of the Role of Early Adverse Experiences, Mental Health Problems, and Disabilities

ERIC Educational Resources Information Center

Barrett, David E.; Katsiyannis, Antonis; Zhang, Dalun; Zhang, Dake

2014-01-01

The authors examined the role of early adverse experiences, mental health problems, and disabilities in the prediction of juvenile delinquency and recidivism, using a matched-control group design. The delinquent group comprised 99,602 youth, born between 1981 and 1988, whose cases had been processed by the South Carolina Department of Juvenile…

Risk factors for idiopathic intracranial hypertension in men: a case-control study

PubMed Central

Fraser, J. Alexander; Bruce, Beau B.; Rucker, Janet; Fraser, Lisa-Ann; Atkins, Edward J.; Newman, Nancy J.; Biousse, Valérie

2009-01-01

Objective To identify risk factors for idiopathic intracranial hypertension (IIH) in men Design Case-control study. A 96-item telephone questionnaire, answered retrospectively, with cases recalling at the age of their diagnosis and controls recalling at the age of their corresponding case's diagnosis. Setting Outpatient clinics in two US tertiary care centers Participants The characteristics of 24 men with IIH were compared to those of 48 controls matched for sex, age, race, and World Health Organization body mass index (BMI) category. Main Outcome Measures Two previously validated questionnaires: the ADAM (Androgen Deficiency in Aging Males) questionnaire for testosterone deficiency and the Berlin questionnaire for obstructive sleep apnea (OSA), embedded within the telephone questionnaire. Analysis with Mantel-Haenszel odds ratios and mixed-effects logistic regression models accounted for matching. Results Cases and controls had similar enrollment matching characteristics. Although matching was successful by BMI category, there was a small difference between BMI values of cases and controls (cases: median 31.7, controls: median 29.9; p=0.03). After adjustment by BMI value, men with IIH were significantly more likely than controls to have a positive ADAM questionnaire for testosterone deficiency (OR: 17.4, 95% CI: 5.6-54.5; p<0.001) and significantly more likely to have either a positive Berlin questionnaire for OSA or history of diagnosed OSA (OR: 4.4, 95% CI: 1.5-12.9; p=0.03). Conclusions Men with IIH are more likely than controls to have symptoms associated with testosterone deficiency and OSA. These associations suggest a possible role for sex hormones and OSA in the pathogenesis of IIH in men. PMID:19945715

Risk and protective factors for meningococcal disease in adolescents: matched cohort study

PubMed Central

Tully, Joanna; Viner, Russell M; Coen, Pietro G; Stuart, James M; Zambon, Maria; Peckham, Catherine; Booth, Clare; Klein, Nigel; Kaczmarski, Ed; Booy, Robert

2006-01-01

Objective To examine biological and social risk factors for meningococcal disease in adolescents. Design Prospective, population based, matched cohort study with controls matched for age and sex in 1:1 matching. Controls were sought from the general practitioner. Setting Six contiguous regions of England, which represent some 65% of the country's population. Participants 15-19 year olds with meningococcal disease recruited at hospital admission in six regions (representing 65% of the population of England) from January 1999 to June 2000, and their matched controls. Methods Blood samples and pernasal and throat swabs were taken from case patients at admission to hospital and from cases and matched controls at interview. Data on potential risk factors were gathered by confidential interview. Data were analysed by using univariate and multivariate conditional logistic regression. Results 144 case control pairs were recruited (74 male (51%); median age 17.6). 114 cases (79%) were confirmed microbiologically. Significant independent risk factors for meningococcal disease were history of preceding illness (matched odds ratio 2.9, 95% confidence interval 1.4 to 5.9), intimate kissing with multiple partners (3.7, 1.7 to 8.1), being a university student (3.4, 1.2 to 10) and preterm birth (3.7, 1.0 to 13.5). Religious observance (0.09, 0.02 to 0.6) and meningococcal vaccination (0.12, 0.04 to 0.4) were associated with protection. Conclusions Activities and events increasing risk for meningococcal disease in adolescence are different from in childhood. Students are at higher risk. Altering personal behaviours could moderate the risk. However, the development of further effective meningococcal vaccines remains a key public health priority. PMID:16473859

Using public control genotype data to increase power and decrease cost of case-control genetic association studies.

PubMed

Ho, Lindsey A; Lange, Ethan M

2010-12-01

Genome-wide association (GWA) studies are a powerful approach for identifying novel genetic risk factors associated with human disease. A GWA study typically requires the inclusion of thousands of samples to have sufficient statistical power to detect single nucleotide polymorphisms that are associated with only modest increases in risk of disease given the heavy burden of a multiple test correction that is necessary to maintain valid statistical tests. Low statistical power and the high financial cost of performing a GWA study remains prohibitive for many scientific investigators anxious to perform such a study using their own samples. A number of remedies have been suggested to increase statistical power and decrease cost, including the utilization of free publicly available genotype data and multi-stage genotyping designs. Herein, we compare the statistical power and relative costs of alternative association study designs that use cases and screened controls to study designs that are based only on, or additionally include, free public control genotype data. We describe a novel replication-based two-stage study design, which uses free public control genotype data in the first stage and follow-up genotype data on case-matched controls in the second stage that preserves many of the advantages inherent when using only an epidemiologically matched set of controls. Specifically, we show that our proposed two-stage design can substantially increase statistical power and decrease cost of performing a GWA study while controlling the type-I error rate that can be inflated when using public controls due to differences in ancestry and batch genotype effects.

Bayes and empirical Bayes methods for reduced rank regression models in matched case-control studies.

PubMed

Satagopan, Jaya M; Sen, Ananda; Zhou, Qin; Lan, Qing; Rothman, Nathaniel; Langseth, Hilde; Engel, Lawrence S

2016-06-01

Matched case-control studies are popular designs used in epidemiology for assessing the effects of exposures on binary traits. Modern studies increasingly enjoy the ability to examine a large number of exposures in a comprehensive manner. However, several risk factors often tend to be related in a nontrivial way, undermining efforts to identify the risk factors using standard analytic methods due to inflated type-I errors and possible masking of effects. Epidemiologists often use data reduction techniques by grouping the prognostic factors using a thematic approach, with themes deriving from biological considerations. We propose shrinkage-type estimators based on Bayesian penalization methods to estimate the effects of the risk factors using these themes. The properties of the estimators are examined using extensive simulations. The methodology is illustrated using data from a matched case-control study of polychlorinated biphenyls in relation to the etiology of non-Hodgkin's lymphoma. © 2015, The International Biometric Society.

Medical Conditions in the First Years of Life Associated with Future Diagnosis of ASD in Children

ERIC Educational Resources Information Center

Alexeeff, Stacey E.; Yau, Vincent; Qian, Yinge; Davignon, Meghan; Lynch, Frances; Crawford, Phillip; Davis, Robert; Croen, Lisa A.

2017-01-01

This study examines medical conditions diagnosed prior to the diagnosis of autism spectrum disorder (ASD). Using a matched case control design with 3911 ASD cases and 38,609 controls, we found that 38 out of 79 medical conditions were associated with increased ASD risk. Developmental delay, mental health, and neurology conditions had the strongest…

A sham case-control study of effectiveness of DTP-Hib-hepatitis B vaccine against rotavirus acute gastroenteritis in Kenya

PubMed Central

2014-01-01

Background In many GAVI-eligible countries, effectiveness of new vaccines will be evaluated by case-control methodology. To inform the design and assess selection bias of a future case-control study of rotavirus vaccine effectiveness (VE) in western Kenya, we performed a sham case-control study evaluating VE of pentavalent vaccine (DTP-Hib-HepB) against rotavirus acute gastroenteritis (AGE). Methods From ongoing rotavirus surveillance, we defined cases as children 12 weeks to 23 months old with EIA-confirmed rotavirus AGE. We enrolled one community-based and two hospital-based control groups. We collected vaccination status from cards at enrollment, or later in homes, and evaluated VE by logistic regression. Results We enrolled 91 cases (64 inpatient, 27 outpatient), 252 non-rotavirus AGE facility-based controls (unmatched), 203 non-AGE facility-based controls (age-matched) and 271 community controls (age-matched). Documented receipt of 3 pentavalent doses was 77% among cases and ranged from 81-86% among controls. One percent of cases and 0-2% of controls had no pentavalent doses. The adjusted odds ratio of three versus zero doses for being a case was 3.27 (95% CI 0.01-1010) for community controls and 0.69 (95% CI 0.06-7.75) for non-rotavirus hospital-based AGE controls, translating to VE of -227% and 31%, respectively, with wide confidence intervals. (No facility-based non-AGE controls were unvaccinated.) Similar results were found for ≥2 pentavalent doses and for severe rotavirus AGE. Conclusions The study showed that it is feasible to carry out a real case control in the study area, but this needs to be done as soon as the vaccine is introduced to capture the real impact. Sham case-control or pilot studies before vaccine introduction can be useful in designing case-control VE studies. PMID:24517198

A sham case-control study of effectiveness of DTP-Hib-hepatitis B vaccine against rotavirus acute gastroenteritis in Kenya.

PubMed

Khagayi, Sammy; Tate, Jacqueline E; Onkoba, Reuben; Parashar, Umesh; Odhiambo, Frank; Burton, Deron; Laserson, Kayla; Feikin, Daniel R

2014-02-11

In many GAVI-eligible countries, effectiveness of new vaccines will be evaluated by case-control methodology. To inform the design and assess selection bias of a future case-control study of rotavirus vaccine effectiveness (VE) in western Kenya, we performed a sham case-control study evaluating VE of pentavalent vaccine (DTP-Hib-HepB) against rotavirus acute gastroenteritis (AGE). From ongoing rotavirus surveillance, we defined cases as children 12 weeks to 23 months old with EIA-confirmed rotavirus AGE. We enrolled one community-based and two hospital-based control groups. We collected vaccination status from cards at enrollment, or later in homes, and evaluated VE by logistic regression. We enrolled 91 cases (64 inpatient, 27 outpatient), 252 non-rotavirus AGE facility-based controls (unmatched), 203 non-AGE facility-based controls (age-matched) and 271 community controls (age-matched). Documented receipt of 3 pentavalent doses was 77% among cases and ranged from 81-86% among controls. One percent of cases and 0-2% of controls had no pentavalent doses. The adjusted odds ratio of three versus zero doses for being a case was 3.27 (95% CI 0.01-1010) for community controls and 0.69 (95% CI 0.06-7.75) for non-rotavirus hospital-based AGE controls, translating to VE of -227% and 31%, respectively, with wide confidence intervals. (No facility-based non-AGE controls were unvaccinated.) Similar results were found for ≥2 pentavalent doses and for severe rotavirus AGE. The study showed that it is feasible to carry out a real case control in the study area, but this needs to be done as soon as the vaccine is introduced to capture the real impact. Sham case-control or pilot studies before vaccine introduction can be useful in designing case-control VE studies.

Improved Temperature Dynamic Model of Turbine Subcomponents for Facilitation of Generalized Tip Clearance Control

NASA Technical Reports Server (NTRS)

Kypuros, Javier A.; Colson, Rodrigo; Munoz, Afredo

2004-01-01

This paper describes efforts conducted to improve dynamic temperature estimations of a turbine tip clearance system to facilitate design of a generalized tip clearance controller. This work builds upon research previously conducted and presented in and focuses primarily on improving dynamic temperature estimations of the primary components affecting tip clearance (i.e. the rotor, blades, and casing/shroud). The temperature profiles estimated by the previous model iteration, specifically for the rotor and blades, were found to be inaccurate and, more importantly, insufficient to facilitate controller design. Some assumptions made to facilitate the previous results were not valid, and thus improvements are presented here to better match the physical reality. As will be shown, the improved temperature sub- models, match a commercially validated model and are sufficiently simplified to aid in controller design.

Early Complications and Outcomes in Combat Injury Related Invasive Fungal Wound Infections: A Case-Control Analysis

PubMed Central

Lewandowski, Louis R.; Weintrob, Amy C.; Tribble, David R.; Rodriguez, Carlos J.; Petfield, Joseph; Lloyd, Bradley A.; Murray, Clinton K.; Stinner, Daniel; Aggarwal, Deepak; Shaikh, Faraz; Potter, Benjamin K.

2015-01-01

Objective Clinicians have anecdotally noted that combat-related invasive fungal wound infections (IFIs) lead to residual limb shortening, additional days and operative procedures prior to initial wound closure, and high early complication rates. We evaluated the validity of these observations and identified risk factors that may impact time to initial wound closure. Design Retrospective review and case-control analysis. Setting Military hospitals. Patients/Participants United States military personnel injured during combat operations (2009–2011). The IFI cases were identified based upon the presence of recurrent, necrotic extremity wounds with mold growth in culture and/or histopathologic fungal evidence. Non-IFI controls were matched on injury pattern and severity. In a supplemental matching analysis, non-IFI controls were also matched by blood volume transfused within 24 hours of injury. Intervention None. Main Outcome Measurements Amputation revision rate and loss of functional levels. Results Seventy-one IFI cases (112 fungal-infected extremity wounds) were identified and matched to 160 control patients (315 non-IFI extremity wounds). The IFI wounds resulted in significantly more changes in amputation level (p<0.001). Additionally, significantly (p<0.001) higher number of operative procedures and longer duration to initial wound closure was associated with IFI. A shorter duration to initial wound closure was significantly associated with wounds lacking IFIs (Hazard ratio: 1.53; 95% CI: 1.17, 2.01). The supplemental matching analysis found similar results. Conclusions Our analysis indicates that IFIs adversely impact wound healing and patient recovery, requiring more frequent proximal amputation revisions and leading to higher early complication rates. PMID:26360542

Comparison of lateral abdominal muscle thickness between weightlifters and matched controls.

PubMed

Sitilertpisan, Patraporn; Pirunsan, Ubon; Puangmali, Aatit; Ratanapinunchai, Jonjin; Kiatwattanacharoen, Suchart; Neamin, Hudsaleark; Laskin, James J

2011-11-01

To compare lateral abdominal muscle thickness between weightlifters and matched controls. A case control study design. University laboratory. 16 female Thai national weightlifters and 16 matched controls participated in this study. Ultrasound imaging with a 12-MHz linear array was used to measure the resting thickness of transversus abdominis (TrA), internal oblique (IO) and total thickness (Total) of lateral abdominal muscle (LAM) on the right side of abdominal wall. The absolute muscle thickness and the relative contribution of each muscle to the total thickness were determined. Weightlifters had significantly thicker absolute TrA and IO muscles than matched controls (p < 0.01). Further, the relative thickness of the IO was significantly greater in weightlifters than matched controls (p < 0.05). The findings of this study suggest that routine Olympic style weight training among female weightlifters appears to result in preferential hypertrophy or adaptation of the IO muscle. Copyright © 2011 Elsevier Ltd. All rights reserved.

Outcomes of preterm neonates with frontal horn cysts: a retrospective study.

PubMed

Trawber, Rory; Rao, Shripada; Srinivasjois, Ravisha; Thonell, Sven; Nagarajan, Lakshmi; French, Noel; Jacoby, Peter; McMichael, Judy

2010-11-01

Isolated paraventricular frontal horn cysts are sometimes encountered on cranial ultrasound examinations of preterm neonates. The etiology and clinical significance of these lesions are unclear. The authors aimed to identify antenatal/intrapartum risk factors associated with the occurrence of these cysts and to assess developmental outcomes of preterm neonates with isolated frontal horn cysts. A retrospective cohort study with matched control design was used. A total of 28 cases were matched for gestation with 56 controls. No antenatal/intrapartum factors were associated with these cysts. At corrected age of 1 year, there was no difference in the mean general quotient between cases and controls (97.75 ± 17.28 vs 94.94 ± 9.86; P = .410). In all, 1 case and no controls had a diagnosis of cerebral palsy and 1 case and 3 controls had general quotients less than 80. The authors conclude that isolated paraventricular frontal horn cysts are benign, with no effect on neurodevelopment.

Hyperactivity of the default-mode network in first-episode, drug-naive schizophrenia at rest revealed by family-based case-control and traditional case-control designs.

PubMed

Guo, Wenbin; Liu, Feng; Chen, Jindong; Wu, Renrong; Li, Lehua; Zhang, Zhikun; Chen, Huafu; Zhao, Jingping

2017-03-01

Abnormal regional activity and functional connectivity of the default-mode network (DMN) have been reported in schizophrenia. However, previous studies may have been biased by unmatched case-control design. To limit such bias, the present study used both the family-based case-control design and the traditional case-control design to investigate abnormal regional activity of the DMN in patients with schizophrenia at rest.Twenty-eight first-episode, drug-naive patients with schizophrenia, 28 age-, sex-matched unaffected siblings of the patients (family-based controls, FBC), and 40 healthy controls (HC) underwent resting-state functional magnetic resonance imaging (fMRI) scans. The group-independent component analysis and fractional amplitude of low-frequency fluctuation (fALFF) methods were used to analyze the data.Patients with schizophrenia show increased fALFF in an overlapped region of the right superior medial prefrontal cortex (MPFC) relative to the FBC and the HC. Compared with the HC, the patients and the FBC exhibit increased fALFF in an overlapped region of the left posterior cingulate cortex/precuneus (PCC/PCu). Furthermore, the z values of the 2 overlapped regions can separate the patients from the FBC/HC, and separate the patients/FBC from the HC with relatively high sensitivity and specificity.Both the family-based case-control and traditional case-control designs reveal hyperactivity of the DMN in first-episode, drug-naive patients with paranoid schizophrenia, which highlights the importance of the DMN in the neurobiology of schizophrenia. Family-based case-control design can limit the confounding effects of environmental factors in schizophrenia. Combination of the family-based case-control and traditional case-control designs may be a viable option for the neuroimaging studies.

Psychosocial factors in childhood pedestrian injury: a matched case-control study. Kid's'n'Cars Team.

PubMed

Christoffel, K K; Donovan, M; Schofer, J; Wills, K; Lavigne, J V

1996-01-01

Psychosocial factors--such as hyperactivity and low family cohesion--contribute to the risk for child pedestrian injury (PI), even after controlling for known demographic risk factors. Urban PI victims aged 5 to 12 years were recruited from one large, urban pediatric trauma center in a large city. One hundred twenty-eight cases were matched to uninjured children on age, sex, race, location of residence, and parental education. Among matched cases: 70% were male, 41% were black, 33% were Hispanic, and 66% of the mothers had a high school education or less. RESEARCH DESIGN AND MEASUREMENTS: Case-control comparisons on 19 psychosocial variables drawn from interviews and standardized tests, using one-tailed matched-pairs t tests and conditional logistic regression analyses. Cases had higher reported physical quotient [PQ] (P = .01), self-help quotient (P = .04), and family stress (P = .02), and lower family supportiveness (P = .03). Multivariate analyses confirmed that PQ was higher in cases (10-point increase: odds ratio (OR) = 1.32 [90% confidence interval (CI) 1.01-1.76], that stress was higher in cases (1 log increase: OR 2.13, [1.26-3.61]), and that cases had lower family supportiveness (25-point decrease: OR 1.43 [1.25-1.63]). It also identified household crowding as a factor for non-black cases (OR for increase of 0.25 people per room: 2.18, [1.31-3.62]). Even when controlling for demographic risk, several family factors and one child factor place children at risk for PI. Clinicians may choose to use these as indicators for injury prevention counseling. Research on family effects may help clarify means to protect children who are demographically at risk for PI.

Intrapartum fetal heart rate patterns of trisomy 21 fetuses: A case-control study.

PubMed

Koren, Inbal; Michaelson-Cohen, Rachel; Chen, Daniela; Michaeli, Jennia; Schimmel, Michael; Tsafrir, Avi; Shen, Ori

2016-01-01

To determine whether there are specific characteristic intrapartum heart rate patterns for fetuses with trisomy 21(T21). Intrapartum fetal heart rate (FHR) tracings of T21 fetuses were compared to those of euploid fetuses in a retrospective, observational, matched, case-control study. The study group consisted of 42 fetuses with T21 and 42 matched euploid controls. Matching was designed to accommodate possible confounders. The sign test and McNemar's test were used for categorical variables. The paired t test was used for comparison between quantitative variables. Intrapartum baseline FHR of fetuses with T21 was found to be slightly decreased compared to controls (122.5 vs 129.05 beats per minute, p=0.028). No differences were detected in the presence of periodic changes, or FHR variability between the groups. When evaluating intrapartum FHR of fetuses with T21, decreased baseline FHR can be expected. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Methodology Series Module 2: Case-control Studies.

PubMed

Setia, Maninder Singh

2016-01-01

Case-Control study design is a type of observational study. In this design, participants are selected for the study based on their outcome status. Thus, some participants have the outcome of interest (referred to as cases), whereas others do not have the outcome of interest (referred to as controls). The investigator then assesses the exposure in both these groups. The investigator should define the cases as specifically as possible. Sometimes, definition of a disease may be based on multiple criteria; thus, all these points should be explicitly stated in case definition. An important aspect of selecting a control is that they should be from the same 'study base' as that of the cases. We can select controls from a variety of groups. Some of them are: General population; relatives or friends; and hospital patients. Matching is often used in case-control control studies to ensure that the cases and controls are similar in certain characteristics, and it is a useful technique to increase the efficiency of the study. Case-Control studies can usually be conducted relatively faster and are inexpensive - particularly when compared with cohort studies (prospective). It is useful to study rare outcomes and outcomes with long latent periods. This design is not very useful to study rare exposures. Furthermore, they may also be prone to certain biases - selection bias and recall bias.

Nested case-control studies: should one break the matching?

PubMed

Borgan, Ørnulf; Keogh, Ruth

2015-10-01

In a nested case-control study, controls are selected for each case from the individuals who are at risk at the time at which the case occurs. We say that the controls are matched on study time. To adjust for possible confounding, it is common to match on other variables as well. The standard analysis of nested case-control data is based on a partial likelihood which compares the covariates of each case to those of its matched controls. It has been suggested that one may break the matching of nested case-control data and analyse them as case-cohort data using an inverse probability weighted (IPW) pseudo likelihood. Further, when some covariates are available for all individuals in the cohort, multiple imputation (MI) makes it possible to use all available data in the cohort. In the paper we review the standard method and the IPW and MI approaches, and compare their performance using simulations that cover a range of scenarios, including one and two endpoints.

Alternative approaches to analytical designs in occupational injury epidemiology.

PubMed

Mittleman, M A; Maldonado, G; Gerberich, S G; Smith, G S; Sorock, G S

1997-08-01

In this paper, we discuss the theoretical framework upon which observational studies of occupational injuries are based. Following a general description of how causal effects are estimated, the challenges faced by researchers working in this area are outlined, with an emphasis on case-control studies. These challenges include defining the at-risk period for workers whose tasks change over time and whose hazard period may be very brief, evaluating the underreporting of both exposures and injuries, and considering the effects of multiple injuries per individual on study design and data analysis. We review both the theoretical and practical considerations in the design and conduct of traditional case-control studies, based on the collection of individual level data, as well as other approaches, such as using information culled from administrative and descriptive databases, and case-control studies in which the plant or work site is the unit of analysis. The case-crossover design is also reviewed and its utility for reducing confounding due to differences between individuals by self-matching is highlighted. While this design has not yet been applied to the work setting, its potential for increasing our understanding of the causes of acute-onset occupational injuries seems promising. Finally, a variety of hybrid designs are discussed, including combinations of case-control, case-crossover, and cohort designs.

A concordance index for matched case-control studies with applications in cancer risk.

PubMed

Brentnall, Adam R; Cuzick, Jack; Field, John; Duffy, Stephen W

2015-02-10

In unmatched case-control studies, the area under the receiver operating characteristic (ROC) curve (AUC) may be used to measure how well a variable discriminates between cases and controls. The AUC is sometimes used in matched case-control studies by ignoring matching, but it lacks interpretation because it is not based on an estimate of the ROC for the population of interest. We introduce an alternative measure of discrimination that is the concordance of risk factors conditional on the matching factors. Parametric and non-parametric estimators are given for different matching scenarios, and applied to real data from breast and lung cancer case-control studies. Diagnostic plots to verify the constancy of discrimination over matching factors are demonstrated. The proposed simple measure is easy to use, interpret, more efficient than unmatched AUC statistics and may be applied to compare the conditional discrimination performance of risk factors. Copyright © 2014 John Wiley & Sons, Ltd.

An evaluation of the genetic-matched pair study design using genome-wide SNP data from the European population.

PubMed

Lu, Timothy Tehua; Lao, Oscar; Nothnagel, Michael; Junge, Olaf; Freitag-Wolf, Sandra; Caliebe, Amke; Balascakova, Miroslava; Bertranpetit, Jaume; Bindoff, Laurence Albert; Comas, David; Holmlund, Gunilla; Kouvatsi, Anastasia; Macek, Milan; Mollet, Isabelle; Nielsen, Finn; Parson, Walther; Palo, Jukka; Ploski, Rafal; Sajantila, Antti; Tagliabracci, Adriano; Gether, Ulrik; Werge, Thomas; Rivadeneira, Fernando; Hofman, Albert; Uitterlinden, André Gerardus; Gieger, Christian; Wichmann, Heinz-Erich; Ruether, Andreas; Schreiber, Stefan; Becker, Christian; Nürnberg, Peter; Nelson, Matthew Roberts; Kayser, Manfred; Krawczak, Michael

2009-07-01

Genetic matching potentially provides a means to alleviate the effects of incomplete Mendelian randomization in population-based gene-disease association studies. We therefore evaluated the genetic-matched pair study design on the basis of genome-wide SNP data (309,790 markers; Affymetrix GeneChip Human Mapping 500K Array) from 2457 individuals, sampled at 23 different recruitment sites across Europe. Using pair-wise identity-by-state (IBS) as a matching criterion, we tried to derive a subset of markers that would allow identification of the best overall matching (BOM) partner for a given individual, based on the IBS status for the subset alone. However, our results suggest that, by following this approach, the prediction accuracy is only notably improved by the first 20 markers selected, and increases proportionally to the marker number thereafter. Furthermore, in a considerable proportion of cases (76.0%), the BOM of a given individual, based on the complete marker set, came from a different recruitment site than the individual itself. A second marker set, specifically selected for ancestry sensitivity using singular value decomposition, performed even more poorly and was no more capable of predicting the BOM than randomly chosen subsets. This leads us to conclude that, at least in Europe, the utility of the genetic-matched pair study design depends critically on the availability of comprehensive genotype information for both cases and controls.

Determinants of unwanted pregnancies in India using matched case-control designs.

PubMed

Dixit, Priyanka; Ram, Faujdar; Dwivedi, Laxmi Kant

2012-08-11

In India, while the total fertility rate has been declined from 3.39 in 1992-93 to 2.68 in 2005-06, the prevalence of unintended pregnancy is still stagnant over the same period. A review of existing literature shows that within the country, there are variations in fertility preferences between different regions. Also there is a strong argument that the availability of a health facility at the village level plays an important role in reshaping the fertility behavior of women. Keeping in mind the fact that there is no information at the village level (which is the lowest geographical boundary) in the recent round of National Family Health Survey (NFHS-3), the specific objective of this study is to examine the impact of individual and household level variables on unwanted pregnancies without controlling the village level variation. Further, once the village level variation (i.e. unobserved variation) has been controlled, it is necessary to study whether there has been any alteration in the contribution of factors from earlier results of without adjusting the village level variation. This paper attempts to examine the associated factors of unwanted pregnancies, without matching the village and after matching the village, by using the matched case-control design. Nationwide data from India's latest NFHS-3 conducted during 2005-06 was used for the present study. Frequency and pair wise matching has been applied in the present paper and conditional logistic regression analysis was used to work out the models and to find out the factors associated with unwanted pregnancies. A major finding of this study was that 1:3 case-control study (without matching the village) shows that women belonging to non Hindu/Muslim religion, Scheduled Tribe, women who have experienced child loss and if the previous birth interval is 24 through 36 months were significant predictors of unwanted pregnancy. However, this relationship did not hold significant after village wise matching. Other factors such as Muslim religion, women and their partners with high school education and above, women belonging to the richest wealth index and if the sex of the last child was female, emerge as significant predictors of unwanted pregnancies. This study clearly underscores the importance of adjusting the village (PSU) level variation in explaining unwanted pregnancies.

Primary health care utilization prior to suicide: a retrospective case-control study among active-duty military personnel.

PubMed

Hochman, Eldar; Shelef, Leah; Mann, J John; Portugese, Shirly; Krivoy, Amir; Shoval, Gal; Weiser, Mark; Fruchter, Eyal

2014-08-01

About 45% of civilians who died by suicide had contact with a doctor within 1 month of death. Thus, educating primary care physicians (PCP) to detect and mitigate depression is an important suicide-prevention strategy. However, the PCP consulting rate before suicide has not been examined in a military population. We investigated the utilization of primary health care and mental health services by active-duty military personnel suicide cases prior to death in comparison to matched military controls. All suicides (N = 170) were extracted from a cohort of all active-duty Israeli military male personnel between 2002 and 2012. Applying a retrospective, nested case-control design, we compared primary care services utilization by suicide cases with demographic and occupationally matched military controls (N = 500). Whereas 38.3% of suicide cases contacted a PCP within the last month before death, only 27.6% of suicide cases contacted a mental health specialist during their entire service time. The PCP contact rate within 1 month before death or index day did not differ between suicide cases and military controls (38.3% vs. 33.8%, χ²₁ = 1.05, P = .3). More suicide cases contacted a mental health specialist within service time than did military controls (27.6% vs. 13.6%, χ²₁ = 10.85, P = .001). Even though PCP contact rate by military personnel who died by suicide is slightly lower than that reported for civilians who died by suicide prior to their death, it is higher than mental health specialist contact rate and higher than that by age-matched civilians who died by suicide. These results imply that PCPs education is a viable approach to suicide prevention in a military setting. © Copyright 2014 Physicians Postgraduate Press, Inc.

Methods for analyzing matched designs with double controls: excess risk is easily estimated and misinterpreted when evaluating traffic deaths.

PubMed

Redelmeier, Donald A; Tibshirani, Robert J

2018-06-01

To demonstrate analytic approaches for matched studies where two controls are linked to each case and events are accumulating counts rather than binary outcomes. A secondary intent is to clarify the distinction between total risk and excess risk (unmatched vs. matched perspectives). We review past research testing whether elections can lead to increased traffic risks. The results are reinterpreted by analyzing both the total count of individuals in fatal crashes and the excess count of individuals in fatal crashes, each time accounting for the matched double controls. Overall, 1,546 individuals were in fatal crashes on the 10 election days (average = 155/d), and 2,593 individuals were in fatal crashes on the 20 control days (average = 130/d). Poisson regression of total counts yielded a relative risk of 1.19 (95% confidence interval: 1.12-1.27). Poisson regression of excess counts yielded a relative risk of 3.22 (95% confidence interval: 2.72-3.80). The discrepancy between analyses of total counts and excess counts replicated with alternative statistical models and was visualized in graphical displays. Available approaches provide methods for analyzing count data in matched designs with double controls and help clarify the distinction between increases in total risk and increases in excess risk. Copyright © 2018 Elsevier Inc. All rights reserved.

Methodology Series Module 2: Case-control Studies

PubMed Central

Setia, Maninder Singh

2016-01-01

Case-Control study design is a type of observational study. In this design, participants are selected for the study based on their outcome status. Thus, some participants have the outcome of interest (referred to as cases), whereas others do not have the outcome of interest (referred to as controls). The investigator then assesses the exposure in both these groups. The investigator should define the cases as specifically as possible. Sometimes, definition of a disease may be based on multiple criteria; thus, all these points should be explicitly stated in case definition. An important aspect of selecting a control is that they should be from the same ‘study base’ as that of the cases. We can select controls from a variety of groups. Some of them are: General population; relatives or friends; and hospital patients. Matching is often used in case-control control studies to ensure that the cases and controls are similar in certain characteristics, and it is a useful technique to increase the efficiency of the study. Case-Control studies can usually be conducted relatively faster and are inexpensive – particularly when compared with cohort studies (prospective). It is useful to study rare outcomes and outcomes with long latent periods. This design is not very useful to study rare exposures. Furthermore, they may also be prone to certain biases – selection bias and recall bias. PMID:27057012

Resolving Controlled Vocabulary in DITA Markup: A Case Example in Agroforestry

ERIC Educational Resources Information Center

Zschocke, Thomas

2012-01-01

Purpose: This paper aims to address the issue of matching controlled vocabulary on agroforestry from knowledge organization systems (KOS) and incorporating these terms in DITA markup. The paper has been selected for an extended version from MTSR'11. Design/methodology/approach: After a general description of the steps taken to harmonize controlled…

Case-control study of infections with Salmonella enteritidis phage type 4 in England.

PubMed Central

Cowden, J. M.; Lynch, D.; Joseph, C. A.; O'Mahony, M.; Mawer, S. L.; Rowe, B.; Bartlett, C. L.

1989-01-01

OBJECTIVE--To determine the source of indigenous sporadic infection with Salmonella enteritidis phage type 4. DESIGN--Case-control study of primary sporadic cases identified by the Public Health Laboratory Service between 1 August and 30 September 1988. SETTING--PHLS Communicable Disease Surveillance Centre, Division of Enteric Pathogens, 11 PHLS laboratories, and 42 local authority environmental health departments in England. SUBJECTS--232 Patients (cases) with confirmed primary sporadic infection, for 160 of whom (88 female) (median age 30 years, age range 4 months to 85 years) data were obtained by questionnaire about consumption of fresh eggs, egg products, precooked chicken, and minced meat in the three days and one week before onset of the symptoms. Up to three controls, matched for neighbourhood, age, and sex (if aged greater than 11 years), were asked the same questions for the same calendar period. MAIN OUTCOME MEASURE--Association of primary sporadic infection with consumption of suspected food items. RESULTS--Illness due to S enteritidis phage type 4 was significantly associated with consumption of raw shell egg products (homemade mayonnaise, ice cream, and milk drinks containing eggs) (matched p = 0.02) and shop bought sandwiches containing mayonnaise (matched p = 0.00004) or eggs (matched p = 0.02). Illness was also significantly associated with eating lightly cooked eggs (unmatched p = 0.02), but not soft boiled eggs, and precooked hot chicken (matched p = 0.006). Reported consumption of eggs was not appreciably different between cases and controls before or after the median date of interview. CONCLUSIONS--Fresh shell eggs, egg products, and precooked hot chicken are vehicles of S enteritidis phage type 4 infection in indigenous sporadic cases. Public health education and reduction in contamination of eggs and infection of poultry with S enteritidis are needed to reduce the incidence of human infection. PMID:2508916

Early Urinary Markers of Diabetic Kidney Disease: A Nested Case-Control Study From the Diabetes Control and Complications Trial (DCCT)

PubMed Central

Kern, Elizabeth O; Erhard, Penny; Sun, Wanjie; Genuth, Saul; Weiss, Miriam F

2010-01-01

Background Urinary markers were tested as predictors of macroalbuminuria or microalbuminuria in type 1 diabetes. Study Design Nested case:control of participants in the Diabetes Control and Complications Trial (DCCT) Setting & Participants Eighty-seven cases of microalbuminuria were matched to 174 controls in a 1:2 ratio, while 4 cases were matched to 4 controls in a 1:1 ratio, resulting in 91 cases and 178 controls for microalbuminuria. Fifty-five cases of macroalbuminuria were matched to 110 controls in a 1:2 ratio. Controls were free of micro/macroalbuminuria when their matching case first developed micro/macroalbuminuria. Predictors Urinary N-acetyl-β-D-glucosaminidase, pentosidine, AGE fluorescence, albumin excretion rate (AER) Outcomes Incident microalbuminuria (two consecutive annual AER > 40 but <= 300 mg/day), or macroalbuminuria (AER > 300 mg/day) Measurements Stored urine samples from DCCT entry, and 1–9 years later when macroalbuminuria or microalbuminuria occurred, were measured for the lysosomal enzyme, N-acetyl-β-D-glucosaminidase, and the advanced glycosylation end-products (AGEs) pentosidine and AGE-fluorescence. AER and adjustor variables were obtained from the DCCT. Results Sub-microalbuminuric levels of AER at baseline independently predicted microalbuminuria (adjusted OR 1.83; p<.001) and macroalbuminuria (adjusted OR 1.82; p<.001). Baseline N-acetyl-β-D-glucosaminidase independently predicted macroalbuminuria (adjusted OR 2.26; p<.001), and microalbuminuria (adjusted OR 1.86; p<.001). Baseline pentosidine predicted macroalbuminuria (adjusted OR 6.89; p=.002). Baseline AGE fluorescence predicted microalbuminuria (adjusted OR 1.68; p=.02). However, adjusted for N-acetyl-β-D-glucosaminidase, pentosidine and AGE-fluorescence lost predictive association with macroalbuminuria and microalbuminuria, respectively. Limitations Use of angiotensin converting-enzyme inhibitors was not directly ascertained, although their use was proscribed during the DCCT. Conclusions Early in type 1 diabetes, repeated measurements of AER and urinary NAG may identify individuals susceptible to future diabetic nephropathy. Combining the two markers may yield a better predictive model than either one alone. Renal tubule stress may be more severe, reflecting abnormal renal tubule processing of AGE-modified proteins, among individuals susceptible to diabetic nephropathy. PMID:20138413

Using ancestry matching to combine family-based and unrelated samples for genome-wide association studies‡

PubMed Central

Crossett, Andrew; Kent, Brian P.; Klei, Lambertus; Ringquist, Steven; Trucco, Massimo; Roeder, Kathryn; Devlin, Bernie

2015-01-01

We propose a method to analyze family-based samples together with unrelated cases and controls. The method builds on the idea of matched case–control analysis using conditional logistic regression (CLR). For each trio within the family, a case (the proband) and matched pseudo-controls are constructed, based upon the transmitted and untransmitted alleles. Unrelated controls, matched by genetic ancestry, supplement the sample of pseudo-controls; likewise unrelated cases are also paired with genetically matched controls. Within each matched stratum, the case genotype is contrasted with control pseudo-control genotypes via CLR, using a method we call matched-CLR (mCLR). Eigenanalysis of numerous SNP genotypes provides a tool for mapping genetic ancestry. The result of such an analysis can be thought of as a multidimensional map, or eigenmap, in which the relative genetic similarities and differences amongst individuals is encoded in the map. Once constructed, new individuals can be projected onto the ancestry map based on their genotypes. Successful differentiation of individuals of distinct ancestry depends on having a diverse, yet representative sample from which to construct the ancestry map. Once samples are well-matched, mCLR yields comparable power to competing methods while ensuring excellent control over Type I error. PMID:20862653

Generalisability of vaccine effectiveness estimates: an analysis of cases included in a postlicensure evaluation of 13-valent pneumococcal conjugate vaccine in the USA

PubMed Central

Link-Gelles, Ruth; Westreich, Daniel; Aiello, Allison E; Shang, Nong; Weber, David J; Rosen, Jennifer B; Motala, Tasneem; Mascola, Laurene; Eason, Jeffery; Scherzinger, Karen; Holtzman, Corinne; Reingold, Arthur L; Barnes, Meghan; Petit, Susan; Farley, Monica M; Harrison, Lee H; Zansky, Shelley; Thomas, Ann; Schaffner, William; McGee, Lesley; Whitney, Cynthia G; Moore, Matthew R

2017-01-01

Objectives External validity, or generalisability, is the measure of how well results from a study pertain to individuals in the target population. We assessed generalisability, with respect to socioeconomic status, of estimates from a matched case–control study of 13-valent pneumococcal conjugate vaccine effectiveness for the prevention of invasive pneumococcal disease in children in the USA. Design Matched case–control study. Setting Thirteen active surveillance sites for invasive pneumococcal disease in the USA. Participants Cases were identified from active surveillance and controls were age and zip code matched. Outcome measures Socioeconomic status was assessed at the individual level via parent interview (for enrolled individuals only) and birth certificate data (for both enrolled and unenrolled individuals) and at the neighbourhood level by geocoding to the census tract (for both enrolled and unenrolled individuals). Prediction models were used to determine if socioeconomic status was associated with enrolment. Results We enrolled 54.6% of 1211 eligible cases and found a trend toward enrolled cases being more affluent than unenrolled cases. Enrolled cases were slightly more likely to have private insurance at birth (p=0.08) and have mothers with at least some college education (p<0.01). Enrolled cases also tended to come from more affluent census tracts. Despite these differences, our best predictive model for enrolment yielded a concordance statistic of only 0.703, indicating mediocre predictive value. Variables retained in the final model were assessed for effect measure modification, and none were found to be significant modifiers of vaccine effectiveness. Conclusions We conclude that although enrolled cases are somewhat more affluent than unenrolled cases, our estimates are externally valid with respect to socioeconomic status. Our analysis provides evidence that this study design can yield valid estimates and the assessing generalisability of observational data is feasible, even when unenrolled individuals cannot be contacted. PMID:28851801

Combining epidemiology and biomechanics in sports injury prevention research: a new approach for selecting suitable controls.

PubMed

Finch, Caroline F; Ullah, Shahid; McIntosh, Andrew S

2011-01-01

Several important methodological issues need to be considered when designing sports injury case-control studies. Major design goals for case-control studies include the accounting for prior injury risk exposure, and optimal definitions of both cases and suitable controls are needed to ensure this. This article reviews methodological aspects of published sports injury case-control studies, particularly with regard to the selection of controls. It argues for a new approach towards selecting controls for case-control studies that draws on an interface between epidemiological and biomechanical concepts. A review was conducted to identify sport injury case-control studies published in the peer-review literature during 1985-2008. Overall, 32 articles were identified, of which the majority related to upper or lower extremity injuries. Matching considerations were used for control selection in 16 studies. Specific mention of application of biomechanical principles in the selection of appropriate controls was absent from all studies, including those purporting to evaluate the benefits of personal protective equipment to protect against impact injury. This is a problem because it could lead to biased conclusions, as cases and controls are not fully comparable in terms of similar biomechanical impact profiles relating to the injury incident, such as site of the impact on the body. The strength of the conclusions drawn from case-control studies, and the extent to which results can be generalized, is directly influenced by the definition and recruitment of cases and appropriate controls. Future studies should consider the interface between epidemiological and biomechanical concepts when choosing appropriate controls to ensure that proper adjustment of prior exposure to injury risk is made. To provide necessary guidance for the optimal selection of controls in case-control studies of interventions to prevent sports-related impact injury, this review outlines a new case-control selection strategy that reflects the importance of biomechanical considerations, which ensures that controls are selected based on the presence of the same global injury mechanism as the cases. To summarize, the general biomechanical principles that should apply to the selection of controls in future case-control studies are as follows: (i) each control must have been exposed to the same global injury mechanism as the case, (e.g. head impact, fall onto outstretched arm); and (ii) intrinsic (individual) factors (e.g. age, sex, skill level) that might modify the person's response to the relevant biomechanical loads are adjusted when either selecting the controls or are in the analysis phase. The same considerations for control selection apply to other study designs such as matched cohort studies or case-crossover studies.

Are steroids useful to treat cerebral venous thrombosis?

PubMed

Canhão, Patrícia; Cortesão, Ana; Cabral, Marta; Ferro, José M; Stam, Jan; Bousser, Marie-Germaine; Barinagarrementeria, Fernando

2008-01-01

No randomized controlled trial has evaluated the efficacy of steroids in acute cerebral venous thrombosis (CVT). We aimed to analyze the effect of steroids on the outcome of patients in the International Study on Cerebral Veins and Dural Sinus Thrombosis (ISCVT). ISCVT is a prospective observational study that included 624 CVT patients. Death or dependence at 6 months was compared between cases (patients treated with steroids) and controls (patients not treated with steroids), using 3 designs: (1) Matched case-control study (each case matched with a control for prognostic factors); (2) Nonmatched case-control study of the ISCVT cohort; (3) Case-control study in different strata according to the number of poor prognostic variables in each patient. One hundred and fifty (24%) patients were treated with steroids. (1) In the matched case-control study, poor outcome was similar in the two groups of patients (26/146 versus 17/149, OR=1.7; 95% CI 0.9 to 3.3, P=0.119). (2) In the ISCVT cohort, no significant difference in poor outcomes was found whether patients were treated with steroids or not (26/146 versus 60/469, OR=1.5; 95% CI 0.9 to 2.4). Patients without parenchymal lesions treated with steroids had worse prognosis than those treated without steroids (8/45 versus 9/184, OR=4.2, 95% CI 1.6 to 11.6, P=0.008). (3) Treatment with steroids was not associated with a better outcome in any strata of patients according to the number of poor prognostic factors. Steroids in the acute phase of CVT were not useful and were detrimental in patients without parenchymal cerebral lesions. These results do not support the use of steroids in CVT (evidence level III).

Analysis of Clinical Cohort Data Using Nested Case-control and Case-cohort Sampling Designs. A Powerful and Economical Tool.

PubMed

Ohneberg, K; Wolkewitz, M; Beyersmann, J; Palomar-Martinez, M; Olaechea-Astigarraga, P; Alvarez-Lerma, F; Schumacher, M

2015-01-01

Sampling from a large cohort in order to derive a subsample that would be sufficient for statistical analysis is a frequently used method for handling large data sets in epidemiological studies with limited resources for exposure measurement. For clinical studies however, when interest is in the influence of a potential risk factor, cohort studies are often the first choice with all individuals entering the analysis. Our aim is to close the gap between epidemiological and clinical studies with respect to design and power considerations. Schoenfeld's formula for the number of events required for a Cox' proportional hazards model is fundamental. Our objective is to compare the power of analyzing the full cohort and the power of a nested case-control and a case-cohort design. We compare formulas for power for sampling designs and cohort studies. In our data example we simultaneously apply a nested case-control design with a varying number of controls matched to each case, a case cohort design with varying subcohort size, a random subsample and a full cohort analysis. For each design we calculate the standard error for estimated regression coefficients and the mean number of distinct persons, for whom covariate information is required. The formula for the power of a nested case-control design and the power of a case-cohort design is directly connected to the power of a cohort study using the well known Schoenfeld formula. The loss in precision of parameter estimates is relatively small compared to the saving in resources. Nested case-control and case-cohort studies, but not random subsamples yield an attractive alternative for analyzing clinical studies in the situation of a low event rate. Power calculations can be conducted straightforwardly to quantify the loss of power compared to the savings in the num-ber of patients using a sampling design instead of analyzing the full cohort.

Packed red blood cell transfusion is not associated with increased risk of necrotizing enterocolitis in premature infants

PubMed Central

Sharma, R; Kraemer, DF; Torrazza, RM; Mai, V; Neu, J; Shuster, JJ; Hudak, ML

2015-01-01

OBJECTIVE Recent reports have posited a temporal association between blood transfusion with packed red blood cells (BT) and necrotizing enterocolitis (NEC). We evaluated the relationship between BT and NEC among infants at three hospitals who were consented at birth into a prospective observational study of NEC. STUDY DESIGN We used a case–control design to match each case of NEC in our study population of infants born at <33 weeks postmenstrual age (PMA) to one control infant using hospital of birth, PMA, birth weight and date of birth. RESULT The number of transfusions per infant did not differ between 42 NEC cases and their controls (4.0 ± 4.6 vs 5.4 ± 4.1, mean ± s.d., P = 0.063). A matched-pair analysis did not identify an association of transfusion with NEC in either the 48-h or 7-day time periods before the onset of NEC. Stratifying on matched-sets, the Cox proportional hazard model did not identify any difference in the total number of BTs between the two groups (hazard ratio 0.78, 95% confidence interval 0.57 to 1.07, P = 0.11). CONCLUSION In contrast to previous studies, our case–control study did not identify a significant temporal association between BT and NEC. Additional large prospective randomized studies are needed to clarify the relationship between BT and NEC. PMID:25144159

The Role of Procurement Biopsies in Acceptance Decisions for Kidneys Retrieved for Transplant

PubMed Central

Stewart, Darren E.; Bista, Bipin R.; Salkowski, Nicholas; Snyder, Jon J.; Israni, Ajay K.; Crary, Gretchen S.; Rosendale, John D.; Matas, Arthur J.; Delmonico, Francis L.

2014-01-01

Background and objectives There is a shortage of kidneys for transplant, and many patients on the deceased donor kidney transplant waiting list would likely benefit from kidneys that are currently being discarded. In the United States, the most common reason given for discarding kidneys retrieved for transplant is procurement biopsy results. This study aimed to compare biopsy results from discarded kidneys with discard attributed to biopsy findings, with biopsy results from comparable kidneys that were successfully transplanted. Design, setting, participants, & measurements In this retrospective, observational, case-control study, biopsy reports were examined from 83 kidneys discarded in 2010 due to biopsy findings (cases), 83 contralateral transplanted kidneys from the same donor (contralateral controls), and 83 deceased donors randomly matched to cases by donor risk profile (randomly matched controls). A second procurement biopsy was obtained in 64 of 332 kidneys (19.3%). Results The quality of biopsy reports was low, with amounts of tubular atrophy, interstitial inflammation, arteriolar hyalinosis, and acute tubular necrosis often not indicated; 69% were wedge biopsies and 94% used frozen tissue. The correlation between first and second procurement biopsies was poor; only 25% of the variability (R2) in glomerulosclerosis was explained by biopsies being from the same kidney. The percentages of glomerulosclerosis overlapped substantially between cases, contralateral controls, and randomly matched controls: 17.1%±15.3%, 9.0%±6.6%, and 5.0%±5.9%, respectively. Of all biopsy findings, only glomerulosclerosis>20% was independently correlated with discard (cases versus contralateral controls; odds ratio, 15.09; 95% confidence interval, 2.47 to 92.41; P=0.003), suggesting that only this biopsy result was used in acceptance decisions. One-year graft survival was 79.5% and 90.7% in contralateral and randomly matched controls, respectively, versus 91.6% among all deceased donor transplants in the Scientific Registry of Transplant Recipients. Conclusions Routine use of biopsies could lead to unnecessary kidney discards. PMID:24558053

Case Selection via Matching

ERIC Educational Resources Information Center

Nielsen, Richard A.

2016-01-01

This article shows how statistical matching methods can be used to select "most similar" cases for qualitative analysis. I first offer a methodological justification for research designs based on selecting most similar cases. I then discuss the applicability of existing matching methods to the task of selecting most similar cases and…

Design and implementation of active members for precision space structures

NASA Technical Reports Server (NTRS)

Webster, M. S.; Fanson, J. L.; Lurie, B. J.; O'Brien, J. F.

1992-01-01

This paper describes the development and implementation of an active member in a precision truss structure. The active member utilizes a piezoelectric actuator motor imbedded in a steel case with built-in displacement sensor. This active member is used in structural quieting. Collocated active damping control loops are designed in order to impedance match piezoelectric active members to the structure. Results from application of these controllers and actuators to the JPL Phase B testbed are given.

Keeping children safe at home: protocol for three matched case–control studies of modifiable risk factors for falls

PubMed Central

Kendrick, Denise; Stewart, Jane; Clacy, Rose; Coffey, Frank; Cooper, Nicola; Coupland, Carol; Hayes, Mike; McColl, Elaine; Reading, Richard; Sutton, Alex; M L Towner, Elizabeth; Craig Watson, Michael

2012-01-01

Background Childhood falls result in considerable morbidity, mortality and health service use. Despite this, little evidence exists on protective factors or effective falls prevention interventions in young children. Objectives To estimate ORs for three types of medically attended fall injuries in young children in relation to safety equipment, safety behaviours and hazard reduction and explore differential effects by child and family factors and injury severity. Design Three multicentre case–control studies in UK hospitals with validation of parental reported exposures using home observations. Cases are aged 0–4 years with a medically attended fall injury occurring at home, matched on age and sex with community controls. Children attending hospital for other types of injury will serve as unmatched hospital controls. Matched analyses will use conditional logistic regression to adjust for potential confounding variables. Unmatched analyses will use unconditional logistic regression, adjusted for age, sex, deprivation and distance from hospital in addition to other confounders. Each study requires 496 cases and 1984 controls to detect an OR of 0.7, with 80% power, 5% significance level, a correlation between cases and controls of 0.1 and a range of exposure prevalences. Main outcome measures Falls on stairs, on one level and from furniture. Discussion As the largest in the field to date, these case control studies will adjust for potential confounders, validate measures of exposure and investigate modifiable risk factors for specific falls injury mechanisms. Findings should enhance the evidence base for falls prevention for young children. PMID:22628151

Critical issues in ALS case-control studies: the case of the Euro-MOTOR study.

PubMed

D'Ovidio, Fabrizio; Rooney, James P K; Visser, Anne E; Vermeulen, Roel C H; Veldink, Jan H; Van Den Berg, Leonard H; Hardiman, Orla; Logroscino, Giancarlo; Chiò, Adriano; Beghi, Ettore

2017-08-01

Backround: Political and sociocultural differences between countries can affect the outcome of clinical and epidemiological studies in ALS. Cross-national studies represent the ideal process by which risk factors can be assessed using the same methodology in different geographical areas. A survey of three European countries (The Netherlands, Ireland and Italy) has been conducted in which incident ALS patients and matched controls were recruited in a population-based study based on age, gender and area of residency, under the Euro-MOTOR systems biology programme of research. We have identified strengths and limitations during the trajectory of the Euro-MOTOR study, from the research design to data analysis. We have analysed the implications of factors including cross-national differences in healthcare systems, sample size, types of matching, the definition of exposures and statistical analysis. Addressing critical methodological aspects of the design of the Euro-MOTOR project minimises bias and will facilitate scientific assessment of the independent role of well-defined exposures.

Obstacles to action in arthritis: a community case-control study.

PubMed

Hutton, Ingrid; Gamble, Greg; McLean, Grant; Butcher, Hugh; Gow, Peter; Dalbeth, Nicola

2009-07-01

Despite the benefits of physical activity, people with arthritis are less active than the general population. The aim of this study was to determine the motivators and obstacles to physical activity for adults with arthritis. Participants were identified from the Obstacles to Action Study, a community based study of 8163 adults, which explored barriers and motivators to physical activity. A 1:1 case-control study was designed; cases were identified as those participants who reported arthritis (n = 1106). Each case was matched with an age, sex and ethnicity-matched non-arthritis control (n = 1106). Cases were less likely to achieve recommended physical activity targets (58.8% vs. 68.1% P = 0.00001). Furthermore, fewer people with arthritis believed that physical activity would help them lead healthy lives (86.7% vs. 91.3% P = 0.006) or viewed physical activity as a priority (53.8% vs. 59.8% P = 0.005). Cases were less confident in their abilities to try a new activity (37.1% vs. 43.7% P = 0.002) or maintain a healthy weight (65.0% vs. 74.3% P = 0.00001). Cases also reported greater negative impact scores for barriers to activity, particularly arthritis, accessibility, cost and discomfort while exercising. Motivators and environmental barriers to activity were similar for cases and controls. These findings persisted after adjusting for educational level, body mass index and comorbidities. People with arthritis are less active and demonstrate different attitudes toward physical activity. Although people with arthritis identify similar environmental barriers, they have different psychosocial barriers. In order to design effective physical activity programs for people with arthritis, these barriers must be specifically addressed.

Effectiveness of oral polio vaccination against paralytic poliomyelitis: a matched case-control study in Somalia.

PubMed

Mahamud, Abdirahman; Kamadjeu, Raoul; Webeck, Jenna; Mbaeyi, Chukwuma; Baranyikwa, Marie Therese; Birungi, Julianne; Nurbile, Yassin; Ehrhardt, Derek; Shukla, Hemant; Chatterjee, Anirban; Mulugeta, Abraham

2014-11-01

After the last case of type 1 wild poliovirus (WPV1) was reported in 2007, Somalia experienced another outbreak of WPV1 (189 cases) in 2013. We conducted a retrospective, matched case-control study to evaluate the vaccine effectiveness (VE) of oral polio vaccine (OPV). We retrieved information from the Somalia Surveillance Database. A case was defined as any case of acute flaccid paralysis (AFP) with virological confirmation of WPV1. We selected two groups of controls for each case: non-polio AFP cases ("NPAFP controls") matched to WPV1 cases by age, date of onset of paralysis and region; and asymptomatic "neighborhood controls," matched by age. Using conditional logistic regression, we estimated the VE of OPV as (1-odds ratio)×100. We matched 99 WPV cases with 99 NPAFP controls and 134 WPV1 cases with 268 neighborhood controls. Using NPAFP controls, the overall VE was 70% (95% confidence interval [CI], 37-86), 59% (2-83) among 1-3 dose recipients, 77% (95% CI, 46-91) among ≥4 dose recipients. In neighborhood controls, the overall VE was 95% (95% CI, 84-98), 92% (72-98) among 1-3 dose recipients, and 97% (89-99) among ≥4 dose recipients. When the analysis was limited to cases and controls ≤24 months old, the overall VE in NPAFP and neighborhood controls was 95% (95% CI, 65-99) and 97% (95% CI, 76-100), respectively. Among individuals who were fully vaccinated with OPV, vaccination was effective at preventing WPV1 in Somalia. Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2014. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Comparative study of control selection in a national population-based case-control study: Estimating risk of smoking on cancer deaths in Chinese men.

PubMed

Jiang, Jingmei; Liu, Boqi; Nasca, Philip C; Han, Wei; Zou, Xiaonong; Zeng, Xianjia; Tian, Xiaobing; Wu, Yanping; Zhao, Ping; Li, Junyao

2009-10-28

To assess the validation of a novel control selection design by comparing the consistency between the new design and a routine design in a large case-control study that was incorporated into a nationwide mortality survey in China. A nationwide mortality study was conducted during 1989-1991. Surviving spouses or other relatives of all adults who died during 1986-1988 provided detailed information about their own as well as the deceased person's smoking history. In this study, 130,079 males who died of various smoking-related cancers at age 35 or over were taken as cases, while 103,248 male surviving spouses (same age range with cases) of women who died during the same period and 49,331 males who died from causes other than those related to smoking were used as control group 1 and control group 2, respectively. Consistency in the results when comparing cases with each of the control groups was assessed. Consistency in the results was observed in the analyses using different control groups although cancer deaths varied with region and age. Equivalence could be ascertained using a 15% criterion in most cancer deaths which had high death rates in urban areas, but they were uncertain for most cancers in rural areas irrespective of whether the hypothesis testing showed significant differences or not. Sex-matched living spouse control design as an alternative control selection for a case-control study is valid and feasible, and the basic principles of the equivalence study are also supported by epidemiological survey data.

Dietary habits after myocardial infarction - results from a cross-sectional study.

PubMed

Wallström, P; Mattisson, I; Tydén, P; Berglund, G; Janzon, L

2005-04-01

Comparing habitual nutrient intakes in persons with a history of acute myocardial infarction (AMI), and age-matched controls. Design. Cross-sectional study. Subjects. Men and women (525 cases and 1890 matched controls), aged 47-73 years, of the population-based Malmö Diet and Cancer cohort. Nutrient intakes were assessed by a validated modified diet history method. Body fatness was assessed by bioimpedance analysis. Case ascertainment was provided by national and regional registries. Men and women were analysed separately. Median time since AMI was 5.5 years in men and 3.8 years in women. Cases reported lower energy intakes (EIs) than controls, despite having similar basal metabolic rates. After adjustment for total EI, both male and female cases had lower fat intake and higher intake of several micronutrients, such as ascorbic acid, folate, and vitamin E, than controls, the difference being largest in men. Most of the cases reporting dietary change quoted 'disease' as their main reason for change. They had lower EI and lower energy-adjusted intake of fat than other cases. Survivors of AMI reported dietary habits more in line with current recommendations, particularly those who afterwards reported having changed their dietary habits. The possible bias introduced by social desirability is discussed.

Experience with multiple control groups in a large population-based case-control study on genetic and environmental risk factors.

PubMed

Pomp, E R; Van Stralen, K J; Le Cessie, S; Vandenbroucke, J P; Rosendaal, F R; Doggen, C J M

2010-07-01

We discuss the analytic and practical considerations in a large case-control study that had two control groups; the first control group consisting of partners of patients and the second obtained by random digit dialling (RDD). As an example of the evaluation of a general lifestyle factor, we present body mass index (BMI). Both control groups had lower BMIs than the patients. The distribution in the partner controls was closer to that of the patients, likely due to similar lifestyles. A statistical approach was used to pool the results of both analyses, wherein partners were analyzed with a matched analysis, while RDDs were analyzed without matching. Even with a matched analysis, the odds ratio with partner controls remained closer to unity than with RDD controls, which is probably due to unmeasured confounders in the comparison with the random controls as well as intermediary factors. However, when studying injuries as a risk factor, the odds ratio remained higher with partner control subjects than with RRD control subjects, even after taking the matching into account. Finally we used factor V Leiden as an example of a genetic risk factor. The frequencies of factor V Leiden were identical in both control groups, indicating that for the analyses of this genetic risk factor the two control groups could be combined in a single unmatched analysis. In conclusion, the effect measures with the two control groups were in the same direction, and of the same order of magnitude. Moreover, it was not always the same control group that produced the higher or lower estimates, and a matched analysis did not remedy the differences. Our experience with the intricacies of dealing with two control groups may be useful to others when thinking about an optimal research design or the best statistical approach.

Does functional vision behave differently in low-vision patients with diabetic retinopathy?--A case-matched study.

PubMed

Ahmadian, Lohrasb; Massof, Robert

2008-09-01

A retrospective case-matched study designed to compare patients with diabetic retinopathy (DR) and other ocular diseases, managed in a low-vision clinic, in four different types of functional vision. Reading, mobility, visual motor, and visual information processing were measured in the patients (n = 114) and compared with those in patients with other ocular diseases (n = 114) matched in sex, visual acuity (VA), general health status, and age, using the Activity Inventory as a Rasch-scaled measurement tool. Binocular distance visual acuity was categorized as normal (20/12.5-20/25), near normal (20/32-20/63), moderate (20/80-20/160), severe (20/200-20/400), profound (20/500-20/1000), and total blindness (20/1250 to no light perception). Both Wilcoxon matched pairs signed rank test and the sign test of matched pairs were used to compare estimated functional vision measures between DR cases and controls. Cases ranged in age from 19 to 90 years (mean age, 67.5), and 59% were women. The mean visual acuity (logMar scale) was 0.7. Based on the Wilcoxon signed rank test analyses and after adjusting the probability for multiple comparisons, there was no statistically significant difference (P > 0.05) between patients with DR and control subjects in any of four functional visions. Furthermore, diabetic retinopathy patients did not differ (P > 0.05) from their matched counterparts in goal-level vision-related functional ability and total visual ability. Visual impairment in patients with DR appears to be a generic and non-disease-specific outcome that can be explained mainly by the end impact of the disease in the patients' daily lives and not by the unique disease process that results in the visual impairment.

Campylobacteriosis in New Zealand: results of a case-control study.

PubMed Central

Eberhart-Phillips, J; Walker, N; Garrett, N; Bell, D; Sinclair, D; Rainger, W; Bates, M

1997-01-01

STUDY OBJECTIVE: To identify and assess the contributions of major risk factors for campylobacteriosis in New Zealand. DESIGN: Case-control study. Home interviews were conducted over nine months using a standardised questionnaire to assess recent food consumption and other exposures. SETTING: Four centres in New Zealand with high notification rates of campylobacter infections--Auckland, Hamilton, Wellington, and Christchurch. PARTICIPANTS: Case patients were 621 people notified between 1 June 1994 and 28 February 1995 as having campylobacter infection. Control subjects were selected randomly from telephone directories, and were matched 1:1 with case patients in relation to sex, age group, and home telephone prefix. RESULTS: Risk of campylobacteriosis was strongly associated with recent consumption of raw or undercooked chicken (matched odds ratio 4.52, 95% confidence interval 2.88, 7.10). There was also an increased risk with chicken eaten in restaurants (matched odds ratio 3.85; 2.52, 5.88). Recent consumption of baked or roasted chicken seemed to be protective. Campylobacteriosis was also associated with recent overseas travel, rainwater as a source of water at home, consumption of raw dairy products, and contact with puppies and cattle, particularly calves. CONCLUSIONS: Improperly cooked chicken seems to be associated with a large proportion of campylobacteriosis in New Zealand. Thorough cooking of chicken in homes and restaurants could reduce considerably the incidence of this disease. PMID:9519133

Inspection of aeronautical mechanical parts with a pan-tilt-zoom camera: an approach guided by the computer-aided design model

NASA Astrophysics Data System (ADS)

Viana, Ilisio; Orteu, Jean-José; Cornille, Nicolas; Bugarin, Florian

2015-11-01

We focus on quality control of mechanical parts in aeronautical context using a single pan-tilt-zoom (PTZ) camera and a computer-aided design (CAD) model of the mechanical part. We use the CAD model to create a theoretical image of the element to be checked, which is further matched with the sensed image of the element to be inspected, using a graph theory-based approach. The matching is carried out in two stages. First, the two images are used to create two attributed graphs representing the primitives (ellipses and line segments) in the images. In the second stage, the graphs are matched using a similarity function built from the primitive parameters. The similarity scores of the matching are injected in the edges of a bipartite graph. A best-match-search procedure in the bipartite graph guarantees the uniqueness of the match solution. The method achieves promising performance in tests with synthetic data including missing elements, displaced elements, size changes, and combinations of these cases. The results open good prospects for using the method with realistic data.

High reprint orders in medical journals and pharmaceutical industry funding: case-control study

PubMed Central

Handel, Adam E; Patel, Sunil V; Pakpoor, Julia; Ebers, George C; Goldacre, Ben

2012-01-01

Objectives To assess the extent to which funding and study design are associated with high reprint orders. Design Case-control study. Setting Top articles by size of reprint orders in seven journals, 2002-09. Participants Lancet, Lancet Neurology, Lancet Oncology (Lancet Group), BMJ, Gut, Heart, and Journal of Neurology, Neurosurgery & Psychiatry (BMJ Group) matched to contemporaneous articles not in the list of high reprint orders. Main outcome measures Funding and design of randomised controlled trials or other study designs. Results Median reprint orders for the seven journals ranged from 3000 to 126 350. Papers with high reprint orders were more likely to be funded by the pharmaceutical industry than were control papers (industry funding versus other or none: odds ratio 8.64, 95% confidence interval 5.09 to 14.68, and mixed funding versus other or none: 3.72, 2.43 to 5.70). Conclusions Funding by the pharmaceutical industry is associated with high numbers of reprint orders. PMID:22745328

Case-control vaccine effectiveness studies: Preparation, design, and enrollment of cases and controls.

PubMed

Verani, Jennifer R; Baqui, Abdullah H; Broome, Claire V; Cherian, Thomas; Cohen, Cheryl; Farrar, Jennifer L; Feikin, Daniel R; Groome, Michelle J; Hajjeh, Rana A; Johnson, Hope L; Madhi, Shabir A; Mulholland, Kim; O'Brien, Katherine L; Parashar, Umesh D; Patel, Manish M; Rodrigues, Laura C; Santosham, Mathuram; Scott, J Anthony; Smith, Peter G; Sommerfelt, Halvor; Tate, Jacqueline E; Victor, J Chris; Whitney, Cynthia G; Zaidi, Anita K; Zell, Elizabeth R

2017-06-05

Case-control studies are commonly used to evaluate effectiveness of licensed vaccines after deployment in public health programs. Such studies can provide policy-relevant data on vaccine performance under 'real world' conditions, contributing to the evidence base to support and sustain introduction of new vaccines. However, case-control studies do not measure the impact of vaccine introduction on disease at a population level, and are subject to bias and confounding, which may lead to inaccurate results that can misinform policy decisions. In 2012, a group of experts met to review recent experience with case-control studies evaluating the effectiveness of several vaccines; here we summarize the recommendations of that group regarding best practices for planning, design and enrollment of cases and controls. Rigorous planning and preparation should focus on understanding the study context including healthcare-seeking and vaccination practices. Case-control vaccine effectiveness studies are best carried out soon after vaccine introduction because high coverage creates strong potential for confounding. Endpoints specific to the vaccine target are preferable to non-specific clinical syndromes since the proportion of non-specific outcomes preventable through vaccination may vary over time and place, leading to potentially confusing results. Controls should be representative of the source population from which cases arise, and are generally recruited from the community or health facilities where cases are enrolled. Matching of controls to cases for potential confounding factors is commonly used, although should be reserved for a limited number of key variables believed to be linked to both vaccination and disease. Case-control vaccine effectiveness studies can provide information useful to guide policy decisions and vaccine development, however rigorous preparation and design is essential. Published by Elsevier Ltd.

Impact of traffic oscillations on freeway crash occurrences.

PubMed

Zheng, Zuduo; Ahn, Soyoung; Monsere, Christopher M

2010-03-01

Traffic oscillations are typical features of congested traffic flow that are characterized by recurring decelerations followed by accelerations (stop-and-go driving). The negative environmental impacts of these oscillations are widely accepted, but their impact on traffic safety has been debated. This paper describes the impact of freeway traffic oscillations on traffic safety. This study employs a matched case-control design using high-resolution traffic and crash data from a freeway segment. Traffic conditions prior to each crash were taken as cases, while traffic conditions during the same periods on days without crashes were taken as controls. These were also matched by presence of congestion, geometry and weather. A total of 82 cases and about 80,000 candidate controls were extracted from more than three years of data from 2004 to 2007. Conditional logistic regression models were developed based on the case-control samples. To verify consistency in the results, 20 different sets of controls were randomly extracted from the candidate pool for varying control-case ratios. The results reveal that the standard deviation of speed (thus, oscillations) is a significant variable, with an average odds ratio of about 1.08. This implies that the likelihood of a (rear-end) crash increases by about 8% with an additional unit increase in the standard deviation of speed. The average traffic states prior to crashes were less significant than the speed variations in congestion. Published by Elsevier Ltd.

Novel application of the matched case-control design to compare food supply chains during an Escherichia coli O157 outbreak, United Kingdom, 2016.

PubMed

Inns, Thomas; Cleary, Paul; Bundle, Nick; Foulkes, Sarah; Sharp, Ashley; Utsi, Lara; McBrien, Chris; Teagle, Rehman; Waldram, Alison; Williams, Chris; McCann, Cathy; Smith, Rob; Saleh, Sepeedeh; McCarthy, Noel; Vivancos, Roberto; Hawker, Jeremy; Decraene, Valerie

2018-05-01

There is a need for innovative methods to investigate outbreaks of food-borne infection linked to produce with a complex distribution network. The investigation of a large outbreak of Escherichia coli O157 PT34 infection in the United Kingdom in 2016 indicated that catering venues associated with multiple cases had used salad leaves sourced from one supplier. Our aim was to investigate whether catering venues linked to cases were more likely to have used salad leaves from this supplier. We conducted a matched case-control study, with catering venues as the units of analysis. We compared venues linked to cases to those without known linked cases. We included 43 study pairs and obtained information on salad leaf products received by each venue. The odds of a case venue being supplied with salad leaves by Supplier A were 7.67 times (95% confidence interval: 2.30-25.53) those of control venues. This association provided statistical evidence to support the findings of the other epidemiological investigations undertaken for this outbreak. This is a novel approach which is labour-intensive but which addresses the challenge of investigating exposures to food across a complex distribution network.

The incidence of histological chorioamnionitis in IVF/GIFT preterm births.

PubMed

Williams, H; Jeffery, H

1994-08-01

A retrospective case control study was designed to investigate the role of subclinical infection as a risk factor for the high rate of preterm deliveries in IVF/GIFT pregnancies. The cases and the controls were identified from the records of consecutive livebirths of < 35 weeks' gestational age (GA), at King George V Hospital from 1987-1993. Fifty one singleton and 58 twin IVF/GIFT preterm births were matched for GA, year of birth, plurality, maternal age, parity, preclampsia and antepartum haemorrhage. As a marker of subclinical infection, the incidence of histological chorioamnionitis (HCA) in the 2 groups (as defined by the standardized, semiquantitative method of Benirschke) was compared. The matched variables did not differ significantly between the IVF/GIFT group and the control group. No significant difference in the incidence of HCA was detected between IVF/GIFT and control groups for singletons or twins. Overall 24% of IVF/GIFT and 30% of controls showed evidence of HCA, odds ratio (95% confidence intervals), 0.72 (0.40-1.31). This study showed no evidence that the incidence of HCA, is significantly increased in IVF/GIFT preterm births compared with other matched, preterm births. Therefore, we conclude that subclinical infection/inflammation cannot explain the 4-fold increase in preterm births in the IVF/GIFT population.

Insulin Dynamics in Young Women with Polycystic Ovary Syndrome and Normal Glucose Tolerance across Categories of Body Mass Index

PubMed Central

Manco, Melania; Castagneto-Gissey, Lidia; Arrighi, Eugenio; Carnicelli, Annamaria; Brufani, Claudia; Luciano, Rosa; Mingrone, Geltrude

2014-01-01

Background Evidence favours insulin resistance and compensatory hyperinsulinemia as the predominant, perhaps primary, defects in polycystic ovary syndrome (PCOS). The aim of the present study was to evaluate insulin metabolism in young women with PCOS but normal glucose tolerance as compared with age, body mass index and insulin resistance-matched controls to answer the question whether women with PCOS hypersecrete insulin in comparison to appropriately insulin resistance-matched controls. Research Design and Methods Sixty-nine cases were divided according to their body mass index (BMI) in normal-weight (N = 29), overweight (N = 24) and obese patients (N = 16). Controls were 479 healthy women (age 16–49 y). Whole body Insulin Sensitivity (WBISI), fasting, and total insulin secretion were estimated following an oral glucose tolerance test (C-peptide deconvolution method). Results Across classes of BMI, PCOS patients had greater insulin resistance than matched controls (p<0.0001 for all the comparisons), but they showed higher fasting and total insulin secretion than their age, BMI and insulin resistance-matched peers (p<0.0001 for all the comparisons). Conclusion Women with PCOS show higher insulin resistance but also larger insulin secretion to maintain normal glucose homeostasis than age-, BMI- and insulin resistance-matched controls. PMID:24705280

Mitochondrial dysfunction in Gulf War illness revealed by 31Phosphorus Magnetic Resonance Spectroscopy: a case-control study.

PubMed

Koslik, Hayley J; Hamilton, Gavin; Golomb, Beatrice A

2014-01-01

Approximately 1/3 of 1990-1 Gulf War veterans developed chronic multisymptom health problems. Implicated exposures bear mechanisms that adversely affect mitochondria. Symptoms emphasize fatigue, cognition and muscle (brain and muscle are aerobically demanding); with protean additional domains affected, compatible with mitochondrial impairment. Recent evidence supports treatments targeting cell bioenergetics (coenzyme10) to benefit Gulf War illness symptoms. However, no evidence has directly documented mitochondrial or bioenergetic impairment in Gulf War illness. We sought to objectively assess for mitochondrial dysfunction, examining post-exercise phosphocreatine-recovery time constant (PCr-R) using (31)Phosphorus Magnetic Resonance Spectroscopy ((31)P-MRS), in Gulf War veterans with Gulf War illness compared to matched healthy controls. PCr-R has been described as a "robust and practical" index of mitochondrial status. Case-control study from 2012-2013. Fourteen community-dwelling Gulf War veterans and matched controls from the San Diego area comprised 7 men meeting CDC and Kansas criteria for Gulf War illness, and 7 non-deployed healthy controls matched 1:1 to cases on age, sex, and ethnicity. Calf muscle phosphocreatine was evaluated by (31)P-MRS at rest, through 5 minutes of foot pedal depression exercise, and in recovery, to assess PCr-R. Paired t-tests compared cases to matched controls. PCr-R was significantly prolonged in Gulf War illness cases vs their matched controls: control values, mean ± SD, 29.0 ± 8.7 seconds; case values 46.1 ± 18.0 seconds; difference 17.1 ± 14.9 seconds; p = 0.023. PCr-R was longer for cases relative to their matched controls for all but one pair; moreover while values clustered under 31 seconds for all but one control, they exceeded 35 seconds (with a spread up to 70 seconds) for all but one case. These data provide the first direct evidence supporting mitochondrial dysfunction in Gulf War illness. Findings merit replication in a larger study and/or corroboration with additional mitochondrial assessment tools.

Design and validity of a clinic-based case-control study on the molecular epidemiology of lymphoma

PubMed Central

Cerhan, James R; Fredericksen, Zachary S; Wang, Alice H; Habermann, Thomas M; Kay, Neil E; Macon, William R; Cunningham, Julie M; Shanafelt, Tait D; Ansell, Stephen M; Call, Timothy G; Witzig, Thomas E; Slager, Susan L; Liebow, Mark

2011-01-01

We present the design features and implementation of a clinic-based case-control study on the molecular epidemiology of lymphoma conducted at the Mayo Clinic (Rochester, Minnesota, USA), and then assess the internal and external validity of the study. Cases were newly diagnosed lymphoma patients from Minnesota, Iowa and Wisconsin seen at Mayo and controls were patients from the same region without lymphoma who had a pre-scheduled general medical examination, frequency matched on age, sex and residence. Overall response rates were 67% for cases and 70% for controls; response rates were lower for cases and controls over age 70 years, cases with more aggressive disease, and controls from the local area, although absolute differences were modest. Cases and controls were well-balanced on age, sex, and residence characteristics. Demographic and disease characteristics of NHL cases were similar to population-based cancer registry data. Control distributions were similar to population-based data on lifestyle factors and minor allele frequencies of over 500 SNPs, although smoking rates were slightly lower. Associations with NHL in the Mayo study for smoking, alcohol use, family history of lymphoma, autoimmune disease, asthma, eczema, body mass index, and single nucleotide polymorphisms in TNF (rs1800629), LTA (rs909253), and IL10 (rs1800896) were at a magnitude consistent with estimates from pooled studies in InterLymph, with history of any allergy the only directly discordant result in the Mayo study. These data suggest that this study should have strong internal and external validity. This framework may be useful to others who are designing a similar study. PMID:21686124

An Algorithm for Creating Virtual Controls Using Integrated and Harmonized Longitudinal Data.

PubMed

Hansen, William B; Chen, Shyh-Huei; Saldana, Santiago; Ip, Edward H

2018-06-01

We introduce a strategy for creating virtual control groups-cases generated through computer algorithms that, when aggregated, may serve as experimental comparators where live controls are difficult to recruit, such as when programs are widely disseminated and randomization is not feasible. We integrated and harmonized data from eight archived longitudinal adolescent-focused data sets spanning the decades from 1980 to 2010. Collectively, these studies examined numerous psychosocial variables and assessed past 30-day alcohol, cigarette, and marijuana use. Additional treatment and control group data from two archived randomized control trials were used to test the virtual control algorithm. Both randomized controlled trials (RCTs) assessed intentions, normative beliefs, and values as well as past 30-day alcohol, cigarette, and marijuana use. We developed an algorithm that used percentile scores from the integrated data set to create age- and gender-specific latent psychosocial scores. The algorithm matched treatment case observed psychosocial scores at pretest to create a virtual control case that figuratively "matured" based on age-related changes, holding the virtual case's percentile constant. Virtual controls matched treatment case occurrence, eliminating differential attrition as a threat to validity. Virtual case substance use was estimated from the virtual case's latent psychosocial score using logistic regression coefficients derived from analyzing the treatment group. Averaging across virtual cases created group estimates of prevalence. Two criteria were established to evaluate the adequacy of virtual control cases: (1) virtual control group pretest drug prevalence rates should match those of the treatment group and (2) virtual control group patterns of drug prevalence over time should match live controls. The algorithm successfully matched pretest prevalence for both RCTs. Increases in prevalence were observed, although there were discrepancies between live and virtual control outcomes. This study provides an initial framework for creating virtual controls using a step-by-step procedure that can now be revised and validated using other prevention trial data.

Risk of Guillain-Barré syndrome after 2010-2011 influenza vaccination.

PubMed

Galeotti, Francesca; Massari, Marco; D'Alessandro, Roberto; Beghi, Ettore; Chiò, Adriano; Logroscino, Giancarlo; Filippini, Graziella; Benedetti, Maria Donata; Pugliatti, Maura; Santuccio, Carmela; Raschetti, Roberto

2013-05-01

Influenza vaccination has been implicated in Guillain Barré Syndrome (GBS) although the evidence for this link is controversial. A case-control study was conducted between October 2010 and May 2011 in seven Italian Regions to explore the relation between influenza vaccination and GBS. The study included 176 GBS incident cases aged ≥18 years from 86 neurological centers. Controls were selected among patients admitted for acute conditions to the Emergency Department of the same hospital as cases. Each control was matched to a case by sex, age, Region and admission date. Two different analyses were conducted: a matched case-control analysis and a self-controlled case series analysis (SCCS). Case-control analysis included 140 cases matched to 308 controls. The adjusted matched odds ratio (OR) for GBS occurrence within 6 weeks after influenza vaccination was 3.8 (95 % CI: 1.3, 10.5). A much stronger association with gastrointestinal infections (OR = 23.8; 95 % CI 7.3, 77.6) and influenza-like illness or upper respiratory tract infections (OR = 11.5; 95 % CI 5.6, 23.5) was highlighted. The SCCS analysis included all 176 GBS cases. Influenza vaccination was associated with GBS, with a relative risk of 2.1 (95 % CI 1.1, 3.9). According to these results the attributable risk in adults ranges from two to five GBS cases per 1,000,000 vaccinations.

Clinical effects of internal fixation for ulnar styloid fractures associated with distal radius fractures: A matched case-control study.

PubMed

Sawada, Hideyoshi; Shinohara, Takaaki; Natsume, Tadahiro; Hirata, Hitoshi

2016-11-01

Ulnar styloid fractures are often associated with distal radius fractures. However, controversy exists regarding whether to treat ulnar styloid fractures. This study aimed to evaluate clinical effects of internal fixation for ulnar styloid fractures after distal radius fractures were treated with the volar locking plate system. We used prospectively collected data of distal radius fractures. 111 patients were enrolled in this study. A matched case-control study design was used. We selected patients who underwent fixation for ulnar styloid fractures (case group). Three control patients for each patient of the case group were matched on the basis of age, sex, and fracture type of distal radius fractures from among patients who did not undergo fixation for ulnar styloid fractures (control group). The case group included 16 patients (7 men, 9 women; mean age: 52.6 years; classification of ulnar styloid fractures: center, 3; base, 11; and proximal, 2). The control group included 48 patients (15 men, 33 women; mean age: 61.1 years; classification of ulnar styloid fractures: center, 10; base, 31; and proximal, 7). For radiographic examination, the volar tilt angle, radial inclination angle, and ulnar variance length were measured, and the union of ulnar styloid fractures was judged. For clinical examination, the range of motions, grip strength, Hand20 score, and Numeric Rating Scale score were evaluated. There was little correction loss for each radiological parameter of fracture reduction, and these parameters were not significantly different between the groups. The bone-healing rate of ulnar styloid fractures was significantly higher in the case group than in the control group, but the clinical results were not significantly different. We revealed that there was no need to fix ulnar styloid fractures when distal radius fractures were treated via open reduction and internal fixation with a volar locking plate system. Copyright © 2016 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

The Association Between Neurocysticercosis and Hippocampal Atrophy is Related to Age

PubMed Central

Del Brutto, Oscar H.; Issa, Naoum P.; Salgado, Perla; Del Brutto, Victor J.; Zambrano, Mauricio; Lama, Julio; García, Héctor H.

2017-01-01

Neurocysticercosis (NCC) has been associated with hippocampal atrophy, but the prevalence and pathogenic mechanisms implicated in this relationship are unknown. Using a population-based, case–control study design, residents in a rural village (Atahualpa) aged ≥ 40 years with calcified NCC were identified as cases and paired to NCC-free individuals (control subjects) matched by age, sex, and level of education. Cases and control subjects underwent magnetic resonance imaging for hippocampal rating according to the Scheltens' scale for medial temporal atrophy and were interviewed to identify those with a clinical seizure disorder. The prevalence of hippocampal atrophy was compared between cases and control subjects by the use of the McNemar's test for correlated proportions. Seventy-five individuals with calcified NCC and their matched control subjects were included in the analysis. Hippocampal atrophy was noted in 26 (34.7%) cases and nine (12%) control subjects (odds ratio: 4.4; 95% confidence interval: 1.6–14.9, P < 0.0021). Stratification of pairs according to tertiles of age revealed an age-related trend in this association, which became significant only in those aged ≥ 68 years (P = 0.027). Only five cases and one control had recurrent seizures (P = 0.221); three of these five cases had hippocampal atrophy, and the single control subject had normal hippocampi. This study confirms an association between NCC and hippocampal atrophy, and shows that this association is stronger in older age groups. This suggests that NCC-related hippocampal atrophy takes a long time to develop. PMID:28077750

A Step-by-Step Guide to Propensity Score Matching in R

ERIC Educational Resources Information Center

Randolph, Justus J.; Falbe, Kristina; Manuel, Austin Kureethara; Balloun, Joseph L.

2014-01-01

Propensity score matching is a statistical technique in which a treatment case is matched with one or more control cases based on each case's propensity score. This matching can help strengthen causal arguments in quasi-experimental and observational studies by reducing selection bias. In this article we concentrate on how to conduct propensity…

The case for social marketing in gonorrhoea prevention: insights from sexual lifestyles in Glasgow genitourinary medicine clinic attendees.

PubMed

Scoular, Anne; Abu-Rajab, Kirsty; Winter, Andy; Connell, Judith; Hart, Graham

2008-08-01

We conducted a matched case-control study to investigate social factors associated with gonorrhoea acquisition among genitourinary (GU) medicine clinic attendees, designed to inform appropriate prevention strategies. Detailed social and behavioural data were elicited using a self-completed questionnaire. The effect sizes of these characteristics were quantified using univariate and multivariable conditional logistic regression in 53 cases and 106 matched controls. Homo-bisexual orientation was the strongest independent predictor of gonorrhoea acquisition (Adjusted odds ratio 31.1 (95% confidence intervals, 3.09-312.92). Other independent predictors were not currently being in a relationship and concordant residential characteristics. Three principal implications for sexual health policy were identified; social marketing approaches to gonorrhoea prevention should focus on gay men and individuals not in established relationships; gonorrhoea prevention should be more closely integrated with wider social inclusion policies; finally, more proactive, systematic and theory-based approaches should capitalize on opportunities for sexual health promotion in GU medicine clinic settings.

Traumatic child death and documented maltreatment history, Los Angeles.

PubMed Central

Sorenson, S B; Peterson, J G

1994-01-01

OBJECTIVES. Child abuse is a presumed but largely untested risk factor for child homicide. This research investigated the social and child protective service history of child homicide victims. METHODS. A pairwise matched case-control design was used to assess documented child maltreatment as a risk factor for homicide vs unintentional injury death. Homicide victims aged 0 to 14 years were identified through Los Angeles Police Department case summaries. Control subjects (children who died of an unintentional injury) were matched to case subjects (children who died from homicide) by age, sex, race/ethnicity, and date of death. Case and control subjects were linked with county service records to determine any known history of maltreatment. RESULTS. A total of 220 children were homicide victims during 1978 through 1987 in the city of Los Angeles. Only one in six children who died (of homicide or unintentional injury) or his/her family was known to county social or child protective services prior to the death. Recorded history of child protective services was associated with homicide victimization (adjusted odds ratio = 3.40, 95% confidence interval = 1.25, 9.27). CONCLUSIONS. Current service systems need assistance in identifying and protecting children at high risk of homicide. PMID:8154567

Investigation to identify a resource-efficient case-control methodology for determining antibiotics associated with Clostridium difficile infection.

PubMed

Chung, Philip; Currie, Brian; Guo, Yi; Talansky, Moshe; Brown, Shakara; Ostrowsky, Belinda

2014-10-01

Antimicrobial exposure remains an important risk factor for developing Clostridium difficile infection (CDI). Efficient method to identify antibiotics associated with CDI is important for formulating strategies to curtail their use. As a prelude to a more extensive Agency for Healthcare Research and Quality-funded project (Evaluation & Research on Antimicrobial Stewardship's Effect on Clostridium difficile), we undertook an exploratory evaluation to determine a resource-efficient method for identifying antibiotic targets for antimicrobial stewardship interventions. The study compared a series of 6 focused case-control studies. Cases consisted of patients with laboratory-confirmed CDI admitted from July-October 2009. Controls were selected from patients without CDI hospitalized during the same period. Five groups of controls were matched to cases (2:1 ratio) using group-specific matching criteria, including admission date, age, type of admission, length of stay (LOS) to discharge, and/or LOS to CDI diagnosis. The final control group was selected from patients who received antibiotics during hospitalization. Data, including demographics and antibiotic usage, were compared between case and control groups. A total of 126 cases were matched to 6 groups of 252 controls. For control groups 1-5, the use of piperacillin and tazobactam, ceftriaxone or cefepime, ciprofloxacin or moxifloxacin, intravenous vancomycin, azithromycin, and antibiotics of last resort were significantly more frequent in case than control patients. For the final control group, the associations between ceftriaxone or cefepime, and ciprofloxacin or moxifloxacin use and CDI no longer persisted. This could in part be explained by differences in comorbidities between case and control patients even with stringent matching criteria. Use of a simple matching strategy to conduct case-control studies is an efficient and feasible compromise strategy, especially in resource-limited settings, to identify high-risk antibiotics associated with CDI. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Fasting urinary calcium-to-creatinine and oxalate-to-creatinine ratios in dogs with calcium oxalate urolithiasis and breed-matched controls.

PubMed

Furrow, E; Patterson, E E; Armstrong, P J; Osborne, C A; Lulich, J P

2015-01-01

Hypercalciuria and hyperoxaluria are risk factors for calcium oxalate (CaOx) urolithiasis, but breed-specific reports of urinary metabolites and their relationship with stone status are lacking. To compare urinary metabolites (calcium and oxalate) and blood ionized calcium (iCa) concentrations between CaOx stone formers and breed-matched stone-free controls for the Miniature Schnauzer, Bichon Frise, and Shih Tzu breeds. Forty-seven Miniature Schnauzers (23 cases and 24 controls), 27 Bichons Frise (14 cases and 13 controls), and 15 Shih Tzus (7 cases and 8 controls). Prospective study. Fasting spot urinary calcium-to-creatinine and oxalate-to-creatinine ratios (UCa/Cr and UOx/Cr, respectively) and blood iCa concentrations were measured and compared between cases and controls within and across breeds. Regression models were used to test the effect of patient and environmental factors on these variables. UCa/Cr was higher in cases than controls for each of the 3 breeds. In addition to stone status, being on a therapeutic food designed to prevent CaOx stone recurrence was associated with higher UCa/Cr. UOx/Cr did not differ between cases and controls for any of the breeds. Blood iCa was higher in cases than controls in the Miniature Schnauzer and Bichon Frise breeds and had a moderate correlation with UCa/Cr. Hypercalciuria is associated with CaOx stone status in the Miniature Schnauzer, Bichon Frise, and Shih Tzu breeds. UOx/Cr did not correlate with stone status in these 3 breeds. These findings may influence breed-specific stone prevention recommendations. Copyright © 2015 by the American College of Veterinary Internal Medicine.

Return to Sport and Performance After Microfracture in the Knees of National Basketball Association Players

PubMed Central

Harris, Joshua D.; Walton, David M.; Erickson, Brandon J.; Verma, Nikhil N.; Abrams, Geoffrey D.; Bush-Joseph, Charles A.; Bach, Bernard R.; Cole, Brian J.

2013-01-01

Background: Use of microfracture in the knees of National Basketball Association (NBA) players is controversial. Hypotheses: (1) There would be a high rate of return to sport (RTS) in NBA players following microfracture, (2) players would RTS the season following surgery, (3) preoperative player performance would not be significantly different on RTS, and (4) there would be no significant difference in RTS rate or postoperative performance in players undergoing microfracture in comparison with an age-, position-, NBA experience–, and performance-matched control group. Study Design: Cohort study; Level of evidence, 3. Methods: NBA players undergoing microfracture were evaluated. Age-, body mass index–, position-, NBA experience–, and performance-matched controls were selected from the NBA during the same years as those undergoing microfracture. An index year was selected (controls) to match the number of seasons of NBA experience in microfracture cases. RTS and performance were analyzed and compared between cases and controls. Student t tests were performed for analysis of within- and between-group variables. Results: A total of 41 NBA players underwent microfracture and were compared with 41 demographic- and performance-matched controls. Rate of RTS after microfracture was 73% in the NBA and 83% in professional basketball (NBA, D-league, and International Basketball Federation [FIBA]). Time to RTS in NBA was 9.20 ± 4.88 months. Seventy-one percent (29/41) of players RTS the season following microfracture. Length of NBA career following microfracture (4.10 ± 3.91 years) was not significantly different from controls. After microfracture, case athletes played fewer games per season and with fewer points and steals per game (relative to premicrofracture; P < .05). Performance was better in control (after index year) versus case players (after microfracture) with regard to points per game, games played per season, and field goal and free throw percentage (P < .05). Conclusion: Eighty-three percent of NBA players undergoing microfracture returned to professional basketball. Career length was not significantly different between players undergoing microfracture and controls. However, following microfracture, players competed in fewer games per season with fewer points and steals. PMID:26535256

On the use and misuse of scalar scores of confounders in design and analysis of observational studies.

PubMed

Pfeiffer, R M; Riedl, R

2015-08-15

We assess the asymptotic bias of estimates of exposure effects conditional on covariates when summary scores of confounders, instead of the confounders themselves, are used to analyze observational data. First, we study regression models for cohort data that are adjusted for summary scores. Second, we derive the asymptotic bias for case-control studies when cases and controls are matched on a summary score, and then analyzed either using conditional logistic regression or by unconditional logistic regression adjusted for the summary score. Two scores, the propensity score (PS) and the disease risk score (DRS) are studied in detail. For cohort analysis, when regression models are adjusted for the PS, the estimated conditional treatment effect is unbiased only for linear models, or at the null for non-linear models. Adjustment of cohort data for DRS yields unbiased estimates only for linear regression; all other estimates of exposure effects are biased. Matching cases and controls on DRS and analyzing them using conditional logistic regression yields unbiased estimates of exposure effect, whereas adjusting for the DRS in unconditional logistic regression yields biased estimates, even under the null hypothesis of no association. Matching cases and controls on the PS yield unbiased estimates only under the null for both conditional and unconditional logistic regression, adjusted for the PS. We study the bias for various confounding scenarios and compare our asymptotic results with those from simulations with limited sample sizes. To create realistic correlations among multiple confounders, we also based simulations on a real dataset. Copyright © 2015 John Wiley & Sons, Ltd.

Association Between Swimming Lessons and Drowning in Childhood

PubMed Central

Brenner, Ruth A.; Taneja, Gitanjali Saluja; Haynie, Denise L.; Trumble, Ann C.; Qian, Cong; Klinger, Ron M.; Klebanoff, Mark A.

2014-01-01

Objective To estimate the association between swimming lessons and the risk of drowning among children aged 1 to 19 years. Design Case-control study. Setting Cases were identified from medical examiners’/ coroners’ offices between mid-2003 and mid-2005. Jurisdictions included the states of Maryland and North Carolina, 14 districts (33 counties) in Florida, 3 counties in California, 1 county in Texas, and 1 county in New York. Participants Cases were children and adolescents aged 1 to 19 years who died of unintentional drowning. Interviews were conducted with 88 families of children who drowned and 213 matched controls. Main Exposure Swimming lessons. Main Outcome Measure Death due to unintentional drowning. Drownings that were intentional, of undetermined intent, or that occurred under conditions in which swimming ability was unlikely to impact risk (eg, in ice water or bathtubs) were excluded. Results Of the 61 cases in the 1- to 4-year age group, 2 (3%) had participated in formal swimming lessons vs 35 of 134 matched controls (26%) (adjusted odds ratio [OR], 0.12; 95% confidence interval [CI], 0.01–0.97). Among the 27 cases aged 5 to 19 years, 7 (27%) had ever taken formal swimming lessons vs 42 of 79 matched controls (53%) (adjusted OR, 0.36; 95% CI, 0.09–1.51). In adjusted analyses, there was no statistically significant association between informal instruction and drowning risk. Conclusions Participation in formal swimming lessons was associated with an 88% reduction in the risk of drowning in the 1- to 4-year-old children, although our estimates were imprecise and 95% CIs included risk reductions ranging from 3% to 99%. PMID:19255386

Prostate-Specific Antigen Screening and Mortality from Prostate Cancer

PubMed Central

Rhoads, George G.; Carson, Jeffrey L.; Merlino, Frances; Wilcox, Homer

2008-01-01

Background There is no available evidence from randomized trials that early detection of prostate cancer improves health outcomes, but the prostate-specific antigen (PSA) test is commonly used to screen men for prostate cancer. Objective The objective of the study is to see if screening with PSA decreases mortality from prostate cancer. Design, setting, and participants This is a case-control study using one-to-one matching on race, age, and time of availability of exposure to PSA screening. Decedents, 380, from New Jersey Vital Statistics 1997 to 2000 inclusive, 55–79 years of age at diagnosis were matched to living controls without metastatic prostate cancer. Medical records were obtained from all providers, and we abstracted information about PSA tests from 1989 to the time of diagnosis in each index case. Measurements Measurements consist of a comparison of screening (yes, no) between cases and controls. Measure of association was the odds ratio. Results Eligible cases were diagnosed each year from 1989 to 1999 with the median year being 1993. PSA screening was evident in 23.2–29.2% of cases and 21.8–26.1% of controls depending on the screening criteria. The unadjusted, matched odds ratio for dying of prostate cancer if ever screened was 1.09 (95% CI 0.76 to 1.60) for the most restrictive criteria and 1.19 (95% CI, 0.85 to 1.66) for the least restrictive. Adjustment for comorbidity and education level made no significant differences in these values. There were no significant interactions by age or race. Conclusions PSA screening using an ever/never tabulation for tests from 1989 until 2000 did not protect New Jersey men from prostate cancer mortality. PMID:18172740

Performance of Disease Risk Score Matching in Nested Case-Control Studies: A Simulation Study.

PubMed

Desai, Rishi J; Glynn, Robert J; Wang, Shirley; Gagne, Joshua J

2016-05-15

In a case-control study, matching on a disease risk score (DRS), which includes many confounders, should theoretically result in greater precision than matching on only a few confounders; however, this has not been investigated. We simulated 1,000 hypothetical cohorts with a binary exposure, a time-to-event outcome, and 13 covariates. Each cohort comprised 2 subcohorts of 10,000 patients each: a historical subcohort and a concurrent subcohort. DRS were estimated in the historical subcohorts and applied to the concurrent subcohorts. Nested case-control studies were conducted in the concurrent subcohorts using incidence density sampling with 2 strategies-matching on age and sex, with adjustment for additional confounders, and matching on DRS-followed by conditional logistic regression for 9 outcome-exposure incidence scenarios. In all scenarios, DRS matching yielded lower average standard errors and mean squared errors than did matching on age and sex. In 6 scenarios, DRS matching also resulted in greater empirical power. DRS matching resulted in less relative bias than did matching on age and sex at lower outcome incidences but more relative bias at higher incidences. Post-hoc analysis revealed that the effect of DRS model misspecification might be more pronounced at higher outcome incidences, resulting in higher relative bias. These results suggest that DRS matching might increase the statistical efficiency of case-control studies, particularly when the outcome is rare. © The Author 2016. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Driver Mortality in Paired Side Impact Collisions Due to Incompatible Vehicle Types

PubMed Central

Crandall, C.S.

2003-01-01

Using a matched case control design, this study measured the mortality associated with paired passenger car-sport utility vehicle side impact (‘T-bone’) collisions using FARS data. Survival versus fatal outcome within the matched crash pairs was measured with matched pair odds ratios. Conditional logistic regression adjusted for multiple effects. Overall, passenger car drivers experienced greater mortality than did SUV drivers, regardless if they were in the struck or striking vehicle (odds ratio: 10.0; 95% confidence interval: 7.9, 12.5). Differential mortality persisted after adjustment for confounders. Efforts should be sought to improve passenger car side impact crashworthiness and to reduce SUV aggressivity. PMID:12941243

Control selection and confounding factors: A lesson from a Japanese case-control study to examine acellular pertussis vaccine effectiveness.

PubMed

Ohfuji, Satoko; Okada, Kenji; Nakano, Takashi; Ito, Hiroaki; Hara, Megumi; Kuroki, Haruo; Hirota, Yoshio

2017-08-24

When using a case-control study design to examine vaccine effectiveness, both the selection of control subjects and the consideration of potential confounders must be the important issues to ensure accurate results. In this report, we described our experience from a case-control study conducted to evaluate the effectiveness of acellular pertussis vaccine combined with diphtheria-tetanus toxoids (DTaP vaccine). Newly diagnosed pertussis cases and age- and sex-matched friend-controls were enrolled, and the history of DTaP vaccination was compared between groups. Logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) of vaccination for development of pertussis. After adjustment for potential confounders, four doses of DTaP vaccination showed a lower OR for pediatrician-diagnosed pertussis (OR=0.11, 95% CI, 0.01-0.99). In addition, the decreasing OR of four doses vaccination was more pronounced for laboratory-confirmed pertussis (OR=0.07, 95%CI, 0.01-0.82). Besides, positive association with pertussis was observed in subjects with a history of steroid treatment (OR=5.67) and those with a recent contact with a lasting cough (OR=4.12). When using a case-control study to evaluate the effectiveness of vaccines, particularly those for uncommon infectious diseases such as pertussis, the use of friend-controls may be optimal due to the fact that they shared a similar experience for exposure to the pathogen as the cases. In addition, to assess vaccine effectiveness as accurately as possible, the effects of confounding should be adequately controlled with a matching or analysis technique. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Knee movement patterns of injured and uninjured adolescent basketball players when landing from a jump: A case-control study

PubMed Central

Louw, Quinette; Grimmer, Karen; Vaughan, Christopher

2006-01-01

Background A common knee injury mechanism sustained during basketball is landing badly from a jump. Landing is a complex task and requires good coordination, dynamic muscle control and flexibility. For adolescents whose coordination and motor control has not fully matured, landing badly from a jump can present a significant risk for injury. There is currently limited biomechanical information regarding the lower limb kinetics of adolescents when jumping, specifically regarding jump kinematics comparing injured with uninjured adolescents. This study reports on an investigation of biomechanical differences in landing patterns of uninjured and injured adolescent basketball players. Methods A matched case-control study design was employed. Twenty-two basketball players aged 14–16 years participated in the study: eleven previously knee-injured and eleven uninjured players matched with cases for age, gender, weight, height and years of play, and playing for the same club. Six high-speed, three-dimensional Vicon 370 cameras (120 Hz), Vicon biomechanical software and SAS Version 8 software were employed to analyse landing patterns when subjects performed a "jump shot". Linear correlations determined functional relationships between the biomechanical performance of lower limb joints, and paired t-tests determined differences between the normalised peak biomechanical parameters. Results The average peak vertical ground reaction forces between the cases and controls were similar. The average peak ground reaction forces between the cases and controls were moderately correlated (r = -0.47). The control (uninjured) players had significantly greater hip and knee flexion angles and significantly greater eccentric activity on landing than the uninjured cases (p < 0.01). Conclusion The findings of the study indicate that players with a history of knee injuries had biomechanically compromised landing techniques when compared with uninjured players matched for gender, age and club. Descriptions (norms) of expected levels of knee control, proprioceptive acuity and eccentric strength relative to landing from a jump, at different ages and physical developmental stages, would assist clinicians and coaches to identify players with inappropriate knee performance comparable to their age or developmental stage. PMID:16522210

Psychological autopsy study comparing suicide decedents, suicide ideators, and propensity score matched controls: results from the study to assess risk and resilience in service members (Army STARRS).

PubMed

Nock, M K; Dempsey, C L; Aliaga, P A; Brent, D A; Heeringa, S G; Kessler, R C; Stein, M B; Ursano, R J; Benedek, D

2017-11-01

The suicide rate has increased significantly among US Army soldiers over the past decade. Here we report the first results from a large psychological autopsy study using two control groups designed to reveal risk factors for suicide death among soldiers beyond known sociodemographic factors and the presence of suicide ideation. Informants were next-of-kin and Army supervisors for: 135 suicide cases, 137 control soldiers propensity-score-matched on known sociodemographic risk factors for suicide and Army history variables, and 118 control soldiers who reported suicide ideation in the past year. Results revealed that most (79.3%) soldiers who died by suicide have a prior mental disorder; mental disorders in the prior 30-days were especially strong risk factors for suicide death. Approximately half of suicide decedents tell someone that they are considering suicide. Virtually all of the risk factors identified in this study differed between suicide cases and propensity-score-matched controls, but did not significantly differ between suicide cases and suicide ideators. The most striking difference between suicides and ideators was the presence in the former of an internalizing disorder (especially depression) and multi-morbidity (i.e. 3+ disorders) in the past 30 days. Most soldiers who die by suicide have identifiable mental disorders shortly before their death and tell others about their suicidal thinking, suggesting that there are opportunities for prevention and intervention. However, few risk factors distinguish between suicide ideators and decedents, pointing to an important direction for future research.

Human-Automation Integration: Principle and Method for Design and Evaluation

NASA Technical Reports Server (NTRS)

Billman, Dorrit; Feary, Michael

2012-01-01

Future space missions will increasingly depend on integration of complex engineered systems with their human operators. It is important to ensure that the systems that are designed and developed do a good job of supporting the needs of the work domain. Our research investigates methods for needs analysis. We included analysis of work products (plans for regulation of the space station) as well as work processes (tasks using current software), in a case study of Attitude Determination and Control Officers (ADCO) planning work. This allows comparing how well different designs match the structure of the work to be supported. Redesigned planning software that better matches the structure of work was developed and experimentally assessed. The new prototype enabled substantially faster and more accurate performance in plan revision tasks. This success suggests the approach to needs assessment and use in design and evaluation is promising, and merits investigatation in future research.

Traffic rule violations of private bus drivers and bus crashes in Sri Lanka: a case-control study.

PubMed

Jayatilleke, Achala Upendra; Poudel, Krishna C; Nakahara, Shinji; Dharmaratne, Samath D; Jayatilleke, Achini Chinthika; Jimba, Masamine

2010-06-01

To explore the association between self-reported traffic rule violations of private sector bus drivers and bus crashes in the Kandy district, Sri Lanka. We carried out a case-control study from August to September 2006. Cases were all the private bus drivers registered in the Kandy district and involved in crashes reported to the police between November 2005 and April 2006 (n = 63). We included two control groups: the private bus drivers working on the same routes of the cases (n = 90; matched controls) and the drivers selected randomly from the other routes of the district (n = 111; unmatched controls). We used a self-administered questionnaire to collect data on the self-reported traffic rule violations and analyzed the association between the self-reported traffic rule violations and crashes using logistic regression. The following variables showed significant associations with private bus crashes: illegal overtaking (matched controls, adjusted odds ratio [AOR] = 14.78, unmatched controls, AOR = 1.04), taking passengers outside the bus bays (matched controls, AOR = 3.96, unmatched controls, AOR = 2.29), and overloading (matched controls, AOR = 10.26, unmatched controls, AOR = 1.93). However, we did not observe an association between high-speed driving and bus crashes matched controls, AOR = 1.22, unmatched controls, AOR = 0.81. Traffic rule violations, such as illegal overtaking, overloading, and taking passengers outside the bus bays, are significant risk factors for private bus crashes in Sri Lanka.

IS PAIN IN ONE KNEE ASSOCIATED WITH ISOMETRIC MUSCLE STRENGTH IN THE CONTRALATERAL LIMB? - DATA FROM THE OSTEOARTHRITIS INITIATIVE (OAI)

PubMed Central

Steidle, E.; Wirth, W.; Glass, N.; Ruhdorfer, A.; Cotofana, S.; Eckstein, F.; Segal, N. A.

2014-01-01

Objective Knee pain and muscle weakness confer risk for knee osteoarthritis incidence and progression. The purpose of this study was to determine whether unilateral knee pain influences contralateral thigh muscle strength. Design Of 4796 Osteoarthritis Initiative participants, 224 (mean±SD age 63.9±8.9 years) cases could be matched to a control. Cases were defined as having unilateral knee pain (numerical rating scale (NRS)≥4/10; ≥infrequent pain) and one pain-free knee (NRS 0–1; ≤infrequent pain; WOMAC≤1). Controls were defined as having bilaterally pain-free knees (NRS 0–1; ≤infrequent pain; WOMAC≤1). Maximal isometric muscle strength [N] was compared between limbs in participants with unilateral pain (cases), and between pain-free limbs of cases and controls. Results Knee extensor/flexor strength in pain-free limbs of cases was lower than in bilaterally pain-free controls (−5.5%/–8.4%; p=0.043/p=0.022). Within cases, maximum extensor/flexor strength was significantly lower in the painful than in the pain-free limb (−6.4%/4.1%; p<0.0001/p=0.015). Conclusions These results suggest that strength in limbs without knee pain is associated with the pain status of the contralateral knee. The strength difference between unilateral pain-free cases and matched bilateral pain-free controls was similar to that between limbs in persons with unilateral knee pain. Lower strength due to contralateral knee pain might be centrally mediated. PMID:25768069

Combining matched and unmatched control groups in case-control studies.

PubMed

le Cessie, Saskia; Nagelkerke, Nico; Rosendaal, Frits R; van Stralen, Karlijn J; Pomp, Elisabeth R; van Houwelingen, Hans C

2008-11-15

Multiple control groups in case-control studies are used to control for different sources of confounding. For example, cases can be contrasted with matched controls to adjust for multiple genetic or unknown lifestyle factors and simultaneously contrasted with an unmatched population-based control group. Inclusion of different control groups for a single exposure analysis yields several estimates of the odds ratio, all using only part of the data. Here the authors introduce an easy way to combine odds ratios from several case-control analyses with the same cases. The approach is based upon methods used for meta-analysis but takes into account the fact that the same cases are used and that the estimated odds ratios are therefore correlated. Two ways of estimating this correlation are discussed: sandwich methodology and the bootstrap. Confidence intervals for the pooled estimates and a test for checking whether the odds ratios in the separate case-control studies differ significantly are derived. The performance of the method is studied by simulation and by applying the methods to a large study on risk factors for thrombosis, the MEGA Study (1999-2004), wherein cases with first venous thrombosis were included with a matched control group of partners and an unmatched population-based control group.

The lack of selection bias in a snowball sampled case-control study on drug abuse.

PubMed

Lopes, C S; Rodrigues, L C; Sichieri, R

1996-12-01

Friend controls in matched case-control studies can be a potential source of bias based on the assumption that friends are more likely to share exposure factors. This study evaluates the role of selection bias in a case-control study that used the snowball sampling method based on friendship for the selection of cases and controls. The cases selected fro the study were drug abusers located in the community. Exposure was defined by the presence of at least one psychiatric diagnosis. Psychiatric and drug abuse/dependence diagnoses were made according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R) criteria. Cases and controls were matched on sex, age and friendship. The measurement of selection bias was made through the comparison of the proportion of exposed controls selected by exposed cases (p1) with the proportion of exposed controls selected by unexposed cases (p2). If p1 = p2 then, selection bias should not occur. The observed distribution of the 185 matched pairs having at least one psychiatric disorder showed a p1 value of 0.52 and a p2 value of 0.51, indicating no selection bias in this study. Our findings support the idea that the use of friend controls can produce a valid basis for a case-control study.

A case control study of senile cataract in a hospital based population.

PubMed

Badrinath, S S; Sharma, T; Biswas, J; Srinivas, V

1996-12-01

A case-control study (244 cases and 264 controls) was done during 1986-89 on a hospital based population to evaluate the risk factors associated with the etiology of senile cataract. Patient with age between 40-60 years, visual acuity of 6/9 or less, and presence of lenticular opacity of senile origin were included as cases. Age matched individuals with absence of lenticular opacity made up the controls. Multivariate logistic regression analysis revealed that higher systolic BP and number of meals were significantly (P < or = 0.05) associated with presence of senile cataract; whereas higher weight, education and income, and utilization of cooking water had a significant protective effect against senile cataract. The present study helps the clinician to understand the possible risk factors associated with the development of senile cataract and could be helpful in designing a intervention strategy in future.

Association of young and advanced age of pregnant women with the risk of isolated congenital abnormalities in Hungary - a population-based case-matched control study.

PubMed

Csermely, Gyula; Susánszky, Éva; Czeizel, Andrew E

2015-03-01

To analyze the possible association of maternal age with the risk of all congenital abnormalities (CAs) in a population-based large case-matched control data set. The Hungarian Case-Control Surveillance of Congenital Abnormalities included 21,494 cases with isolated CA and their 34,311 matched controls. First the distribution of maternal age groups in 24 CA-groups and their matched controls was compared. In the second step, young (19 years or less) and advanced (35 years or more) age groups were compared. Finally, the subgroups of neural-tube defects, congenital heart defects and abdominal wall's CA were evaluated separately. A higher risk of gastroschisis, congenital heart defects, particularly left-sided obstructive defects, undescended testis and clubfoot was found in the youngest age group (19 years or less) of cases. The higher proportion of pregnant women with advanced age (i.e. 35 years or more) showed only a borderline excess in cases with clubfoot. The so-called U-shaped risk of maternal age distribution was found in cases with clubfoot and in the total group of isolated CAs. The maternal age is a contributing factor to the origin of some isolated CAs mainly in young pregnant women.

Decreased hospital length of stay associated with presentation of cases at morning report with librarian support

PubMed Central

Banks, Daniel E.; Shi, Runhua; Timm, Donna F.; Christopher, Kerri Ann; Duggar, David Charles; Comegys, Marianne; McLarty, Jerry

2007-01-01

Objective: The research sought to determine whether case discussion at residents' morning report (MR), accompanied by a computerized literature search and librarian support, affects hospital charges, length of stay (LOS), and thirty-day readmission rate. Methods: This case-control study, conducted from August 2004 to March 2005, compared outcomes for 105 cases presented at MR within 24 hours of admission to 19,210 potential matches, including cases presented at MR and cases not presented at MR. With matching criteria of patient age (± 5 years), identical primary diagnosis, and secondary diagnoses (within 3 additional diagnoses) using International Classification of Diseases (ICD-9) codes, 55 cases were matched to 136 controls. Statistical analyses included Student's t tests, chi-squared tests, and nonparametric methods. Results: LOS differed significantly between matched MR cases and controls (3 days vs. 5 days, P < 0.024). Median total hospital charges were $7,045 for the MR group and $10,663 for the control group. There was no difference in 30-day readmission rate between the 2 groups. Discussion/Conclusion: Presentation of a case at MR, followed by the timely dissemination of the results of an online literature review, resulted in a shortened LOS and lower hospital charges compared with controls. MR, in association with a computerized literature search guided by the librarians, was an effective means for introducing evidence-based medicine into patient care practices. PMID:17971885

Maximum likelihood estimation for Cox's regression model under nested case-control sampling.

PubMed

Scheike, Thomas H; Juul, Anders

2004-04-01

Nested case-control sampling is designed to reduce the costs of large cohort studies. It is important to estimate the parameters of interest as efficiently as possible. We present a new maximum likelihood estimator (MLE) for nested case-control sampling in the context of Cox's proportional hazards model. The MLE is computed by the EM-algorithm, which is easy to implement in the proportional hazards setting. Standard errors are estimated by a numerical profile likelihood approach based on EM aided differentiation. The work was motivated by a nested case-control study that hypothesized that insulin-like growth factor I was associated with ischemic heart disease. The study was based on a population of 3784 Danes and 231 cases of ischemic heart disease where controls were matched on age and gender. We illustrate the use of the MLE for these data and show how the maximum likelihood framework can be used to obtain information additional to the relative risk estimates of covariates.

A Simple and Robust Method for Partially Matched Samples Using the P-Values Pooling Approach

PubMed Central

Kuan, Pei Fen; Huang, Bo

2013-01-01

This paper focuses on statistical analyses in scenarios where some samples from the matched pairs design are missing, resulting in partially matched samples. Motivated by the idea of meta-analysis, we recast the partially matched samples as coming from two experimental designs, and propose a simple yet robust approach based on the weighted Z-test to integrate the p-values computed from these two designs. We show that the proposed approach achieves better operating characteristics in simulations and a case study, compared to existing methods for partially matched samples. PMID:23417968

Pituitary Antibodies in Women with Hashimoto's Thyroiditis: Prevalence in Diagnostic and Prediagnostic Sera

PubMed Central

Guaraldi, Federica; Landek-Salgado, Melissa A.; Hutfless, Susan; Samoni, Francesca; Talor, Monica V.; Matos, Peter G.; Salvatori, Roberto; Rose, Noel R.

2012-01-01

Background Pituitary antibodies have been reported with greater frequency in patients with Hashimoto's thyroiditis than in healthy controls, although there is significant variability in the strength of the association and the methodologies used. Methods We designed a nested case–control study to characterize the prevalence of pituitary antibodies at the time of the clinical diagnosis of Hashimoto's thyroiditis, as well as at 2, 5, and 7 years before diagnosis. Active component female service member cases (n=87) and matched female controls (n=107) were selected using the Defense Medical Surveillance System database (DMSSD) between January 1998 and December 2007. Pituitary antibodies were measured by immunofluorescence using human pituitary glands collected at autopsy as the substrate. Results At diagnosis, pituitary antibodies were present in 9% of cases with Hashimoto's (8 of 87) and 3% of controls (3 of 107). When the data were analyzed using a conditional logistic regression model, which takes into account the matching on age and work status, pituitary antibodies increased the odds of having Hashimoto's thyroiditis by sevenfold (95% confidence interval from 1.3 to 40.1, p=0.028), after adjusting for components of the DMSSD-category-termed race and for thyroperoxidase antibodies. Before diagnosis, pituitary antibodies were positive in 3 of the 11 subjects (2 cases and 1 control) at the −2-year time point, and negative in all 11 subjects at the −5- and −7-year time points. Conclusions In summary, using a nested case–control design, we confirm that pituitary antibodies are more common in Hashimoto's thyroiditis and suggest that they appear late during its natural history. PMID:22468943

The effect of maternal subclinical hypothyroidism on IQ in 7- to 8-year-old children: A case-control review.

PubMed

Murphy, Niamh C; Diviney, Mairead M; Donnelly, Jennifer C; Cooley, Sharon M; Kirkham, Colin H; Foran, Adrienne M; Breathnach, Fionnuala M; Malone, Fergal D; Geary, Michael P

2015-10-01

In Ireland, pregnant women are not routinely screened for subclinical hypothyroidism (SCH). Our objective was to compare the intelligence quotient (IQ) of children whose mothers had been diagnosed with SCH prenatally with matched controls using a case-control retrospective study. In a previous study from our group, 1000 healthy nulliparous women were screened anonymously for SCH. This was a laboratory diagnosis involving elevated TSH with normal fT4 or normal TSH with hypothyroxinaemia. We identified 23 cases who agreed to participate. These were matched with 47 controls. All children underwent neurodevelopmental assessment at age 7-8. Wechsler Intelligence Scale for Children IV assessment scores were used to compare the groups. Our main outcome measure was to identify whether there was a difference in IQ between the groups. From the cohort of cases, 23 mothers agreed to the assessment of their children as well as 47 controls. The children in the control group had higher mean scores than those in the case group across Verbal Comprehension Intelligence, Perceptual Reasoning Intelligence, Working Memory Intelligence, Processing Speed Intelligence and Full Scale IQ. Mann-Whitney U-test confirmed a significant difference in IQ between the cases (composite score 103.87) and the controls (composite score 109.11) with a 95% confidence interval (0.144, 10.330). Our results highlight significant differences in IQ of children of mothers who had unrecognised SCH during pregnancy. While our study size and design prevents us from making statements on causation, our data suggest significant potential public health implications for routine prenatal screening. © 2015 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.

Estimating the Counterfactual Impact of Conservation Programs on Land Cover Outcomes: The Role of Matching and Panel Regression Techniques.

PubMed

Jones, Kelly W; Lewis, David J

2015-01-01

Deforestation and conversion of native habitats continues to be the leading driver of biodiversity and ecosystem service loss. A number of conservation policies and programs are implemented--from protected areas to payments for ecosystem services (PES)--to deter these losses. Currently, empirical evidence on whether these approaches stop or slow land cover change is lacking, but there is increasing interest in conducting rigorous, counterfactual impact evaluations, especially for many new conservation approaches, such as PES and REDD, which emphasize additionality. In addition, several new, globally available and free high-resolution remote sensing datasets have increased the ease of carrying out an impact evaluation on land cover change outcomes. While the number of conservation evaluations utilizing 'matching' to construct a valid control group is increasing, the majority of these studies use simple differences in means or linear cross-sectional regression to estimate the impact of the conservation program using this matched sample, with relatively few utilizing fixed effects panel methods--an alternative estimation method that relies on temporal variation in the data. In this paper we compare the advantages and limitations of (1) matching to construct the control group combined with differences in means and cross-sectional regression, which control for observable forms of bias in program evaluation, to (2) fixed effects panel methods, which control for observable and time-invariant unobservable forms of bias, with and without matching to create the control group. We then use these four approaches to estimate forest cover outcomes for two conservation programs: a PES program in Northeastern Ecuador and strict protected areas in European Russia. In the Russia case we find statistically significant differences across estimators--due to the presence of unobservable bias--that lead to differences in conclusions about effectiveness. The Ecuador case illustrates that if time-invariant unobservables are not present, matching combined with differences in means or cross-sectional regression leads to similar estimates of program effectiveness as matching combined with fixed effects panel regression. These results highlight the importance of considering observable and unobservable forms of bias and the methodological assumptions across estimators when designing an impact evaluation of conservation programs.

Multiple imputation of missing data in nested case-control and case-cohort studies.

PubMed

Keogh, Ruth H; Seaman, Shaun R; Bartlett, Jonathan W; Wood, Angela M

2018-06-05

The nested case-control and case-cohort designs are two main approaches for carrying out a substudy within a prospective cohort. This article adapts multiple imputation (MI) methods for handling missing covariates in full-cohort studies for nested case-control and case-cohort studies. We consider data missing by design and data missing by chance. MI analyses that make use of full-cohort data and MI analyses based on substudy data only are described, alongside an intermediate approach in which the imputation uses full-cohort data but the analysis uses only the substudy. We describe adaptations to two imputation methods: the approximate method (MI-approx) of White and Royston () and the "substantive model compatible" (MI-SMC) method of Bartlett et al. (). We also apply the "MI matched set" approach of Seaman and Keogh () to nested case-control studies, which does not require any full-cohort information. The methods are investigated using simulation studies and all perform well when their assumptions hold. Substantial gains in efficiency can be made by imputing data missing by design using the full-cohort approach or by imputing data missing by chance in analyses using the substudy only. The intermediate approach brings greater gains in efficiency relative to the substudy approach and is more robust to imputation model misspecification than the full-cohort approach. The methods are illustrated using the ARIC Study cohort. Supplementary Materials provide R and Stata code. © 2018, The International Biometric Society.

Identification of Occupational Cancer Risks in British Columbia, Canada: A Population-Based Case—Control Study of 1,155 Cases of Colon Cancer

PubMed Central

Fang, Raymond; Le, Nhu; Band, Pierre

2011-01-01

Objective Cancer has been recognized to have environmental origin, but occupational cancer risk studies have not been fully documented. The objective of this paper was to identify occupations and industries with elevated colon cancer risk based on lifetime occupational histories collected from 15,463 incident cancer cases. Method A group matched case-control design was used. All cases were diagnosed with histologically proven colon cancers, with cancer controls being all other cancer sites, excluding rectum, lung and unknown primary, diagnosed at the same period of time from the British Columbia Cancer Registry. Data analyses were done on all 597 Canadian standard occupation titles and 1,104 standard industry titles using conditional logistic regression for matched data sets and the likelihood ratio test. Results Excess colon cancer risks was observed in a number of occupations and industries, particularly those with low physical activity and those involving exposure to asbestos, wood dusts, engine exhaust and diesel engine emissions, and ammonia. Discussion The results of our study are in line with those from the literature and further suggest that exposure to wood dusts and to ammonia may carry an increased occupational risk of colon cancer. PMID:22073015

The need to scale up HIV indicator condition-guided testing for early case-finding: a case-control study in primary care.

PubMed

Joore, Ivo K; Twisk, Denise E; Vanrolleghem, Ann M; de Ridder, Maria; Geerlings, Suzanne E; van Bergen, Jan E A M; van den Broek, Ingrid V

2016-11-17

European guidelines recommend offering an HIV test to individuals who display HIV indicator conditions (ICs). We aimed to investigate the incidence of ICs in primary care reported in medical records prior to HIV diagnosis. We did a cross-sectional search in an electronic general practice database using a matched case-control design to identify which predefined ICs registered by Dutch GPs were most associated with an HIV-positive status prior to the time of diagnosis. We included 224 HIV cases diagnosed from 2009 to 2013, which were matched with 2,193 controls. Almost two thirds (n = 136, 60.7%) of cases were diagnosed with one or more ICs in the period up to five years prior to the index date compared to 18.7% (n = 411) of controls. Cases were more likely to have an IC than controls: in the one year prior to the index date, the odds ratio (OR) for at least one condition was 11.7 (95% CI: 8.3 to 16.4). No significant differences were seen in the strength of the association between HIV diagnosis and ICs when comparing genders, age groups or urbanisation levels. There is no indication that subgroups require a different testing strategy. Our study shows that there are opportunities for IC-guided testing in primary care. We recommend that IC-guided testing be more integrated in GPs' future guidelines and that education strategies be used to facilitate its implementation in daily practice.

The association of contact lens solution use and Acanthamoeba keratitis

PubMed Central

Joslin, Charlotte E.; Tu, Elmer Y.; Shoff, Megan E.; Booton, Gregory C.; Fuerst, Paul A.; McMahon, Timothy T.; Anderson, Robert J.; Dworkin, Mark S.; Sugar, Joel; Davis, Faith G.; Stayner, Leslie T.

2009-01-01

Purpose Diagnosis of Acanthamoeba keratitis, a rare but serious corneal infection, has recently increased significantly at the University of Illinois at Chicago (UIC) Cornea Service. The purpose is to investigate Acanthamoeba keratitis risk factors. Design Retrospective case-control study. Methods Setting University, tertiary care hospital. Patients Fifty-five Acanthamoeba keratitis cases with contact lens use were diagnosed between May 1, 2003 and September 15, 2006. Clinic-matched controls with contact lens use were recruited. Subjects completed surveys targeting lens hygiene, contact lens solution use, and water exposure. Main Outcome Measure Acanthamoeba keratitis. Results Thirty-nine (73.6%) cases and 113 (65.3%) controls participated; 38 cases had complete contact lens data. Thirty-five of 38 cases (92.1%) and 47 of 100 controls (47.0%) used soft lenses. Analysis was performed on 30 cases and 39 controls with matched pairs with soft lens use. Exclusive use of AMO Complete MoisturePlus Multi-Purpose Solution was independently associated with Acanthamoeba keratitis in multivariable analysis (55.2% vs. 10.5%; OR, 16.67; 95% CI, 2.11–162.63; p = 0.008). However, 38.8% of cases reported no use of AMO Complete MoisturePlus Multi-Purpose Solution or used it in combination with other solutions. Although not statistically significant, additional hygiene-related variables (solution ‘reuse’, lack of ‘rubbing’, and showering with lenses) suggest a pattern of risk,. Conclusions AMO Complete MoisturePlus Multi-Purpose Solution use is independently associated with Acanthamoeba keratitis among soft contact lens users. However, it does not explain all cases, suggesting additional factors. Further research into environmental risk factors and hygiene practices is warranted, especially considering this is the second outbreak of an atypical, contact lens-related infection. PMID:17588524

Modelling the role of dietary habits and eating behaviours on the development of acute coronary syndrome or stroke: aims, design, and validation properties of a case-control study.

PubMed

Kastorini, Christina-Maria; Milionis, Haralampos J; Goudevenos, John A; Panagiotakos, Demosthenes B

2010-09-14

In this paper the methodology and procedures of a case-control study that will be developed for assessing the role of dietary habits and eating behaviours on the development of acute coronary syndrome and stroke is presented. Based on statistical power calculations, 1000 participants will be enrolled; of them, 250 will be consecutive patients with a first acute coronary event, 250 consecutive patients with a first ischaemic stroke, and 500 population-based healthy subjects (controls), age and sex matched to the cases. Socio-demographic, clinical, dietary, psychological, and other lifestyle characteristics will be measured. Dietary habits and eating behaviours will be evaluated with a special questionnaire that has been developed for the study.

Control design for robust stability in linear regulators: Application to aerospace flight control

NASA Technical Reports Server (NTRS)

Yedavalli, R. K.

1986-01-01

Time domain stability robustness analysis and design for linear multivariable uncertain systems with bounded uncertainties is the central theme of the research. After reviewing the recently developed upper bounds on the linear elemental (structured), time varying perturbation of an asymptotically stable linear time invariant regulator, it is shown that it is possible to further improve these bounds by employing state transformations. Then introducing a quantitative measure called the stability robustness index, a state feedback conrol design algorithm is presented for a general linear regulator problem and then specialized to the case of modal systems as well as matched systems. The extension of the algorithm to stochastic systems with Kalman filter as the state estimator is presented. Finally an algorithm for robust dynamic compensator design is presented using Parameter Optimization (PO) procedure. Applications in a aircraft control and flexible structure control are presented along with a comparison with other existing methods.

Characterization of dermatitis after PD-1/PD-L1 inhibitor therapy and association with multiple oncologic outcomes: a retrospective case-control study.

PubMed

Min Lee, Charles Kyung; Li, Shufeng; Tran, Duy Cong; Zhu, Gefei Alex; Kim, Jinah; Kwong, Bernice Y; Chang, Anne Lynn S

2018-05-29

Cutaneous adverse events are common with Programmed Death (PD)-1/ PD-Ligand (L)1 inhibitors. However, the nature of the specific cutaneous adverse event of dermatitis has not been investigated across various PD-1/PD-L1 inhibitors. Oncologic outcomes potentially associated with dermatitis are not well characterized. (s): To assess the nature of dermatitis after PD-1/PD-L1 inhibitor exposure and oncologic outcomes associated with dermatitis. Retrospective, matched, case-control study conducted at a single academic center. The most common histologic patterns were lichenoid dermatitis (50%) and spongiotic dermatitis (40%). Overall tumor response rate was 65.0% for cases and 17.0% for controls (p=0.0007), odds ratio: 7.3 (95% CI 2.3-23.1). Progression Free Survival (PFS) and Overall Survival (OS) times were significantly longer for cases than controls by Kaplan-Meier analysis (p<0.0001 and 0.0203, respectively). Retrospective design and relatively small sample size precluded matching on all cancer types. Lichenoid and spongiotic dermatitis associated with PD-1/PD-L1 inhibitors could be a sign of robust immune response and improved oncologic outcomes. The predictive value of PD-1/PD-L1 related dermatitis on cancer outcomes awaits investigation through prospective multicenter studies for specific cancer types. Copyright © 2018. Published by Elsevier Inc.

Specific features of colorectal cancer in patients with metabolic syndrome: a matched case-control analysis of 772 patients.

PubMed

Zarzavadjian Le Bian, Alban; Denet, Christine; Tabchouri, Nicolas; Donatelli, Gianfranco; Wind, Philippe; Louvet, Christophe; Bennamoun, Mostefa; Christidis, Christos; Perniceni, Thierry; Fuks, David; Gayet, Brice

2018-06-01

Although association between colorectal cancer (CRC) and metabolic syndrome (MetS) is established, specific features of CRC arising in patients presenting with MetS have not been clearly identified. All patients who underwent colectomy for CRC from January 2005 to December 2014 at Institut Mutualiste Montsouris were identified from a prospectively collected database and characteristics were compared in the entire population and in a 1:2 matched case-control analysis [variables on which matching was performed were CRC localization (right- or left-sided) and AJCC stage (0 to IV)]. Out of the 772 identified patients, 98 (12.7%) presented with MetS. Entire population analysis revealed that CRC associated with MetS was more frequent in men (71.4 vs. 47.8%, p < 0.001), more often right-sided (71.4 vs. 50.4%, p < 0.001) and presented with less synchronous liver metastasis (4.1 vs. 8.7%, p = 0.002). Case-control analysis confirmed the gender association (p < 0.001) and showed HNPCC (p < 0.001) and history family of CRC (p = 0.010) to be significantly more frequent in Non-MetS patients. CRC associated with MetS is more frequent in men, more often right-sided, and presents with fewer synchronous metastasis. Further investigations should be designed in order to confirm these results and to enhance our knowledge of carcinogenesis related to MetS.

Risk factors for infection with highly pathogenic influenza A virus (H5N1) in commercial chickens in Bangladesh.

PubMed

Biswas, P K; Christensen, J P; Ahmed, S S U; Barua, H; Das, A; Rahman, M H; Giasuddin, M; Hannan, A S M A; Habib, A M; Debnath, N C

2009-06-13

A matched case-control study was carried out to identify risk factors for highly pathogenic avian influenza A virus (subtype H5N1) infection in commercial chickens in Bangladesh. A total of 33 commercial farms diagnosed with H5N1 before September 9, 2007, were enrolled as cases, and 99 geographically matched unaffected farms were enrolled as control farms. Farm data were collected using a pretested questionnaire, and analysed by matched-pair analysis and multivariate conditional logistic regression. Two factors independently and positively associated with H5N1 infection remained in the final model. They were 'farm accessible to feral and wild animals' (odds ratio [OR] 5.71, 95 per cent confidence interval [CI] 1.81 to 18.0, P=0.003) and 'footbath at entry to farm/shed' (OR 4.93, 95 per cent CI 1.61 to 15.1, P=0.005). The use of a designated vehicle for sending eggs to a vendor or market appeared to be a protective factor (OR 0.14, 95 per cent CI 0.02 to 0.88, P=0.036).

Rebar: Reinforcing a Matching Estimator with Predictions from High-Dimensional Covariates

ERIC Educational Resources Information Center

Sales, Adam C.; Hansen, Ben B.; Rowan, Brian

2018-01-01

In causal matching designs, some control subjects are often left unmatched, and some covariates are often left unmodeled. This article introduces "rebar," a method using high-dimensional modeling to incorporate these commonly discarded data without sacrificing the integrity of the matching design. After constructing a match, a researcher…

Stereo Sound Field Controller Design Using Partial Model Matching on the Frequency Domain

NASA Astrophysics Data System (ADS)

Kumon, Makoto; Miike, Katsuhiro; Eguchi, Kazuki; Mizumoto, Ikuro; Iwai, Zenta

The objective of sound field control is to make the acoustic characteristics of a listening room close to those of the desired system. Conventional methods apply feedforward controllers, such as digital filters, to achieve this objective. However, feedback controllers are also necessary in order to attenuate noise or to compensate the uncertainty of the acoustic characteristics of the listening room. Since acoustic characteristics are well modeled on the frequency domain, it is efficient to design controllers with respect to frequency responses, but it is difficult to design a multi input multi output (MIMO) control system on a wide frequency domain. In the present study, a partial model matching method on the frequency domain was adopted because this method requires only sampled data, rather than complex mathematical models of the plant, in order to design controllers for MIMO systems. The partial model matching method was applied to design two-degree-of-freedom controllers for acoustic equalization and noise reduction. Experiments demonstrated effectiveness of the proposed method.

Risk and protective factors for meningococcal disease in adolescents: matched cohort study.

PubMed

Tully, Joanna; Viner, Russell M; Coen, Pietro G; Stuart, James M; Zambon, Maria; Peckham, Catherine; Booth, Clare; Klein, Nigel; Kaczmarski, Ed; Booy, Robert

2006-02-25

To examine biological and social risk factors for meningococcal disease in adolescents. Prospective, population based, matched cohort study with controls matched for age and sex in 1:1 matching. Controls were sought from the general practitioner. Six contiguous regions of England, which represent some 65% of the country's population. 15-19 year olds with meningococcal disease recruited at hospital admission in six regions (representing 65% of the population of England) from January 1999 to June 2000, and their matched controls. Blood samples and pernasal and throat swabs were taken from case patients at admission to hospital and from cases and matched controls at interview. Data on potential risk factors were gathered by confidential interview. Data were analysed by using univariate and multivariate conditional logistic regression. 144 case control pairs were recruited (74 male (51%); median age 17.6). 114 cases (79%) were confirmed microbiologically. Significant independent risk factors for meningococcal disease were history of preceding illness (matched odds ratio 2.9, 95% confidence interval 1.4 to 5.9), intimate kissing with multiple partners (3.7, 1.7 to 8.1), being a university student (3.4, 1.2 to 10) and preterm birth (3.7, 1.0 to 13.5). Religious observance (0.09, 0.02 to 0.6) and meningococcal vaccination (0.12, 0.04 to 0.4) were associated with protection. Activities and events increasing risk for meningococcal disease in adolescence are different from in childhood. Students are at higher risk. Altering personal behaviours could moderate the risk. However, the development of further effective meningococcal vaccines remains a key public health priority.

Control Theory based Shape Design for the Incompressible Navier-Stokes Equations

NASA Astrophysics Data System (ADS)

Cowles, G.; Martinelli, L.

2003-12-01

A design method for shape optimization in incompressible turbulent viscous flow has been developed and validated for inverse design. The gradient information is determined using a control theory based algorithm. With such an approach, the cost of computing the gradient is negligible. An additional adjoint system must be solved which requires the cost of a single steady state flow solution. Thus, this method has an enormous advantage over traditional finite-difference based algorithms. The method of artificial compressibility is utilized to solve both the flow and adjoint systems. An algebraic turbulence model is used to compute the eddy viscosity. The method is validated using several inverse wing design test cases. In each case, the program must modify the shape of the initial wing such that its pressure distribution matches that of the target wing. Results are shown for the inversion of both finite thickness wings as well as zero thickness wings which can be considered a model of yacht sails.

Using the entire history in the analysis of nested case cohort samples.

PubMed

Rivera, C L; Lumley, T

2016-08-15

Countermatching designs can provide more efficient estimates than simple matching or case-cohort designs in certain situations such as when good surrogate variables for an exposure of interest are available. We extend pseudolikelihood estimation for the Cox model under countermatching designs to models where time-varying covariates are considered. We also implement pseudolikelihood with calibrated weights to improve efficiency in nested case-control designs in the presence of time-varying variables. A simulation study is carried out, which considers four different scenarios including a binary time-dependent variable, a continuous time-dependent variable, and the case including interactions in each. Simulation results show that pseudolikelihood with calibrated weights under countermatching offers large gains in efficiency if compared to case-cohort. Pseudolikelihood with calibrated weights yielded more efficient estimators than pseudolikelihood estimators. Additionally, estimators were more efficient under countermatching than under case-cohort for the situations considered. The methods are illustrated using the Colorado Plateau uranium miners cohort. Furthermore, we present a general method to generate survival times with time-varying covariates. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Intrahousehold resource allocation and child growth in Mozambique: an ethnographic case-control study.

PubMed

Pfeiffer, J; Gloyd, S; Ramirez Li, L

2001-07-01

This study examines the effect of intrahousehold cash income control and decision-making patterns on child growth in the rural town of Sussundenga in Manica Province, Mozambique. A case-control study design was used to examine the influence of men's and women's disaggregated cash incomes on child growth. The research tested whether greater maternal share of household cash income was associated with (1) increased maternal decision-making and bargaining power in the household, and (2) better child growth. Fifty case households, with children 1-4 years old exhibiting poor growth, were matched with 50 control households of similar socioeconomic status in which all children under five demonstrated healthy growth. Data were gathered on gender-specific income generation and expenditure, specific intrahousehold allocation processes, diet, and sociodemographic variables using a formal survey. Key informant interviews, focus groups, and observation over one year provided ethnographic context for the case-control findings. Case-control differences were analyzed using McNemar's test, paired t-test, and conditional logistic regression. In spite of matching households for socioeconomic status, control household incomes were still slightly greater than cases. Male spouse income was also higher among controls while maternal income, and maternal proportion of household income, were not significantly different. Household meat, fish and poultry consumption, and maternal education were significantly greater among control households than cases. Greater maternal share of household income was not associated with greater maternal decision-making around cash. However, mothers must spend what little cash they earn on daily food supplies and usually request additional cash from spouses to cover these costs. There is evidence that if mothers earn enough to cover these socially prescribed costs, they can spend cash for other needs. Above this threshold, women's earnings may confer more bargaining power. The research also revealed a nuclearization of households, attenuation of community bonds of mutual aid, and increasing importance of cash for survival.

Abuse and deliberate self-poisoning in women: a matched case-control study.

PubMed

Coll, X; Law, F; Tobías, A; Hawton, K; Tomàs, J

2001-10-01

Controlled studies have shown deliberate self-harm to be more common in abused populations, but no controlled studies have shown abuse to be more common in self-harming populations. This is the first controlled study to determine whether abuse experiences (sexual, physical, and psychological) occurred more commonly in women who take overdoses than in controls. The design was a matched (1:1) case-control study set in a district general hospital in England. The subjects were 36 women admitted following deliberate self-poisoning. They were matched with the next non-overdose admission to the same hospital on six variables (sex, age, ethnicity, social class, marital status, and geographical locality). The main outcome measures used were modified versions of standardized self-report questionnaires of sexual, physical, and psychological abuse, together with measures of parenting style and general psychopathology. Women who had taken an overdose were more likely (odds ratio 15.0, 95% confidence interval 2.0 to 113.6) to have been sexually abused, and somewhat more likely to have been psychologically (1.02, 1.00 to 1.05) but not physically abused. They also had higher measures of psychopathology (GHQ-30: 1.19, 1.07 to 1.31), were more likely to have been abused at a younger age, exposed to the "affectionless control" style of parenting by their mothers, and to have harmed themselves in other ways. The management of women presenting to hospital after self-poisoning should include assessment of abuse experiences, and instigation of appropriate treatment in those with significant sequelae of abuse.

Impact of organised mammography screening on breast cancer mortality in a case–control and cohort study

PubMed Central

Heinävaara, Sirpa; Sarkeala, Tytti; Anttila, Ahti

2016-01-01

Background: The usefulness of case–control studies has been questioned. Our aim was to evaluate the long-term effect of screening on breast cancer mortality within the population-based mammography programme in Finland using a case–control design, and to compare the analyses with the earlier cohort study. Methods: The cases were women invited to screening, diagnosed and died from breast cancer in 1992–2011 while being 50–84 years at death. We chose 10 controls for each case with non-restrictive eligibility criteria. Our data included 1907 cases and 18 978 matched controls. We analysed associations between the screening participation and the risk of breast cancer death using the conditional Cox proportional hazards model. The effect estimates were corrected for self-selection bias. Results: An overall effect of screening was 0.67 (95% confidence interval (CI): 0.49–0.90), and that remained unchanged over time. Analyses with matching criteria comparable to the cohort study yielded an effect (0.70, 95% CI: 0.49–1.00) in 1992–2003 similar to that of the previous cohort analysis (0.72, 95% CI: 0.56–0.88). Conclusions: Organised mammography screening decreases mortality from breast cancer by 33% among the participants. If made comparable, a case–cohort study can yield effect estimates similar to a cohort study. PMID:27010748

Injury risk in professional boxing.

PubMed

Bledsoe, Gregory H; Li, Guohu; Levy, Fred

2005-10-01

Although a popular endeavor, boxing has fallen under increased scrutiny because of its association with traumatic brain injury. However, few studies have investigated the overall epidemiology of boxing injuries from representative samples, and no study has ever documented the incidence of injuries in female boxers. This study is a review of professional boxing data from the state of Nevada from September 2001 through March 2003. Medical and outcome data for all professional boxing matches occurring in Nevada between September 2001 and March 2003 (n = 524 matches) were analyzed on the basis of a pair-matched, case-control design. Cases were boxers who received an injury during the boxing matches. Boxers who were not injured served as control subjects. Both conditional and unconditional logistic regression models were used to assess risk factors for injury. The overall incidence rate of injury was 17.1 per 100 boxer-matches, or 3.4 per 100 boxer-rounds. Facial laceration accounted for 51% of all injuries, followed by hand injury (17%), eye injury (14%), and nose injury (5%). Male boxers were significantly more likely than female boxers to receive injuries (3.6 versus 1.2 per 100 boxer-rounds, P = 0.01). Male boxing matches also ended in knockouts and technical knockouts more often than did female matches (P < 0.001). The risk of injury for those who lost the matches was nearly twice the risk for the winners. Those who lost by knockout had double the risk of injury compared with those who lost by other means. Neither age nor weight was significantly associated with the risk of injury. The injury rate in professional boxing matches is high, particularly among male boxers. Superficial facial lacerations are the most common injury reported. Male boxers have a higher rate of knockout and technical knockouts than female boxers. Further research is necessary to determine the outcomes of injury, particularly the long-term neurologic outcome differences between sexes.

Guillain-Barré syndrome and adjuvanted pandemic influenza A (H1N1) 2009 vaccine: multinational case-control study in Europe

PubMed Central

Dieleman, Jeanne; Romio, Silvana; Johansen, Kari; Weibel, Daniel; Bonhoeffer, Jan

2011-01-01

Objective To assess the association between pandemic influenza A (H1N1) 2009 vaccine and Guillain-Barré syndrome. Design Case-control study. Setting Five European countries. Participants 104 patients with Guillain-Barré syndrome and its variant Miller-Fisher syndrome matched to one or more controls. Case status was classified according to the Brighton Collaboration definition. Controls were matched to cases on age, sex, index date, and country. Main outcome measures Relative risk estimate for Guillain-Barré syndrome after pandemic influenza vaccine. Results Case recruitment and vaccine coverage varied considerably between countries; the most common vaccines used were adjuvanted (Pandemrix and Focetria). The unadjusted pooled risk estimate for all countries was 2.8 (95% confidence interval 1.3 to 6.0). After adjustment for influenza-like illness/upper respiratory tract infection and seasonal influenza vaccination, receipt of pandemic influenza vaccine was not associated with an increased risk of Guillain-Barré syndrome (adjusted odds ratio 1.0, 0.3 to 2.7). The 95% confidence interval shows that the absolute effect of vaccination could range from one avoided case of Guillain-Barré syndrome up to three excess cases within six weeks after vaccination in one million people. Conclusions The risk of occurrence of Guillain-Barré syndrome is not increased after pandemic influenza vaccine, although the upper limit does not exclude a potential increase in risk up to 2.7-fold or three excess cases per one million vaccinated people. When assessing the association between pandemic influenza vaccines and Guillain-Barré syndrome it is important to account for the effects of influenza-like illness/upper respiratory tract infection, seasonal influenza vaccination, and calendar time. PMID:21750072

Epidemiologic study of residential proximity to transmission lines and childhood cancer in California: description of design, epidemiologic methods and study population

PubMed Central

Kheifets, Leeka; Crespi, Catherine M; Hooper, Chris; Oksuzyan, Sona; Cockburn, Myles; Ly, Thomas; Mezei, Gabor

2015-01-01

We conducted a large epidemiologic case-control study in California to examine the association between childhood cancer risk and distance from the home address at birth to the nearest high-voltage overhead transmission line as a replication of the study of Draper et al. in the United Kingdom. We present a detailed description of the study design, methods of case ascertainment, control selection, exposure assessment and data analysis plan. A total of 5788 childhood leukemia cases and 3308 childhood central nervous system cancer cases (included for comparison) and matched controls were available for analysis. Birth and diagnosis addresses of cases and birth addresses of controls were geocoded. Distance from the home to nearby overhead transmission lines was ascertained on the basis of the electric power companies’ geographic information system (GIS) databases, additional Google Earth aerial evaluation and site visits to selected residences. We evaluated distances to power lines up to 2000 m and included consideration of lower voltages (60–69 kV). Distance measures based on GIS and Google Earth evaluation showed close agreement (Pearson correlation >0.99). Our three-tiered approach to exposure assessment allowed us to achieve high specificity, which is crucial for studies of rare diseases with low exposure prevalence. PMID:24045429

Case-spouse control design in practice: an experience in estimating smoking and chronic obstructive pulmonary disease deaths in Chinese adults.

PubMed

Jiang, Jingmei; Liu, Boqi; Sitas, Freddy; Zeng, Xianjia; Chen, Junshi; Han, Wei; Zou, Xiaonong; Wu, Yanping; Zhao, Ping; Li, Junyao

2010-05-01

We assessed the effect of smoking on death from chronic obstructive pulmonary disease (COPD) in China by employing a large population-based, case-spouse control study design using data from a nationwide survey of mortality. During 1989-1991, a nationwide retrospective survey of mortality was conducted in China. For approximately 1,000,000 adults dying from all causes during 1986-1988, their surviving spouses or other informants provided detailed information about their own as well as the deceased person's smoking history. For this study, 183,393 individuals who died of COPD at age > or = 40 years were taken as cases, while 272,984 sex-matched surviving spouses of subjects who died from any cause were taken as controls. COPD death rates for smokers were more than twice as high as those of non-smokers, with a dose-response risk pattern, despite the fact that COPD death rates varied widely by region and age. Tobacco accounted for 41.4% of COPD deaths in men, but only 13.5% of those in women, who had a lower rate of smoking. A case-spouse control study, as an alternative design, is valid and feasible in utilizing information from population-based, retrospective mortality survey data for an analytical epidemiological study of disease etiology. Copyright 2010 Formosan Medical Association & Elsevier. Published by Elsevier B.V. All rights reserved.

Serum Vitamin D Is Significantly Inversely Associated with Disease Severity in Caucasian Adults with Obstructive Sleep Apnea Syndrome.

PubMed

Kerley, Conor P; Hutchinson, Katrina; Bolger, Kenneth; McGowan, Aisling; Faul, John; Cormican, Liam

2016-02-01

To evaluate vitamin D (25(OH)D) levels in obstructive sleep apnea syndrome (OSAS) and possible relationships to OSAS severity, sleepiness, lung function, nocturnal heart rate (HR), and body composition. We also aimed to compare the 25(OH)D status of a subset of OSAS patients compared to controls matched for important determinants of both OSAS and vitamin D deficiency (VDD). This was a cross-sectional study conducted at an urban, clinical sleep medicine outpatient center. We recruited newly diagnosed, Caucasian adults who had recently undergone nocturnal polysomnography. We compared body mass index (BMI), body composition (bioelectrical impedance analysis), neck circumference, sleepiness (Epworth Sleepiness Scale), lung function, and vitamin D status (serum 25-hydrpoxyvitamin D (25(OH)D) across OSAS severity categories and non-OSAS subjects. Next, using a case-control design, we compared measures of serum 25(OH)D from OSAS cases to non-OSAS controls who were matched for age, gender, skin pigmentation, sleepiness, season, and BMI. 106 adults (77 male; median age = 54.5; median BMI = 34.3 kg/m(2)) resident in Dublin, Ireland (latitude 53°N) were recruited and categorized as non-OSAS or mild/moderate/severe OSAS. 98% of OSAS cases had insufficient 25(OH)D (< 75 nmol/L), including 72% with VDD (< 50 nmol/L). 25(OH)D levels decreased with OSAS severity (P = 0.003). 25(OH)D was inversely correlated with BMI, percent body fat, AHI, and nocturnal HR. Subsequent multivariate regression analysis revealed that 25(OH)D was independently associated with both AHI (P = 0.016) and nocturnal HR (P = 0.0419). Our separate case-control study revealed that 25(OH)D was significantly lower in OSAS cases than matched, non-OSAS subjects (P = 0.001). We observed widespread vitamin D deficiency and insufficiency in a Caucasian, OSAS population. There were significant, independent, inverse relationships between 25(OH)D and AHI as well as nocturnal HR, a known cardiovascular risk factor. Further, 25(OH)D was significantly lower in OSAS cases compared to matched, non-OSAS subjects. We provide evidence that 25(OH)D and OSAS are related, but the role, if any, of replenishment has not been investigated. © 2016 Associated Professional Sleep Societies, LLC.

Estimating the Counterfactual Impact of Conservation Programs on Land Cover Outcomes: The Role of Matching and Panel Regression Techniques

PubMed Central

Jones, Kelly W.; Lewis, David J.

2015-01-01

Deforestation and conversion of native habitats continues to be the leading driver of biodiversity and ecosystem service loss. A number of conservation policies and programs are implemented—from protected areas to payments for ecosystem services (PES)—to deter these losses. Currently, empirical evidence on whether these approaches stop or slow land cover change is lacking, but there is increasing interest in conducting rigorous, counterfactual impact evaluations, especially for many new conservation approaches, such as PES and REDD, which emphasize additionality. In addition, several new, globally available and free high-resolution remote sensing datasets have increased the ease of carrying out an impact evaluation on land cover change outcomes. While the number of conservation evaluations utilizing ‘matching’ to construct a valid control group is increasing, the majority of these studies use simple differences in means or linear cross-sectional regression to estimate the impact of the conservation program using this matched sample, with relatively few utilizing fixed effects panel methods—an alternative estimation method that relies on temporal variation in the data. In this paper we compare the advantages and limitations of (1) matching to construct the control group combined with differences in means and cross-sectional regression, which control for observable forms of bias in program evaluation, to (2) fixed effects panel methods, which control for observable and time-invariant unobservable forms of bias, with and without matching to create the control group. We then use these four approaches to estimate forest cover outcomes for two conservation programs: a PES program in Northeastern Ecuador and strict protected areas in European Russia. In the Russia case we find statistically significant differences across estimators—due to the presence of unobservable bias—that lead to differences in conclusions about effectiveness. The Ecuador case illustrates that if time-invariant unobservables are not present, matching combined with differences in means or cross-sectional regression leads to similar estimates of program effectiveness as matching combined with fixed effects panel regression. These results highlight the importance of considering observable and unobservable forms of bias and the methodological assumptions across estimators when designing an impact evaluation of conservation programs. PMID:26501964

Determinants of first trimester attendance at antenatal care clinics in the Amazon region of Peru: A case-control study

PubMed Central

Moore, Nora; Blouin, Brittany; Razuri, Hugo; Casapia, Martin; Gyorkos, Theresa W.

2017-01-01

Objective To identify determinants which influence the timing of the first antenatal care (ANC) visit in pregnant women. Design Retrospective matched nested case-control study. Setting Two health centres, Belén and 6 de Octubre, in the Peruvian Amazon. Population All pregnant women who had attended ANC during the years 2010, 2011, and 2012. Methods All cases (819 women initiating ANC in their first trimester) were selected from ANC registries from 2010 to 2012. A random sample of controls (819 women initiating ANC in their second or third trimester) was matched 1:1 to cases on health centre and date of first ANC visit. Data were obtained from ANC registries. Conditional logistic regression analyses were performed. Main outcome measure Case-control status of each woman determined by the gestational age at first ANC visit. Results Cases had higher odds of: 1) being married or cohabiting (aOR = 1.69; 95% CI: 1.19, 2.41); 2) completing secondary school or attending post-secondary school (aOR = 1.45; 95% CI: 1.02, 2.06); 3) living in an urban environment (aOR = 1.79; 95% CI: 1.04, 3.10) and 4) having had a previous miscarriage (aOR = 1.56; 95% CI: 1.13, 2.15), compared to controls. No statistically significant difference in odds was found for parity (aOR = 1.08; 95% CI: 0.85, 1.36). Conclusions This study provides empirical evidence of determinants of first ANC attendance. These findings are crucial to the planning and timing of local interventions, like deworming, aimed at pregnant women so that they can access and benefit fully from all government-provided ANC services. PMID:28207749

A dynamic system matching technique for improving the accuracy of MEMS gyroscopes

NASA Astrophysics Data System (ADS)

Stubberud, Peter A.; Stubberud, Stephen C.; Stubberud, Allen R.

2014-12-01

A classical MEMS gyro transforms angular rates into electrical values through Euler's equations of angular rotation. Production models of a MEMS gyroscope will have manufacturing errors in the coefficients of the differential equations. The output signal of a production gyroscope will be corrupted by noise, with a major component of the noise due to the manufacturing errors. As is the case of the components in an analog electronic circuit, one way of controlling the variability of a subsystem is to impose extremely tight control on the manufacturing process so that the coefficient values are within some specified bounds. This can be expensive and may even be impossible as is the case in certain applications of micro-electromechanical (MEMS) sensors. In a recent paper [2], the authors introduced a method for combining the measurements from several nominally equal MEMS gyroscopes using a technique based on a concept from electronic circuit design called dynamic element matching [1]. Because the method in this paper deals with systems rather than elements, it is called a dynamic system matching technique (DSMT). The DSMT generates a single output by randomly switching the outputs of several, nominally identical, MEMS gyros in and out of the switch output. This has the effect of 'spreading the spectrum' of the noise caused by the coefficient errors generated in the manufacture of the individual gyros. A filter can then be used to eliminate that part of the spread spectrum that is outside the pass band of the gyro. A heuristic analysis in that paper argues that the DSMT can be used to control the effects of the random coefficient variations. In a follow-on paper [4], a simulation of a DSMT indicated that the heuristics were consistent. In this paper, analytic expressions of the DSMT noise are developed which confirm that the earlier conclusions are valid. These expressions include the various DSMT design parameters and, therefore, can be used as design tools for DSMT systems.

A dynamic system matching technique for improving the accuracy of MEMS gyroscopes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stubberud, Peter A., E-mail: stubber@ee.unlv.edu; Stubberud, Stephen C., E-mail: scstubberud@ieee.org; Stubberud, Allen R., E-mail: stubberud@att.net

A classical MEMS gyro transforms angular rates into electrical values through Euler's equations of angular rotation. Production models of a MEMS gyroscope will have manufacturing errors in the coefficients of the differential equations. The output signal of a production gyroscope will be corrupted by noise, with a major component of the noise due to the manufacturing errors. As is the case of the components in an analog electronic circuit, one way of controlling the variability of a subsystem is to impose extremely tight control on the manufacturing process so that the coefficient values are within some specified bounds. This canmore » be expensive and may even be impossible as is the case in certain applications of micro-electromechanical (MEMS) sensors. In a recent paper [2], the authors introduced a method for combining the measurements from several nominally equal MEMS gyroscopes using a technique based on a concept from electronic circuit design called dynamic element matching [1]. Because the method in this paper deals with systems rather than elements, it is called a dynamic system matching technique (DSMT). The DSMT generates a single output by randomly switching the outputs of several, nominally identical, MEMS gyros in and out of the switch output. This has the effect of 'spreading the spectrum' of the noise caused by the coefficient errors generated in the manufacture of the individual gyros. A filter can then be used to eliminate that part of the spread spectrum that is outside the pass band of the gyro. A heuristic analysis in that paper argues that the DSMT can be used to control the effects of the random coefficient variations. In a follow-on paper [4], a simulation of a DSMT indicated that the heuristics were consistent. In this paper, analytic expressions of the DSMT noise are developed which confirm that the earlier conclusions are valid. These expressions include the various DSMT design parameters and, therefore, can be used as design tools for DSMT systems.« less

Psychosocial correlates of nutritional status among people living with HIV on antiretroviral therapy: A matched case-control study in Central zone of Tigray, Northern Ethiopia.

PubMed

Weldehaweria, Negassie Berhe; Abreha, Elsa Hagos; Weldu, Meresa Gebremedhin; Misgina, Kebede Haile

2017-01-01

Malnutrition hastens progression to Acquired Human Immunodeficiency Syndromes (AIDS) related illnesses; undermines adherence and response to antiretroviral therapy (ART) in resource-poor settings. However, nutritional status of people living with HIV (PLHIV) can be affected by various psychosocial factors which have not been well explored in Ethiopia. Therefore, the objective of this study was to determine psychosocial correlates of nutritional status among people living with HIV (PLHIV) on ART in Central zone of Tigray, Northern Ethiopia. A matched case-control study design was conducted to assess psychosocial correlates of nutritional status among PLHIV on ART. Data were collected by an interviewer-administered technique using structured pre-tested questionnaire, record review using a checklist and anthropometric measurements. Cases were selected by simple random sampling and controls purposively to match the selected cases. Conditional logistic regression was used to compute relevant associations by STATA version 12. The psychosocial factors independently associated with malnutrition were ever consuming alcohol after starting ART [AOR = 4.7, 95% CI: 1.8-12.3], ever smoking cigarette after starting ART [AOR = 7.6, 95% CI: 2.3-25.5], depression [AOR = 2.8, 95% CI: 1.3, 6.1], not adhering to ART [AOR = 6.8,95% CI: 2.0-23.0] and being in the second lowest wealth quintile [AOR = 4.3,95% CI: 1.1-17.7]. Ever consuming alcohol and ever smoking cigarette after starting ART, depression, not adhering to ART and being in the second lowest wealth quintile were significantly associated with malnutrition. Therefore; policies, strategies, and programs targeting people living with HIV should consider psychosocial factors that can impact nutritional status of people living with HIV enrolled on ART.

Bus Stops and Pedestrian-Motor Vehicle Collisions in Lima, Peru: A Matched Case-Control Study

PubMed Central

Quistberg, D. Alex; Koepsell, Thomas D.; Johnston, Brian D.; Boyle, Linda Ng; Miranda, J. Jaime; Ebel, Beth E.

2015-01-01

Objective To evaluate the relationship between bus stop characteristics and pedestrian-motor vehicle collisions. Design Matched case-control study where the units of study were pedestrian crossing. Setting Random sample of 11 police commissaries in Lima, Peru. Data collection occurred from February, 2011 to September, 2011. Participants 97 intersection cases representing 1,134 collisions and 40 mid-block cases representing 469 collisions that occurred between October, 2010 and January, 2011 and their matched controls. Main Exposures Presence of a bus stop and specific bus stop characteristics. Main Outcome Occurrence of a pedestrian-motor vehicle collision. Results Intersections with bus stops were three times more likely to have a pedestrian-vehicle collision (OR 3.28, 95% CI 1.53-7.03), relative to intersections without bus stops. Both formal and informal bus stops were associated with a higher odds of a collision at intersections (OR 6.23, 95% CI 1.76-22.0 and OR 2.98, 1.37-6.49). At mid-block sites, bus stops on a bus-dedicated transit lane were also associated with collision risk (OR 2.36, 95% CI 1.02-5.42). All bus stops were located prior to the intersection, contrary to practices in most high income countries. Conclusions In urban Lima, the presence of a bus stop was associated with a three-fold increase in risk of a pedestrian collision. The highly competitive environment among bus companies may provide an economic incentive for risky practices such as dropping off passengers in the middle of traffic and jockeying for position with other buses. Bus stop placement should be considered to improve pedestrian safety. PMID:24357516

Case-control Studies on the Effectiveness of Breast Cancer Screening: Insights from the UK Age Trial.

PubMed

van der Waal, Daniëlle; Broeders, Mireille J M; Verbeek, André L M; Duffy, Stephen W; Moss, Sue M

2015-07-01

Ongoing breast cancer screening programs can only be evaluated using observational study designs. Most studies have observed a reduction in breast cancer mortality, but design differences appear to have resulted in different estimates. Direct comparison of case-control and trial analyses gives more insight into this variation. Here, we performed case-control analyses within the randomized UK Age Trial. The Age Trial assessed the effect of screening on breast cancer mortality in women ages 40-49 years. In our approach, case subjects were defined as breast cancer deaths between trial entry (1991-1997) and 2004. Women were ages 39-41 years at entry. For every case subject, five control subjects were selected. All case subjects were included in analyses of screening invitation (356 case subjects, 1,780 controls), whereas analyses of attendance were restricted to women invited to screening (105 case subjects, 525 age-matched controls). Odds ratios (OR) were estimated with conditional logistic regression. We used and compared two methods to correct for self-selection bias. Screening invitation resulted in a breast cancer mortality reduction of 17% (95% confidence interval [CI]: -36%, +6%), similar to trial results. Different exposure definitions and self-selection adjustments influenced the observed breast cancer mortality reduction. Depending on the method, "ever screened" appeared to be associated with a small reduction (OR: 0.86, 95% CI: 0.40, 1.89) or no reduction (OR: 1.02, 95% CI: 0.48, 2.14) using the two methods of correction. Recent attendance resulted in an adjusted mortality reduction of 36% (95% CI: -69%, +31%) or 45% (95% CI: -71%, +5%). Observational studies, and particularly case-control studies, are an important monitoring tool for breast cancer screening programs. The focus should be on diminishing bias in observational studies and gaining a better understanding of the influence of study design on estimates of mortality reduction.

A case-control study of self-reported health, quality-of-life and general functioning among recent immigrants and age- and sex-matched Swedish-born controls.

PubMed

Löfvander, Monica; Rosenblad, Andreas; Wiklund, Tony; Bennström, Halina; Leppert, Jerzy

2014-12-01

To examine whether new immigrants had inferior quality-of-life, well-being and general functioning compared with Swedish age- and sex-matched controls. A prospective case-control study was designed including immigrants from non-European countries, 18-65 years of age, with recent Permanent Permits to Stay (PPS) in Sweden, and age- and sex-matched Swedish-born (SB) persons from the general population in Västmanland County, Sweden. The General Health Questionnaire (GHQ-12), the brief version of the World Health Organization Quality-of-Life (WHOQOL-BREF) Scale and the General Activity Functioning Assessment Scale (GAF) from DSM-IV were posted (SB), or applied in personal interviews (PPS) with interpreters. Differences between the PPS and SB groups were measured using McNemar's test and Wilcoxon signed-rank test conducted separately for observations at baseline, 6- and 12-month follow-up. There were 93 pairs (mean age 36 years). Persons from Somalia (67%) and Iraq (27%) dominated the PPS group. The differences between the groups were statistically significant for all time points for the Psychological health and Social relationship domains of WHOQOL-BREF, and for the baseline and 6-month follow-up time points of GHQ-12 where the PPS-group had a higher degree of well-being, health and quality-of-life than the SB. This tendency applied for both sexes in the immigrant group. These new immigrants did not have inferior physical or psychological health, quality-of-life, well-being or social functioning compared with their age- and sex-matched Swedish born pairs during a 1-year follow-up. Thus, there is reason to advocate immigrants' fast integration into society. © 2014 the Nordic Societies of Public Health.

Association between dietary patterns and metabolic syndrome in Chinese adults: a propensity score-matched case-control study.

PubMed

Xia, Yang; Gu, Yeqing; Yu, Fei; Zhang, Qing; Liu, Li; Meng, Ge; Wu, Hongmei; Du, Huanmin; Shi, Hongbin; Guo, Xiaoyan; Liu, Xing; Li, Chunlei; Han, Peipei; Dong, Renwei; Wang, Xiuyang; Bao, Xue; Su, Qian; Fang, Liyun; Liu, Fangfang; Yang, Huijun; Kang, Li; Ma, Yixuan; Yu, Bin; Sun, Shaomei; Wang, Xing; Zhou, Ming; Jia, Qiyu; Guo, Qi; Wu, Yuntang; Song, Kun; Huang, Guowei; Wang, Guolin; Niu, Kaijun

2016-10-06

Previous studies indicated that dietary patterns were associated with metabolic syndrome (MS), but little is known in Chinese. We design this case-control study to evaluate the associations between dietary patterns and MS in Chinese adults. In this study, 1492 participants with MS were matched with 1492 controls using the 1:1 ratio propensity score matching methods. Dietary intake was assessed using a valid self-administered food frequency questionnaire, and MS was defined in accordance with the criteria of the American Heart Association scientific statement of 2009. Higher scores for the high-protein/cholesterol pattern were associated with higher prevalence of MS. Compared with the participants in the lowest quartile, the odds ratio (OR) for the extreme quartile was 1.36 (95% confidence interval (CI), 1.10-1.68) and the P for trend <0.01 after adjusted for the other two dietary pattern scores. We also found a moderate consumption of the balanced pattern was associated with the lowest prevalence of MS. The ORs across quartiles of the balanced pattern were 1 (reference), 0.83 (95% CI, 0.68-1.02), 0.69 (95% CI, 0.56-0.85), and 0.84 (95% CI, 0.68-1.04) after adjustment. Our study demonstrates that there is a strong association between a diet rich in animal offal, animal blood, meat, and sausage and a higher prevalence of MS.

Argyrophilic grain disease as a neurodegenerative substrate in late-onset schizophrenia and delusional disorders.

PubMed

Nagao, Shigeto; Yokota, Osamu; Ikeda, Chikako; Takeda, Naoya; Ishizu, Hideki; Kuroda, Shigetoshi; Sudo, Koichiro; Terada, Seishi; Murayama, Shigeo; Uchitomi, Yosuke

2014-06-01

To study the relationship between neurodegenerative diseases including argyrophilic grain disease (AGD) and late-onset schizophrenia and delusional disorders (LOSD; onset ≥40 years of age), we pathologically examined 23 patients with LOSD, 71 age-matched normal controls, and 22 psychiatric disease controls (11 depression, six personality disorder, two bipolar disorders, and three neurotic disorders cases). In all LOSD cases (compared to age-matched normal controls), the frequencies of Lewy body disease (LBD), AGD, and corticobasal degeneration (CBD) were 26.1 % (11.3 %), 21.7 % (8.5 %), and 4.3 % (0.0 %), respectively. There was no case of pure Alzheimer's disease (AD). The total frequency of LBD, AGD, and CBD was significantly higher in LOSD cases than in normal controls. Argyrophilic grains were significantly more severe in LOSD than in controls, but were almost completely restricted to the limbic system and adjacent temporal cortex. In LOSD patients whose onset occurred at ≥65 years of age (versus age-matched normal controls), the frequencies of LBD and AGD were 36.4 % (19.4 %) and 36.4 % (8.3 %), respectively, and AGD was significantly more frequent in LOSD patients than in normal controls. In LOSD patients whose onset occurred at <65 years of age, the frequencies of LBD, AGD, and CBD were 16.7, 8.3, and 8.3 %, comparable to those of age-matched normal controls (10.2, 5.1, and 0.0 %). In all psychiatric cases, delusion was significantly more frequent in AGD cases than in cases bearing minimal AD pathology alone. Given these findings, LOSD patients may have heterogeneous pathological backgrounds, and AGD may be associated with the occurrence of LOSD especially after 65 years of age.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Shan; Cui, Lishan; Hao, Shijie

This study investigated the elastic deformation behaviour of Nb nanowires embedded in a NiTi matrix. The Nb nanowires exhibited an ultra-large elastic deformation, which is found to be dictated by the martensitic transformation of the NiTi matrix, thus exhibiting unique characteristics of locality and rapidity. These are in clear contrast to our conventional observation of elastic deformations of crystalline solids, which is a homogeneous lattice distortion with a strain rate controlled by the applied strain. The Nb nanowires are also found to exhibit elastic-plastic deformation accompanying the martensitic transformation of the NiTi matrix in the case when the transformation strainmore » of the matrix over-matches the elastic strain limit of the nanowires, or exhibit only elastic deformation in the case of under-matching. Such insight provides an important opportunity for elastic strain engineering and composite design.« less

Pedestrian signalization and the risk of pedestrian-motor vehicle collisions in Lima, Peru

PubMed Central

Quistberg, D. Alex; Koepsell, Thomas D.; Boyle, Linda Ng; Miranda, J. Jaime; Johnston, Brian D.; Ebel, Beth E.

2014-01-01

Safe walking environments are essential for protecting pedestrians and promoting physical activity. In Peru, pedestrians comprise of over three-quarters of road fatality victims. Pedestrian signalization plays an important role managing pedestrian and vehicle traffic and may help improve pedestrian safety. We examined the relationship between pedestrian-motor vehicle collisions and the presence of visible traffic signals, pedestrian signals, and signal timing to determine whether these countermeasures improved pedestrian safety. A matched case-control design was used where the units of study were crossing locations. We randomly sampled 97 control-matched collisions (weighted N=1134) at intersections occurring from October, 2010 to January, 2011 in Lima. Each case-control pair was matched on proximity, street classification, and number of lanes. Sites were visited between February, 2011 and September, 2011. Each analysis accounted for sampling weight and matching and was adjusted for vehicle and pedestrian traffic flow, crossing width, and mean vehicle speed. Collisions were more common where a phased pedestrian signal (green or red-lit signal) was present compared to no signalization (odds ratio [OR] 8.88, 95% Confidence Interval [CI] 1.32–59.6). A longer pedestrian-specific signal duration was associated with collision risk (OR 5.31, 95% CI 1.02–9.60 per 15-second interval). Collisions occurred more commonly in the presence of any signalization visible to pedestrians or pedestrian-specific signalization, though these associations were not statistically significant. Signalization efforts were not associated with lower risk for pedestrians; rather, they were associated with an increased risk of pedestrian-vehicle collisions. PMID:24821630

Pedestrian signalization and the risk of pedestrian-motor vehicle collisions in Lima, Peru.

PubMed

Quistberg, D Alex; Koepsell, Thomas D; Boyle, Linda Ng; Miranda, J Jaime; Johnston, Brian D; Ebel, Beth E

2014-09-01

Safe walking environments are essential for protecting pedestrians and promoting physical activity. In Peru, pedestrians comprise over three-quarters of road fatality victims. Pedestrian signalization plays an important role managing pedestrian and vehicle traffic and may help improve pedestrian safety. We examined the relationship between pedestrian-motor vehicle collisions and the presence of visible traffic signals, pedestrian signals, and signal timing to determine whether these countermeasures improved pedestrian safety. A matched case-control design was used where the units of study were crossing locations. We randomly sampled 97 control-matched collisions (weighted N=1134) at intersections occurring from October, 2010 to January, 2011 in Lima. Each case-control pair was matched on proximity, street classification, and number of lanes. Sites were visited between February, 2011 and September, 2011. Each analysis accounted for sampling weight and matching and was adjusted for vehicle and pedestrian traffic flow, crossing width, and mean vehicle speed. Collisions were more common where a phased pedestrian signal (green or red-light signal) was present compared to no signalization (odds ratio [OR] 8.88, 95% Confidence Interval [CI] 1.32-59.6). A longer pedestrian-specific signal duration was associated with collision risk (OR 5.31, 95% CI 1.02-9.60 per 15-s interval). Collisions occurred more commonly in the presence of any signalization visible to pedestrians or pedestrian-specific signalization, though these associations were not statistically significant. Signalization efforts were not associated with lower risk for pedestrians; rather, they were associated with an increased risk of pedestrian-vehicle collisions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fatal injuries in the slums of Nairobi and their risk factors: results from a matched case-control study.

PubMed

Ziraba, Abdhalah Kasiira; Kyobutungi, Catherine; Zulu, Eliya Msiyaphazi

2011-06-01

Injuries contribute significantly to the rising morbidity and mortality attributable to non-communicable diseases in the developing world. Unfortunately, active injury surveillance is lacking in many developing countries, including Kenya. This study aims to describe and identify causes of and risk factors for fatal injuries in two slums in Nairobi city using a demographic surveillance system framework. The causes of death are determined using verbal autopsies. We used a nested case-control study design with all deaths from injuries between 2003 and 2005 as cases. Two controls were randomly selected from the non-injury deaths over the same period and individually matched to each case on age and sex. We used conditional logistic regression modeling to identity individual- and community-level factors associated with fatal injuries. Intentional injuries accounted for about 51% and unintentional injuries accounted for 49% of all injuries. Homicides accounted for 91% of intentional injuries and 47% of all injury-related deaths. Firearms (23%) and road traffic crashes (22%) were the leading single causes of deaths due to injuries. About 15% of injuries were due to substance intoxication, particularly alcohol, which in this community comes from illicit brews and is at times contaminated with methanol. Results suggest that in the pervasively unsafe and insecure environment that characterizes the urban slums, ethnicity, residence, and area level factors contribute significantly to the risk of injury-related mortality.

A case-control study of the effectiveness of tissue plasminogen activator on 6 month patients--reported outcomes and health care utilization.

PubMed

Lang, Catherine E; Bland, Marghuretta D; Cheng, Nuo; Corbetta, Maurizio; Lee, Jin-Moo

2014-01-01

We examined the benefit of tissue plasminogen activator (tPA), delivered as part of usual stroke management, on patient-reported outcomes and health care utilization. Using a case control design, patients who received tPA as part of usual stroke management were compared with patients who would have received tPA had they arrived to the hospital within the therapeutic time window. Data were collected from surveys 6 months after stroke using standardized patient-reported outcome measures and questions about health care utilization. Demographic and medical data were acquired from hospital records. Patients were matched on stroke severity, age, race, and gender. Matching was done with 1:2 ratio of tPA to controls. Results were compared between groups with 1-tailed tests because of a directionally specific hypothesis in favor of the tPA group. The tPA (n = 78) and control (n = 156) groups were matched across variables, except for stroke severity, which was better in the control group; subsequent analyses controlled for this mismatch. The tPA group reported better physical function, communication, cognitive ability, depressive symptomatology, and quality of life/participation compared with the control group. Fewer people in the tPA group reported skilled nursing facility stays, emergency department visits, and rehospitalizations after their stroke compared with controls. Reports of other postacute services were not different between groups. Although it is known that tPA reduces disability, this is the first study to demonstrate the effectiveness of tPA in improving meaningful, patient-reported outcomes. Thus, use of tPA provides a large benefit to the daily lives of people with ischemic stroke. Copyright © 2014 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Robotic Single-Site and Conventional Laparoscopic Surgery in Gynecology: Clinical Outcomes and Cost Analysis of a Matched Case-Control Study.

PubMed

El Hachem, Lena; Andikyan, Vaagn; Mathews, Shyama; Friedman, Kathryn; Poeran, Jashvant; Shieh, Kenneth; Geoghegan, Michael; Gretz, Herbert F

2016-01-01

To assess the clinical outcomes and costs associated with robotic single-site (RSS) surgery compared with those of conventional laparoscopy (CL) in gynecology. Retrospective case-control study (Canadian Task Force classification II-2). University-affiliated community hospital. Female patients undergoing RSS or CL gynecologic procedures. Comparison of consecutive RSS gynecologic procedures (cases) undertaken between October 2013 and March 2014 with matched CL procedures (controls) completed during the same time period by the same surgeon. Patient demographic data, operative data, and hospital financial data were abstracted from the electronic charts and financial systems. An incremental cost analysis based on the use of disposable equipment was performed. Total hospital charges were determined for matched RSS cases vs CL cases. RSS surgery was completed in 25 out of 33 attempts; 3 cases were aborted before docking, and 5 were converted to a multisite surgery. There were no intraoperative complications or conversions to laparotomy. The completed cases included 11 adnexal cases and 14 hysterectomies, 3 of which included pelvic lymph node dissection. Compared with the CL group, total operative times were higher in the RSS group; however, there were no significant between-group differences in estimated blood loss, length of hospital stay, or complication rates. Disposable equipment cost per case, direct costs, and total hospital charges were evaluated. RSS was associated with an increased disposable cost per case of $248 to $378, depending on the method used for vaginal cuff closure. The average total hospital charges for matched outpatient adnexal surgery were $15,450 for the CL controls and $18,585 for the RSS cases (p < .001), and the average total hospital charges for matched outpatient benign hysterectomy were $14,623 for the CL controls and $21,412 for the RSS cases (p < .001). Although RSS surgery and CL have comparable clinical outcomes in selected patients, RSS surgery remains associated with increased incremental disposable cost per case and total hospital charges. Careful case selection and judicious use of equipment are necessary to maximize cost-effectiveness in RSS gynecologic surgery. Copyright © 2016 AAGL. Published by Elsevier Inc. All rights reserved.

Laryngospasm during emergency department ketamine sedation: a case-control study.

PubMed

Green, Steven M; Roback, Mark G; Krauss, Baruch

2010-11-01

The objective of this study was to assess predictors of emergency department (ED) ketamine-associated laryngospasm using case-control techniques. We performed a matched case-control analysis of a sample of 8282 ED ketamine sedations (including 22 occurrences of laryngospasm) assembled from 32 prior published series. We sequentially studied the association of each of 7 clinical variables with laryngospasm by assigning 4 controls to each case while matching for the remaining 6 variables. We then used univariate statistics and conditional logistic regression to analyze the matched sets. We found no statistical association of age, dose, oropharyngeal procedure, underlying physical illness, route, or coadministered anticholinergics with laryngospasm. Coadministered benzodiazepines showed a borderline association in the multivariate but not univariate analysis that was considered anomalous. This case-control analysis of the largest available sample of ED ketamine-associated laryngospasm did not demonstrate evidence of association with age, dose, or other clinical factors. Such laryngospasm seems to be idiosyncratic, and accordingly, clinicians administering ketamine must be prepared for its rapid identification and management. Given no evidence that they decrease the risk of laryngospasm, coadministered anticholinergics seem unnecessary.

Changes to Hospital Inpatient Volume After Newspaper Reporting of Medical Errors.

PubMed

Fukuda, Haruhisa

2017-06-30

The aim of this study was to investigate the influence of medical error case reporting by national newspapers on inpatient volume at acute care hospitals. A case-control study was conducted using the article databases of 3 major Japanese newspapers with nationwide circulation between fiscal years 2012 and 2013. Data on inpatient volume at acute care hospitals were obtained from a Japanese government survey between fiscal years 2011 and 2014. Panel data were constructed and analyzed using a difference-in-differences design. Acute care hospitals in Japan. Hospitals named in articles that included the terms "medical error" and "hospital" were designated case hospitals, which were matched with control hospitals using corresponding locations, nurse-to-patient ratios, and bed numbers. Medical error case reporting in newspapers. Changes to hospital inpatient volume after error reports. The sample comprised 40 case hospitals and 40 control hospitals. Difference-in-differences analyses indicated that newspaper reporting of medical errors was not significantly associated (P = 0.122) with overall inpatient volume. Medical error case reporting by newspapers showed no influence on inpatient volume. Hospitals therefore have little incentive to respond adequately and proactively to medical errors. There may be a need for government intervention to improve the posterror response and encourage better health care safety.

A case-control study of Parkinson's disease and tobacco use: gene-tobacco interactions.

PubMed

De Palma, Giuseppe; Dick, Finlay D; Calzetti, Stefano; Scott, Neil W; Prescott, Gordon J; Osborne, Aileen; Haites, Neva; Mozzoni, Paola; Negrotti, Anna; Scaglioni, Augusto; Mutti, Antonio

2010-05-15

A case-control study of genetic, environmental, and occupational risk factors for Parkinson's disease (PD) was carried out in five European countries (Italy, Malta, Romania, Scotland, and Sweden) to explore the possible contribution of interactions among host and environmental factors in sporadic PD. Whereas smoking habits confirmed its negative association with PD, a possible modulatory role of genetic polymorphisms was investigated to obtain further mechanistic insights. We recruited 767 cases of PD and 1989 age-matched and gender-matched controls. Participants completed an interviewer-administered questionnaire including the history of smoking habits. The polymorphisms of genes involved either in metabolism of compounds contained in tobacco smoke (CYP2D6, CYP1B1, GSTM1, GSTT1, GSTM3, GSTP1, NQO1, SOD2, EPHX and NAT2) or in dopaminergic neurotransmission (MAOA, MAOB, DAT1 and DRD2) were characterized by PCR based methods on genomic DNA. We found evidence of statistically significant gene-tobacco interaction for GSTM1, NAT2, and GSTP1, the negative association between tobacco smoking and PD being significantly enhanced in subjects expressing GSTM1-1 activity, in NAT2 fast acetylators, and in those with the GSTP1*B*C haplotype. Owing to the retrospective design of the study, these results require confirmation. (c) 2010 Movement Disorder Society.

Predictors of diarrheal mortality and patterns of caregiver health seeking behavior in in Karachi, Pakistan

PubMed Central

Qamar, Farah Naz; Zaman, Umber; Quadri, Farheen; Khan, Asia; Shaikh, Babar Tasneem; Azam, Iqbal; Nasrin, Dilruba; Kotloff, Karen; Levine, Myron; Brown, Nick; Zaidi, Anita K M

2016-01-01

Background Pakistan is unfortunately among the five countries that contributed to the most deaths due to diarrhea and pneumonia in 2010. To explore factors associated with diarrheal deaths we assessed care–seeking behavior and other predictors of diarrhea–related mortality in children in selected low–income peri–urban communities of Karachi, Pakistan. Methods A mixed methods study (qualitative and quantitative) using matched case–control design and focus group discussions with parents of children with moderate to severe diarrhea (MSD) was undertaken. Cases were children  <5 years of age who died within 60 days of developing an episode of MSD. Controls were age–matched children who survived after 60 days of an episode of MSD. Demographic, clinical, and care–related behavioral predictors of mortality were assessed. Conditional logistic regression was performed, matched adjusted odds ratios (mOR) are reported. Results Parents of 77 cases and 154 controls were interviewed. Cases were less likely to receive appropriate care compared to controls (mOR = 0.2, 95% confidence interval (CI) 0.05–0.91). Refusal for hospital admission (OR = 8.9, 95% CI 2.6–30.8), and delays in reaching the health facility (OR = 3.6, 95% CI 1.0–12.9) were significant independent predictors of mortality. We found strong beliefs in traditional and spiritual healing in the population; use of both modern and traditional/spiritual treatments concurrently was common. Conclusion Appropriate care seeking behavior predicts survival in children with diarrhea in Pakistan. There is a complex belief system relating to traditional and standard therapies. Health education for appropriate health care seeking should be implemented in order to achieve a substantial decline in diarrheal disease mortality in Pakistan. PMID:27606059

Forefoot Adduction Is a Risk Factor for Jones Fracture.

PubMed

Fleischer, Adam E; Stack, Rebecca; Klein, Erin E; Baker, Jeffrey R; Weil, Lowell; Weil, Lowell Scott

Jones fractures are among the most common fractures of the foot; however, much remains unknown about their etiology. The purpose of the present study was to further examine the risk factors of forefoot and hindfoot alignment on Jones fractures using an epidemiologic study design. We used a retrospective, matched, case-control study design. Cases consisted of patients with acute, isolated Jones fractures confirmed on plain film radiographs seen at our institute from January 2009 to December 2013. Patients presenting with pain unrelated to metatarsal fractures served as controls. Controls were matched to cases by age (±2 years), gender, and year of presentation. Weightbearing foot radiographs were assessed for 13 angular relationships by a single rater. Conditional multivariable logistic regression was used to identify important risk factors. Fifty patients with acute Jones fractures and 200 controls were included. The only significant variables in the final multivariable model were the metatarsus adductus angle (odds ratio [OR] 1.16, 95% confidence interval [CI] 1.08 to 1.25) and fourth/fifth intermetatarsal angle (OR 0.69, 95% CI 0.57 to 0.83)-both measures of static forefoot adduction. The presence of metatarsus adductus (defined as >15°) on foot radiographs was associated with a 2.4 times greater risk of a Jones fracture (adjusted OR 2.4, 95% CI 1.2 to 4.8). We have concluded that the risk of Jones fracture increases with an adducted forefoot posture. In our population, which consisted primarily of patients presenting after a fall (10 of 50; 20%) or misstep/inversion injury (19 of 50; 38%), the hindfoot alignment appeared to be a less important factor. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Risk factors associated with asbestos-related diseases: a community-based case-control study.

PubMed

Rosell-Murphy, Magdalena-Isabel; Abós-Herràndiz, Rafael; Olivella, Josep Tarrés; Alberti-Casas, Constança; Allas, Isabel García; Artés, Xavier Martinez; Günther, Ilona Krier; Malet, Isidre Grimau; Martínez, Ramon Orriols; Canela-Soler, Jaume

2013-08-06

Asbestos is a first level carcinogen. However, few epidemiological studies analyse the risk and protective factors associated with asbestos-related diseases and follow up these conditions in the general population. Pleural mesothelioma, caused by inhalation of asbestos fibres at work, at home or in the environment, is the most representative asbestos-related disease.The objectives of this study are to analyse the risk and protective factors associated with asbestos-related diseases and to investigate the incidence of new clinical manifestations in patients already diagnosed with some form of ARD. We have designed a matched case-control study with follow up of both cohorts from a population of a health district of the Barcelona province that has been exposed to asbestos for a period of 90 years. A better understanding of asbestos-related diseases should improve i) the clinical and epidemiological follow up of patients with this condition; ii) the design of new treatment strategies; iii) and the development of preventive activities. At the end of the study, the two cohorts created in this study (affected cases and healthy controls) will constitute the basis for future research.

Matching technique yields optimum LNA performance. [Low Noise Amplifiers

NASA Technical Reports Server (NTRS)

Sifri, J. D.

1986-01-01

The present article is concerned with a case in which an optimum noise figure and unconditional stability have been designed into a 2.385-GHz low-noise preamplifier via an unusual method for matching the input with a suspended line. The results obtained with several conventional line-matching techniques were not satisfactory. Attention is given to the minimization of thermal noise, the design procedure, requirements for a high-impedance line, a sampling of four matching networks, the noise figure of the single-line matching network as a function of frequency, and the approaches used to achieve unconditional stability.

Clinically observed chickenpox and the risk of childhood-onset multiple sclerosis.

PubMed

Mikaeloff, Yann; Caridade, Guillaume; Suissa, Samy; Tardieu, Marc

2009-05-15

The authors conducted a population-based case-control study to investigate whether clinically observed chickenpox, linked with a level of intensity for clinical expression, increases the risk of multiple sclerosis (MS) in childhood. The cases were MS patients whose disease onset occurred between 1994 and 2003, before age 16 years, in France. Each case was matched for age, sex, and geographic origin with as many as 12 controls randomly selected from the general population. Information about clinically observed chickenpox in cases and controls before the index date regarding onset of MS was collected with a standardized questionnaire and was checked against health certificates. Conditional logistic regression was used to estimate the odds ratio for an association between MS and chickenpox. The 137 MS cases were matched with 1,061 controls. Clinically observed chickenpox had occurred in 76.6% of the cases and 84.9% of their matched controls. The adjusted odds ratio of MS onset associated with chickenpox occurrence was 0.58 (95% confidence interval: 0.36, 0.92). The authors concluded that clinically observed chickenpox was associated with a lower risk of childhood-onset MS in a French population.

ADAPTIVE MATCHING IN RANDOMIZED TRIALS AND OBSERVATIONAL STUDIES

PubMed Central

van der Laan, Mark J.; Balzer, Laura B.; Petersen, Maya L.

2014-01-01

SUMMARY In many randomized and observational studies the allocation of treatment among a sample of n independent and identically distributed units is a function of the covariates of all sampled units. As a result, the treatment labels among the units are possibly dependent, complicating estimation and posing challenges for statistical inference. For example, cluster randomized trials frequently sample communities from some target population, construct matched pairs of communities from those included in the sample based on some metric of similarity in baseline community characteristics, and then randomly allocate a treatment and a control intervention within each matched pair. In this case, the observed data can neither be represented as the realization of n independent random variables, nor, contrary to current practice, as the realization of n/2 independent random variables (treating the matched pair as the independent sampling unit). In this paper we study estimation of the average causal effect of a treatment under experimental designs in which treatment allocation potentially depends on the pre-intervention covariates of all units included in the sample. We define efficient targeted minimum loss based estimators for this general design, present a theorem that establishes the desired asymptotic normality of these estimators and allows for asymptotically valid statistical inference, and discuss implementation of these estimators. We further investigate the relative asymptotic efficiency of this design compared with a design in which unit-specific treatment assignment depends only on the units’ covariates. Our findings have practical implications for the optimal design and analysis of pair matched cluster randomized trials, as well as for observational studies in which treatment decisions may depend on characteristics of the entire sample. PMID:25097298

Long term outcome of neonatal meningitis

PubMed Central

Stevens, J; Eames, M; Kent, A; Halket, S; Holt, D; Harvey, D

2003-01-01

Objectives: To quantify long term impairment after neonatal meningitis. Design: Longitudinal case-control study over 9–10 years. Subjects and methods: A total of 111 children who had suffered neonatal meningitis were seen and compared with 113 matched controls from their birth hospital and 49 controls from general practices. Assessments included the WISC IIIUK , movement assessment battery for children (mABC), audiometry, vision testing, and social and medical data. Statistical analysis was by multiple regression, analysis of variance, and χ2 tests. Results: Some 10.8% of cases had a severe and 9% a moderate overall outcome compared with 0% and 1.8% for the hospital controls. The mean intelligence quotient (IQ) of the cases (88.8) was significantly less than that of the hospital controls (99.4) or the GP controls (99.6) . The mABC score was significantly worse for the cases (7.08) than the hospital (5) or GP (4) controls. Some 3.6% of cases had sensorineural hearing loss, 2.7% had persisting hydrocephalus; no controls did. Some 5.4% of cases and 1.7% of hospital controls had treatment for seizures. Conclusions: Severe neurodisability and milder motor and psychometric impairment result from neonatal meningitis. Both clinical follow up and comprehensive developmental assessment are needed after this disease. PMID:12719389

Regression Artifacts in Nonequivalent Control Group Designs: An Empirical Investigation of Bias in ANCOVA and Matching Designs.

ERIC Educational Resources Information Center

Vermillion, James E.

The presence of artifactual bias in analysis of covariance (ANCOVA) and in matching nonequivalent control group (NECG) designs was empirically investigated. The data set was obtained from a study of the effects of a television program on children from three day care centers in Mexico in which the subjects had been randomly selected within centers.…

The relationship between prior antimicrobial prescription and meningitis: a case–control study

PubMed Central

Armstrong, David; Ashworth, Mark; Dregan, Alex; White, Patrick

2016-01-01

Background Recent research into the role of the human microbiome in maintaining health has identified the potentially harmful impact of antimicrobials. Aim The association with bacterial and viral meningitis following antimicrobial prescription during the previous year was investigated to determine whether antimicrobials have a deleterious effect on the nasopharyngeal microbiome. Design and setting A case-control study (1:4 cases to controls) was conducted examining the rate of previous antimicrobial exposure in cases of meningitis and in a matched control group. Data from a UK primary care clinical database were analysed using conditional logistic regression. Results A total of 7346 cases of meningitis were identified, 3307 (45%) viral, 1812 (25%) bacterial, and 2227 (30%) unspecified. The risks of viral (adjusted odds ratio [AOR] 2.45; 95% confidence interval [CI] = 2.24 to 2.68) or bacterial (AOR 1.98; 95% CI = 1.71 to 2.30) meningitis were both increased following antimicrobial prescription in the preceding year. Patients who received ≥4 antimicrobial prescriptions in the preceding year were at significantly increased risk of all types of meningitis (AOR 2.85; 95% CI = 2.44 to 3.34), bacterial meningitis (AOR 3.06; 95% CI = 2.26 to 4.15) and viral meningitis (AOR 3.23; 95% CI = 2.55 to 4.08) compared to their matched controls. Conclusion There was an increased risk of meningitis following antimicrobial prescription in the previous year. It is possible that this increase was due to an effect of antimicrobials on the microbiome or reflected an increased general susceptibility to infections in these patients. PMID:26965030

Modifiable Neighborhood Features Associated With Adolescent Homicide

PubMed Central

Culyba, Alison J.; Jacoby, Sara F.; Richmond, Therese S.; Fein, Joel A.; Hohl, Bernadette C.; Branas, Charles C.

2016-01-01

IMPORTANCE Homicide is a leading cause of adolescent mortality. To our knowledge, relatively little has been studied in terms of the association between environmental neighborhood features, such as streets, buildings, and natural surroundings, and severe violent injury among youth. OBJECTIVE To assess associations between environmental neighborhood features and adolescent homicide in order to identify targets for future place-based interventions. DESIGN, SETTING, AND PARTICIPANTS Population-based case-control study conducted in Philadelphia, Pennsylvania, from April 15, 2008, to March 31, 2014. We identified adolescents who died by homicide at 13 to 20 years of age from 2010 to 2012 while residing in Philadelphia. We used incidence-density sampling and random-digit dialing to recruit control participants ages 13 to 20 years matched on sex and indoor-outdoor location at the time of each index case participant’s homicide. EXPOSURES To obtain environmental data about modifiable features that were present in the immediate surroundings of our case and control participants, blinded field researchers used standardized techniques to photograph case and control participant outdoor locations. Photographic data were stitched together to create 360° panoramic images that were coded for 60 elements of the visible environment. MAIN OUTCOME AND MEASURE Adolescent homicide. RESULTS We enrolled 143 homicide case participants (mean [SD] age, 18.4 [1.5] years) and 155 matched control participants (mean [SD] age, 17.2 [2.1] years) who were both outdoors at the time of the homicide. In adjusted analyses, multiple features of Philadelphia streets, buildings, and natural surroundings were associated with adolescent homicide. The presence of street lighting (odds ratio [OR], 0.24; 95% CI, 0.09-0.70), illuminated walk/don’t walk signs (OR, 0.16; 95% CI, 0.03-0.92), painted marked crosswalks (OR, 0.17; 95% CI, 0.04-0.63), public transportation (OR, 0.13; 95% CI, 0.03-0.49), parks (OR, 0.09; 95% CI, 0.01-0.88), and maintained vacant lots (OR, 0.17; 95% CI, 0.03-0.81) were significantly associated with decreased odds of homicide. The odds of homicide were significantly higher in locations with stop signs (OR, 4.34; 95% CI, 1.40-13.45), security bars/gratings on houses (OR, 9.23; 95% CI, 2.45-34.80), and private bushes/plantings (OR, 3.44; 95% CI, 1.18-10.01). CONCLUSIONS AND RELEVANCE Using a population-based case-control design, we identified multiple modifiable environmental features that might be targeted in future randomized intervention trials designed to reduce youth violence by improving neighborhood context. PMID:26954939

Delivery outcome among women employed in the plastics industry in Sweden and Norway.

PubMed

Ahlborg, G; Bjerkedal, T; Egenaes, J

1987-01-01

In Sweden and Norway separate case-control studies of pregnancy outcome for the period 1973-1981 among female workers in the plastics industry were carried out with similar design. Employment records were obtained from companies producing and/or processing plastics and these were matched with the national medical birth and malformation registers. Within the cohorts of pregnancies during which the mother held employment in a plastics industry (1.397 in the Swedish and 288 in the Norwegian study), cases of stillbirths or infant deaths, selected malformations, or low birthweight (less than 2,000 g) were identified. For each case two controls from the same source were individually matched with regard to date of birth, age of mother, and parity. Exposure data concerning the 44 Swedish and ten Norwegian triplets were obtained from the employers. An increased odds ratio was found for processing of polyvinylchloride (PVC) plastics (95% CI Sweden 1.0-5.1; total material 1.1-4.5). However, processing of cold plastics yielded a higher odds ratio than processing of heated plastics. No increased odds ratio was found for processing of styrene or polyurethane plastics. Since not all of the plastics industries in the two countries participated in the studies and the number of cases was small, the result must be interpreted with caution.

A case-control study of bladder cancer in the United States rubber and tyre industry.

PubMed

Checkoway, H; Smith, A H; McMichael, A J; Jones, F S; Monson, R R; Tyroler, H A

1981-08-01

A case-control study of bladder cancer was conducted in five United States rubber and tyre companies to determine if there were high-risk jobs and work areas within the industry. The study included 220 male cases of bladder cancer, of whom 107 were identified from hospital record reviews and 113 from death certificates. Each case was matched individually with two industry controls by sex, race, year of birth, and company. One control was matched additionally by year of hire and duration of employment. Comparisons of cases and controls not matched by year of hire and age of hire showed no differences for those variables, which suggests that age and calendar period of first exposure to the industry were not risk determinants. When the work histories of both cases and controls were contrasted it was found that cases were more likely than controls to have worked in milling (odds ratio (OR) = 1.91) and calender operation (OR = 2.21) jobs. The relative risk estimates for milling and calender operation both exhibited linear trends of increase with duration of exposure. Milling and calender operation jobs entail potential exposures to volatilised reaction products from heated rubber stock. A better understanding of aetiological associations with job type will require more detailed characterisation of the work environment with regard to the sources and levels of aromatic amines and other suspected bladder carcinogens.

A case-control study of bladder cancer in the United States rubber and tyre industry.

PubMed Central

Checkoway, H; Smith, A H; McMichael, A J; Jones, F S; Monson, R R; Tyroler, H A

1981-01-01

A case-control study of bladder cancer was conducted in five United States rubber and tyre companies to determine if there were high-risk jobs and work areas within the industry. The study included 220 male cases of bladder cancer, of whom 107 were identified from hospital record reviews and 113 from death certificates. Each case was matched individually with two industry controls by sex, race, year of birth, and company. One control was matched additionally by year of hire and duration of employment. Comparisons of cases and controls not matched by year of hire and age of hire showed no differences for those variables, which suggests that age and calendar period of first exposure to the industry were not risk determinants. When the work histories of both cases and controls were contrasted it was found that cases were more likely than controls to have worked in milling (odds ratio (OR) = 1.91) and calender operation (OR = 2.21) jobs. The relative risk estimates for milling and calender operation both exhibited linear trends of increase with duration of exposure. Milling and calender operation jobs entail potential exposures to volatilised reaction products from heated rubber stock. A better understanding of aetiological associations with job type will require more detailed characterisation of the work environment with regard to the sources and levels of aromatic amines and other suspected bladder carcinogens. PMID:7272236

Determinants of unwanted pregnancies in India using matched case-control designs

PubMed Central

2012-01-01

Background In India, while the total fertility rate has been declined from 3.39 in 1992–93 to 2.68 in 2005–06, the prevalence of unintended pregnancy is still stagnant over the same period. A review of existing literature shows that within the country, there are variations in fertility preferences between different regions. Also there is a strong argument that the availability of a health facility at the village level plays an important role in reshaping the fertility behavior of women. Keeping in mind the fact that there is no information at the village level (which is the lowest geographical boundary) in the recent round of National Family Health Survey (NFHS-3), the specific objective of this study is to examine the impact of individual and household level variables on unwanted pregnancies without controlling the village level variation. Further, once the village level variation (i.e. unobserved variation) has been controlled, it is necessary to study whether there has been any alteration in the contribution of factors from earlier results of without adjusting the village level variation. Methods This paper attempts to examine the associated factors of unwanted pregnancies, without matching the village and after matching the village, by using the matched case–control design. Nationwide data from India’s latest NFHS-3 conducted during 2005–06 was used for the present study. Frequency and pair wise matching has been applied in the present paper and conditional logistic regression analysis was used to work out the models and to find out the factors associated with unwanted pregnancies. Results A major finding of this study was that 1:3 case–control study (without matching the village) shows that women belonging to non Hindu/Muslim religion, Scheduled Tribe, women who have experienced child loss and if the previous birth interval is 24 through 36 months were significant predictors of unwanted pregnancy. However, this relationship did not hold significant after village wise matching. Other factors such as Muslim religion, women and their partners with high school education and above, women belonging to the richest wealth index and if the sex of the last child was female, emerge as significant predictors of unwanted pregnancies. Conclusions This study clearly underscores the importance of adjusting the village (PSU) level variation in explaining unwanted pregnancies. PMID:22883933

Validation and comparison of clinical prediction rules for invasive candidiasis in intensive care unit patients: a matched case-control study

PubMed Central

2011-01-01

Introduction Due to the increasing prevalence and severity of invasive candidiasis, investigators have developed clinical prediction rules to identify patients who may benefit from antifungal prophylaxis or early empiric therapy. The aims of this study were to validate and compare the Paphitou and Ostrosky-Zeichner clinical prediction rules in ICU patients in a 689-bed academic medical center. Methods We conducted a retrospective matched case-control study from May 2003 to June 2008 to evaluate the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of each rule. Cases included adults with ICU stays of at least four days and invasive candidiasis matched to three controls by age, gender and ICU admission date. The clinical prediction rules were applied to cases and controls via retrospective chart review to evaluate the success of the rules in predicting invasive candidiasis. Paphitou's rule included diabetes, total parenteral nutrition (TPN) and dialysis with or without antibiotics. Ostrosky-Zeichner's rule included antibiotics or central venous catheter plus at least two of the following: surgery, immunosuppression, TPN, dialysis, corticosteroids and pancreatitis. Conditional logistic regression was performed to evaluate the rules. Discriminative power was evaluated by area under the receiver operating characteristic curve (AUC ROC). Results A total of 352 patients were included (88 cases and 264 controls). The incidence of invasive candidiasis among adults with an ICU stay of at least four days was 2.3%. The prediction rules performed similarly, exhibiting low PPVs (0.041 to 0.054), high NPVs (0.983 to 0.990) and AUC ROCs (0.649 to 0.705). A new prediction rule (Nebraska Medical Center rule) was developed with PPVs, NPVs and AUC ROCs of 0.047, 0.994 and 0.770, respectively. Conclusions Based on low PPVs and high NPVs, the rules are most useful for identifying patients who are not likely to develop invasive candidiasis, potentially preventing unnecessary antifungal use, optimizing patient ICU care and facilitating the design of forthcoming antifungal clinical trials. PMID:21846332

Environmental, maternal, and reproductive risk factors for childhood acute lymphoblastic leukemia in Egypt: a case-control study.

PubMed

Ezzat, Sameera; Rashed, Wafaa M; Salem, Sherin; Dorak, M Tevfik; El-Daly, Mai; Abdel-Hamid, Mohamed; Sidhom, Iman; El-Hadad, Alaa; Loffredo, Christopher

2016-08-20

Acute lymphocytic leukemia (ALL) is the most common pediatric cancer. The exact cause is not known in most cases, but past epidemiological research has suggested a number of potential risk factors. This study evaluated associations between environmental and parental factors and the risk for ALL in Egyptian children to gain insight into risk factors in this developing country. We conducted a case-control design from May 2009 to February 2012. Cases were recruited from Children's Cancer Hospital, Egypt (CCHE). Healthy controls were randomly selected from the general population to frequency-match the cumulative group of cases by sex, age groups (<1; 1 - 5; >5 - 10; >10 years) and region of residence (Cairo metropolitan region, Nile Delta region (North), and Upper Egypt (South)). Mothers provided answers to an administered questionnaire about their environmental exposures and health history including those of the father. Odds ratios (ORs) and 95 % confidence intervals (CI) were calculated using logistic regression with adjustment for covariates. Two hundred ninety nine ALL cases and 351 population-based controls frequency-matched for age group, gender and location were recruited. The risk of ALL was increased with the mother's use of medications for ovulation induction (ORadj = 2.5, 95 % CI =1.2 -5.1) and to a lesser extend with her age (ORadj = 1.8, 95 % CI = 1.1 - 2.8, for mothers ≥ 30 years old). Delivering the child by Cesarean section, was also associated with increased risk (ORadj = 2.01, 95 % CI =1.24-2.81). In Egypt, the risk for childhood ALL appears to be associated with older maternal age, and certain maternal reproductive factors.

Immediate processing of erotic stimuli in paedophilia and controls: a case control study.

PubMed

Habermeyer, Benedikt; Esposito, Fabrizio; Händel, Nadja; Lemoine, Patrick; Klarhöfer, Markus; Mager, Ralph; Dittmann, Volker; Seifritz, Erich; Graf, Marc

2013-03-19

Most neuroimaging studies investigating sexual arousal in paedophilia used erotic pictures together with a blocked fMRI design and long stimulus presentation time. While this approach allows the detection of sexual arousal, it does not enable the assessment of the immediate processing of erotically salient stimuli. Our study aimed to identify neuronal networks related to the immediate processing of erotic stimuli in heterosexual male paedophiles and healthy age-matched controls. We presented erotic pictures of prepubescent children and adults in an event related fMRI-design to eight paedophilic subjects and age-matched controls. Erotic pictures of females elicited more activation in the right temporal lobe, the right parietal lobe and both occipital lobes and erotic pictures of children activated the right dorsomedial prefrontal cortex in both groups. An interaction of sex, age and group was present in the right anteriolateral oribitofrontal cortex. Our event related study design confirmed that erotic pictures activate some of the brain regions already known to be involved in the processing of erotic pictures when these are presented in blocks. In addition, it revealed that erotic pictures of prepubescent children activate brain regions critical for choosing response strategies in both groups, and that erotically salient stimuli selectively activate a brain region in paedophilic subjects that had previously been attributed to reward and punishment, and that had been shown to be implicated in the suppression of erotic response and deception.

Iodine 125 Brachytherapy With Vitrectomy and Silicone Oil in the Treatment of Uveal Melanoma: 1-to-1 Matched Case-Control Series

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCannel, Tara A., E-mail: TMcCannel@jsei.ucla.edu; McCannel, Colin A.

Purpose: We initially reported the radiation-attenuating effect of silicone oil 1000 centistokes for iodine 125. The purpose of this report was to compare the clinical outcomes in case patients who had iodine 125 brachytherapy with vitrectomy and silicone oil 1000 centistokes with the outcomes in matched control patients who underwent brachytherapy alone. Methods and Materials: Consecutive patients with uveal melanoma who were treated with iodine 125 plaque brachytherapy and vitrectomy with silicone oil with minimum 1-year follow-up were included. Control patients who underwent brachytherapy alone were matched for tumor size, location, and sex. Baseline patient and tumor characteristics and tumor response tomore » radiation, final visual acuity, macular status, central macular thickness by ocular coherence tomography (OCT), cataract progression, and metastasis at last follow-up visit were compared. Surgical complications were also determined. Results: Twenty case patients met the inclusion criteria. The average follow-up time was 22.1 months in case patients and 19.4 months in control patients. The final logMAR vision was 0.81 in case patients and 1.1 in control patients (P=.071); 8 case patients and 16 control patients had abnormal macular findings (P=.011); and the average central macular thickness by OCT was 293.2 μm in case patients and 408.5 μm in control patients (P=.016). Eleven case patients (55%) and 1 control patient (5%) had required cataract surgery at last follow-up (P=.002). Four patients in the case group and 1 patient in the control group experienced metastasis (P=.18). Among the cases, intraoperative retinal tear occurred in 3 patients; total serous retinal detachment and macular hole developed in 1 case patient each. There was no case of rhegmatogenous retinal detachment, treatment failure, or local tumor dissemination in case patients or control patients. Conclusions: With up to 3 years of clinical follow-up, silicone oil during brachytherapy for the treatment of uveal melanoma resulted in fewer abnormal maculas, lower central macular thickness on OCT, and a trend toward better final visual acuity in comparison with matched control patients who underwent brachytherapy alone.« less

Tibial lengthening over intramedullary nails

PubMed Central

Burghardt, R. D.; Manzotti, A.; Bhave, A.; Paley, D.

2016-01-01

Objectives The purpose of this study was to compare the results and complications of tibial lengthening over an intramedullary nail with treatment using the traditional Ilizarov method. Methods In this matched case study, 16 adult patients underwent 19 tibial lengthening over nails (LON) procedures. For the matched case group, 17 patients who underwent 19 Ilizarov tibial lengthenings were retrospectively matched to the LON group. Results The mean external fixation time for the LON group was 2.6 months and for the matched case group was 7.6 months. The mean lengthening amounts for the LON and the matched case groups were 5.2 cm and 4.9 cm, respectively. The radiographic consolidation time in the LON group was 6.6 months and in the matched case group 7.6 months. Using a clinical and radiographic outcome score that was designed for this study, the outcome was determined to be excellent in 17 and good in two patients for the LON group. The outcome was excellent in 14 and good in five patients in the matched case group. The LON group had increased blood loss and increased cost. The LON group had four deep infections; the matched case group did not have any deep infections. Conclusions The outcomes in the LON group were comparable with the outcomes in the matched case group. The LON group had a shorter external fixation time but experienced increased blood loss, increased cost, and four cases of deep infection. The advantage of reducing external fixation treatment time may outweigh these disadvantages in patients who have a healthy soft-tissue envelope. Cite this article: J. E. Herzenberg. Tibial lengthening over intramedullary nails: A matched case comparison with Ilizarov tibial lengthening. Bone Joint Res 2016;5:1–10. doi: 10.1302/2046-3758.51.2000577 PMID:26764351

Statin Use and Fatal Prostate Cancer: A Matched Case-Control Study

PubMed Central

Marcella, Stephen W.; David, Alice; Ohman-Strickland, Pamela A.; Carson, Jeffery; Rhoads, George G.

2015-01-01

Background Statins are one of the most commonly prescribed medications in medical practice and prostate cancer is the most common male malignancy. While there has been no consistent evidence that statins affect cancer incidence, including prostate cancer, several reports suggest they may decrease the rate of advanced prostate cancer. However, no study has examined statin use and prostate cancer mortality specifically. We report here a population-based case-control investigation that examines this association. Methods We conducted a matched case-control study. Cases were residents of New Jersey ages 55 – 79 who died from prostate cancer between 1997–2000. We individually matched population-based controls by five-year age-group and race. Medication data were obtained identically for cases and controls from blinded medical chart review. We used conditional logistic regression to adjust for confounders. Results We identified 718 cases and obtained cooperation from 77% of their spouses (N=553). After review of medical records, 387 were eligible and 380 were matched to a control. The unadjusted odds ratio was 0.49 (95% CI, 0.34–0.70) which decreased to 0.37 (p<0.0001) after adjustment for education, waist size, BMI, comorbidities, and anti-hypertensive medication. There was little difference between lipophilic and hydrophilic statins but more risk reduction was noted for hi-potency statins (73%, p<0.0001) as compared to low-potency statins (31%, p=0.32). Conclusion Statin use is associated with substantial protection against prostate cancer death, adding to the epidemiologic evidence for an inhibitory effect on prostate cancer. PMID:22180145

Psychiatric comorbidity may not predict suicide during and after hospitalization. A nested case-control study with blinded raters.

PubMed

Walby, Fredrik A; Odegaard, Erik; Mehlum, Lars

2006-06-01

To investigate the differential impact of DSM-IV axis-I and axis-II disorders on completed suicide and to study if psychiatric comorbidity increases the risk of suicide in currently and previously hospitalized psychiatric patients. A nested case-control design based on case notes from 136 suicides and 166 matched controls. All cases and controls were rediagnosed using the SCID-CV for axis-I and the DSM-IV criteria for axis-II disorders and the inter-rater reliability was satisfactory. Raters were blind to the case and control status and the original hospital diagnoses. Depressive disorders and bipolar disorders were associated with an increased risk of suicide. No such effect was found for comorbidity between axis-I disorders and for comorbidity between axis-I and axis-II disorders. Psychiatric diagnoses, although made using a structured and criteria-based approach, was based on information recorded in case notes. Axis-II comorbidity could only be investigated at an aggregated level. Psychiatric comorbidity did not predict suicide in this sample. Mood disorders did, however, increase the risk significantly independent of history of previous suicide attempts. Both findings can inform identification and treatment of patients at high risk for completed suicide.

Risk of injury after alcohol consumption from case-crossover studies in five countries from the America’s

PubMed Central

Borges, Guilherme; Orozco, Ricardo; Monteiro, Maristela; Cherpitel, Cheryl; Then, Eddy Pérez; López, Víctor A.; Bassier-Paltoo, Marcia; Weil A., Donald; de Bradshaw, Aldacira M

2012-01-01

Aims This study aimed to: 1) provide relative risk (RR) estimates between acute alcohol use and injuries from emergency departments in the Dominican Republic, Guatemala, Guyana, Nicaragua and Panama, and 2) test whether the RR differs if two control periods for the estimates were used. Design Case-crossover methodology was used to obtain estimates of the RR of having an injury within six hours after drinking alcohol, using a pair-matching design with control periods of the same time of day the day prior to injury, and the same time of day and day of week the week prior to injury. Setting Emergency departments(EDs). Participants 2,503 injured patients from EDs were interviewed between 2010–2011, with a response rate of 92.6%. Measurements Number of drinks consumed within six hours prior to the injury and in the two control periods. Findings The RR of injury after drinking alcohol was 4.38 (95% confidence interval CI= 3.29–5.84) using as the control period the prior week, and 5.35 (CI=3.50–8.17) using as a control period the prior day. The RR was 5.08 (CI=4.15–6.23) in multiple matching. Those drinking 1–2 drinks had a RR of 4.85 (CI=3.12–7.54); those drinking 3–5 a RR of 5.00 (CI =3.47–7.18); those drinking 6–15 a RR of 4.54 (CI=3.36–6.14); and those drinking 16 or more a RR of 10.42 (CI=4.38–24.79). Conclusions As in other countries, alcohol drinking is a trigger for an injury in all five countries. The use of more than one control period give further strength to these findings from case-crossover analysis. PMID:22775508

Risk factors for hematemesis in Hoima and Buliisa Districts, Western Uganda, September-October 2015.

PubMed

Kabwama, Steven Ndugwa; Mafigiri, Richardson; Balinandi, Stephen; Kagirita, Atek; Riolexus, Alex Ario; Zhu, Bao-Ping

2017-01-01

On 17 September 2015, Buliisa District Health Office reported multiple deaths due to haemorrhage to the Uganda Ministry of Health. We conducted an investigation to verify the existence of an outbreak and to identify the disease nature, mode of transmission and risk factors. We defined a suspected case as onset of hematemesis between 1 June 2015 and 15 October 2015 in a resident of Hoima, Buliisa or neighbouring districts. We identified cases by reviewing medical records and actively searching in the community. We interviewed case-patients and health-care workers and performed descriptive epidemiology to generate hypotheses on possible exposures. In a case-control study we compared exposures between 21 cases and 81 controls, matched by age (± 10 years), sex and village of residence. We collected 22 biological specimens from 19 case-patients to test for Viral Haemorrhagic Fevers (VHF). We analysed the data using the Mantel-Haenszel method to account for the matched study design. We identified 56 cases with onset from June to October (attack rate 15/100,000 in Buliisa District and 5.2/100,000 in Hoima District). The age-specific attack rate was highest in persons aged 31-60 years (15/100,000 in Hoima and 47/100,000 in Buliisa); no persons below 15 years of age had the illness. In the case-control study, 42% (5/12) of cases vs. 0.0% (0/77) of controls had liver disease (OR M-H = ∞; 95%CI = 3.7-∞); 71% (10/14) of cases vs. 35% (28/81) of controls had ulcer disease (OR M-H = 13; 95% CI = 1.6-98); 27% (3/11) of cases vs. 14% (11/81) of controls used indomethacin prior to disease onset (OR M-H = 6.0; 95% CI = 1.0-36). None of the blood samples were positive for any of the VHFs. This reported cluster of hematemesis illness was due to predisposing conditions and use of Non-Steroidal Anti-inflammatory Drugs (NSAID). Health education should be conducted on the danger of NSAIDs misuse, especially in persons with pre-disposing conditions.

Factors Related to Suicide in LGBT Populations.

PubMed

Skerrett, Delaney Michael; Kõlves, Kairi; De Leo, Diego

2016-09-01

There is evidence of heightened vulnerability to nonfatal suicidal behaviors among LGBT populations yet a paucity of studies into fatal behaviors. The specific aim of this article was to identify factors related to suicide in LGBT individuals in Australia. The psychological autopsy (PA) method with a matched case-control study design was used. PA interviews were conducted with 27 next-of-kin of an LGBT person that had died by suicide. Three living LGBT controls per suicide case, matched by age and gender, were also interviewed. The key factors relating to suicide in LGBT people were a lack of acceptance by family and self (reflected in higher internalized homophobia and shame), negative feelings about own sexuality/gender, and dissatisfaction with appearance. LGBT people who died by suicide also tended to go through coming out milestones 2 years earlier than controls. There was a higher prevalence of aggressive behaviors and a more predominant history of physical and sexual abuse. Additionally, there was greater incidence of depression and anxiety and alcohol and substance use disorders. Specific predictive factors for suicide in LGBT populations in Australia were identified, including significantly poorer mental health outcomes and more violence across an array of measures.

Statin use and fatal prostate cancer: a matched case-control study.

PubMed

Marcella, Stephen W; David, Alice; Ohman-Strickland, Pamela A; Carson, Jeffery; Rhoads, George G

2012-08-15

Statins are some of the most commonly prescribed medications in medical practice, and prostate cancer is the most common malignancy among men. Although there has been no consistent evidence that statins affect cancer incidence, including prostate cancer, several reports suggest they may decrease the rate of advanced prostate cancer. However, no study to date has specifically examined statin use and prostate cancer mortality. The authors conducted this population-based case-control investigation to examine this association. This was a matched case-control study. Cases were residents of New Jersey ages 55 to 79 years who died from prostate cancer between 1997 and 2000. The cases were matched individually to population-based controls by 5-year age group and race. Medication data were obtained identically for cases and controls from blinded medical chart review. Conditional logistic regression was used to adjust for confounders. In total, 718 cases were identified, and cooperation was obtained from 77% of their spouses (N = 553). After a review of medical records, 387 men were eligible, and 380 were matched to a control. The unadjusted odds ratio was 0.49 (95% confidence interval, 0.34-0.70) and decreased to 0.37 (P < .0001) after adjusting for education, waist size, body mass index, comorbidities, and antihypertensive medication. There was little difference between lipophilic and hydrophilic statins, but more risk reduction was noted for high-potency statins (73%; P < .0001) compared with low-potency statins (31%; P = .32). Statin use was associated with substantial protection against prostate cancer death, adding to the epidemiologic evidence for an inhibitory effect on prostate cancer. Copyright © 2011 American Cancer Society.

Patterns of Somatic Diagnoses in Older People with Intellectual Disability: A Swedish Eleven Year Case-Control Study of Inpatient Data

ERIC Educational Resources Information Center

Sandberg, Magnus; Ahlström, Gerd; Kristensson, Jimmie

2017-01-01

Background: Knowledge about diagnoses patterns in older people with intellectual disabilities is limited. Methods: The case group (n = 7936) comprised people with intellectual disabilities aged 55 years and older. The control group (n = 7936) was age matched and sex matched. Somatic inpatient diagnoses (2002-2012) were collected retrospectively.…

Is case-chaos methodology an appropriate alternative to conventional case-control studies for investigating outbreaks?

PubMed

Edelstein, Michael; Wallensten, Anders; Kühlmann-Berenzon, Sharon

2014-08-15

Case-chaos methodology is a proposed alternative to case-control studies that simulates controls by randomly reshuffling the exposures of cases. We evaluated the method using data on outbreaks in Sweden. We identified 5 case-control studies from foodborne illness outbreaks that occurred between 2005 and 2012. Using case-chaos methodology, we calculated odds ratios 1,000 times for each exposure. We used the median as the point estimate and the 2.5th and 97.5th percentiles as the confidence interval. We compared case-chaos matched odds ratios with their respective case-control odds ratios in terms of statistical significance. Using Spearman's correlation, we estimated the correlation between matched odds ratios and the proportion of cases exposed to each exposure and quantified the relationship between the 2 using a normal linear mixed model. Each case-control study identified an outbreak vehicle (odds ratios = 4.9-45). Case-chaos methodology identified the outbreak vehicle 3 out of 5 times. It identified significant associations in 22 of 113 exposures that were not associated with outcome and 5 of 18 exposures that were significantly associated with outcome. Log matched odds ratios correlated with their respective proportion of cases exposed (Spearman ρ = 0.91) and increased significantly with the proportion of cases exposed (b = 0.054). Case-chaos methodology missed the outbreak source 2 of 5 times and identified spurious associations between a number of exposures and outcome. Measures of association correlated with the proportion of cases exposed. We recommended against using case-chaos analysis during outbreak investigations. © The Author 2014. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Locality and rapidity of the ultra-large elastic deformation of Nb nanowires in a NiTi phase-transforming matrix

DOE PAGES

Wang, Shan; Cui, Lishan; Hao, Shijie; ...

2014-10-24

This study investigated the elastic deformation behaviour of Nb nanowires embedded in a NiTi matrix. The Nb nanowires exhibited an ultra-large elastic deformation, which is found to be dictated by the martensitic transformation of the NiTi matrix, thus exhibiting unique characteristics of locality and rapidity. These are in clear contrast to our conventional observation of elastic deformations of crystalline solids, which is a homogeneous lattice distortion with a strain rate controlled by the applied strain. The Nb nanowires are also found to exhibit elastic-plastic deformation accompanying the martensitic transformation of the NiTi matrix in the case when the transformation strainmore » of the matrix over-matches the elastic strain limit of the nanowires, or exhibit only elastic deformation in the case of under-matching. Such insight provides an important opportunity for elastic strain engineering and composite design.« less

Pilot case-control study of paediatric falls from windows.

PubMed

Johnston, Brian D; Quistberg, D Alexander; Shandro, Jamie R; Partridge, Rebecca L; Song, Hyun Rae; Ebel, Beth E

2011-12-01

Unintentional falls from windows are an important cause of paediatric morbidity. There have been no controlled studies to identify modifiable environmental risk factors for window falls in young children. The authors have piloted a case-control study to test procedures for case identification, subject enrolment, and environmental data collection. Case windows were identified when a child 0-9 years old presented for care after a fall from that window. Control windows were identified (1) from the child's home and (2) from the home of an age- and gender-matched child seeking care for an injury diagnosis not related to a window fall. Study staff visited enrolled homes to collect window measurements and conduct window screen performance tests. The authors enrolled and collected data on 18 case windows, 18 in-home controls, and 14 matched community controls. Six potential community controls were contacted for every one enrolled. Families who completed the home visit viewed study procedures positively. Case windows were more likely than community controls to be horizontal sliders (100% vs 50%), to have deeper sills (6.28 vs 4.31 inches), to be higher above the exterior surface (183 vs 82 inches), and to have screens that failed below a threshold derived from the static pressure of a 3-year-old leaning against the mesh (60.0% vs 16.7%). Case windows varied very little from in-home controls. Case-control methodology can be used to study risk factors for paediatric falls from windows. Recruitment of community controls is challenging but essential, because in-home controls tend to be over-matched on important variables. A home visit allows direct measurement of window type, height, sill depth, and screen performance. These variables should all be investigated in subsequent, larger studies covering major housing markets.

Possible association of first and high birth order of pregnant women with the risk of isolated congenital abnormalities in Hungary - a population-based case-matched control study.

PubMed

Csermely, Gyula; Susánszky, Éva; Czeizel, Andrew E; Veszprémi, Béla

2014-08-01

In epidemiological studies at the estimation of risk factors in the origin of specified congenital abnormalities in general birth order (parity) is considered as confounder. The aim of this study was to analyze the possible association of first and high (four or more) birth order with the risk of congenital abnormalities in a population-based case-matched control data set. The large dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities included 21,494 cases with different isolated congenital abnormality and their 34,311 matched controls. First the distribution of birth order was compared of 24 congenital abnormality groups and their matched controls. In the second step the possible association of first and high birth order with the risk of congenital abnormalities was estimated. Finally some subgroups of neural-tube defects, congenital heart defects and abdominal wall's defects were evaluated separately. A higher risk of spina bifida aperta/cystica, esophageal atresia/stenosis and clubfoot was observed in the offspring of primiparous mothers. Of 24 congenital abnormality groups, 14 had mothers with larger proportion of high birth order. Ear defects, congenital heart defects, cleft lip± palate and obstructive defects of urinary tract had a linear trend from a lower proportion of first born cases to the larger proportion of high birth order. Birth order showed U-shaped distribution of neural-tube defects and clubfoot, i.e. both first and high birth order had a larger proportion in cases than in their matched controls. Birth order is a contributing factor in the origin of some isolated congenital abnormalities. The higher risk of certain congenital abnormalities in pregnant women with first or high birth order is worth considering in the clinical practice, e.g. ultrasound scanning. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Use of Self-Matching to Control for Stable Patient Characteristics While Addressing Time-Varying Confounding on Treatment Effect: A Case Study of Older Intensive Care Patients.

PubMed

Han, Ling; Pisani, M A; Araujo, K L B; Allore, Heather G

Exposure-crossover design offers a non-experimental option to control for stable baseline confounding through self-matching while examining causal effect of an exposure on an acute outcome. This study extends this approach to longitudinal data with repeated measures of exposure and outcome using data from a cohort of 340 older medical patients in an intensive care unit (ICU). The analytic sample included 92 patients who received ≥1 dose of haloperidol, an antipsychotic medication often used for patients with delirium. Exposure-crossover design was implemented by sampling the 3-day time segments prior ( Induction) and posterior ( Subsequent) to each treatment episode of receiving haloperidol. In the full cohort, there was a trend of increasing delirium severity scores (Mean±SD: 4.4±1.7) over the course of the ICU stay. After exposure-crossover sampling, the delirium severity score decreased from the Induction (4.9) to the Subsequent (4.1) intervals, with the treatment episode falling in-between (4.5). Based on a GEE Poisson model accounting for self-matching and within-subject correlation, the unadjusted mean delirium severity scores was -0.55 (95% CI: -1.10, -0.01) points lower for the Subsequent than the Induction intervals. The association diminished by 32% (-0.38, 95%CI: -0.99, 0.24) after adjusting only for ICU confounding, while being slightly increased by 7% (-0.60, 95%CI: -1.15, -0.04) when adjusting only for baseline characteristics. These results suggest that longitudinal exposure-crossover design is feasible and capable of partially removing stable baseline confounding through self-matching. Loss of power due to eliminating treatment-irrelevant person-time and uncertainty around allocating person-time to comparison intervals remain methodological challenges.

Identification and selection of cases and controls in the Pneumonia Etiology Research for Child Health project.

PubMed

Deloria-Knoll, Maria; Feikin, Daniel R; Scott, J Anthony G; O'Brien, Katherine L; DeLuca, Andrea N; Driscoll, Amanda J; Levine, Orin S

2012-04-01

Methods for the identification and selection of patients (cases) with severe or very severe pneumonia and controls for the Pneumonia Etiology Research for Child Health (PERCH) project were needed. Issues considered include eligibility criteria and sampling strategies, whether to enroll hospital or community controls, whether to exclude controls with upper respiratory tract infection (URTI) or nonsevere pneumonia, and matching criteria, among others. PERCH ultimately decided to enroll community controls and an additional human immunodeficiency virus (HIV)-infected control group at high HIV-prevalence sites matched on age and enrollment date of cases; controls with symptoms of URTI or nonsevere pneumonia will not be excluded. Systematic sampling of cases (when necessary) and random sampling of controls will be implemented. For each issue, we present the options that were considered, the advantages and disadvantages of each, the rationale for the methods selected for PERCH, and remaining implications and limitations.

Contacts with children and young people and adult risk of suffering herpes zoster.

PubMed

Salleras, M; Domínguez, A; Soldevila, N; Prat, A; Garrido, P; Torner, N; Borrás, E; Salleras, L

2011-10-13

We carried out a matched case-control study to analyze the possible association between exposure to the children and the risk of suffering herpes-zoster in adulthood. Cases of herpes zoster in immunocompetent healthy patients aged ≥ 25 years seen in the dermatology department of the Sagrado Corazón Hospital in 2007-2008 were matched with four controls. Data were analyzed using conditional logistic regression. 153 cases and 604 matched controls were included. Contacts with children were significantly associated with a reduction in the risk of suffering herpes zoster in adulthood (adjusted OR 0.56 [0.37-0.85]). Herpes-zoster vaccination in immunocompetent people aged ≥ 50 years could counteract the possible negative effects of mass varicella vaccination in childhood on the epidemiology of herpes zoster in adults. Copyright © 2011 Elsevier Ltd. All rights reserved.

ICU telemedicine and critical care mortality: a national effectiveness study

PubMed Central

Kahn, Jeremy M; Le, Tri Q.; Barnato, Amber E.; Hravnak, Marilyn; Kuza, Courtney C.; Pike, Francis; Angus, Derek C.

2015-01-01

Background Intensive care unit (ICU) telemedicine is an increasingly common strategy for improving the outcome of critical care, but its overall impact is uncertain. Objectives To determine the effectiveness of ICU telemedicine in a national sample of hospitals and quantify variation in effectiveness across hospitals. Research design We performed a multi-center retrospective case-control study using 2001–2010 Medicare claims data linked to a national survey identifying United States hospitals adopting ICU telemedicine. We matched each adopting hospital (cases) to up to 3 non-adopting hospitals (controls) based on size, case-mix and geographic proximity during the year of adoption. Using ICU admissions from 2 years before and after the adoption date, we compared outcomes between case and control hospitals using a difference-in-differences approach. Results 132 adopting case hospitals were matched to 389 similar non-adopting control hospitals. The pre- and post-adoption unadjusted 90-day mortality was similar in both case hospitals (24.0% vs. 24.3%, p=0.07) and control hospitals (23.5% vs. 23.7%, p<0.01). In the difference-in-differences analysis, ICU telemedicine adoption was associated with a small relative reduction in 90-day mortality (ratio of odds ratios: 0.96, 95% CI = 0.95–0.98, p<0.001). However, there was wide variation in the ICU telemedicine effect across individual hospitals (median ratio of odds ratios: 1.01; interquartile range 0.85–1.12; range 0.45–2.54). Only 16 case hospitals (12.2%) experienced statistically significant mortality reductions post-adoption. Hospitals with a significant mortality reduction were more likely to have large annual admission volumes (p<0.001) and be located in urban areas (p=0.04) compared to other hospitals. Conclusions Although ICU telemedicine adoption resulted in a small relative overall mortality reduction, there was heterogeneity in effect across adopting hospitals, with large-volume urban hospitals experiencing the greatest mortality reductions. PMID:26765148

Cost savings of outpatient versus standard inpatient total knee arthroplasty

PubMed Central

Huang, Adrian; Ryu, Jae-Jin; Dervin, Geoffrey

2017-01-01

Background With diminishing reimbursement rates and strained public payer budgets, a high-volume inpatient procedure, such as total knee arthroplasty (TKA), is a common target for improving cost efficiencies. Methods This prospective case–control study compared the cost-minimization of same day discharge (SDD) versus inpatient TKA. We examined if and where cost savings can be realized and the magnitude of savings that can be achieved without compromising quality of care. Outcome variables, including detailed case costs, return to hospital rates and complications, were documented and compared between the first 20 SDD cases and 20 matched inpatient controls. Results In every case–control match, the SDD TKA was less costly than the inpatient procedure and yielded a median cost savings of approximately 30%. The savings came primarily from costs associated with the inpatient encounter, such as surgical ward, pharmacy and patient meal costs. At 1 year, there were no major complications and no return to hospital or readmission encounters for either group. Conclusion Our results are consistent with previously published data on the cost savings associated with short stay or outpatient TKA. We have gone further by documenting where those savings were in a matched cohort design. Furthermore, we determined where cost savings could be realized during the patient encounter and to what degree. In carefully selected patients, outpatient TKA is a feasible alternative to traditional inpatient TKA and is significantly less costly. Furthermore, it was deemed to be safe in the perioperative period. PMID:28234591

Uncovering clinical and radiological associations of triphasic waves in acute encephalopathy: a case-control study.

PubMed

Sutter, R; Kaplan, P W

2014-04-01

Triphasic waves (TWs) are archetypal waveforms seen on electroencephalography (EEG) in some forms of encephalopathy. Their particular underlying pathological substrates are largely unexplored. This case-control study was designed to identify and quantify specific clinical and neuroradiological associations underlying TWs and to determine if TWs predicate outcome. From 2004 to 2012, adult encephalopathic patients with TWs (cases) were matched 1:1 with encephalopathic patients without TWs (controls) by Glasgow Coma Scale (GCS) and the frequency range of EEG background activity. Clinical characteristics, neuroimaging and outcomes were assessed. The mean age of 190 patients (95 with and 95 without TWs) was 66.6 years (±15.6). In multivariable analyses, patients with TWs had significantly higher odds for liver insufficiency [odds ratio (OR) = 8.10, 95% confidence interval (CI) 1.98-33.08], alcohol abuse (OR = 3.65, 95% CI 1.25-10.63), subcortical brain atrophy (OR = 2.82, 95% CI 1.39-5.71) and respiratory tract infections (OR = 1.28, 95% CI 1.01-4.71). With each additional independent predictor, the odds increased for the occurrence of TWs (1 predictor, OR = 2.40, 95% CI 1.16-5.13; ≥2 predictors, OR = 9.20, 95% CI 3.27-25.62). Mortality was 15% and tended to be higher in patients with TWs (19% with vs. 11% without TWs). Alcohol abuse, liver insufficiency, infections and subcortical brain atrophy were independently associated with TWs in patients matched for clinical and EEG features of encephalopathy. These associations strengthen the hypothesis that TWs evolve from an interplay of pathological neurostructural, metabolic and toxic conditions. When matched for EEG background activity and GCS, TWs were not associated with death. © 2014 The Author(s) European Journal of Neurology © 2014 EFNS.

Child maltreatment as a risk factor for opioid dependence: Comparison of family characteristics and type and severity of child maltreatment with a matched control group.

PubMed

Conroy, Elizabeth; Degenhardt, Louisa; Mattick, Richard P; Nelson, Elliot C

2009-06-01

To examine the prevalence, characteristics and risk factors for child maltreatment among opioid-dependent persons compared to a community sample of similar social disadvantage. The study employed a case-control design. Cases had a history of opioid pharmacotherapy. Controls were frequency matched to cases with regard to age, sex and unemployment and were restricted to those with a lifetime opioid use of less than five times. The interview covered child maltreatment, family environment, drug use and psychiatric history. This study found a high prevalence of child maltreatment among both cases and controls. Despite the elevated prevalence among controls, opioid-dependent males had a higher prevalence of physical and emotional abuse; female cases had a higher prevalence and greater severity of sexual abuse. The prevalence of neglect was similar for both groups. Early parental separation was more prevalent among female cases compared to female controls; otherwise the prevalence of the risk factors was comparable for both groups. The risk factors significantly associated with child maltreatment were also similar for both cases and controls. Given the documented association between child maltreatment and adult mental disorder, child maltreatment may be an important antecedent of current psychological distress in persons presenting to treatment for opioid dependence. Apart from a possible association between early parental separation and sexual abuse among female cases, the increased prevalence of child maltreatment associated with opioid dependence did not appear to be related to differences in early childhood risk factors considered in this paper. Other risk factors may be more pertinent for those with opioid dependence. The high prevalence of child maltreatment among the opioid-dependent sample has implications for the assessment and treatment of clients presenting with opioid dependence. Assessment of child maltreatment history could help inform the development of individual treatment plans to better address those factors contributing to the development and maintenance of opioid dependence. Specifically, management of co-morbid mental disorder associated with child maltreatment could be the focus of relapse prevention programmes and also have a positive influence on treatment retention.

Child maltreatment as a risk factor for opioid dependence: comparison of family characteristics and type and severity of child maltreatment with a matched control group

PubMed Central

Conroy, Elizabeth; Degenhardt, Louisa; Mattick, Richard P.; Nelson, Elliot C.

2009-01-01

Objective To examine the prevalence, characteristics and risk factors for child maltreatment among opioid-dependent persons compared to a community sample of similar social disadvantage. Method The study employed a case-control design. Cases had a history of opioid pharmacotherapy. Controls were frequency matched to cases with regard to age, sex and unemployment and were restricted to those with a lifetime opioid use of less than five times. The interview covered child maltreatment, family environment, drug use and psychiatric history. Results This study found a high prevalence of child maltreatment among both cases and controls. Despite the elevated prevalence among controls, opioid-dependent males had a higher prevalence of physical and emotional abuse; female cases had a higher prevalence and greater severity of sexual abuse. The prevalence of neglect was similar for both groups. Early parental separation was more prevalent among female cases compared to female controls; otherwise the prevalence of the risk factors was comparable for both groups. The risk factors significantly associated with child maltreatment were also similar for both cases and controls. Conclusions Given the documented association between child maltreatment and adult mental disorder, child maltreatment may be an important antecedent of current psychological distress in persons presenting to treatment for opioid dependence. Apart from a possible association between early parental separation and sexual abuse among female cases, the increased prevalence of child maltreatment associated with opioid-dependence did not appear to be related to differences in early childhood risk factors considered in this paper. Other risk factors may be more pertinent for those with opioid dependence. Practice Implications The high prevalence of child maltreatment among the opioid-dependent sample has implications for the assessment and treatment of clients presenting with opioid dependence. Assessment of child maltreatment history could help inform the development of individual treatment plans to better address those factors contributing to the development and maintenance of opiate dependence. Specifically, management of co-morbid mental disorder associated with child maltreatment could be the focus of relapse prevention programmes and also have a positive influence on treatment retention. PMID:19477004

Predictors of immunological failure of antiretroviral therapy among HIV infected patients in Ethiopia: a matched case-control study.

PubMed

Teshome, Wondu; Asefa, Anteneh; Assefa, Anteneh

2014-01-01

In resource constrained settings, immunological assessment through CD4 count is used to assess response to first line Highly Active Antiretroviral Therapy (HAART). In this study, we aim to investigate factors associated with immunological treatment failure. A matched case-control study design was used. Cases were subjects who already experienced immunological treatment failure and controls were those without immunological failure after an exactly or approximately equivalent duration of first line treatment with cases. Data were analyzed using SPSS v16.0. Conditional logistic regression was carried out. A total of 134 cases and 134 controls were included in the study. At baseline, the mean age ± 1 SD of cases was 37.5 ± 9.7 years whereas it was 36.9 ± 9.2 years among controls. The median baseline CD4 counts of cases and controls were 121.0 cells/µl (IQR: 47-183 cells/µl) and 122.0 cells/µl (IQR: 80.0-189.8 cells/µl), respectively. The median rate of CD4 cells increase was comparable for the two groups in the first six months of commencing HAART (P = 0.442). However, the median rate of CD4 increase was significantly different for the two groups in the next 6 months period (M6 to M12). The rate of increment was 8.8 (IQR: 0.5, 14.6) and 1.8 (IQR: 8.8, 11.3) cells/µl/month for controls and cases, respectively (Mann-Whitney U test, P = 0.003). In conditional logistic regressions grouped baseline CD4 count (P = 0.028), old age group and higher educational status (P<0.001) were significant predictors of immunological treatment failure. Subjects with immunological treatment failure have an optimal rate of immunological recovery in the first 6 months of treatment with first line HAART, but relative to the non-failing group the rate declines at a later period, notably between 6 and 12 months. Low baseline CD4 count, old age and higher educational status were associated with immunological treatment failure.

Serum Vitamin D Is Significantly Inversely Associated with Disease Severity in Caucasian Adults with Obstructive Sleep Apnea Syndrome

PubMed Central

Kerley, Conor P.; Hutchinson, Katrina; Bolger, Kenneth; McGowan, Aisling; Faul, John; Cormican, Liam

2016-01-01

Study Objectives: To evaluate vitamin D (25(OH)D) levels in obstructive sleep apnea syndrome (OSAS) and possible relationships to OSAS severity, sleepiness, lung function, nocturnal heart rate (HR), and body composition. We also aimed to compare the 25(OH)D status of a subset of OSAS patients compared to controls matched for important determinants of both OSAS and vitamin D deficiency (VDD). Methods: This was a cross-sectional study conducted at an urban, clinical sleep medicine outpatient center. We recruited newly diagnosed, Caucasian adults who had recently undergone nocturnal polysomnography. We compared body mass index (BMI), body composition (bioelectrical impedance analysis), neck circumference, sleepiness (Epworth Sleepiness Scale), lung function, and vitamin D status (serum 25-hydrpoxyvitamin D (25(OH)D) across OSAS severity categories and non-OSAS subjects. Next, using a case-control design, we compared measures of serum 25(OH)D from OSAS cases to non-OSAS controls who were matched for age, gender, skin pigmentation, sleepiness, season, and BMI. Results: 106 adults (77 male; median age = 54.5; median BMI = 34.3 kg/m2) resident in Dublin, Ireland (latitude 53°N) were recruited and categorized as non-OSAS or mild/moderate/severe OSAS. 98% of OSAS cases had insufficient 25(OH)D (< 75 nmol/L), including 72% with VDD (< 50 nmol/L). 25(OH)D levels decreased with OSAS severity (P = 0.003). 25(OH)D was inversely correlated with BMI, percent body fat, AHI, and nocturnal HR. Subsequent multivariate regression analysis revealed that 25(OH)D was independently associated with both AHI (P = 0.016) and nocturnal HR (P = 0.0419). Our separate case-control study revealed that 25(OH)D was significantly lower in OSAS cases than matched, non-OSAS subjects (P = 0.001). Conclusions: We observed widespread vitamin D deficiency and insufficiency in a Caucasian, OSAS population. There were significant, independent, inverse relationships between 25(OH)D and AHI as well as nocturnal HR, a known cardiovascular risk factor. Further, 25(OH)D was significantly lower in OSAS cases compared to matched, non-OSAS subjects. We provide evidence that 25(OH)D and OSAS are related, but the role, if any, of replenishment has not been investigated. Citation: Kerley CP, Hutchinson K, Bolger K, McGowan A, Faul J, Comican L. Serum vitamin D is significantly inversely associated with disease severity in Caucasian adults with obstructive sleep apnea syndrome. SLEEP 2016;39(2):293–300. PMID:26414899

Sources of heterogeneity in case-control studies on associations between statins, ACE-inhibitors, and proton pump inhibitors and risk of pneumonia.

PubMed

de Groot, Mark C H; Klungel, Olaf H; Leufkens, Hubert G M; van Dijk, Liset; Grobbee, Diederick E; van de Garde, Ewoudt M W

2014-10-01

The heterogeneity in case-control studies on the associations between community-acquired pneumonia (CAP) and ACE-inhibitors (ACEi), statins, and proton pump inhibitors (PPI) hampers translation to clinical practice. Our objective is to explore sources of this heterogeneity by applying a common protocol in different data settings. We conducted ten case-control studies using data from five different health care databases. Databases varied on type of patients (hospitalised vs. GP), level of case validity, and mode of exposure ascertainment (prescription or dispensing based). Identified CAP patients and controls were matched on age, gender, and calendar year. Conditional logistic regression was used to calculate odds ratios (OR) for the associations between the drugs of interest and CAP. Associations were adjusted by a common set of potential confounders. Data of 38,742 cases and 118,019 controls were studied. Comparable patterns of variation between case-control studies were observed for ACEi, statins and PPI use and pneumonia risk with adjusted ORs varying from 1.04 to 1.49, 0.82 to 1.50 and 1.16 to 2.71, respectively. Overall, higher ORs were found for hospitalised CAP patients matched to population controls versus GP CAP patients matched to population controls. Prevalence of drug exposure was higher in dispensing data versus prescription data. We show that case-control selection and methods of exposure ascertainment induce bias that cannot be adjusted for and to a considerable extent explain the heterogeneity in results obtained in case-control studies on statins, ACEi and PPIs and CAP. The common protocol approach helps to better understand sources of variation in observational studies.

Proton-pump inhibitors are associated with a reduced risk for bleeding and perforated gastroduodenal ulcers attributable to non-steroidal anti-inflammatory drugs: a nested case-control study

PubMed Central

Vonkeman, Harald E; Fernandes, Robert W; van der Palen, Job; van Roon, Eric N; van de Laar, Mart AFJ

2007-01-01

Treatment with non-steroidal anti-inflammatory drugs (NSAIDs) is hampered by gastrointestinal ulcer complications, such as ulcer bleeding and perforation. The efficacy of proton-pump inhibitors in the primary prevention of ulcer complications arising from the use of NSAIDs remains unproven. Selective cyclooxygenase-2 (COX-2) inhibitors reduce the risk for ulcer complications, but not completely in high-risk patients. This study determines which patients are especially at risk for NSAID ulcer complications and investigates the effectiveness of different preventive strategies in daily clinical practice. With the use of a nested case-control design, a large cohort of NSAID users was followed for 26 months. Cases were patients with NSAID ulcer complications necessitating hospitalisation; matched controls were selected from the remaining cohort of NSAID users who did not have NSAID ulcer complications. During the observational period, 104 incident cases were identified from a cohort of 51,903 NSAID users with 10,402 patient years of NSAID exposure (incidence 1% per year of NSAID use, age at diagnosis 70.4 ± 16.7 years (mean ± SD), 55.8% women), and 284 matched controls. Cases were characterised by serious, especially cardiovascular, co-morbidity. In-hospital mortality associated with NSAID ulcer complications was 10.6% (incidence 21.2 per 100,000 NSAID users). Concomitant proton-pump inhibitors (but not selective COX-2 inhibitors) were associated with a reduced risk for NSAID ulcer complications (the adjusted odds ratio 0.33; 95% confidence interval 0.17 to 0.67; p = 0.002). Especially at risk for NSAID ulcer complications are elderly patients with cardiovascular co-morbidity. Proton-pump inhibitors are associated with a reduced risk for NSAID ulcer complications. PMID:17521422

Vaccine Effectiveness against Influenza in 2015/16 in Hospital and Ambulatory Medical Care Facilities: Polish Results of the European I-MOVE+ Multicenter Study.

PubMed

Paradowska-Stankiewicz, Iwona; Korczyńska, Monika R; Cieślak, Katarzyna; Kowalczyk, Dorota; Szymański, Karol; Brydak, Lidia B

2018-01-01

Influenza vaccination is the best measure available to prevent seasonal influenza infection. The majority of studies on vaccine effectiveness in the 2015/16 season conducted in the European I-MOVE+ Project, show that a match between the circulating influenza strains in the general public and those included in the vaccine for the Northern Hemisphere was low to moderate. As part of I-MOVE+, Poland has implemented a case control negative study design and molecular biology methods, such as real time RT-PCR, to assess the vaccine match and effectiveness. The research described herein consisted of two major influenza vaccine effectiveness investigations conducted in Poland in the 2015/16 season. The general practice part of the study included 228 cases consisting of 159 type A, 65 type B, and 4 coinfections (types A + B), and 312 negative control cases. The hospital study part included 26 cases consisting of 21 type A, 2 type B, and 3 coinfections, and 13 negative control cases. The data were collected from patients of all ages recruited by 46 volunteering doctors in 15 Poland's provinces and three hospitals, respectively. In both study parts, only were seven patients and 12 control subjects vaccinated. Low vaccine coverage, a major limitation of the Polish study, makes the calculation of vaccine effectiveness for the Polish population hardly applicable statistically. Despite the crudeness of data, they were included into the common European analysis. The overall vaccine effectiveness amounted to 21.0% (95% CI: 74-122). It was somehow better for type B virus: 53.9% (95% CI: 47-87) and type A virus: 23.6% (95% CI: 83-185). A larger sample size is needed to achieve a desired interpretation of results on influenza vaccine effectiveness in Poland.

Sickle cell disease and venous thromboembolism in pregnancy and the puerperium.

PubMed

Noubouossie, Denis; Key, Nigel S

2015-02-01

Recent data strongly suggest an increased risk of venous thromboembolism in subjects with sickle cell disease and to a lesser extent, sickle cell trait. However, most studies have been retrospective, case-control or cross-sectional based on data obtained from administrative databases. More data from adequately powered prospective studies that include matched controls are needed to definitely establish the link between venous thromboembolism during pregnancy and sickle hemoglobin disorders. Similarly, there remains a need for properly designed randomized control trials to establish the safety of various hormonal contraceptive methods in women with sickle cell disorders. © 2015 Elsevier Ltd. All rights reserved.

Injuries in adolescents with childhood-onset epilepsy compared with sibling controls

PubMed Central

Baca, Christine B.; Vickrey, Barbara G.; Vassar, Stefanie D.; Cook, Aaron; Berg, Anne T.

2013-01-01

Objective To compare the occurrence of injuries in adolescents with childhood-onset epilepsy and matched sibling controls. Study design Retrospective case-control lifetime injury assessments were obtained from a community-based cohort of adolescents with childhood-onset epilepsy diagnosed 9-years earlier, and their siblings. Children with epilepsy (n=501; mean age 15.3 years) included children with complicated (abnormal neurological exam or IQ<80; n=133) and uncomplicated (normal neurological exam and IQ≥80; n=368) epilepsy. Children with uncomplicated epilepsy were matched to sibling controls (n=210 pairs). Children reported whether they had ever (before and after epilepsy diagnosis) experienced injuries, “serious enough to require medical attention” and the type of treatment required. Results 49.1% of children with epilepsy experienced any injury, of whom 8.9% required surgery/hospitalization and 17.1% had an injury due to a seizure; fewer children with uncomplicated epilepsy had seizure-related injuries versus those with complicated epilepsy (13.6% vs. 27.4%; p≤0.01). The proportion of children with epilepsy with any injury by types (not mutually exclusive) were: 25.2% (n=126) fractures, 24.4% (n=122) head, 10.2% (n=51) other, 8.4% (n=42) dental and 8% (n=40) burns/scalds. A similar proportion of children with uncomplicated epilepsy experienced any injury (overall and by type) compared with matched sibling controls, with the exception that more children with uncomplicated epilepsy had head injuries (30.0% vs. 19.5%; p<0.02). Conclusion With the exception of head injuries, in a representative cohort of children with epilepsy compared with siblings there was no evidence of an increased risk of injury. This may reflect that the sample was not biased to more severe cases or that safety precautions to prevent injury were widely employed. PMID:24054432

Clinical and psychological features of normal-weight women with subthreshold anorexia nervosa: a pilot case-control observational study.

PubMed

Tagliabue, Anna; Ferraris, Cinzia; Martinelli, Valentina; Pinelli, Giovanna; Repossi, Ilaria; Trentani, Claudia

2012-01-01

Weight preoccupations have been frequently reported in normal-weight subjects. Subthreshold anorexia nervosa (s-AN, all DSM IV TR criteria except amenorrhea or underweight) is a form of eating disorder not otherwise specified that has received scarce scientific attention. Under a case-control design we compared the general characteristics, body composition, and psychopathological features of normal-weight patients with s-AN with those of BMI- and sex-matched controls. Participants in this pilot study included 9 normal-weight women who met the DSM IV TR criteria for s-AN and 18 BMI-matched normal-weight controls. The general characteristics of the study participants were collected by questionnaire. Body composition was measured by bioelectrical impedance. Behavioral and psychological measures included the standardized symptom checklist (SCL-90-R) and the eating disorder inventory (EDI-2). There were no differences in age, education, employment status, marital status, and history of previous slimming treatment in the two study groups. In addition, anthropometric measures and body composition of s-AN patients and BMI-matched normal weight controls were not significantly different. In the s-AN subgroup, we found a significant relationship between waist circumference and the SCL-90-R obsessivity-compulsivity scale (n=9, r=-0.69, p<0.05). After multiple regression analysis, the SCL-90-R obsessivity-compulsivity scale (beta = 0.61, t=2.7, p=0.017) was the only independent predictor of the presence s-AN in our study cohort. These pilot results suggest that psychopathological criteria (particularly related to the obsessivity-compulsivity dimension) may be more useful than anthropometric measures for screening of s-AN in normal-weight women.

Genetic susceptibility to chronic wasting disease in free-ranging white-tailed deer: complement component C1q and Prnp polymorphisms

USGS Publications Warehouse

Blanchong, Julie A.; Heisey, Dennis M.; Scribner, Kim T.; Libants, Scot V.; Johnson, Chad; Aiken, Judd M.; Langenberg, Julia A.; Samuel, Michael D.

2009-01-01

The genetic basis of susceptibility to chronic wasting disease (CWD) in free-ranging cervids is of great interest. Association studies of disease susceptibility in free-ranging populations, however, face considerable challenges including: the need for large sample sizes when disease is rare, animals of unknown pedigree create a risk of spurious results due to population admixture, and the inability to control disease exposure or dose. We used an innovative matched case–control design and conditional logistic regression to evaluate associations between polymorphisms of complement C1q and prion protein (Prnp) genes and CWD infection in white-tailed deer from the CWD endemic area in south-central Wisconsin. To reduce problems due to admixture or disease-risk confounding, we used neutral genetic (microsatellite) data to identify closely related CWD-positive (n = 68) and CWD-negative (n = 91) female deer to serve as matched cases and controls. Cases and controls were also matched on factors (sex, location, age) previously demonstrated to affect CWD infection risk. For Prnp, deer with at least one Serine (S) at amino acid 96 were significantly less likely to be CWD-positive relative to deer homozygous for Glycine (G). This is the first characterization of genes associated with the complement system in white-tailed deer. No tests for association between any C1q polymorphism and CWD infection were significant at p < 0.05. After controlling for Prnp, we found weak support for an elevated risk of CWD infection in deer with at least one Glycine (G) at amino acid 56 of the C1qC gene. While we documented numerous amino acid polymorphisms in C1q genes none appear to be strongly associated with CWD susceptibility.

The role of HIV infection in the etiology and epidemiology of diarrheal disease among children aged 0-59 months in Manhiça district, Rural Mozambique.

PubMed

Acácio, Sozinho; Nhampossa, Tacilta; Quintó, Llorenç; Vubil, Delfino; Sacoor, Charfudin; Kotloff, Karen; Farag, Tamer; Dilruba, Nasrin; Macete, Eusebio; Levine, Myron M; Alonso, Pedro; Mandomando, Inácio; Bassat, Quique

2018-05-28

Diarrhea is an important health problem among HIV-infected patients. This study evaluates the role of HIV on the epidemiology, etiology and severity of diarrheal disease among children. The Global Enteric Multicenter Study enrolled children with moderate-to-severe (MSD) and less severe (LSD) diarrhea between December 2007 and November 2012. One to three controls for MSD cases and one per LSD case were enrolled and matched by age, sex and neighborhood. All children were tested for HIV. Clinical, anthropometric data and stools were collected. A follow-up was performed at 60 days. 214 MSD cases and 418 controls, together with 349 LSD cases and 214 controls were tested. HIV prevalence among MSD cases was 25% (4% for matched controls) and 6% among LSD cases (6% among matched controls). HIV-infected children were more likely to have MSD (OR=5.6, p< 0.0001). Mortality rates were higher among HIV-infected children compared with uninfected (34 vs. 5 per 1000 children-weeks at risk; p=0.0039). Cryptosporidium, Giardia, EAEC (aatA only) were more prevalent among HIV-infected MSD-cases than uninfected ones. HIV is an important risk factor for MSD. The high mortality rate implies that children with MSD should be screened for HIV and managed accordingly. Copyright © 2018. Published by Elsevier Ltd.

Higher sweat chloride levels in patients with asthma: a case-control study.

PubMed

Awasthi, Shally; Dixit, Pratibha; Maurya, Nutan

2015-02-01

To screen asthmatic patients by sweat chloride test to identify proportion with Cystic Fibrosis (CF); (Sweat chloride level >60 mmol/L). Also, to compare sweat chloride levels between cases of bronchial asthma and age and sex matched healthy children aged 5 mo-15 y. The present case-control study was conducted in a tertiary care hospital in India. Cases of bronchial asthma, diagnosed by GINA guideline 2008, and age matched healthy controls were included. Case to control ratio was 2:1. Sweat Chloride test was done by Pilocarpine Iontophoresis method. From April 2010 through May 2012, 216 asthmatics and 112 controls were recruited. Among asthmatics, there was no case of Cystic Fibrosis. Mean sweat chloride levels in asthmatics was 22.39 ± 8.45 mmol/L (inter-quartile range - 15-28 mmol/L) and in controls 19.55 ± 7.04 mmol/L (inter-quartile range - 15-23.5 mmol/L) (p value = 0.048). No Cystic Fibrosis case was identified among asthmatics. Mean sweat chloride levels were higher in asthmatics as compared to controls.

Do body mass index trajectories affect the risk of type 2 diabetes? A case-control study.

PubMed

Mano, Yoshihiko; Yokomichi, Hiroshi; Suzuki, Kohta; Takahashi, Atsunori; Yoda, Yoshioki; Tsuji, Masahiro; Sato, Miri; Shinohara, Ryoji; Mizorogi, Sonoko; Mochizuki, Mie; Yamagata, Zentaro

2015-07-28

Although obesity is a well-studied risk factor for diabetes, there remains an interest in whether "increasing body mass index (BMI)," "high BMI per se," or both are the actual risk factors for diabetes. The present study aimed to retrospectively compare BMI trajectories of individuals with and without diabetes in a case-control design and to assess whether increasing BMI alone would be a risk factor. Using comprehensive health check-up data measured over ten years, we conducted a case-control study and graphically drew the trajectories of BMIs among diabetic patients and healthy subjects, based on coefficients in fitted linear mixed-effects models. Patient group was matched with healthy control group at the onset of diabetes with an optimal matching method in a 1:10 ratio. Simple fixed-effects models assessed the differences in increasing BMIs over 10 years between patient and control groups. At the time of matching, the mean ages in male patients and controls were 59.3 years [standard deviation (SD) = 9.2] and 57.7 years (SD = 11.2), whereas the mean BMIs were 25.0 kg/m(2) (SD = 3.1) and 25.2 kg/m(2) (SD = 2.9), respectively. In female patients and controls, the mean ages were 61.4 years (SD = 7.9) and 60.1 years (SD = 9.6), whereas the mean BMIs were 24.8 kg/m(2) (SD = 3.5) and 24.9 kg/m(2) (SD = 3.4), respectively. The simple fixed-effects models detected no statistical significance for the differences of increasing BMIs between patient and control groups in males (P = 0.19) and females (P = 0.67). Sudden increases in BMI were observed in both male and female patients when compared with BMIs 1 year prior to diabetes onset. The present study suggested that the pace of increasing BMIs is similar between Japanese diabetic patients and healthy individuals. The increasing BMI was not detected to independently affect the onset of type 2 diabetes.

Preenlistment and Early Service Risk Factors for Traumatic Brain Injury in the Army and Marine Corps: FY 2002-2010.

PubMed

Elmasry, Hoda; Boivin, Michael R; Feng, Xiaoshu; Packnett, Elizabeth R; Cowan, David N

To determine the preenlistment and early service risk factors for traumatic brain injury (TBI)-related disability in Army and Marine Corps service members. Matched case-control design. TBI disability discharges. Army and Marine Corps service members with an enlistment record and disability discharge for TBI were included as cases. Controls were selected from the enlisted population with no disability evaluation record and were matched on fiscal year of enlistment, sex, and service at a ratio of 5:1. Older age at enlistment resulted in a significantly increased risk for TBI disability in the crude and adjusted models (adjusted odds ratio [aOR] = 1.49; 95% confidence interval [CI], 1.16-1.91). An enlistment military occupational specialty (MOS) with a combat arms designation resulted in an almost 3-fold increased odds of TBI disability compared with other MOS categories (aOR = 2.75; 95% CI, 2.46-3.09). This remained a significant risk factor for TBI disability in the multivariate model (aOR = 2.74; 95% CI, 2.45-3.08). Results from this study help inform the existing body of military TBI research by highlighting the preenlistment demographic and early service risk factors for TBI disability. Further research into the role of age on TBI disability in the military is merited.

The Total Synthesis Problem of linear multivariable control. II - Unity feedback and the design morphism

NASA Technical Reports Server (NTRS)

Sain, M. K.; Antsaklis, P. J.; Gejji, R. R.; Wyman, B. F.; Peczkowski, J. L.

1981-01-01

Zames (1981) has observed that there is, in general, no 'separation principle' to guarantee optimality of a division between control law design and filtering of plant uncertainty. Peczkowski and Sain (1978) have solved a model matching problem using transfer functions. Taking into consideration this investigation, Peczkowski et al. (1979) proposed the Total Synthesis Problem (TSP), wherein both the command/output-response and command/control-response are to be synthesized, subject to the plant constraint. The TSP concept can be subdivided into a Nominal Design Problem (NDP), which is not dependent upon specific controller structures, and a Feedback Synthesis Problem (FSP), which is. Gejji (1980) found that NDP was characterized in terms of the plant structural matrices and a single, 'good' transfer function matrix. Sain et al. (1981) have extended this NDP work. The present investigation is concerned with a study of FSP for the unity feedback case. NDP, together with feedback synthesis, is understood as a Total Synthesis Problem.

Restaurant-associated outbreak of Salmonella typhi in Nauru: an epidemiological and cost analysis.

PubMed Central

Olsen, S. J.; Kafoa, B.; Win, N. S.; Jose, M.; Bibb, W.; Luby, S.; Waidubu, G.; O'Leary, M.; Mintz, E.

2001-01-01

Typhoid fever is endemic in the South Pacific. We investigated an outbreak in Nauru. Through interviews and medical records, we identified 50 persons with onset between 1 October 1998 and 10 May 1999, of fever lasting > or = 3 days and one other symptom. Salmonella Typhi was isolated from 19 (38%) cases. Thirty-two (64%) patients were school-aged children, and 17 (34%) were in four households. Case-control studies of (a) culture-confirmed cases and age- and neighbourhood-matched controls; and (b) household index cases and randomly selected age-matched controls implicated two restaurants: Restaurant M (matched OR [MOR] = 11, 95% confidence interval [CI] = 1.3-96) and Restaurant I (MOR = 5.8, 95% CI = 1.2-29). Food-handlers at both restaurants had elevated anti-Vi antibody titres indicative of carrier state. The annual incidence was 5.0/1000 persons. Outbreak-associated costs were $46,000. Routine or emergency immunization campaigns targeting school-aged children may help prevent or control outbreaks of typhoid fever in endemic disease areas. PMID:11811872

Long-term consequences of child abuse and neglect on adult economic well-being.

PubMed

Currie, Janet; Widom, Cathy Spatz

2010-05-01

Child abuse and neglect represent major threats to child health and well-being; however, little is known about consequences for adult economic outcomes. Using a prospective cohort design, court substantiated cases of childhood physical and sexual abuse and neglect during 1967-1971 were matched with nonabused and nonneglected children and followed into adulthood (mean age 41). Outcome measures of economic status and productivity were assessed in 2003-2004 (N 1/4 807). Results indicate that adults with documented histories of childhood abuse and/or neglect have lower levels of education, employment, earnings, and fewer assets as adults, compared to matched control children. There is a 14% gap between individuals with histories of abuse/neglect and controls in the probability of employment in middle age, controlling for background characteristics. Maltreatment appears to affect men and women differently, with larger effects for women than men. These new findings demonstrate that abused and neglected children experience large and enduring economic consequences.

Long-Term Consequences of Child Abuse and Neglect on Adult Economic Well-Being

PubMed Central

Currie, Janet; Widom, Cathy Spatz

2013-01-01

Child abuse and neglect represent major threats to child health and well-being; however, little is known about consequences for adult economic outcomes. Using a prospective cohort design, court substantiated cases of childhood physical and sexual abuse and neglect during 1967–1971 were matched with nonabused and nonneglected children and followed into adulthood (mean age 41). Outcome measures of economic status and productivity were assessed in 2003–2004 (N = 807). Results indicate that adults with documented histories of childhood abuse and/or neglect have lower levels of education, employment, earnings, and fewer assets as adults, compared to matched control children. There is a 14% gap between individuals with histories of abuse/neglect and controls in the probability of employment in middle age, controlling for background characteristics. Maltreatment appears to affect men and women differently, with larger effects for women than men. These new findings demonstrate that abused and neglected children experience large and enduring economic consequences. PMID:20425881

Maternal Infection during Pregnancy and Autism Spectrum Disorders

ERIC Educational Resources Information Center

Zerbo, Ousseny; Qian, Yinge; Yoshida, Cathleen; Grether, Judith K.; Van de Water, Judy; Croen, Lisa A.

2015-01-01

We conducted a nested case-control study including 407 cases and 2,075 frequency matched controls to investigate the association between maternal infections during pregnancy and risk of autism spectrum disorders (ASD). Cases, controls, and maternal infections were ascertained from Kaiser Permanente Northern California clinical databases. No…

The Trade-Offs of Developing a Case Management Model for Chronically Mentally Ill People.

ERIC Educational Resources Information Center

Belcher, John R.

1993-01-01

Addresses role of case management in care of chronically mentally ill persons. Notes that case management can be effective if designed so that services match client needs and service costs are measured accurately. Contends that profit-maximizing nature of U.S. health care system makes some form of capitation likely in design of case management…

Case-Control Study of Writer's Cramp

ERIC Educational Resources Information Center

Roze, E.; Soumare, A.; Pironneau, I.; Sangla, S.; de Cock, V. Cochen; Teixeira, A.; Astorquiza, A.; Bonnet, C.; Bleton, J. P.; Vidailhet, M.; Elbaz, A.

2009-01-01

Task-specific focal dystonias are thought to be due to a combination of individual vulnerability and environmental factors. There are no case-control studies of risk factors for writer's cramp. We undertook a case-control study of 104 consecutive patients and matched controls to identify risk factors for the condition. We collected detailed data…

Oral contraceptive use, parity, and constitutional characteristics in soft tissue sarcoma: a Swedish population-based case-control study 1988-2009.

PubMed

Wagner, Philippe; Alvegård, Thor; Ranstam, Jonas; Rydholm, Anders; Vult von Steyern, Fredrik; Olsson, Håkan

2014-09-01

The study was designed to investigate the influence of surrogate factors associated with sex (SH) and growth hormones (GH) on the risk of developing soft tissue sarcomas (STS). The etiology of soft tissue sarcoma is largely unknown. We have studied the effect of hormone related factors on STS in the Swedish population between 1988 and 2009 using a population-based matched case-control design. Our study is the largest on this topic to date, including 634 cases in a primary matched analysis and 855 cases in an unmatched sensitivity analysis. We identified protective effects connected to constitutional characteristics, hormonal and reproductive factors. Being shorter than your peers at age 11 was associated with an odds ratio (OR) of 0.51 (0.36-0.74). Having used oral contraceptives (OC), OR 0.75 (0.49-1.15), and high parity, OR 0.16 (0.04-0.63), comparing three or more children to two or less, also appeared to reduce the risk of STS. The risk was further reduced with the duration of OC use (p = 0.01), comparing use for 11 years or more to use for 3 years or less yielded an OR of 0.10 (0.02-0.41). No effect was observed for ever having had perimenopausal hormone therapy OR 1.02 (0.70-1.47). The effect of BMI varied significantly with subtype (p = 0.03) and tumor location (p < 0.001). We observed surrogates of SH, GH, and insulin-like growth factor 1 to be associated with STS development. These findings are important as they may connect STSs to the group of hormone-dependent tumors, potentially revealing common treatment and prevention targets.

Major risk factors for aneurysmal subarachnoid hemorrhage in the young are modifiable.

PubMed

Broderick, Joseph P; Viscoli, Catherine M; Brott, Thomas; Kernan, Walter N; Brass, Lawrence M; Feldmann, Edward; Morgenstern, Lewis B; Wilterdink, Janet Lee; Horwitz, Ralph I

2003-06-01

To identify risk factors for subarachnoid hemorrhage (SAH) and intracerebral hemorrhage, we designed a case-control study of men and women 18 to 49 years of age (the Hemorrhagic Stroke Project [HSP]). This report focuses on SAH. Patients were recruited from 44 hospitals in the United States. Cases with SAH must have had a ruptured aneurysm documented by angiography or surgery. Two controls, identified by random digit dialing and matched to each patient for age, sex, race, and telephone exchange, were sought for each case subject. Between 1994 and 1999, 425 patients with SAH were enrolled in HSP, and 312 cases met the criteria for aneurysmal SAH. The present analyses also included 618 matched controls. Of the 312 cases, 66% were current cigarette smokers compared with 30% of controls (adjusted odds ratio [OR], 3.73; 95% CI, 2.67 to 5.21). Cocaine use within the previous 3-day period was reported by 3% of cases and no controls (bivariate exact OR, 24.97; 95% exact CI, 3.95 to infinity; adjusted estimate not calculable). Other independent risk factors in the multivariable model included hypertension (adjusted OR, 2.21; 95% CI, 1.48 to 3.29), low body mass index (OR, 1.59; 95% CI, 1.08 to 2.35), primary family history of hemorrhagic stroke (OR, 3.83; 95% CI, 1.73 to 8.46), caffeine in pharmaceutical products (OR, 2.48; 95% CI, 1.19 to 5.20), lower educational achievement (OR, 2.36; 95% CI, 1.44 to 3.87), and nicotine in pharmaceutical products (adjusted estimate not calculable). Aneurysmal SAH may be largely a preventable disease among the young and middle-aged because several prevalent risk factors can be modified by medication (eg, hypertension) or behavioral change (eg, cigarette smoking, cocaine use). The association of caffeine and nicotine in pharmaceutical products and aneurysmal SAH warrants further study.

Association study of Demodex bacteria and facial dermatoses based on DGGE technique.

PubMed

Zhao, YaE; Yang, Fan; Wang, RuiLing; Niu, DongLing; Mu, Xin; Yang, Rui; Hu, Li

2017-03-01

The role of bacteria is unclear in the facial skin lesions caused by Demodex. To shed some light on this issue, we conducted a case-control study comparing cases with facial dermatoses with controls with healthy skin using denaturing gradient gel electrophoresis (DGGE) technique. The bacterial diversity, composition, and principal component were analyzed for Demodex bacteria and the matched facial skin bacteria. The result of mite examination showed that all 33 cases were infected with Demodex folliculorum (D. f), whereas 16 out of the 30 controls were infected with D. f, and the remaining 14 controls were infected with Demodex brevis (D. b). The diversity analysis showed that only evenness index presented statistical difference between mite bacteria and matched skin bacteria in the cases. The composition analysis showed that the DGGE bands of cases and controls were assigned to 12 taxa of 4 phyla, including Proteobacteria (39.37-52.78%), Firmicutes (2.7-26.77%), Actinobacteria (0-5.71%), and Bacteroidetes (0-2.08%). In cases, the proportion of Staphylococcus in Firmicutes was significantly higher than that in D. f controls and D. b controls, while the proportion of Sphingomonas in Proteobacteria was significantly lower than that in D. f controls. The between-group analysis (BGA) showed that all the banding patterns clustered into three groups, namely, D. f cases, D. f controls, and D. b controls. Our study suggests that the bacteria in Demodex should come from the matched facial skin bacteria. Proteobacteria and Firmicutes are the two main taxa. The increase of Staphylococcus and decrease of Sphingomonas might be associated with the development of facial dermatoses.

Results of routine restaurant inspections can predict outbreaks of foodborne illness: the Seattle-King County experience.

PubMed Central

Irwin, K; Ballard, J; Grendon, J; Kobayashi, J

1989-01-01

To analyze the association between the results of routine inspections and foodborne outbreaks in restaurants, we conducted a matched case-control study using available data from Seattle-King County, Washington. Case restaurants were facilities with a reported foodborne outbreak between January 1, 1986 and March 31, 1987 (N = 28). Two control restaurants with no reported outbreaks during this period were matched to each case restaurant on county health district and date of routine inspection (N = 56). Data from the routine inspection that preceded the outbreak (for case restaurants) or the date-matched routine inspection (for control restaurants) were abstracted from computerized inspection records. Case restaurants had a significantly lower mean inspection score (83.8 on a 0 to 100 point scale) than control restaurants (90.9). Restaurants with poor inspection scores and violations of proper temperature controls of potentially hazardous foods were, respectively, five and ten times more likely to have outbreaks than restaurants with better results. Although this study demonstrates that Seattle-King County's routine inspection form can successfully identify restaurants at increased risk of foodborne outbreaks, it also illustrates that more emphasis on regulation and education is needed to prevent outbreaks in restaurants with poor inspection results. PMID:2705592

Study on casing treatment and stator matching on multistage fan

NASA Astrophysics Data System (ADS)

Wu, Chuangliang; Yuan, Wei; Deng, Zhe

2017-10-01

Casing treatments are required for expanding the stall margin of multi-stage high-load turbofans designed with high blade-tip Mach numbers and high leakage flow. In the case of a low mass flow, the casing treatment effectively reduces the blockages caused by the leakage flow and enlarges the stall margin. However, in the case of a high mass flow, the casing treatment affects the overall flow capacity of the fan, the thrust when operating at the high speeds usually required by design-point specifications. Herein, we study a two-stage high-load fan with three-dimensional numerical simulations. We use the simulation results to propose a scheme that enlarges the stall margin of multistage high-load fans without sacrificing the flow capacity when operating with a large mass flow. Furthermore, a circumferential groove casing treatment is used and adjustments are made to the upstream stator angle to match the casing treatment. The stall margin is thus increased to 16.3%, with no reduction in the maximum mass flow rate or the design thrust performance.

Immediate processing of erotic stimuli in paedophilia and controls: a case control study

PubMed Central

2013-01-01

Background Most neuroimaging studies investigating sexual arousal in paedophilia used erotic pictures together with a blocked fMRI design and long stimulus presentation time. While this approach allows the detection of sexual arousal, it does not enable the assessment of the immediate processing of erotically salient stimuli. Our study aimed to identify neuronal networks related to the immediate processing of erotic stimuli in heterosexual male paedophiles and healthy age-matched controls. Methods We presented erotic pictures of prepubescent children and adults in an event related fMRI-design to eight paedophilic subjects and age-matched controls. Results Erotic pictures of females elicited more activation in the right temporal lobe, the right parietal lobe and both occipital lobes and erotic pictures of children activated the right dorsomedial prefrontal cortex in both groups. An interaction of sex, age and group was present in the right anteriolateral oribitofrontal cortex. Conclusions Our event related study design confirmed that erotic pictures activate some of the brain regions already known to be involved in the processing of erotic pictures when these are presented in blocks. In addition, it revealed that erotic pictures of prepubescent children activate brain regions critical for choosing response strategies in both groups, and that erotically salient stimuli selectively activate a brain region in paedophilic subjects that had previously been attributed to reward and punishment, and that had been shown to be implicated in the suppression of erotic response and deception. PMID:23510246

Hospitalisation for chronic obstructive pulmonary disease and risk of suicide: a population-based case–control study

PubMed Central

Strid, Jennie Maria Christin; Christiansen, Christian Fynbo; Olsen, Morten; Qin, Ping

2014-01-01

Objectives To examine risk of suicide among individuals with hospitalised chronic obstructive pulmonary disease (COPD) and to profile differences according to sex, age, psychiatric history, and recency and frequency of COPD hospitalisations. Design Nested case–control study. Setting Data were retrieved from Danish national registries. Participants All suicide cases aged 40–95 years deceased between 1981 and 2006 in Denmark (n=19 869) and up to 20 live population controls per case matched on sex and date of birth (n=321 867 controls). Main outcome measures The relative risk of suicide associated with COPD was computed using conditional logistic regression and adjusted for effects of psychiatric history and important sociodemographic factors. Results In our study population, 3% of suicide cases had been hospitalised for COPD compared with 1% of matched population controls. Thus, a hospitalised COPD was associated with a significantly increased risk for suicide (OR 2.6; 95% CI 2.3 to 2.8). The increased risk remained significant after adjustment for psychiatric history and sociodemographic variables (OR 2.0; 95% CI 1.8 to 2.2), and increased progressively with frequency and recency of COPD hospitalisation. At the same time, suicide risk associated with COPD differed significantly by sex, age and psychiatric status. The relative risk was more pronounced in women, in individuals older than 60 years and in persons with no history of psychiatric illness. Conclusions COPD confers an important risk factor for suicide completion. Risk assessment and prevention efforts should take patients’ sex, age and psychiatric history into consideration. PMID:25421339

A Measure Approximation for Distributionally Robust PDE-Constrained Optimization Problems

DOE PAGES

Kouri, Drew Philip

2017-12-19

In numerous applications, scientists and engineers acquire varied forms of data that partially characterize the inputs to an underlying physical system. This data is then used to inform decisions such as controls and designs. Consequently, it is critical that the resulting control or design is robust to the inherent uncertainties associated with the unknown probabilistic characterization of the model inputs. Here in this work, we consider optimal control and design problems constrained by partial differential equations with uncertain inputs. We do not assume a known probabilistic model for the inputs, but rather we formulate the problem as a distributionally robustmore » optimization problem where the outer minimization problem determines the control or design, while the inner maximization problem determines the worst-case probability measure that matches desired characteristics of the data. We analyze the inner maximization problem in the space of measures and introduce a novel measure approximation technique, based on the approximation of continuous functions, to discretize the unknown probability measure. Finally, we prove consistency of our approximated min-max problem and conclude with numerical results.« less

Numerical Evaluation of the "Dual-Kernel Counter-flow" Matric Convolution Integral that Arises in Discrete/Continuous (D/C) Control Theory

NASA Technical Reports Server (NTRS)

Nixon, Douglas D.

2009-01-01

Discrete/Continuous (D/C) control theory is a new generalized theory of discrete-time control that expands the concept of conventional (exact) discrete-time control to create a framework for design and implementation of discretetime control systems that include a continuous-time command function generator so that actuator commands need not be constant between control decisions, but can be more generally defined and implemented as functions that vary with time across sample period. Because the plant/control system construct contains two linear subsystems arranged in tandem, a novel dual-kernel counter-flow convolution integral appears in the formulation. As part of the D/C system design and implementation process, numerical evaluation of that integral over the sample period is required. Three fundamentally different evaluation methods and associated algorithms are derived for the constant-coefficient case. Numerical results are matched against three available examples that have closed-form solutions.

Risk factors for hospital acquisition of trimethoprim-sulfamethoxazole resistant Stenotrophomonas maltophilia in adults: A matched case-control study.

PubMed

Wang, Ching-Hsun; Lin, Jung-Chung; Chang, Feng-Yee; Yu, Ching-Mei; Lin, Wei-San; Yeh, Kuo-Ming

2017-10-01

The emergence of trimethoprim-sulfamethoxazole resistant Stenotrophomonas maltophilia (TSRSM) represents a serious threat to patients. The aim of current study was to identify risk factors associated with hospital-acquired TSRSM occurrence in adult inpatients. We conducted a matched case-control study in Tri-Service General Hospital, Taipei, Taiwan. From January 2014 through June 2015, case patients with TSRSM and control patients with trimethoprim-sulfamethoxazole susceptible S. maltophilia (TSSSM) during hospitalization were identified. Control patients were matched with TSRSM cases for age (within five years), sex, and site of isolation at a ratio of 1:1. A total of 266 patients were included in our study (133 cases and 133 matched controls). Bivariable analysis showed that previous exposure to fluoroquinolone [odds ratio (OR), 2.693; 95% confidence interval (CI, 1.492-5.884; p = 0.002)], length of intensive care unit stay (OR, 1.015 per day; 95% CI, 1.001-1.030; p = 0.041), and length of hospital stay (OR, 1.012 per day; 95% CI, 1.002-1.023; p = 0.018) prior to S. maltophilia isolation were associated with TSRSM occurrence. A multivariable analysis showed that previous exposure to fluoroquinolone (OR, 3.158; 95% CI, 1.551-6.430; p = 0.002) was an independent risk factor for TSRSM occurrence after adjustment. Previous fluoroquinolone use was an independent risk factor for hospital-acquired TSRSM occurrence in adult inpatients, suggesting that judicious administration of fluoroquinolone may be important for limiting TSRSM occurrence. Copyright © 2017. Published by Elsevier B.V.

Comparison of two control groups for estimation of oral cholera vaccine effectiveness using a case-control study design.

PubMed

Franke, Molly F; Jerome, J Gregory; Matias, Wilfredo R; Ternier, Ralph; Hilaire, Isabelle J; Harris, Jason B; Ivers, Louise C

2017-10-13

Case-control studies to quantify oral cholera vaccine effectiveness (VE) often rely on neighbors without diarrhea as community controls. Test-negative controls can be easily recruited and may minimize bias due to differential health-seeking behavior and recall. We compared VE estimates derived from community and test-negative controls and conducted bias-indicator analyses to assess potential bias with community controls. From October 2012 through November 2016, patients with acute watery diarrhea were recruited from cholera treatment centers in rural Haiti. Cholera cases had a positive stool culture. Non-cholera diarrhea cases (test-negative controls and non-cholera diarrhea cases for bias-indicator analyses) had a negative culture and rapid test. Up to four community controls were matched to diarrhea cases by age group, time, and neighborhood. Primary analyses included 181 cholera cases, 157 non-cholera diarrhea cases, 716 VE community controls and 625 bias-indicator community controls. VE for self-reported vaccination with two doses was consistent across the two control groups, with statistically significant VE estimates ranging from 72 to 74%. Sensitivity analyses revealed similar, though somewhat attenuated estimates for self-reported two dose VE. Bias-indicator estimates were consistently less than one, with VE estimates ranging from 19 to 43%, some of which were statistically significant. OCV estimates from case-control analyses using community and test-negative controls were similar. While bias-indicator analyses suggested possible over-estimation of VE estimates using community controls, test-negative analyses suggested this bias, if present, was minimal. Test-negative controls can be a valid low-cost and time-efficient alternative to community controls for OCV effectiveness estimation and may be especially relevant in emergency situations. Copyright © 2017. Published by Elsevier Ltd.

Point process methods in epidemiology: application to the analysis of human immunodeficiency virus/acquired immunodeficiency syndrome mortality in urban areas.

PubMed

Quesada, Jose Antonio; Melchor, Inmaculada; Nolasco, Andreu

2017-05-26

The analysis of spatio-temporal patterns of disease or death in urban areas has been developed mainly from the ecological studies approach. These designs may have some limitations like the ecological fallacy and instability with few cases. The objective of this study was to apply the point process methodology, as a complement to that of aggregated data, to study HIV/AIDS mortality in men in the city of Alicante (Spain). A case-control study in residents in the city during the period 2004-2011 was designed. Cases were men who died from HIV/AIDS and controls represented the general population, matched by age to cases. The risk surfaces of death over the city were estimated using the log-risk function of intensities, and we contrasted their temporal variations over the two periods. High risk significant areas of death by HIV/AIDS, which coincide with the most deprived areas in the city, were detected. Significant spatial change of the areas at risk between the periods studied was not detected. The point process methodology is a useful tool to analyse the patterns of death by HIV/AIDS in urban areas.

Chromosomal DNA damage measured using the cytokinesis-block micronucleus cytome assay is significantly associated with cognitive impairment in South Australians.

PubMed

Lee, Sau Lai; Thomas, Philip; Hecker, Jane; Faunt, Jeffrey; Fenech, Michael

2015-01-01

Loss of genome integrity may be associated with increased risk for neurodegenerative disease. The aim of this study was to investigate whether mild cognitive impairment (MCI) or Alzheimer's disease (AD) individuals have increased DNA damage relative to age- and gender- matched controls using the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay. DNA damage was measured as micronuclei (MN), nucleoplasmic bridges (NPB), and nuclear buds (NBUD) in binucleated cells. The assay was performed on blood samples from 80 participants consisting of (i) MCI cases (N = 20) and age- and gender- matched controls (N = 20), and (ii) AD cases (N = 20) and age- and gender- matched controls (N = 20). There was a significant increase in MCI NBUD frequency (P = 0.006) relative to controls, which was also observed in male (P = 0.03) and female (P = 0.04) subgroups. For AD cases, there were no significant differences in assay biomarkers relative to controls. There was a significant negative correlation between Mini Mental State Examination (MMSE) and (i) MN in all controls, (R = -0.3, P = 0.04), and AD cases (R = -0.4, P = 0.03), (ii) NPB in all controls, (R = -0.4, P = 0.006) and AD cases (R = -0.5, P = 0.01), and (iii) NBUD in MCI cases (R = -0.5, P = 0.007) and AD cases (R = -0.7, P = 0.0002). The results suggest that an increase in lymphocyte CBMN-Cyt DNA damage biomarkers may be associated with cognitive decline. © 2014 Wiley Periodicals, Inc.

Prediction of Gut Wall Integrity Loss in Viral Gastroenteritis by Non-Invasive Marker

PubMed Central

Elnady, Hala G.; Sherif, Lobna S.; Saleh, Maysa T.; El-Alameey, Inas R.; Youssef, Mai M.; El Shafie, Amal I.; Helwa, Iman; Raouf, Haiam Abdel; EL-Taweel, Ahmed N.

2015-01-01

BACKGROUND: Intestinal fatty acid binding proteins (I-FABPs) are mainly expressed in the intestinal villi, which are the initial site of destruction in viral gastroenteritis. AIM: This study was designed to assess serum I-FABPs as a predictor of gut wall integrity loss in viral gastroenteritis. PATIENTS AND METHODS: This case-control cross-sectional study was conducted on 93 cases of acute viral gastroenteritis. Twenty-eight healthy children matching in age were recruited as control group. Serum I-FABPs were measured using ELISA technique. Viral detection and typing were done by PCR for adenovirus, and by Reverse transcriptase PCR for rotavirus, astrovirus and norovirus. RESULTS: Serum I-FABPs level was significantly higher in the cases compared to the controls and was also higher in the 46 rotavirus gastroenteritis cases compared to other viral gastroenteritis cases. Serum I- FABPs level was significantly higher in severely dehydrated cases as compared to mildly dehydrated ones (P=0.037). CONCLUSION: Serum I-FABPs could be used as an early and sensitive predictor marker of gut wall integrity loss in children with viral gastroenteritis and its level can indicate case severity. PMID:27275194

Trivalent inactivated influenza vaccine and spontaneous abortion.

PubMed

Irving, Stephanie A; Kieke, Burney A; Donahue, James G; Mascola, Maria A; Baggs, James; DeStefano, Frank; Cheetham, T Craig; Jackson, Lisa A; Naleway, Allison L; Glanz, Jason M; Nordin, James D; Belongia, Edward A

2013-01-01

To estimate the association between spontaneous abortion and influenza vaccine receipt with a case-control study utilizing data from six health care organizations in the Vaccine Safety Datalink. Women aged 18-44 years with spontaneous abortion during the autumn of 2005 or 2006 were identified using International Classification of Diseases, 9th Revision, Clinical Modification codes. Cases of spontaneous abortion at 5-16 weeks of gestation were confirmed by medical record review; date of fetal demise was based on ultrasound information when available. Control group individuals with a live birth were individually matched to case group individuals by health care organization and date of last menstrual period (LMP). The primary exposure of interest was influenza vaccination during the 28 days preceding the date of spontaneous abortion of the matched pair. Conditional logistic regression models adjusted for maternal age, health care utilization, maternal diabetes, and parity. Our final analysis included 243 women with spontaneous abortion and 243 matched control group women; 82% of women with spontaneous abortion had ultrasound confirmation of fetal demise. Using clinical diagnosis and ultrasound data, the mean gestational age at fetal demise was 7.8 weeks. Mean ages at LMP of case group women and control group women were 31.7 and 29.3 years, respectively (P<.001). Sixteen women with spontaneous abortion (7%) and 15 (6%) matched control group women received influenza vaccine within the 28-day exposure window. There was no association between spontaneous abortion and influenza vaccination in the 28-day exposure window (adjusted matched odds ratio 1.23, 95% confidence interval 0.53-2.89; P=.63). There was no statistically significant increase in the risk of pregnancy loss in the 4 weeks after seasonal inactivated influenza vaccination. II.

Long-term survival after traumatic brain injury: a population-based analysis controlled for nonhead trauma.

PubMed

Brown, Allen W; Leibson, Cynthia L; Mandrekar, Jay; Ransom, Jeanine E; Malec, James F

2014-01-01

To examine the contribution of co-occurring nonhead injuries to hazard of death after traumatic brain injury (TBI). A random sample of Olmsted County, Minnesota, residents with confirmed TBI from 1987 through 1999 was identified. Each case was assigned an age- and sex-matched, non-TBI "regular control" from the population. For "special cases" with accompanying nonhead injuries, 2 matched "special controls" with nonhead injuries of similar severity were assigned. Vital status was followed from baseline (ie, injury date for cases, comparable dates for controls) through 2008. Cases were compared first with regular controls and second with regular or special controls, depending on case type. In total, 1257 cases were identified (including 221 special cases). For both cases versus regular controls and cases versus regular or special controls, the hazard ratio was increased from baseline to 6 months (10.82 [2.86-40.89] and 7.13 [3.10-16.39], respectively) and from baseline through study end (2.92 [1.74-4.91] and 1.48 [1.09-2.02], respectively). Among 6-month survivors, the hazard ratio was increased for cases versus regular controls (1.43 [1.06-2.15]) but not for cases versus regular or special controls (1.05 [0.80-1.38]). Among 6-month survivors, accounting for nonhead injuries resulted in a nonsignificant effect of TBI on long-term mortality.

Risk of acute liver injury associated with use of antibiotics. Comparative cohort and nested case-control studies using two primary care databases in Europe.

PubMed

Brauer, Ruth; Douglas, Ian; Garcia Rodriguez, Luis Alberto; Downey, Gerald; Huerta, Consuelo; de Abajo, Francisco; Bate, Andrew; Feudjo Tepie, Maurille; de Groot, Mark C H; Schlienger, Raymond; Reynolds, Robert; Smeeth, Liam; Klungel, Olaf; Ruigómez, Ana

2016-03-01

To assess the impact of varying study designs, exposure and outcome definitions on the risk of acute liver injury (ALI) associated with antibiotic use. The source population comprised of patients registered in two primary care databases, in the UK and in Spain. We identified a cohort consisting of new users of antibiotics during the study period (2004-2009) and non-users during the study period or in the previous year. Cases with ALI were identified within this cohort and classified as definite or probable, based on recorded medical information. The relative risk (RR) of ALI associated with antibiotic use was computed using Poisson regression. For the nested case-control analyses, up to five controls were matched to each case by age, sex, date and practice (in CPRD) and odds ratios (OR) were computed with conditional logistic regression. The age, sex and year adjusted RRs of definite ALI in the current antibiotic use periods was 10.04 (95% CI: 6.97-14.47) in CPRD and 5.76 (95% CI: 3.46-9.59) in BIFAP. In the case-control analyses adjusting for life-style, comorbidities and use of medications, the OR of ALI for current users of antibiotics was and 5.7 (95% CI: 3.46-9.36) in CPRD and 2.6 (95% CI: 1.26-5.37) in BIFAP. Guided by a common protocol, both cohort and case-control study designs found an increased risk of ALI associated with the use of antibiotics in both databases, independent of the exposure and case definitions used. However, the magnitude of the risk was higher in CPRD compared to BIFAP. Copyright © 2016 John Wiley & Sons, Ltd.

Issues Related to Obtaining Intelligence Quotient-Matched Controls in Autism Research

PubMed Central

Rao, Vanitha S.; Raman, Vijaya; Mysore, Ashok V.

2015-01-01

Background: Intelligence Quotient (IQ) is considered to be an index of global cognitive functioning and has traditionally been used as a fulcral measure in case-control studies in neuro-developmental disorders such as autism. Aim: The aim is to highlight the issues of “matching for IQ” with controls in autism research. Materials and Methods: Percentile scores on the Coloured Progressive Matrices of 20 children with autism in the age range of 5 to 12 years have been graphically compared with 21 age matched typically developing children. Results and Conclusions: The percentile scores of the so-called high functioning children with autism from special schools were well below that of typically developing children. There are many challenges when using IQ in case-control studies of autism. Alternative approaches need to be considered. PMID:25969598

Associations Between Physical Fitness Indices and Working Memory in Breast Cancer Survivors and Age-Matched Controls

PubMed Central

Mackenzie, Michael J.; Zuniga, Krystle E.; Raine, Lauren B.; Awick, Elizabeth A.; Hillman, Charles H.; Kramer, Arthur F.

2016-01-01

Abstract Background: This study examined the effects of cardiorespiratory fitness, heart rate recovery, and physical activity on working memory in breast cancer survivors and age-matched controls. Method: Using a case-control design, 32 women who had received a breast cancer diagnosis and completed primary treatment within the past 36-months (11 radiation only; 21 chemotherapy) and 30 age-matched women with no previous cancer diagnosis completed a n-back continuous performance task commonly used as an assessment of working memory. In addition, cardiorespiratory fitness and heart rate recovery were measured during a submaximal graded exercise test and physical activity was measured using 7-days of accelerometer monitoring. Results: Breast cancer survivors who had received chemotherapy had poorer heart rate recovery (p = .010) and engaged in less physical activity than women who had received radiation only (p = .004) or non-cancer controls (p = .029). Cancer treatment (radiation; chemotherapy) predicted differences in reaction times on the 1-back working memory task (p = .029). However, more rapid heart rate recovery predicted shorter reaction times on the 1-back task in the age-matched control group (p = .002). All participants with greater cardiorespiratory fitness displayed greater accuracy independent of disease status on the 1-back task (p = .017). No significant group differences in reaction times were observed for 2-back target trials between breast cancer survivors and controls. However, greater total physical activity predicted shorter reaction times in breast cancer survivors (radiation, chemotherapy) on the 2-back task (p = .014). In addition, all participants who exhibited more rapid heart rate recovery demonstrated better greater accuracy regardless of disease status (p = .013). Conclusion: These findings support differences in physical activty participation, heart rate recovery, and 1- and 2-back working memory reaction times between breast cancer survivors and age-matched controls. Greater cardiorespiratory fitness, heart rate recovery, and physical activity were positively associated with better working memory performance across conditions. PMID:26418463

Nitrates in municipal drinking water and non-Hodgkin lymphoma: an ecological cancer case-control study in Taiwan.

PubMed

Chang, Chih-Ching; Tsai, Shang-Shyue; Wu, Trong-Neng; Yang, Chun-Yuh

2010-01-01

The relationship between nitrate levels in drinking water and increased risk of non-Hodgkin lymphoma (NHL) development has been inconclusive. A matched cancer case-control and a nitrate ecology study was used to investigate the association between mortality attributed to NHL and nitrate exposure from Taiwan's drinking water. All deaths due to NHL in Taiwan residents from 2000 through 2006 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to the cases by gender, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each case. Data on nitrate-nitrogen (NO(3)-N) levels of drinking water throughout Taiwan were collected from the Taiwan Water Supply Corporation (TWSC). The municipality of residence for cancer cases and controls was presumed to be the source of the subject's nitrate exposure via drinking water. The adjusted odds ratios (OR) for NHL death for those with high nitrate levels in their drinking water, as compared to the lowest tertile, were 1.02 (0.87-1.2) and 1.05 (0.89-1.24), respectively. The results of the present study show that there was no statistically significant association between nitrates in drinking water at levels in this investigation and increased risk of death attributed to NHL.

Nitrate in drinking water and risk of death from bladder cancer: an ecological case-control study in Taiwan.

PubMed

Chiu, Hui-Fen; Tsai, Shang-Shyue; Yang, Chun-Yuh

2007-06-01

The relationship between nitrate levels in drinking water and bladder cancer development is controversial. A matched cancer case-control with nitrate ecology study was used to investigate the association between bladder cancer mortality occurrence and nitrate exposure from Taiwan drinking water. All bladder cancer deaths of Taiwan residents from 1999 through 2003 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to the cases by gender, year of birth,and year of death. Each matched control was selected randomly from the set of possible controls for each cancer case. Data on nitrate-nitrogen (NO3-N) levels in drinking water throughout Taiwan were collected from Taiwan Water Supply Corporation (TWSC). The municipality of residence for cancer cases and controls was assumed to be the source of the subject's nitrate exposure via drinking water. The adjusted odds ratios for bladder cancer death for those with high nitrate levels in their drinking water were 1.76 (1.28-2.42) and 1.96 (1.41-2.72) as compared to the lowest tertile. The results of the present study show that there was a significant positive relationship between the levels of nitrate in drinking water and risk of death from bladder cancer.

A case-control study of syphilis among men who have sex with men in New York City: association With HIV infection.

PubMed

Paz-Bailey, Gabriela; Meyers, Andrea; Blank, Susan; Brown, James; Rubin, Steve; Braxton, Jim; Zaidi, Akbar; Schafzin, Josh; Weigl, Susan; Markowitz, Laurie E

2004-10-01

The objective of this study was to determine factors associated with syphilis among men who report sex with other men in New York City. DESIGN, SETTING AND STUDY SUBJECTS: We conducted a case-control study among 88 men who reported sex with men in the previous year, 18 to 55 years old and diagnosed with primary or secondary syphilis during 2001; and 176 control subjects frequently matched by age and type of health provider. HIV prevalence among syphilis cases was 48% compared with 15% among control subjects (P <0.001). Variables associated with syphilis in a multivariate model were HIV infection (odds ratio [OR], 7.3; 95% confidence interval [CI], 3.5-15.4), income >$30,000 per year (OR, 2.7; CI, 1.4-5.2), and barebacking (OR, 2.6; CI, 1.4-4.8). The median time since HIV diagnosis for HIV-positive was 6 years for cases and 7 years for control subjects (P = 0.70). Among HIV-infected participants, syphilis cases were more likely than control subjects to report being on antiretroviral therapy (69% vs. 44%, P = 0.05) and to report having undetectable viral load (58% vs. 24%, P = 0.02). HIV infection was strongly associated with syphilis in this study. High-risk behavior reported by both cases and control subjects indicates the potential for increased HIV transmission.

[Risk factors found in suicide attempters].

PubMed

Villa-Manzano, Alberto Iram; Robles-Romero, Miguel Angel; Gutiérrez-Román, Elsa Armida; Martínez-Arriaga, María Guadalupe; Valadez-Toscano, Francisco Javier; Cabrera-Pivaral, Carlos E

2009-01-01

A better understanding of risk factors for suicide in general population is crucial for the design of suicide prevention programs. Our objective was to identify personal and family risk factors in suicide attempters. Case-control design. We searched in patients with an acute intoxication, those subjects with and intoxication attributable to suicide attempt. These patients were matched with controls by gender and the date of intoxication. We use a structured questionnaire to identify personal characteristics, family features and network support. Odds ratio (OR) and 95 % confidence interval were obtained. 25 cases and 25 controls were evaluated. The risk factors associated with suicide attempt adjusted by age, were being a student and smoking habits. Family violence background showed OR = 3.8 (IC 95 % = 1.1-13), family disintegration a OR = 8.5 (IC 95 % = 2.1-35), critical events background OR = 8.8 (IC 95 % = 2.1-36), poor self-esteem OR = 8.2 (IC 95 % 2-35), depression OR = 22 (IC 95 % = 3-190), anxiety OR = 9 (IC 95 % = 2-47), family dysfunction OR = 25 (IC 95 % = 4-151). The principal risk factor for suicide attempt was family dysfunction and psychological traits.

Orbital fractures due to domestic violence: an epidemiologic study.

PubMed

Goldberg, Stuart H.; McRill, Connie M.; Bruno, Christopher R.; Ten Have, Tom; Lehman, Erik

2000-09-01

Domestic violence is an important cause of orbital fractures in women. Physicians who treat patients with orbital fractures may not suspect this mechanism of injury. The purpose of this study was to assess the association between domestic violence and orbital fractures. A medical center-based case-control study with matching on age and site of admission was done. Medical center databases were searched using ICD-9 codes to identify all cases of orbital fractures encountered during a three-year period. Medical records of female patients age 13 and older were reviewed along with those of age, gender and site of admission matched controls. A stratified exact test was employed to test the association between domestic violence and orbital fracture. Among 41 adult female cases with orbital fractures treated at our medical center, three (7.3%) reported domestic violence compared to zero among the matched controls (p = 0.037). We believe that domestic violence may be under-reported in both orbital fracture cases and controls. This may result in an underestimate of the orbital fracture versus domestic violence association. Domestic violence is a serious women's health and societal problem. Domestic violence may have a variety of presentations, including illnesses and injuries. Orbital fracture is an identifiable manifestation of domestic violence. Domestic violence is more likely to be detected in adult female hospital patients with orbital fracture than in matched controls with any other diagnosis. Physicians who treat patients with orbital fractures should be familiar with this mechanism of injury.

The Impact Of Palifermin Use On Hematopoietic Cell Transplant Outcomes In Children

PubMed Central

Saber, Wael; Zhang, Mei-Jie; Steinert, Patricia; Chen, Min; Horowitz, Mary M

2016-01-01

Purpose Clinical trials evaluating palifermin have enrolled few pediatric patients precluding safety analyses in large groups of children. We compared hematopoietic cell transplant (HCT) outcomes among pediatric patients from a large database who did or did not receive palifermin as a preventive treatment for oral mucositis. Patients and Methods Pediatric patients and controls, matched for HCT and donor type, disease, disease status and age, were selected from the Center for International Blood and Marrow Transplant Research (CIBMTR) database and a 1:3 matched cohort analysis was performed. Stratified Cox proportional hazards models were built and propensity score adjustments were used to compare overall and disease-free survival outcomes between palifermin-treated and untreated patients. Results Three controls were identified for 90% of palifermin recipients. The remaining cases were matched with two (8%) or one (2%) controls, for a total of 210 palifermin-treated patients matched with 606 controls. Median follow-up was 31 months in cases and 36 months in controls. 57% of patients underwent allogeneic HCT, mostly for acute leukemia, and 43% underwent autologous HCT, mostly for solid tumors. In univariate analyses, two-year survival and disease-free survival rates after allogeneic HCT (58% vs 66%, P = .109; 49% vs 60%, P = .060) and after autologous HCT (73% vs 77%, P = .474; 60% vs 64%, P = .637) were similar between palifermin-treated patients and matched controls. In multivariate analysis, palifermin treatment did not significantly increase the risk of mortality (relative risk [RR] 1.20, 95% CI 0.87–1.66) or relapse (RR 1.12, 95% CI 0.78–1.62) compared with matched controls. No significant differences in rates of acute or chronic graft-vs-host disease (GVHD) were observed between palifermin-treated patients and matched controls. Conclusion Among the pediatric patients undergoing HCT, overall survival, disease-free survival, neutrophil recovery, and GVHD rates were similar between palifermin-treated patients and matched controls. PMID:27090960

Medical Conditions in the First Years of Life Associated with Future Diagnosis of ASD in Children.

PubMed

Alexeeff, Stacey E; Yau, Vincent; Qian, Yinge; Davignon, Meghan; Lynch, Frances; Crawford, Phillip; Davis, Robert; Croen, Lisa A

2017-07-01

This study examines medical conditions diagnosed prior to the diagnosis of autism spectrum disorder (ASD). Using a matched case control design with 3911 ASD cases and 38,609 controls, we found that 38 out of 79 medical conditions were associated with increased ASD risk. Developmental delay, mental health, and neurology conditions had the strongest associations (ORs 2.0-23.3). Moderately strong associations were observed for nutrition, genetic, ear nose and throat, and sleep conditions (ORs 2.1-3.2). Using machine learning methods, we clustered children based on their medical conditions prior to ASD diagnosis and demonstrated ASD risk stratification. Our findings provide new evidence indicating that children with ASD have a disproportionate burden of certain medical conditions preceding ASD diagnosis.

Lack of association between migraine headache and patent foramen ovale: results of a case-control study.

PubMed

Garg, Pallav; Servoss, Stephen J; Wu, Justina C; Bajwa, Zahid H; Selim, Magdy H; Dineen, Alexis; Kuntz, Richard E; Cook, E Francis; Mauri, Laura

2010-03-30

Clinical observations of migraine headache symptoms in patients with a patent foramen ovale (PFO), both of which conditions are highly prevalent, have raised the question of a possible pathophysiological relationship. We sought to evaluate the assumption of an association between migraine headaches and the presence of PFO by use of a large case-control study. We conducted a case-control study to assess the prevalence of PFO in subjects with and without migraine. Case subjects were those with a history of migraine (diagnosed by neurologists at a specialty academic headache clinic). Control subjects were healthy volunteers without migraine 1:1 matched on the basis of age and sex with case subjects. Presence of PFO was determined by transthoracic echocardiogram with second harmonic imaging and transcranial Doppler ultrasonography during a standardized procedure of infused agitated saline contrast with or without Valsalva maneuver and a review of the results by experts blinded to case-control status. PFO was considered present if both studies were positive. Odds ratios were calculated with conditional logistic regression in the matched cohort (n=288). In the matched analysis, the prevalence of PFO was similar in case and control subjects (26.4% versus 25.7%; odds ratio 1.04, 95% confidence interval 0.62 to 1.74, P=0.90). There was no difference in PFO prevalence in those with migraine with aura and those without (26.8% versus 26.1%; odds ratio 1.03, 95% confidence interval 0.48 to 2.21, P=0.93). We found no association between migraine headaches and the presence of PFO in this large case-control study.

Study design: Evaluating gene–environment interactions in the etiology of breast cancer – the WECARE study

PubMed Central

Bernstein, Jonine L; Langholz, Bryan; Haile, Robert W; Bernstein, Leslie; Thomas, Duncan C; Stovall, Marilyn; Malone, Kathleen E; Lynch, Charles F; Olsen, Jørgen H; Anton-Culver, Hoda; Shore, Roy E; Boice, John D; Berkowitz, Gertrud S; Gatti, Richard A; Teitelbaum, Susan L; Smith, Susan A; Rosenstein, Barry S; Børresen-Dale, Anne-Lise; Concannon, Patrick; Thompson, W Douglas

2004-01-01

Introduction Deficiencies in cellular responses to DNA damage can predispose to cancer. Ionizing radiation can cause cluster damage and double-strand breaks (DSBs) that pose problems for cellular repair processes. Three genes (ATM, BRCA1, and BRCA2) encode products that are essential for the normal cellular response to DSBs, but predispose to breast cancer when mutated. Design To examine the joint roles of radiation exposure and genetic susceptibility in the etiology of breast cancer, we designed a case-control study nested within five population-based cancer registries. We hypothesized that a woman carrying a mutant allele in one of these genes is more susceptible to radiation-induced breast cancer than is a non-carrier. In our study, 700 women with asynchronous bilateral breast cancer were individually matched to 1400 controls with unilateral breast cancer on date and age at diagnosis of the first breast cancer, race, and registry region, and counter-matched on radiation therapy. Each triplet comprised two women who received radiation therapy and one woman who did not. Radiation absorbed dose to the contralateral breast after initial treatment was estimated with a comprehensive dose reconstruction approach that included experimental measurements in anthropomorphic and water phantoms applying patient treatment parameters. Blood samples were collected from all participants for genetic analyses. Conclusions Our study design improves the potential for detecting gene–environment interactions for diseases when both gene mutations and the environmental exposures of interest are rare in the general population. This is particularly applicable to the study of bilateral breast cancer because both radiation dose and genetic susceptibility have important etiologic roles, possibly by interactive mechanisms. By using counter-matching, we optimized the informativeness of the collected dosimetry data by increasing the variability of radiation dose within the case–control sets and enhanced our ability to detect radiation–genotype interactions. PMID:15084244

Risk factors for childhood burns: a case-control study of Ghanaian children.

PubMed Central

Forjuoh, S N; Guyer, B; Strobino, D M; Keyl, P M; Diener-West, M; Smith, G S

1995-01-01

STUDY OBJECTIVE--To study risk factors for childhood burns in order to identify possible preventive strategies. DESIGN--Case-control design with pair matching of controls to cases in relation to age, sex, and area of residence. The cases and controls were identified by a community based, multisite survey. The effects of host and socioenvironmental variables reported by mothers were investigated in a multivariate analysis using conditional logistic regression. SETTING--A developing country setting the Ashanti Region in Ghana. PARTICIPANTS--These comprised 610 cases aged 0-5 years who had been burned (as evidenced by a visible scar) and 610 controls with no burn history. MAIN RESULTS--The presence of a pre-existing impairment in a child was the strongest risk factor in this population (OR = 6.71; 95% CI 2.78, 16.16). Other significant risk factor included: sibling death from a burn (OR = 4.41; 95% CI 1.16, 16.68); history of burn in a sibling (OR = 1.79; 95% CI 1.24, 2.58); and storage of a flammable substance in the home (OR = 1.51; 95% CI 1.03; 2.21). Maternal education had a protective effect against childhood burns, although this effect was not strong (OR = 0.76; 95% CI 0.55, 1.05). CONCLUSIONS--Community programmes to ensure adequate child supervision and general child wellbeing, particularly for those with impairments, as well as parental education about burns are recommended, to reduce childhood burns in this region of Ghana. The public should bed advised against storing flammable substances in the home. PMID:7798049

Relationship of ZNF423 and CTSO with breast cancer risk in two randomised tamoxifen prevention trials.

PubMed

Brentnall, Adam R; Cuzick, Jack; Byers, Helen; Segal, Corrinne; Reuter, Caroline; Detre, Simone; Sestak, Ivana; Howell, Anthony; Powles, Trevor J; Newman, William G; Dowsett, Mitchell

2016-08-01

A case-control study from two randomised breast cancer prevention trials of tamoxifen and raloxifene (P-1 and P-2) identified single-nucleotide polymorphisms (SNPs) in or near genes ZNF423 and CTSO as factors which predict which women will derive most anti-cancer benefit from selective oestrogen receptor modulator (SERM) therapy. In this article, we further examine this question using blood samples from two randomised tamoxifen prevention trials: the International Breast Cancer Intervention Study I (IBIS-I) and the Royal Marsden trial (Marsden). A nested case-control study was designed with 2:1 matching in IBIS-I and 1:1 matching in Marsden. The OncoArray was used for genotyping and included two SNPs previously identified (rs8060157 in ZNF423 and rs10030044 near CTSO), and 102 further SNPs within the same regions. Overall, there were 369 cases and 662 controls, with 148 cases and 268 controls from the tamoxifen arms. Odds ratios were estimated by conditional logistic regression, with Wald 95 % confidence intervals. In the tamoxifen arms, the per-allele odds ratio for rs8060157 was 0.99 (95 %CI 0.73-1.34) and 1.00 (95 %CI 0.76-1.33) for rs10030044. In the placebo arm, the odds ratio was 1.10 (95 %CI 0.87-1.40) for rs8060157 and 1.01 (95 %CI 0.79-1.29) for rs10030044. There was no evidence to suggest that other SNPs in the surrounding regions of these SNPs might predict response to tamoxifen. Results from these two prevention trials do not support the earlier findings. rs8060157 in ZNF423 and rs10030044 near CTSO do not appear to predict response to tamoxifen.

Geographic Region, Weather, Pilot Age and Air Carrier Crashes: a Case-Control Study

PubMed Central

Li, Guohua; Pressley, Joyce C.; Qiang, Yandong; Grabowski, Jurek G.; Baker, Susan P.; Rebok, George W.

2009-01-01

Background Information about risk factors of aviation crashes is crucial for developing effective intervention programs. Previous studies assessing factors associated with crash risk were conducted primarily in general aviation, air taxis and commuter air carriers. Methods A matched case-control design was used to examine the associations of geographic region, basic weather condition, and pilot age with the risk of air carrier (14 CFR Part 121) crash involvement. Cases (n=373) were air carrier crashes involving aircraft made by Boeing, McDonnell Douglas, and Airbus, recorded in the National Transportation Safety Board’s aviation crash database during 1983 through 2002, and controls (n=746) were air carrier incidents involving aircraft of the same three makes selected at random from the Federal Aviation Administration’s aviation incident database. Each case was matched with two controls on the calendar year when the index crash occurred. Conditional logistic regression was used for statistical analysis. Results With adjustment for basic weather condition, pilot age, and total flight time, the risk of air carrier crashes in Alaska was more than three times the risk for other regions [adjusted odds ratio (OR) 3.18, 95% confidence interval (CI) 1.35 – 7.49]. Instrument meteorological conditions were associated with an increased risk for air carrier crashes involving pilot error (adjusted OR 2.26, 95% CI 1.15 – 4.44) and a decreased risk for air carrier crashes without pilot error (adjusted OR 0.57, 95% CI 0.40 – 0.87). Neither pilot age nor total flight time was significantly associated with the risk of air carrier crashes. Conclusions The excess risk of air carrier crashes in Alaska and the effect of adverse weather on pilot-error crashes underscore the importance of environmental hazards in flight safety. PMID:19378910

Geographic region, weather, pilot age, and air carrier crashes: a case-control study.

PubMed

Li, Guohua; Pressley, Joyce C; Qiang, Yandong; Grabowski, Jurek G; Baker, Susan P; Rebok, George W

2009-04-01

Information about risk factors of aviation crashes is crucial for developing effective intervention programs. Previous studies assessing factors associated with crash risk were conducted primarily in general aviation, air taxis, and commuter air carriers. A matched case-control design was used to examine the associations of geographic region, basic weather condition, and pilot age with the risk of air carrier (14 CFR Part 121) crash involvement. Cases (N = 373) were air carrier crashes involving aircraft made by Boeing, McDonnell Douglas, and Airbus recorded in the National Transportation Safety Board's aviation crash database during 1983 through 2002, and controls (N = 746) were air carrier incidents involving aircraft of the same three makes selected at random from the Federal Aviation Administration's aviation incident database. Each case was matched with two controls on the calendar year when the index crash occurred. Conditional logistic regression was used for statistical analysis. With adjustment for basic weather condition, pilot age, and total flight time, the risk of air carrier crashes in Alaska was more than three times the risk for other regions ladjusted odds ratio (OR) 3.18, 95% confidence interval (CI) 1.35-7.49]. Instrument meteorological conditions were associated with an increased risk for air carrier crashes involving pilot error (adjusted OR 2.26, 95% CI 1.15-4.44) and a decreased risk for air carrier crashes without pilot error (adjusted OR 0.60, 95% CI 0.37-0.96). Neither pilot age nor total flight time were significantly associated with the risk of air carrier crashes. The excess risk of air carrier crashes in Alaska and the effect of adverse weather on pilot-error crashes underscore the importance of environmental hazards in flight safety.

A case-control study to examine the association between breastfeeding during late pregnancy and risk of a small-for-gestational-age birth in Lima, Peru.

PubMed

Pareja, Rossina G; Marquis, Grace S; Penny, Mary E; Dixon, Philip M

2015-04-01

Excessive demands on maternal nutritional status may be a risk factor for poor birth outcomes. This study examined the association between breastfeeding during late pregnancy (≥ 28 weeks) and the risk of having a small-for-gestational-age (SGA) newborn, using a matched case-control design (78 SGA cases: birthweight <10th percentile for gestational age; 150 non-SGA controls: 50th percentile

Patterns of Migration and Risks Associated with Leprosy among Migrants in Maranhão, Brazil

PubMed Central

Murto, Christine; Chammartin, Frédérique; Schwarz, Karolin; da Costa, Lea Marcia Melo; Kaplan, Charles; Heukelbach, Jorg

2013-01-01

Leprosy remains a public health problem in Brazil with new case incidence exceeding World Health Organization (WHO) goals in endemic clusters throughout the country. Migration can facilitate movement of disease between endemic and non-endemic areas, and has been considered a possible factor in continued leprosy incidence in Brazil. A study was conducted to investigate migration as a risk factor for leprosy. The study had three aims: (1) examine past five year migration as a risk factor for leprosy, (2) describe and compare geographic and temporal patterns of migration among past 5-year migrants with leprosy and a control group, and (3) examine social determinants of health associated with leprosy among past 5-year migrants. The study implemented a matched case-control design and analysis comparing individuals newly diagnosed with leprosy (n = 340) and a clinically unapparent control group (n = 340) without clinical signs of leprosy, matched for age, sex and location in four endemic municipalities in the state of Maranhão, northeastern Brazil. Fishers exact test was used to conduct bivariate analyses. A multivariate logistic regression analysis was employed to control for possible confounding variables. Eighty cases (23.5%) migrated 5-years prior to diagnosis, and 55 controls (16.2%) migrated 5-years prior to the corresponding case diagnosis. Past 5 year migration was found to be associated with leprosy (OR: 1.59; 95% CI 1.07–2.38; p = 0.02), and remained significantly associated with leprosy after controlling for leprosy contact in the family, household, and family/household contact. Poverty, as well as leprosy contact in the family, household and other leprosy contact, was associated with leprosy among past 5-year migrants in the bivariate analysis. Alcohol consumption was also associated with leprosy, a relevant risk factor in susceptibility to infection that should be explored in future research. Our findings provide insight into patterns of migration to localize focused control efforts in endemic areas with high population mobility. PMID:24040433

Theoretical and experimental investigations on the optimal match between compressor and cold finger of the Stirling-type pulse tube cryocooler

NASA Astrophysics Data System (ADS)

Dang, Haizheng; Tan, Jun; Zhang, Lei

2016-06-01

The match between the pulse tube cold finger (PTCF) and the linear compressor of the Stirling-type pulse tube cryocooler plays a vital role in optimizing the compressor efficiency and in improving the PTCF cooling performance as well. In this paper, the interaction of them has been analyzed in a detailed way to reveal the match mechanism, and systematic investigations on the two-way matching have been conducted. The design method of the PTCF to achieve the optimal matching for the given compressor and the counterpart design method of the compressor to achieve the optimal matching for the given PTCF are put forward. Specific experiments are then carried out to verify the conducted theoretical analyses and modeling. For a given linear compressor, a new in-line PTCF which seeks to achieve the optimal match is simulated, designed and tested. And for a given coaxial PTCF, a new dual-opposed moving-coil linear compressor is also developed to match with it. The simulated and experimental results are compared, and fairly good agreements are found between them in both cases. The matched in-line cooler with the newly-designed PTCF has capacities of 4-11.84 W at 80 K with higher than 17% of Carnot efficiency and the mean motor efficiency of 81.5%, and the matched coaxial cooler with the new-designed compressor can provide 2-5.5 W at 60 K with higher than 9.6% of Carnot efficiency and the mean motor efficiency of 83%, which verify the validity of the theoretical investigations on the optimal match and the proposed design methods.

Environment And Genetics in Lung cancer Etiology (EAGLE) study: an integrative population-based case-control study of lung cancer.

PubMed

Landi, Maria Teresa; Consonni, Dario; Rotunno, Melissa; Bergen, Andrew W; Goldstein, Alisa M; Lubin, Jay H; Goldin, Lynn; Alavanja, Michael; Morgan, Glen; Subar, Amy F; Linnoila, Ilona; Previdi, Fabrizio; Corno, Massimo; Rubagotti, Maurizia; Marinelli, Barbara; Albetti, Benedetta; Colombi, Antonio; Tucker, Margaret; Wacholder, Sholom; Pesatori, Angela C; Caporaso, Neil E; Bertazzi, Pier Alberto

2008-06-06

Lung cancer is the leading cause of cancer mortality worldwide. Tobacco smoking is its primary cause, and yet the precise molecular alterations induced by smoking in lung tissue that lead to lung cancer and impact survival have remained obscure. A new framework of research is needed to address the challenges offered by this complex disease. We designed a large population-based case-control study that combines a traditional molecular epidemiology design with a more integrative approach to investigate the dynamic process that begins with smoking initiation, proceeds through dependency/smoking persistence, continues with lung cancer development and ends with progression to disseminated disease or response to therapy and survival. The study allows the integration of data from multiple sources in the same subjects (risk factors, germline variation, genomic alterations in tumors, and clinical endpoints) to tackle the disease etiology from different angles. Before beginning the study, we conducted a phone survey and pilot investigations to identify the best approach to ensure an acceptable participation in the study from cases and controls. Between 2002 and 2005, we enrolled 2101 incident primary lung cancer cases and 2120 population controls, with 86.6% and 72.4% participation rate, respectively, from a catchment area including 216 municipalities in the Lombardy region of Italy. Lung cancer cases were enrolled in 13 hospitals and population controls were randomly sampled from the area to match the cases by age, gender and residence. Detailed epidemiological information and biospecimens were collected from each participant, and clinical data and tissue specimens from the cases. Collection of follow-up data on treatment and survival is ongoing. EAGLE is a new population-based case-control study that explores the full spectrum of lung cancer etiology, from smoking addiction to lung cancer outcome, through examination of epidemiological, molecular, and clinical data. We have provided a detailed description of the study design, field activities, management, and opportunities for research following this integrative approach, which allows a sharper and more comprehensive vision of the complex nature of this disease. The study is poised to accelerate the emergence of new preventive and therapeutic strategies with potentially enormous impact on public health.

Association Between Smoking Status, Preoperative Exhaled Carbon Monoxide Levels, and Postoperative Surgical Site Infection in Patients Undergoing Elective Surgery

PubMed Central

Martin, David P.; Thompson, Rodney; Schroeder, Darrell R.; Hanson, Andrew C.; Warner, David O.

2017-01-01

Importance Cigarette smoking is a risk factor for many perioperative complications, including surgical site infection (SSI). The duration of abstinence from smoking required to reduce this risk is unknown. Objectives To evaluate if abstinence from smoking on the day of surgery is associated with a decreased frequency of SSI in patients who smoke cigarettes and to confirm that smoking is significantly independently associated with SSI when adjustment is made for potentially relevant covariates, such as body mass index. Design, Setting, and Participants In this observational, nested, matched case-control study, 2 analyses were performed at an academic referral center in the upper Midwest. Cases included all patients undergoing elective surgical procedures at Mayo Clinic, Rochester, Minnesota, between January 1, 2009, and July 31, 2014 (inclusive) who subsequently developed an SSI. Controls for both analyses were matched on age, sex, and type of surgery. Exposures Smoking status and preoperative exhaled carbon monoxide level, assessed by nurses in the preoperative holding area. Patients were classified as smoking on the day of surgery if they self-reported smoking or if their preoperative exhaled carbon monoxide level was 10 ppm or higher. Main Outcomes and Measures Surgical site infection after a surgical procedure at Mayo Clinic, Rochester, as identified by routine clinical surveillance using National Healthcare Safety Network criteria. Results Of the 6919 patients in the first analysis, 3282 (47%) were men and 3637 (53%) were women; median age (interquartile range) for control and SSI cases was 60 (48-70). Of the 392 patients in the second analysis, 182 (46%) were men and 210 (54%) were women; median age (interquartile range) for controls was 53 (45-49) and for SSI cases was 51 (45-60). During the study period, approximately 2% of surgical patients developed SSI annually. Available for the first analysis (evaluating the influence of current smoking status) were 2452 SSI cases matched to 4467 controls. The odds ratio for smoking and SSI was 1.51 (95% CI, 1.20-1.90; P < .001), which remained statistically significant after adjusting for covariates. In the second analysis (evaluating the influence of smoking on the day of surgery), there were 137 SSI cases matched to 255 controls. The odds ratio for smoking on the day of surgery and SSI was 1.96 (95% CI, 1.23-3.13; P < .001), which remained statistically significant after adjusting for covariates. Preoperative exhaled carbon monoxide level was not associated with the frequency of SSI, suggesting that the association between smoking on the day of surgery and SSI was not related to preoperative exhaled carbon monoxide levels. Conclusions and Relevance Current smoking is associated with the development of SSI, and smoking on the day of surgery is independently associated with the development of SSI. These data cannot distinguish whether abstinence per se reduces risk or whether it is associated with other factors that may be causative. PMID:28199450

A nested case-control study of fatal work related injuries among Brazilian steel workers.

PubMed Central

Barreto, S M; Swerdlow, A J; Smith, P G; Higgins, C D

1997-01-01

OBJECTIVES: To estimate the relative risk of death from work related injury in a steelworks, associated with exposure to various occupational hazards, sociodemographic factors, and medical history. MATERIAL AND METHODS: The study was a nested case-control design. It was based on a cohort of men employed in the steel plant of USIMINAS, Brazil between January 1977 and August 1990, who were followed up to November 1992. The cases were defined as all workers in the cohort who died from injury in the study period and whose death had been notified to the Brazilian Ministry of Labour as being related to work. Four controls per case, matched to cases on year of birth, were randomly selected from among workers employed in the plant at the time of death of the matching case. Data on potential risk factors for occupational injury were extracted from company records; for the controls these data were abstracted for the period preceding the death of the matching case. RESULTS: There were 37 deaths related to work injuries during the study period. Four surviving workers were selected as controls for each case, but for eight the personnel records were incomplete, leaving 140 controls in all. Significantly increased risk of fatal injury related to work was associated with exposure to noise, heat, dust and fumes, gases and vapours, rotating shift work, being a manual worker, and working in the steel mill, coke ovens, blast furnaces, and energy and water supply areas. Risk of fatal injury related to work increased with intensity of exposure to noise (P (trend) = 0.004) and heat (P < 0.001), and increased greatly with a hazard score that combined information on noise, heat, dust, and gas exposure (P < 0.001). Number of years of schooling (P = 0.03) and salary level (P = 0.03) were both negatively associated with risk. In a multivariate analysis including all these significant factors, only hazard score and area of work remained associated with death from injury related to work. The highest risks were for men exposed to all four environmental hazards (odds ratio (OR) 19.4; 95% confidence interval (95% CI) 1.1 to 352.1) and those working in the energy supply area (OR 18.0; 1.6 to 198.1). CONCLUSIONS: The study identified parts of the steelworks and types of hazard associated with greatly increased risk of fatal accident. Research and measures to prevent accidents need to concentrate on these areas and the people working in them. The use of a hazard score was successful in identifying high risk, and similar scoring might prove useful in other industrial situations. PMID:9326164

Health care resource use by patients before and after a diagnosis of chronic fatigue syndrome (CFS/ME): a clinical practice research datalink study.

PubMed

Collin, Simon M; Bakken, Inger J; Nazareth, Irwin; Crawley, Esther; White, Peter D

2017-05-05

Our aim was to investigate patterns of health care resource use by patients before and after a diagnosis of CFS/ME, as recorded by Clinical Practice Research Datalink (CPRD) GP practices in the UK. We used a case-control study design in which patients who had a first recorded diagnosis of CFS/ME during the period 01/01/2001 to 31/12/2013 were matched 1:1 with controls by age, sex, and GP practice. We compared rates of GP consultations, diagnostic tests, prescriptions, referrals, and symptoms between the two groups from 15 years (in adults) or 10 years (in children) before diagnosis to 10 years after diagnosis. Data were available for 6710 adult and 916 child (age <18 years) matched case-control pairs. Rates of GP consultations, diagnostic tests, prescriptions, referrals, and symptoms spiked dramatically in the year when a CFS/ME diagnosis was recorded. GP consultation rates were 50% higher in adult cases compared to controls 11-15 years before diagnosis (rate ratio (RR) 1.49 (95% CI 1.46, 1.52)) and 56% higher 6-10 years after diagnosis (RR 1.56 (1.54, 1.57)). In children, consultation rates in cases were 45% higher 6-10 years before diagnosis (RR 1.45 (1.40, 1.51)) and 62% higher 6-10 years after diagnosis (RR 1.62 (1.54, 1.70)). For adults and children, rates of tests, prescriptions, referrals, and symptoms were higher in cases compared to controls for up to 10 years before and after diagnosis. Adults and children with CFS/ME have greater health care needs than the rest of the population for at least ten years before their diagnosis, and these higher levels of health care resource use continue for at least ten years after diagnosis.

Health and Economic Burden of Post-Partum Staphylococcus aureus Breast Abscess

PubMed Central

Branch-Elliman, Westyn; Lee, Grace M.; Golen, Toni H.; Gold, Howard S.; Baldini, Linda M.; Wright, Sharon B.

2013-01-01

Objectives To determine the health and economic burdens of post-partum Staphylococcus aureus breast abscess. Study design We conducted a matched cohort study (N = 216) in a population of pregnant women (N = 32,770) who delivered at our center during the study period from 10/1/03–9/30/10. Data were extracted from hospital databases, or via chart review if unavailable electronically. We compared cases of S. aureus breast abscess to controls matched by delivery date to compare health services utilization and mean attributable medical costs in 2012 United States dollars using Medicare and hospital-based estimates. We also evaluated whether resource utilization and health care costs differed between cases with methicillin-resistant and -susceptible S. aureus isolates. Results Fifty-four cases of culture-confirmed post-partum S. aureus breast abscess were identified. Breastfeeding cessation (41%), milk fistula (11.1%) and hospital readmission (50%) occurred frequently among case patients. Breast abscess case patients had high rates of health services utilization compared to controls, including high rates of imaging and drainage procedures. The mean attributable cost of post-partum S. aureus breast abscess ranged from $2,340–$4,012, depending on the methods and data sources used. Mean attributable costs were not significantly higher among methicillin-resistant vs. –susceptible S. aureus cases. Conclusions Post-partum S. aureus breast abscess is associated with worse health and economic outcomes for women and their infants, including high rates of breastfeeding cessation. Future study is needed to determine the optimal treatment and prevention of these infections. PMID:24039877

The Interpretation of Studies Using the Reading Level Design.

ERIC Educational Resources Information Center

Goswami, Usha; Bryant, Peter

1989-01-01

Argues that only positive results in a reading-level (RL) match and negative results in a chronological-age (CA) match are interpretable; negative results in a CA match and positive results in a RL match are not. Argues that using the RL control is only a first step in research into reading disability. (RS)

Appendectomy, smoking habits and the risk of developing ulcerative colitis: a case control study in private practice setting.

PubMed

de Saussure, Philippe; Clerson, Pierre; Prost, Pierre-Louis; Truong Tan, Nghiep; Bouhnik, Yoram; Gil-Rch

2007-05-01

The strongest environmental factors identified for ulcerative colitis (UC) are cigarette smoking and appendectomy. However, most studies have been performed using case-controls from hospital-based populations. The purpose of this study was to compare the history of previous appendectomy and smoking habits in a group of patients with UC and a control group, followed by gastroenterologists in private practice. We performed a case control study in which 100 physicians recruited UC-patients and age and sex matched controls. Data were collected during a single visit. Based on a standardized questionnaire, UC patients and controls were divided into never, former or current smokers, and into subjects with or without a previous history of appendectomy. One hundred and ninety eight age- and sex-matched pairs of UC patients and controls were included. The prevalence of appendectomy in the UC-patients and control group was 12% and 46%, respectively. The pairwise-matched OR of ulcerative colitis for previous appendectomy was 0.10 (95% CI, 0.05-0.21) (P<0.0001). The OR for former and never smokers versus current smokers was 2.40 (95% CI 1.31-4.38) (P=0.004). In UC-patients, the OR of family history of UC compared with controls was 2.80 (95% CI, 1.01-7.77) (P=0.048). This case-control study confirmed a strong negative correlation between both appendectomy and tobacco smoking, and ulcerative colitis in patients followed-up by gastroenterological practitioners.

Is Statin Use Associated With Tendon Rupture? A Population-Based Retrospective Cohort Analysis.

PubMed

Contractor, Tahmeed; Beri, Abhimanyu; Gardiner, Joseph C; Tang, Xiaoqin; Dwamena, Francesca C

2015-01-01

Previous case reports and small studies have suggested that 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors (HMG-CoA-Is) may increase the risk of tendon rupture. We conducted a population-based retrospective cohort evaluation to better assess this relationship. From approximately 800,000 enrollees of a private insurance database, those who were aged ≤64 years with at least 1 year of continuous enrollment were selected. Exposure was defined as initiation of HMG-CoA-I after the beginning of the study period. Each exposed person was matched with 2 controls of similar age and gender. Baseline characteristics, including known risk factors for tendon rupture, were compared between exposed and control cohorts with fidelity to the study's matched design. After adjusting for differences in follow-up and baseline characteristics, incidence rate ratios for tendon rupture was assessed in HMG-CoA-I users and nonusers. A total of 34,749 exposed patients were matched with 69,498 controls. There was no difference in the occurrence of tendon ruptures in HMG-CoA-I users versus nonusers. The results remained unchanged after adjustment for age and gender. In conclusion, this population-based retrospective cohort evaluation suggests that use of HMG-CoA-Is as a group are not associated with tendon rupture.

Evaluating the use of friend or family controls in epidemiologic case-control studies.

PubMed

Zhong, Charlie; Cockburn, Myles; Cozen, Wendy; Voutsinas, Jenna; Lacey, James V; Luo, Jianning; Sullivan-Halley, Jane; Bernstein, Leslie; Wang, Sophia S

2017-02-01

Traditional methodologies for identifying and recruiting controls in epidemiologic case-control studies, such as random digit dialing or neighborhood walk, suffer from declining response rates. Here, we revisit the feasibility and comparability of using alternative sources of controls, specifically friend and family controls. We recruited from a recently completed case-control study of non-Hodgkin lymphoma (NHL) among women in Los Angeles County where controls from the parent study were ascertained by neighborhood walk. We calculated participation rates and compared questionnaire responses between the friend/family controls and the original matched controls from the parent study. Of the 182 NHL case patients contacted, 111 (61%) agreed to participate in our feasibility study. 70 (63%) provided contact information for potential friend and/or family member controls. We were able to successfully contact and recruit a friend/family member for 92% of the case patients. This represented 46 friend controls and 54 family controls. Family controls significantly differed from original matched controls by sex and household income. Other characteristics were similar between friend controls and the original study's neighborhood controls. The apparent comparability of neighborhood controls to friend and family controls among respondents in this study suggests that these alternative methods of control identification can serve as a complementary source of eligible controls in epidemiologic case-control studies. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Role of Surgical Margin on Local Recurrence in High Risk Extremity Osteosarcoma: A Case-Controlled Study

PubMed Central

Song, Won Seok; Kong, Chang-Bae; Cho, Wan Hyeong; Cho, Sang Hyun; Lee, Jeong Dong; Lee, Soo-Yong

2013-01-01

Background The relationship between surgical margin and local recurrence (LR) in osteosarcoma patients with poor responses to chemotherapy is unclear. Moreover, the incidences of LR according to three different resection planes (bone, soft tissue, and perineurovascular) are not commonly known. Methods We evaluated the incidence of LR in three areas. To assess whether there is a role of surgical margin on LR in patients resistant to preoperative chemotherapy, we designed a case (35 patients with LR) and control (70 patients without LR) study. Controls were matched for age, location, initial tumor volume, and tumor volume change during preoperative chemotherapy. Results LR occurred at the soft tissues in 18 cases (51.4%), at the perineurovascular tissues in 11 cases (31.4%), and at the bones in six cases (17.2%). The proportion of inadequate perineurovascular margin was higher in the case group than in the control group (p = 0.01). Within case-control group (105 patients), a correlation between each margin status and LR at corresponding area was found in the bone (p < 0.001) and perineurovascular area (p = 0.001). Conclusions LR is most common in soft tissues. In patients showing similar unfavorable responses to chemotherapy, the losses of perineurovascular fat plane on preoperative magnetic resonance imaging may be a valuable finding in predicting LR. PMID:24009908

A Prospective Study Investigating Pre-diagnostic Leukocyte Telomere Length and Risk of Developing Rheumatoid Arthritis in Women

PubMed Central

Prescott, Jennifer; Karlson, Elizabeth W.; Orr, Esther H.; Zee, Robert Y.L.; De Vivo, Immaculata; Costenbader, Karen H.

2015-01-01

Objective To prospectively examine the association between leukocyte telomere length (LTL) and subsequent RA development in women. Methods Using a case-control design nested within the prospective Nurses’ Health Study (NHS), Nurses’ Health Study II (NHSII), and Women’s Health Study (WHS), each validated case of RA with a pre-diagnostic blood sample was matched to three controls by cohort, age, menopausal status, postmenopausal hormone therapy, and blood collection covariates. We measured telomere length in genomic DNA extracted from stored buffy coat samples using quantitative PCR. We used unconditional logistic regression to determine odds ratios (OR) and 95% confidence intervals (CI), and random-effects meta-analysis to combine study results. Results In total, we analyzed 296 incident RA cases and 827 matched controls. Mean age of diagnosis among women who developed RA was 60.5 in NHS/NHSII and 61.3 in WHS. Meta-analysis demonstrated that longer pre-diagnostic LTL was associated with increased RA risk when women in the longest vs. shortest LTL tertile were compared (OR=1.51, 95% CI=1.03–2.23; pheterogeneity=0.27). However, statistically significant between study heterogeneity was observed for the intermediate tertile category (pheterogeneity=0.008). We did not observe heterogeneity by menopausal status, inflammatory cytokine levels, age at diagnosis, age at blood collection, body mass index, seropositivity, or HLA-DRB1 shared epitope status. Conclusion Our results do not support a role for short LTL preceding RA development. PMID:26773113

Modifiable Neighborhood Features Associated With Adolescent Homicide.

PubMed

Culyba, Alison J; Jacoby, Sara F; Richmond, Therese S; Fein, Joel A; Hohl, Bernadette C; Branas, Charles C

2016-05-01

Homicide is a leading cause of adolescent mortality. To our knowledge, relatively little has been studied in terms of the association between environmental neighborhood features, such as streets, buildings, and natural surroundings, and severe violent injury among youth. To assess associations between environmental neighborhood features and adolescent homicide in order to identify targets for future place-based interventions. Population-based case-control study conducted in Philadelphia, Pennsylvania, from April 15, 2008, to March 31, 2014. We identified adolescents who died by homicide at 13 to 20 years of age from 2010 to 2012 while residing in Philadelphia. We used incidence-density sampling and random-digit dialing to recruit control participants ages 13 to 20 years matched on sex and indoor-outdoor location at the time of each index case participant's homicide. To obtain environmental data about modifiable features that were present in the immediate surroundings of our case and control participants, blinded field researchers used standardized techniques to photograph case and control participant outdoor locations. Photographic data were stitched together to create 360° panoramic images that were coded for 60 elements of the visible environment. Adolescent homicide. We enrolled 143 homicide case participants (mean [SD] age, 18.4 [1.5] years) and 155 matched control participants (mean [SD] age, 17.2 [2.1] years) who were both outdoors at the time of the homicide. In adjusted analyses, multiple features of Philadelphia streets, buildings, and natural surroundings were associated with adolescent homicide. The presence of street lighting (odds ratio [OR], 0.24; 95% CI, 0.09-0.70), illuminated walk/don't walk signs (OR, 0.16; 95% CI, 0.03-0.92), painted marked crosswalks (OR, 0.17; 95% CI, 0.04-0.63), public transportation (OR, 0.13; 95% CI, 0.03-0.49), parks (OR, 0.09; 95% CI, 0.01-0.88), and maintained vacant lots (OR, 0.17; 95% CI, 0.03-0.81) were significantly associated with decreased odds of homicide. The odds of homicide were significantly higher in locations with stop signs (OR, 4.34; 95% CI, 1.40-13.45), security bars/gratings on houses (OR, 9.23; 95% CI, 2.45-34.80), and private bushes/plantings (OR, 3.44; 95% CI, 1.18-10.01). Using a population-based case-control design, we identified multiple modifiable environmental features that might be targeted in future randomized intervention trials designed to reduce youth violence by improving neighborhood context.

[Clinical and epidemiological differences between Bordetella pertussis and respiratory syncytial virus infections in infants: a matched case control study].

PubMed

Giménez-Sánchez, Francisco; Cobos-Carrascosa, Elena; Sánchez-Forte, Miguel; López-Sánchez, María Ángeles; González-Jiménez, Yolanda; Azor-Martínez, Ernestina

2014-01-01

An increase in cases of pertussis, mainly in young infants, has been reported in the last few years. The clinical presentation of this disease is very similar to that produced by respiratory syncytial virus (RSV), which makes the diagnosis difficult. To compare the clinical and epidemiological characteristics between Bordetella pertussis and RSV infections in infants admitted to hospital. An analytical matched case-control study was conducted during the period 2008-2011. Cases were defined as infants admitted with pertussis confirmed by PCR in nasopharyngeal aspirate. Each case was matched by age, sex and date of admission to two controls defined as patients with RSV infection detected by immunochromatography in nasal aspirate. Demographic, clinical, laboratory data were compared. Seventy eight patients (26 cases of pertussis and 52 controls RSV+) were included. Sociodemographic characteristics were similar in both groups. Cases had more days of symptoms prior to admission, longer hospital stays, and increased frequency of epidemic family environment. Apnoea and cyanosis were more frequent. Cases of pertussis were more likely to have apnoea, cyanosis, and lymphocytosis while RSV infections had more frequent fever, vomiting and respiratory distress. The clinical presentations of pertussis and RSV infection are similar, but there are some characteristics that can help to distinguish between them. Copyright © 2013 Elsevier España, S.L. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

Hypothyroidism among SLE patients: Case-control study.

PubMed

Watad, Abdulla; Mahroum, Naim; Whitby, Aaron; Gertel, Smadar; Comaneshter, Doron; Cohen, Arnon D; Amital, Howard

2016-05-01

The prevalence of hypothyroidism in SLE patients varies considerably and early reports were mainly based on small cohorts. To investigate the association between SLE and hypothyroidism. Patients with SLE were compared with age and sex-matched controls regarding the proportion of hypothyroidism in a case-control study. Chi-square and t-tests were used for univariate analysis and a logistic regression model was used for multivariate analysis. The study was performed utilizing the medical database of Clalit Health Services. The study included 5018 patients with SLE and 25,090 age and sex-matched controls. The proportion of hypothyroidism in patients with SLE was increased compared with the prevalence in controls (15.58% and 5.75%, respectively, P<0.001). In a multivariate analysis, SLE was associated with hypothyroidism (odds ratio 2.644, 95% confidence interval 2.405-2.908). Patients with SLE have a greater proportion of hypothyroidism than matched controls. Therefore, physicians treating patients with SLE should be aware of the possibility of thyroid dysfunction. Copyright © 2016 Elsevier B.V. All rights reserved.

Case-control study on the association between a cluster of childhood haematopoietic malignancies and local environmental factors in Aalsmeer, The Netherlands.

PubMed Central

Mulder, Y M; Drijver, M; Kreis, I A

1994-01-01

STUDY OBJECTIVE AND DESIGN--In Aalsmeer, a horticultural community near the main international airport in The Netherlands, a more than fourfold increase in the incidence of haematopoietic malignancies in young people was observed between 1980 and 1985. In a population based case-control study, the association with local environmental factors was investigated. PARTICIPANTS--For each patient younger than 40 years of age (n = 14) diagnosed between 1975 and 1989, four age and sex matched controls were selected via local general practitioners. METHODS--All parents of patients and controls completed a questionnaire on their lifestyle, living conditions, and health, for several years preceding each individual diagnosis. Odds ratios (ORs) with 95% confidence intervals (CI) were calculated, matched, and, if necessary, stratified for neighbourhood. MAIN RESULTS--Increased ORs were recorded for intensive use of petroleum products and pesticides by the patients themselves and their fathers: OR petroleum products: 8.0 (95% CI 2.2, 129.9) and 9.0 (1.0, 66.1) respectively; OR pesticides: 6.0 (0.6, 49.3) and 3.2 (1.0, 10.1) respectively. Swimming in a local pond was also significantly associated with the disease: OR = 5.3 (1.3, 17.4). In the 1970s this pond had been polluted by petroleum products and pesticides. CONCLUSIONS--The increased incidence of childhood haematopoietic malignancies in Aalsmeer may have been associated with several specific local environmental factors. Interpretation of the results, however, should take into account the fact that confidence intervals were wide because of the limited number of cases. PMID:8189171

Differences in day and night shift clinical performance in anesthesiology.

PubMed

Cao, Caroline G L; Weinger, Matthew B; Slagle, Jason; Zhou, Chuan; Ou, Jennie; Gillin, Shakha; Sheh, Bryant; Mazzei, William

2008-04-01

This study examined whether anesthesia residents (physicians in training) performed clinical duties in the operating room differently during the day versus at night. Fatigue from sleep deprivation and working through the night is common for physicians, particularly during residency training. Using a repeated-measures design, we studied 13 pairs of day-night matched anesthesia cases. Dependent measures included task times, workload ratings, response to an alarm light latency task, and mood. Residents spent significantly less time on manual tasks and more time on monitoring tasks during the maintenance phase at night than during the day. Residents reported more negative mood at night than during the day, both pre- and postoperation. However, time of day had no effect on the mood change between pre- and postoperation. Workload ratings and the response time to an alarm light latency task were not significantly different between night and day cases. Because night shift residents had been awake and working for more than 16 hr, the observed differences in task performance and mood may be attributed to fatigue. The changes in task distribution during night shift work may represent compensatory strategies to maintain patient care quality while keeping perceived workload at a manageable level. Fatigue effects during night shifts should be considered when designing work-rest schedules for clinicians. This matched-case control scheme can also be applied to study other phenomena associated with patient safety in the actual clinical environment.

Incidental Prophylactic Nodal Irradiation and Patterns of Nodal Relapse in Inoperable Early Stage NSCLC Patients Treated With SBRT: A Case-Matched Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lao, Louis; Department of Radiation Oncology, Auckland City Hospital, Auckland; Hope, Andrew J.

2014-09-01

Purpose: Reported rates of non-small cell lung cancer (NSCLC) nodal failure following stereotactic body radiation therapy (SBRT) are lower than those reported in the surgical series when matched for stage. We hypothesized that this effect was due to incidental prophylactic nodal irradiation. Methods and Materials: A prospectively collected group of medically inoperable early stage NSCLC patients from 2004 to 2010 was used to identify cases with nodal relapses. Controls were matched to cases, 2:1, controlling for tumor volume (ie, same or greater) and tumor location (ie, same lobe). Reference (normalized to equivalent dose for 2-Gy fractions [EQD2]) point doses atmore » the ipsilateral hilum and carina, demographic data, and clinical outcomes were extracted from the medical records. Univariate conditional logistical regression analyses were performed with variables of interest. Results: Cases and controls were well matched except for size. The controls, as expected, had larger gross tumor volumes (P=.02). The mean ipsilateral hilar doses were 9.6 Gy and 22.4 Gy for cases and controls, respectively (P=.014). The mean carinal doses were 7.0 Gy and 9.2 Gy, respectively (P=.13). Mediastinal nodal relapses, with and without ipsilateral hilar relapse, were associated with mean ipsilateral hilar doses of 3.6 Gy and 19.8 Gy, respectively (P=.01). The conditional density plot appears to demonstrate an inverse dose-effect relationship between ipsilateral hilar normalized total dose and risk of ipsilateral hilar relapse. Conclusions: Incidental hilar dose greater than 20 Gy is significantly associated with fewer ipsilateral hilar relapses in inoperable early stage NSCLC patients treated with SBRT.« less

Toxoplasma gondii Infection and Headache: A Matched Case-Control Study in a Public Hospital in Durango City, Mexico

PubMed Central

Alvarado-Esquivel, Cosme; Rico-Almochantaf, Yazmin del Rosario; Sanchez-Anguiano, Luis Francisco; Quinones-Canales, Gerardo; Hernandez-Tinoco, Jesus; Torres-Gonzalez, Jorge; Gonzalez-Silva, Maria Felix; Ramirez-Valles, Eda Guadalupe

2018-01-01

Background Toxoplasma gondii (T. gondii) can disseminate to brain in infected hosts. Little is known about the magnitude of the association between this infection and headache. Therefore, we sought to determine the association of T. gondii seropositivity and headache in patients attending neurological consultations in a public hospital in Durango City, Mexico. Methods Through an age- and gender-matched case-control study, 105 patients suffering from headache and 105 subjects without headache were examined for anti-T. gondii IgG and IgM antibodies using commercially available enzyme-linked immunoassays. Seropositive cases were analyzed for detection of T. gondii DNA by polymerase chain reaction. Results Anti-T. gondii IgG antibodies were found in five (4.8%) of the 105 cases and in seven (6.7%) of the 105 controls (odds ratio (OR) = 0.70; 95% confidence interval (CI): 0.21 - 2.28; P = 0.76). The frequency of high (> 150 IU/mL) levels of anti-T. gondii IgG antibodies among anti-T. gondii IgG positive individuals was significantly (P = 0.01) higher in cases (5/5) than in controls (1/7). Anti-T. gondii IgM antibodies were found in one (20.0%) of the five IgG seropositive cases, and in three (42.9%) of the seven IgG seropositive controls (P = 0.60). T. gondii DNA was not detected in any of the five anti-T. gondii IgG positive cases. No association between T. gondii infection and specific headache types was found. Conclusions This is the first matched case-control study on the association between T. gondii infection and headache. Results suggest that high anti-T. gondii IgG antibody levels, but not T. gondii seropositivity, were associated with headache in the population studied. PMID:29238431

Toxoplasma gondii Infection and Headache: A Matched Case-Control Study in a Public Hospital in Durango City, Mexico.

PubMed

Alvarado-Esquivel, Cosme; Rico-Almochantaf, Yazmin Del Rosario; Sanchez-Anguiano, Luis Francisco; Quinones-Canales, Gerardo; Hernandez-Tinoco, Jesus; Torres-Gonzalez, Jorge; Gonzalez-Silva, Maria Felix; Ramirez-Valles, Eda Guadalupe

2018-01-01

Toxoplasma gondii ( T. gondii ) can disseminate to brain in infected hosts. Little is known about the magnitude of the association between this infection and headache. Therefore, we sought to determine the association of T. gondii seropositivity and headache in patients attending neurological consultations in a public hospital in Durango City, Mexico. Through an age- and gender-matched case-control study, 105 patients suffering from headache and 105 subjects without headache were examined for anti- T. gondii IgG and IgM antibodies using commercially available enzyme-linked immunoassays. Seropositive cases were analyzed for detection of T. gondii DNA by polymerase chain reaction. Anti- T. gondii IgG antibodies were found in five (4.8%) of the 105 cases and in seven (6.7%) of the 105 controls (odds ratio (OR) = 0.70; 95% confidence interval (CI): 0.21 - 2.28; P = 0.76). The frequency of high (> 150 IU/mL) levels of anti- T. gondii IgG antibodies among anti- T. gondii IgG positive individuals was significantly (P = 0.01) higher in cases (5/5) than in controls (1/7). Anti- T. gondii IgM antibodies were found in one (20.0%) of the five IgG seropositive cases, and in three (42.9%) of the seven IgG seropositive controls (P = 0.60). T. gondii DNA was not detected in any of the five anti- T. gondii IgG positive cases. No association between T. gondii infection and specific headache types was found. This is the first matched case-control study on the association between T. gondii infection and headache. Results suggest that high anti- T. gondii IgG antibody levels, but not T. gondii seropositivity, were associated with headache in the population studied.

Nitrates in drinking water and risk of death from rectal cancer in Taiwan.

PubMed

Kuo, Hsin-Wei; Wu, Trong-Neng; Yang, Chun-Yuh

2007-10-01

The relationship between nitrate levels in drinking water and rectal cancer development has been inconclusive. A matched case-control and nitrate ecology study was used to investigate the association between mortality attributed to rectal cancer and drinking-water nitrate exposure in Taiwan. All deaths due to rectal cancer of Taiwan residents from 1999 through 2003 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair matched to the cancer cases by gender, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each case. Data on nitrate-nitrogen (NO3-N) levels in drinking water throughout Taiwan were collected from Taiwan Water Supply Corporation (TWSC). The municipality of residence for cancer cases and controls was assumed to be the source of the subject's nitrate exposure via drinking water. The adjusted odds ratios for rectal cancer death for those with high nitrate levels in their drinking water, as compared to the lowest tertile, were 1.22 (0.98-1.52) and 1.36 (1.08-1.70), respectively. The findings of this study warrant further investigation of the role of nitrates in drinking water in the etiology of rectal cancer in Taiwan.

Genome-wide association analysis accounting for environmental factors through propensity-score matching: application to stressful live events in major depressive disorder.

PubMed

Power, Robert A; Cohen-Woods, Sarah; Ng, Mandy Y; Butler, Amy W; Craddock, Nick; Korszun, Ania; Jones, Lisa; Jones, Ian; Gill, Michael; Rice, John P; Maier, Wolfgang; Zobel, Astrid; Mors, Ole; Placentino, Anna; Rietschel, Marcella; Aitchison, Katherine J; Tozzi, Federica; Muglia, Pierandrea; Breen, Gerome; Farmer, Anne E; McGuffin, Peter; Lewis, Cathryn M; Uher, Rudolf

2013-09-01

Stressful life events are an established trigger for depression and may contribute to the heterogeneity within genome-wide association analyses. With depression cases showing an excess of exposure to stressful events compared to controls, there is difficulty in distinguishing between "true" cases and a "normal" response to a stressful environment. This potential contamination of cases, and that from genetically at risk controls that have not yet experienced environmental triggers for onset, may reduce the power of studies to detect causal variants. In the RADIANT sample of 3,690 European individuals, we used propensity score matching to pair cases and controls on exposure to stressful life events. In 805 case-control pairs matched on stressful life event, we tested the influence of 457,670 common genetic variants on the propensity to depression under comparable level of adversity with a sign test. While this analysis produced no significant findings after genome-wide correction for multiple testing, we outline a novel methodology and perspective for providing environmental context in genetic studies. We recommend contextualizing depression by incorporating environmental exposure into genome-wide analyses as a complementary approach to testing gene-environment interactions. Possible explanations for negative findings include a lack of statistical power due to small sample size and conditional effects, resulting from the low rate of adequate matching. Our findings underscore the importance of collecting information on environmental risk factors in studies of depression and other complex phenotypes, so that sufficient sample sizes are available to investigate their effect in genome-wide association analysis. Copyright © 2013 Wiley Periodicals, Inc.

Occupational risk factors for Wilms' tumor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bunin, G.; Kramer, S.; Nass, C.

A matched case-control study of Wilms' tumor investigated parental occupational risk factors. Cases diagnosed in 1970-1983 were identified through a population-based tumor registry and hospital registries in the Greater Philadelphia area. Controls were selected by random digit dialing and were matched to cases on race, birth date (+/- 3 years), and the area code and exchange of the case's telephone number at diagnosis. Parents of 100 matched pairs were interviewed by telephone. Parents of patients and controls were generally similar in demographic characteristics, except that mothers differed in religion. Published schemes were used to group jobs into clusters of similarmore » exposures and to determine exposures from industry and job title. Analyses were done for preconception, pregnancy, and postnatal time periods. More case than control fathers had jobs in a cluster that includes machinists and welders (odds ratios (ORs) = 4.0-5.7, p less than or equal to 0.04). Paternal exposures to lead, silver, tin, and iron (some exposures of this cluster) were associated with Wilms' tumor in some analyses, with moderate odds ratios (ORs = 1.5-3.4). In general, the highest odds ratios were found for the preconception period among the genetic (prezygotic) cases. No maternal job clusters or exposures gave significantly elevated odds ratios. These results support a previous finding that lead is a risk factor, but not radiation, hydrocarbon, or boron exposures.« less

Atypical prediagnosis Epstein-Barr virus serology restricted to EBV-positive Hodgkin lymphoma

PubMed Central

Chang, Ellen T.; Ambinder, Richard F.; Lennette, Evelyne T.; Rubertone, Mark V.; Mann, Risa B.; Borowitz, Michael; Weir, Edward G.; Abbondanzo, Susan L.; Mueller, Nancy E.

2012-01-01

An altered anti–Epstein-Barr virus (EBV) serologic profile preceding diagnosis is associated with an increased risk of Hodgkin lymphoma. It is unknown whether this atypical pattern predicts Hodgkin lymphoma risk further subdivided by determination of EBV in tumor cells. A nested case-control study of 128 incident Hodgkin lymphoma cases and 368 matched controls from active-duty military personnel with archived serum in the US Department of Defense Serum Repository was conducted to determine whether a panel of anti-EBV antibody titers differed in EBV+ and EBV− Hodgkin lymphoma. Among 40 EBV+ Hodgkin lymphoma cases and matched controls, statistically significant increased risks were associated with elevated anti-EBV VCA IgG antibody titers (relative risk = 3.1; 95% confidence interval [CI], 1.1-8.7), and an anti–EBNA-1/anti–EBNA-2 antibody ratio ≤ 1.0 versus > 1.0 (relative risk = 4.7; 95% CI, 1.6-13.8). In contrast, no significant associations were found among 88 EBV− Hodgkin lymphoma cases relative to their matched controls. In case-case analysis, EBV+ disease was significantly associated with a low anti–EBNA-1/anti–EBNA-2 antibody ratio. This distinc-tive serologic response to EBV latent antigens, indicative of immune dysfunction in other clinical settings, is associated with an increased risk of developing EBV+ but not EBV− Hodgkin lymphoma. PMID:22972983

Risk factors, clinical features, and outcomes of toxoplasmosis in solid-organ transplant recipients: a matched case-control study.

PubMed

Fernàndez-Sabé, Núria; Cervera, Carlos; Fariñas, M Carmen; Bodro, Marta; Muñoz, Patricia; Gurguí, Mercè; Torre-Cisneros, Julián; Martín-Dávila, Pilar; Noblejas, Ana; Len, Oscar; García-Reyne, Ana; Del Pozo, José Luis; Carratalà, Jordi

2012-02-01

Solid-organ transplant (SOT) recipients are considered to be at increased risk for toxoplasmosis. However, risk factors for this infection have not been assessed. The aim of this study was to determine the risk factors, clinical features, and outcomes of toxoplasmosis in SOT recipients. A multicenter, matched case-control study (1:2 ratio) was conducted between 2000 and 2009. Control subjects were matched for center, transplant type, and timing. Cases were identified from the hospitals' microbiology and transplantation program databases. Logistic regression was performed to identify independent risk factors. Twenty-two cases (0.14%) of toxoplasmosis were identified among 15 800 SOTs performed in 11 Spanish hospitals, including 12 heart, 6 kidney, and 4 liver recipients. Diagnosis was made by seroconversion (n = 17), histopathologic examination (n = 5), polymerase chain reaction (n = 2), and autopsy (n = 2). In a comparison of case patients with 44 matched control subjects, a negative serostatus prior to transplantation was the only independent risk factor for toxoplasmosis (odds ratio, 15.12 [95% confidence interval, 2.37-96.31]; P = .004). The median time to diagnosis following transplantation was 92 days. Primary infection occurred in 18 (81.8%) cases. Manifestations included pneumonitis (n = 7), myocarditis (n = 5), brain abscesses (n = 5), chorioretinitis (n = 3), lymph node enlargement (n = 2), hepatosplenomegaly (n = 2), and meningitis (n =1). Five patients (22.7%) had disseminated disease. Crude mortality rate was 13.6% (3 of 22 patients). Although uncommon, toxoplasmosis in SOT patients causes substantial morbidity and mortality. Seronegative recipients are at high risk for developing toxoplasmosis and should be given prophylaxis and receive careful follow-up.

77 FR 17044 - Applications for New Awards; Strengthening Institutions Program (SIP)

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-23

... 27637), and apply to the priorities in this notice: Carefully matched comparison group design means a... make when designing a carefully matched comparison group study. Applicants might want to consider...) or not to participate in the project (control group). The effect of the project is the average...

Short Report: Lack of Evidence of Hepatitis C and HIV Co-Infection among Men Who Have Sex with Men in Peru

PubMed Central

Lama, Javier R.; Lucchetti, Aldo; Cabezas, Cesar; Suarez-Ognio, Luis; Sanchez, Jorge

2012-01-01

Hepatitis C virus (HCV) infection occurs among human immunodeficiency virus (HIV)-infected men who have sex with men (MSM) because of shared routes of transmission. To assess the association between HCV and HIV infection among MSM in Peru, we conducted a matched case-control study (162 HIV-positive cases and 324 HIV-negative controls) among participants of an HIV sentinel surveillance survey in six urban cities. The HCV infection was initially screened using anti-HCV ELISA and immunoblot assay, and thereafter confirmed by the HCV RNA qualitative assay. Among cases, no confirmed HCV infection was found while among controls, only two confirmed HCV infections were reported (0.62%). This matched case-control reports a very low probability of association between HCV and HIV co-infection and suggests a very low prevalence of HCV infection among MSM in Peru. PMID:19556587

[Lack of association between MMR vaccination and the incidence of autism in children: a case-control study].

PubMed

Mrozek-Budzyn, Dorota; Kiełtyka, Agnieszka; Majewska, Renata

2009-01-01

The matched case-control study has been undertook to investigate whether measles, mumps, and rubella (MMR) vaccine may be casually associated with autism in children. Cases were children to 14-year old with diagnosis of core autism or atypical autism. Controls were matched on age, sex and general practice. The 96 cases and 192 controls were included. The study provides strong evidence against association of autism with both MMR and a single measles individual vaccine. Additionally children vaccinated with MMR, regardless of age of vaccination (to 18th, 24th and 36th month of life), had risk equal half of that of single measles vaccinated (for vaccinated to 18th month OR=0.41 95%PU: 0.20-0.85). Our findings confirm that MMR vaccination is not associated with an increased risk of autism in children.

Circulatory nucleosome levels are significantly increased in early and late-onset preeclampsia.

PubMed

Zhong, Xiao Yan; Gebhardt, Stefan; Hillermann, Renate; Tofa, Kashefa Carelse; Holzgreve, Wolfgang; Hahn, Sinuhe

2005-08-01

Elevations in circulatory DNA, as measured by real-time PCR, have been observed in pregnancies with manifest preeclampsia. Recent reports have indicated that circulatory nucleosome levels are elevated in the periphery of cancer patients. We have now examined whether circulatory nucleosome levels are similarly elevated in cases with preeclampsia. Maternal plasma samples were prepared from 17 cases with early onset preeclampsia (<34 weeks gestation) with 14 matched normotensive controls, as well as 15 cases late-onset preeclampsia (>34 weeks gestation) with 10 matched normotensive controls. Levels of circulatory nucleosomes were quantified by commercial ELISA (enzyme-linked immunosorbant assay). The level of circulatory nucleosomes was significantly elevated in both study preeclampsia groups, compared to the matched normotensive control group (p = 0.000 and p = 0.001, respectively). Our data suggests that preeclampsia is associated with the elevated presence of circulatory nucleosomes, and that this phenomenon occurs in both early- and late-onset forms of the disorder. Copyright 2005 John Wiley & Sons, Ltd.

Risk factors of post-traumatic stress disorder (PTSD) after Wenchuan earthquake: a case control study.

PubMed

Cheng, Yongzhong; Wang, Fang; Wen, Jin; Shi, Yingkang

2014-01-01

Few clues were found in the literature about the independent risk factors for PTSD among earthquake survivors in Sichuan province three years after the 2008 earthquake. Ours was the first case-control study with matching factors of age and distance from the epicenter among survivors age 16 years or older, three years after the catastrophe. To identify independent risk factors for PTSD among earthquake survivors. We performed a population-based matched case-control study. The cases were drawn from earthquake areas three years after the Wenchuan earthquake, including 113 cases who met positive criteria for PTSD symptoms according to the PCL-C (PTSD Checklist-Civilian Version) score and 452 controls who did not meet the criteria. Cases and controls were matched individually by birth year (+ three years) and the town they lived in when the earthquake occurred. Independent risk factors for PTSD symptoms included two-week disease prevalence (odds ratio [OR],1.92; 95% confidence interval [CI],1.18-3.13), witnessing someone being killed in the earthquake (OR, 2.04;95%CI, 1.17-3.58), having no regular income after the earthquake (OR, 0.52; 95%CI, 0.28-0.98), receiving mental health support only one time after the earthquake (OR, 2.43; 95%CI, 1.09-5.42) and lower social support (lower PSSS score) (OR, 0.95; 95%CI, 0.93-0.97). Earthquake experience, suffering from physical illnesses, lack of stable income, and lower social support were associated with PTSD symptoms.

Outcomes of Arthroscopic Rotator Cuff Repair in Patients Who Are 70 Years of Age or Older Versus Under 70 Years of Age: A Sex- and Tear Size-Matched Case-Control Study.

PubMed

Gwark, Ji-Yong; Sung, Chang-Meen; Na, Jae-Boem; Park, Hyung Bin

2018-05-19

To compare the structural and clinical outcomes after arthroscopic rotator cuff repair (ARCR) of a case group aged 70 and above with those of a control group younger than 70, with the 2 groups matched for sex and tear size. The case group, comprising 53 patients 70 or older, and the control group, comprising 159 patients younger than 70, all received ARCR to 1 shoulder with symptomatic full-thickness rotator cuff tear. The case and the control subjects, who were matched for sex and tear size to minimize bias related to tendon healing, received ARCR during the same period. The mean age was 71.8 ± 2.6 years in the case group and 59.3 ± 7.1 years in the control group. The minimum follow-up period was 1 year in both groups. Cuff integrity was evaluated using ultrasonography. Structural and clinical outcomes of the 2 groups were compared. Regarding structural outcomes, the complete healing, partial-thickness retear, and full-thickness retear rates were 66% (35/53), 15% (8/53), and 19% (10/53) in the case group, and 68% (108/159), 19% (30/159), and 13% (21/159), respectively, in the control group. The 2 groups had no significantly different retear rates (P = .52). Regarding clinical outcomes, the mean improvements in range of motion, pain, muscle strength, and age- and sex-matched Constant scores were not significantly different between the 2 groups (P > .37). The preoperative tear size was significantly associated with retear in both studied groups (P = .02). The clinical and structural outcomes of ARCR in patients 70 or older with symptomatic full-thickness rotator cuff tear are comparable with those in patients younger than 70 with at least 1-year follow-up. Preoperative tear size, a biological factor, is a strong predictor for retear. Level III, a retrospective comparative (case-control) study. Copyright © 2018 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Comparative study on serum levels of macro and trace elements in schizophrenia based on supervised learning methods.

PubMed

Lin, Tong; Liu, Tiebing; Lin, Yucheng; Yan, Lailai; Chen, Zhongxue; Wang, Jingyu

2017-09-01

The etiology and pathophysiology of schizophrenia (SCZ) remain obscure. This study explored the associations between SCZ risk and serum levels of 39 macro and trace elements (MTE). A 1:1 matched case-control study was conducted among 114 schizophrenia patients and 114 healthy controls matched by age, sex and region. Blood samples were collected to determine the concentrations of 39 MTE by ICP-AES and ICP-MS. Both supervised learning methods and classical statistical testing were used to uncover the difference of MTE levels between cases and controls. The best prediction accuracies were 99.21% achieved by support vector machines in the original feature space (without dimensionality reduction), and 98.82% achieved by Naive Bayes with dimensionality reduction. More than half of MTE were found to be significantly different between SCZ patients and the controls. The presented investigation showed that there existed remarkable differences in concentrations of MTE between SCZ patients and healthy controls. The results of this study might be useful to diagnosis and prognosis of SCZ; they also indicated other promising applications in pharmacy and nutrition. However, the results should be interpreted with caution due to limited sample size and the lack of potential confounding factors, such as alcohol, smoking, body mass index (BMI), use of antipsychotics and dietary intakes. In the future the application of the analyses will be useful in designs that have larger sample sizes. Copyright © 2017 Elsevier GmbH. All rights reserved.

Bias reduction in repeated-measures observational studies by the use of propensity score: the case of enteral sedation for critically ill patients.

PubMed

Umbrello, Michele; Mistraletti, Giovanni; Corbella, Davide; Cigada, Marco; Salini, Silvia; Morabito, Alberto; Iapichino, Gaetano

2012-12-01

Within the evidence-based medicine paradigm, randomized controlled trials represent the "gold standard" to produce reliable evidence. Indeed, planning and implementing randomized controlled trials in critical care medicine presents limitations because of intrinsic and structural problems. As a consequence, observational studies still occur frequently. In these cases, propensity score (PS) (probability of receiving a treatment conditional on observed covariates) is an increasingly used technique to adjust the results. Few studies addressed the specific issue of a PS correction of repeated-measures designs. Three techniques for correcting the analysis of nonrandomized designs (matching, stratification, regression adjustment) are presented in a tutorial form and applied to a real case study: the comparison between intravenous and enteral sedative therapy in the intensive care unit setting. After showing the results before and after the use of PS, we suggest that such a tool allows to partially overcoming the bias associated with the observational nature of the study. It permits to correct the estimates for any observed covariate, while unobserved confounders cannot be controlled for. Propensity score represents a useful additional tool to estimate the effects of treatments in nonrandomized studies. In the case study, an enteral sedation approach was equally effective to an intravenous regime, allowing for a lower level of sedation and spare of resources. Copyright © 2012 Elsevier Inc. All rights reserved.

Obesity and Diabetes Mellitus Adversely Affect Outcomes after Cardiac Surgery in Children's Hospitals.

PubMed

Shamszad, Pirouz; Rossano, Joseph W; Marino, Bradley S; Lowry, Adam W; Knudson, Jarrod D

2016-09-01

To assess how obesity or diabetes mellitus impacts outcomes in patients undergoing cardiac surgery in pediatric hospitals. A multi-institutional, matched case-control study of the Pediatric Health Information System database was performed. Tertiary children's hospitals in the United States. All cardiac surgical cases in patients with obesity or diabetes mellitus between 2004 and 2012 were included. Cases were matched to controls by age, sex, race, and Risk Adjustment for Congenital Heart Surgery score. Mortality, surgical complications, and hospital utilization. Differences in outcome measures were assessed by chi-square and Mann-Whitney tests. P value < .05 was significant. Six hundred twenty-nine cardiac surgical cases (median age 17 years [IQR 12-32]) with obesity or diabetes mellitus were matched to 629 controls. Cases demonstrated lower median household income than those in the control group ($38,031 [IQR $31,900-$48,844] vs. ($41,896 [IQR $32,854-$56,020], P < .001). Mortality was similar between cases and controls (22% vs. 1.9%, P =.692). Surgical complications occurred similarly between cases and controls (13.5% vs. 12.4%, P = .535). Cases had longer intensive care unit length of stay than controls (3 vs. 2 days, P = .001), resulting in longer overall hospital length of stay (5 vs. 4 days, P < .001). Cases also had a higher odds of undergoing mechanical ventilation for >96 hours (OR 2.0, 95% CI 1.1-3.7) and higher rate of total parenteral nutrition use (7.2% vs. 4.5%, P = .040). Median hospital charges were higher in cases (clinical: $6,696 vs. $5,872; laboratory: $14,168 vs. $12,251; pharmacy: $12,971 vs. $10,426; imaging: $6,259 vs. $5,660; P ≤ .030 for all). The presence of obesity or diabetes mellitus was associated with increased postoperative morbidity, hospital utilization, and cost in patients undergoing cardiac surgery in pediatric hospitals. © 2016 Wiley Periodicals, Inc.

Efficacy of a Self-expanding Tract Sealant Device in the Reduction of Pneumothorax and Chest Tube Placement Rates After Percutaneous Lung Biopsy: A Matched Controlled Study Using Propensity Score Analysis.

PubMed

Ahrar, Judy U; Gupta, Sanjay; Ensor, Joe E; Mahvash, Armeen; Sabir, Sharjeel H; Steele, Joseph R; McRae, Stephen E; Avritscher, Rony; Huang, Steven Y; Odisio, Bruno C; Murthy, Ravi; Ahrar, Kamran; Wallace, Michael J; Tam, Alda L

2017-02-01

To evaluate the use of a self-expanding tract sealant device (BioSentry™) on the rates of pneumothorax and chest tube insertion after percutaneous lung biopsy. In this retrospective study, we compared 318 patients who received BioSentry™ during percutaneous lung biopsy (treated group) with 1956 patients who did not (control group). Patient-, lesion-, and procedure-specific variables, and pneumothorax and chest tube insertion rates were recorded. To adjust for potential selection bias, patients in the treated group were matched 1:1 to patients in the control group using propensity score matching based on the above-mentioned variables. Patients were considered a match if the absolute difference in their propensity scores was ≤equal to 0.02. Before matching, the pneumothorax and chest tube rates were 24.5 and 13.1% in the control group, and 21.1 and 8.5% in the treated group, respectively. Using propensity scores, a match was found for 317 patients in the treatment group. Chi-square contingency matched pair analysis showed the treated group had significantly lower pneumothorax (20.8 vs. 32.8%; p = 0.001) and chest tube (8.2 vs. 20.8%; p < 0.0001) rates compared to the control group. Sub-analysis including only faculty who had >30 cases of both treatment and control cases demonstrated similar findings: the treated group had significantly lower pneumothorax (17.6 vs. 30.2%; p = 0.002) and chest tube (7.2 vs. 18%; p = 0.001) rates. The self-expanding tract sealant device significantly reduced the pneumothorax rate, and more importantly, the chest tube placement rate after percutaneous lung biopsy.

Injury trends in sanctioned mixed martial arts competition: a 5-year review from 2002 to 2007.

PubMed

Ngai, K M; Levy, F; Hsu, E B

2008-08-01

Professional mixed martial arts (MMA) competition is a full-contact sport that has risen rapidly in popularity in recent years. However, there is limited information regarding the incidence of competition injuries after sanctioning by an athletic commission. We conducted a retrospective cohort study to examine MMA injury patterns during a 5 year period after sanctioning in the state of Nevada. Data from all regulated MMA competitions during the study period from March 2002 to September 2007 (1270 fight exposures) was obtained. Injury odds ratios were calculated by conditional logistic regression on match outcome, age, weight, and fight experience, using a pair-matched case-control design (n = 464) and by multiple logistic regression on match outcome, age, fight experience, weight, combat minutes, and scheduled rounds. During the 635 professional MMA matches, 300 of the 1270 athletes sustained documented injuries with an injury rate of 23.6 per 100 fight participations. Most common reported injuries were lacerations and upper limb injuries. Severe concussion rate was 15.4 per 1000 athlete exposures, or 3% of all matches. No deaths or critical sports-related injuries resulted from any of the regulated matches during the study period. Age, weight and fight experience did not statistically increase the likelihood of injuries after controlling for other covariates. Injury rates in regulated professional MMA competition are similar to other combat sports; the overall risk of critical sports-related injury seems to be low. Additional study is warranted to achieve a better understanding of injury trends and ways to further lower injury risk in MMA.

Maternal characteristics and birth outcomes of pregnant women who had offspring with congenital ear abnormalities - a population-based case-control study.

PubMed

Paput, László; Bánhidy, Ferenc; Czeizel, Andrew E

2011-09-01

To describe the maternal characteristics and birth outcomes of newborn infants affected with isolated ear congenital abnormalities (IECA), mainly isolated anotia/microtia and unclassified multiple congenital abnormalities (CAs) including anotia/microtia (UMAM). Cases with IECA and UMAM were compared with their matched controls and all controls without any defect and malformed controls affected with other defects in the population-based large dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities. The mothers of 354 cases with IECA did not show significant difference in age, but their mean birth order was higher while their socio-economic status based on the maternal employment status was lower compared to the figures of their matched controls. There was a male excess among cases with microtia and mainly with UMAM. The evaluation of birth outcomes of newborns affected with IECA indicated intrauterine fetal growth retardation. Newborn infants with isolated microtia had intrauterine growth retardation and the association of this developmental defect localized for a small region of head with the general fetal development raises interesting theoretical question.

The Association Between Mild Intraoperative Hypotension and Stroke in General Surgery Patients.

PubMed

Hsieh, Jason K; Dalton, Jarrod E; Yang, Dongsheng; Farag, Ehab S; Sessler, Daniel I; Kurz, Andrea M

2016-10-01

Intraoperative hypotension may contribute to perioperative strokes. We therefore tested the hypothesis that intraoperative hypotension is associated with perioperative stroke. After institutional review board approval for this case-control study, we identified patients who had nonneurological, noncardiac, and noncarotid surgery under general anesthesia at the Cleveland Clinic between 2005 and 2011 and experienced a postoperative stroke. Control patients not experiencing postoperative stroke were matched in a 4-to-1 ratio using propensity scores and restriction to the same procedure type as stroke patients. The association between intraoperative hypotension, measured as time-integrated area under a mean arterial pressure (MAP) of 70 mm Hg, and postoperative stroke was assessed using zero-inflated negative binomial regression. Among 106 337 patients meeting inclusion criteria, we identified 120 who had confirmed postoperative stroke events based on manual chart review. Four-to-one propensity matching yielded a final matched sample of 104 stroke cases and 398 controls. There was no association between stroke and intraoperative hypotension. Stroke patients were not more likely than controls to have been hypotensive (odds ratio, 0.49 [0.18-1.38]), and among patients with intraoperative hypotension, stroke patients did not experience a greater degree of hypotension than controls (ratio of geometric means, 1.07 [0.76-1.53]). In our propensity score-matched case-control study, we did not find an association between intraoperative hypotension, defined as MAP < 70 mm Hg, and postoperative stroke.

Bayesian adjustment for measurement error in continuous exposures in an individually matched case-control study.

PubMed

Espino-Hernandez, Gabriela; Gustafson, Paul; Burstyn, Igor

2011-05-14

In epidemiological studies explanatory variables are frequently subject to measurement error. The aim of this paper is to develop a Bayesian method to correct for measurement error in multiple continuous exposures in individually matched case-control studies. This is a topic that has not been widely investigated. The new method is illustrated using data from an individually matched case-control study of the association between thyroid hormone levels during pregnancy and exposure to perfluorinated acids. The objective of the motivating study was to examine the risk of maternal hypothyroxinemia due to exposure to three perfluorinated acids measured on a continuous scale. Results from the proposed method are compared with those obtained from a naive analysis. Using a Bayesian approach, the developed method considers a classical measurement error model for the exposures, as well as the conditional logistic regression likelihood as the disease model, together with a random-effect exposure model. Proper and diffuse prior distributions are assigned, and results from a quality control experiment are used to estimate the perfluorinated acids' measurement error variability. As a result, posterior distributions and 95% credible intervals of the odds ratios are computed. A sensitivity analysis of method's performance in this particular application with different measurement error variability was performed. The proposed Bayesian method to correct for measurement error is feasible and can be implemented using statistical software. For the study on perfluorinated acids, a comparison of the inferences which are corrected for measurement error to those which ignore it indicates that little adjustment is manifested for the level of measurement error actually exhibited in the exposures. Nevertheless, a sensitivity analysis shows that more substantial adjustments arise if larger measurement errors are assumed. In individually matched case-control studies, the use of conditional logistic regression likelihood as a disease model in the presence of measurement error in multiple continuous exposures can be justified by having a random-effect exposure model. The proposed method can be successfully implemented in WinBUGS to correct individually matched case-control studies for several mismeasured continuous exposures under a classical measurement error model.

Performance Outcomes After Hook of Hamate Fractures in Major League Baseball Players.

PubMed

Guss, Michael S; Begly, John P; Ramme, Austin J; Taormina, David P; Rettig, Michael E; Capo, John T

2017-07-17

Major League Baseball (MLB) players are at risk of hook of hamate fractures. There is a paucity of data assessing the effect of a hook of hamate fracture on MLB players' future athletic performance. To determine if MLB players who sustain hook of hamate fractures demonstrate decreased performance upon return to competition when compared with their performance before injury and that of their control-matched peers. Retrospective Case-Control Design. Retrospective Database Study. 18 MLB players who sustained hook of hamate fractures. Data for 18 MLB players with hook of hamate fractures incurred over 26 seasons (1989 to 2014) were obtained from injury reports, press releases, and player profiles ( www.mlb.com and www.baseballreference.com ). Player age, position, number of years in the league, mechanism of injury and treatment were recorded. Individual season statistics for the two seasons immediately prior to injury and the two seasons after injury for the main performance variable - wins above replacement (WAR) were obtained. Eighteen controls matched by player position, age, and performance statistics were identified. A performance comparison of the cohorts was performed. Post-injury performance compared to pre-injury performance and matched-controls. Mean age at the time of injury was 25.1 years with a mean of 4.4 seasons of MLB experience prior to injury. All injuries were sustained to their nondominant batting hand. All players underwent operative intervention. There was no significant change in WAR or ISO when pre-injury and post-injury performance was compared. When compared with matched-controls, no significant decline in performance in WAR the first season and second season after injury was found. MLB players sustaining hook of hamate fractures can reasonably expect to return to their pre-injury performance levels following operative treatment.

The Impact of Palifermin Use on Hematopoietic Cell Transplant Outcomes in Children.

PubMed

Saber, Wael; Zhang, Mei-Jie; Steinert, Patricia; Chen, Min; Horowitz, Mary M

2016-08-01

Clinical trials evaluating palifermin have enrolled few pediatric patients, precluding safety analyses in large groups of children. We compared hematopoietic cell transplantation (HCT) outcomes among pediatric patients who did or did not receive palifermin as a preventive treatment for oral mucositis. Pediatric patients and controls, matched for HCT and donor type, disease, disease status, and age, were selected from the Center for International Blood and Marrow Transplant Research database and a 1:3 matched cohort analysis was performed. Stratified Cox proportional hazards models were built and propensity score adjustments were used to compare overall and disease-free survival outcomes between palifermin-treated and untreated patients. Three controls were identified for 90% of palifermin recipients. The remaining cases were matched with 2 (8%) controls or 1 (2%) control, for a total of 210 palifermin-treated patients matched with 606 controls. Median follow-up was 31 months in cases and 36 months in controls. Fifty-seven percent of patients underwent allogeneic HCT, mostly for acute leukemia, and 43% underwent autologous HCT, mostly for solid tumors. In univariate analyses, 2-year survival and disease-free survival rates after allogeneic HCT (58% versus 66%, P = .109; 49% versus 60%, P = .06) and after autologous HCT (73% versus 77%, P = .474; 60% versus 64%, P = .637) were similar between palifermin-treated patients and matched controls. In multivariate analysis, palifermin treatment did not significantly increase the risk of mortality (relative risk [RR], 1.20; 95% confidence interval [CI], .87 to 1.66) or of relapse (RR, 1.12; 95% CI, .78 to 1.62) compared with matched controls. No significant differences in rates of acute or chronic graft-versus-host disease (GVHD) were observed between palifermin-treated patients and matched controls. Among pediatric patients undergoing HCT, overall survival, disease-free survival, neutrophil recovery, and GVHD rates were similar between palifermin-treated patients and matched controls. Copyright © 2016 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

Lack of Association Between Cytomegalovirus Infection and Hypertensive Disorders in Pregnancy: A Case-Control Study in Durango, Mexico.

PubMed

Alvarado-Esquivel, Cosme; Sandoval-Carrillo, Ada A; Vazquez-Alaniz, Fernando; Salas-Pacheco, José M; Hernández-Tinoco, Jesús; Sánchez-Anguiano, Luis Francisco; Antuna-Salcido, Elizabeth Irasema

2017-09-01

It is not clear whether infection with cytomegalovirus (CMV) is associated with hypertensive disorders in pregnant women. Through a case-control study design, 146 women suffering from hypertensive disorders in pregnancy (cases) and 146 age-matched normotensive pregnant women (controls) were examined for the presence of anti-CMV IgG and IgM antibodies with enzyme-linked immunoassays. IgM seropositive samples were further assayed by enzyme-linked fluorescent assay (ELFA). Anti-CMV IgG antibodies were found in 138 (94.5%) controls and in 136 (93.2%) cases (odds ratio [OR] = 0.78; 95% confidence interval [CI]: 0.30-2.05; P = 0.62). High (>18 IU/ml) levels of anti-CMV IgG antibodies were found in 37.7% of the 138 seropositive controls and in 34.6% of the 136 seropositive cases (OR = 0.87; 95% CI: 0.53-1.43; P = 0.59). Anti-CMV IgM antibodies were found in 1 (0.7%) of the controls but in none of the cases using ELFA ( P = 1.0). Seropositivity to CMV was not associated with a previous preeclampsia and was similar among cases regardless their mean systolic and diastolic blood pressures, and mean arterial blood pressure. No serological evidence of an association between CMV infection and hypertensive disorders of pregnancy was found. Further research to elucidate the role of CMV in hypertensive disorders in pregnancy should be conducted.

Heart Disease, Hypertension, Gestational Diabetes Mellitus, and Preeclampsia/Eclampsia in Mothers With Juvenile Arthritis: A Nested Case-Control Study.

PubMed

Feldman, Debbie E; Vinet, Évelyne; Bérard, Anick; Duffy, Ciarán; Hazel, Beth; Meshefedjian, Garbis; Sylvestre, Marie-Pierre; Bernatsky, Sasha

2017-02-01

To determine whether women with a history of juvenile arthritis are at higher risk for heart disease and hypertension and for developing adverse maternal outcomes: gestational diabetes mellitus, maternal hypertension, and preeclampsia/eclampsia. We designed a nested case-control study from a cohort of first-time mothers with prior physician billing codes suggesting juvenile arthritis, and a matched comparison group without juvenile arthritis. For the nested case-control design, we selected 3 controls for each case for the outcomes of heart disease (n = 403), prepregnancy hypertension (n = 66), gestational diabetes mellitus (n = 285), maternal hypertension (n = 561), and preeclampsia/eclampsia (n = 236). We used conditional logistic regression, adjusting for maternal age and education. Having juvenile arthritis was associated with heart disease (odds ratio [OR] 2.44 [95% confidence interval (95% CI) 1.15-5.15]) but not with gestational hypertension, diabetes mellitus, or preeclampsia/eclampsia. All 66 cases of prepregnancy hypertension had juvenile arthritis. Having prepregnancy hypertension was strongly associated with preeclampsia/eclampsia (OR 8.05 [95% CI 2.69-24.07]). Women with a history of juvenile arthritis had a higher risk of heart disease. This risk signals the potential importance of cardiac prevention strategies in juvenile arthritis. As this was a retrospective study, it was not possible to correct for some relevant potential confounders. Further studies should assess the impact of medications, disease severity, and other factors (e.g., obesity) on cardiac outcomes in juvenile arthritis. © 2016, American College of Rheumatology.

Risk assessment in ginecology and obstetrics in Sicily: an approach based on Wolff's Criteria.

PubMed

Matranga, D; Marsala, M G L; Vadalà, M; Morici, M; Restivo, V; Ferrara, C; Vitale, F; Firenze, A

2013-01-01

To apply Wolff's Criteria to hospital discharge records (HDR) in order to detect adverse events worthy of further study. Gynecology and Obstetrics Units of three Sicilian hospitals were considered and HDR regarding ordinary and day hospital admissions in 2008 were collected. A matched case-control study was designed, by random selection of 10 controls at maximum for each case. Matching was performed on the variables age and speciality of admission (gynecology or obstetrics). Out of a total of 7011 HDR examined, 114 cases were identified with Wolff's Criteria. Multivariate analysis confirmed a statistically significant association with the origin of admission, diagnosis at the acceptance and length of stay: there was a decreased risk of Wolff's event in patients having urgent admission compared to elective (OR = 0.47, 95% CI = [0.28-0.78]), an increased risk in patients reporting tumor (OR = 5:41, 95 % CI [1.89-15.47]) and other causes (OR = 2.16, 95% CI [1.10-4.24]) compared to delivery diagnosis at acceptance and in patients whose length of stay was more than 6 days (OR = 23.17, 95% CI = [12.56-42.7]) compared to less or equal than 3 days Wolff's Criteria can be applied for the analysis of clinical risk in hospitals with different structural characteristics, on condition that the HDR database is complete and good quality.

Querying Event Sequences by Exact Match or Similarity Search: Design and Empirical Evaluation

PubMed Central

Wongsuphasawat, Krist; Plaisant, Catherine; Taieb-Maimon, Meirav; Shneiderman, Ben

2012-01-01

Specifying event sequence queries is challenging even for skilled computer professionals familiar with SQL. Most graphical user interfaces for database search use an exact match approach, which is often effective, but near misses may also be of interest. We describe a new similarity search interface, in which users specify a query by simply placing events on a blank timeline and retrieve a similarity-ranked list of results. Behind this user interface is a new similarity measure for event sequences which the users can customize by four decision criteria, enabling them to adjust the impact of missing, extra, or swapped events or the impact of time shifts. We describe a use case with Electronic Health Records based on our ongoing collaboration with hospital physicians. A controlled experiment with 18 participants compared exact match and similarity search interfaces. We report on the advantages and disadvantages of each interface and suggest a hybrid interface combining the best of both. PMID:22379286

Optimal control model predictions of system performance and attention allocation and their experimental validation in a display design study

NASA Technical Reports Server (NTRS)

Johannsen, G.; Govindaraj, T.

1980-01-01

The influence of different types of predictor displays in a longitudinal vertical takeoff and landing (VTOL) hover task is analyzed in a theoretical study. Several cases with differing amounts of predictive and rate information are compared. The optimal control model of the human operator is used to estimate human and system performance in terms of root-mean-square (rms) values and to compute optimized attention allocation. The only part of the model which is varied to predict these data is the observation matrix. Typical cases are selected for a subsequent experimental validation. The rms values as well as eye-movement data are recorded. The results agree favorably with those of the theoretical study in terms of relative differences. Better matching is achieved by revised model input data.

Mental illness, poverty and stigma in India: a case–control study

PubMed Central

Trani, Jean-Francois; Bakhshi, Parul; Kuhlberg, Jill; Narayanan, Sreelatha S; Venkataraman, Hemalatha; Mishra, Nagendra N; Groce, Nora E; Jadhav, Sushrut; Deshpande, Smita

2015-01-01

Objective To assess the effect of experienced stigma on depth of multidimensional poverty of persons with severe mental illness (PSMI) in Delhi, India, controlling for gender, age and caste. Design Matching case (hospital)–control (population) study. Setting University Hospital (cases) and National Capital Region (controls), India. Participants A case–control study was conducted from November 2011 to June 2012. 647 cases diagnosed with schizophrenia or affective disorders were recruited and 647 individuals of same age, sex and location of residence were matched as controls at a ratio of 1:2:1. Individuals who refused consent or provided incomplete interview were excluded. Main outcome measures Higher risk of poverty due to stigma among PSMI. Results 38.5% of PSMI compared with 22.2% of controls were found poor on six dimensions or more. The difference in multidimensional poverty index was 69% between groups with employment and income of the main contributors. Multidimensional poverty was strongly associated with stigma (OR 2.60, 95% CI 1.27 to 5.31), scheduled castes/scheduled tribes/other backward castes (2.39, 1.39 to 4.08), mental illness (2.07, 1.25 to 3.41) and female gender (1.87, 1.36 to 2.58). A significant interaction between stigma, mental illness and gender or caste indicates female PSMI or PSMI from ‘lower castes’ were more likely to be poor due to stigma than male controls (p<0.001) or controls from other castes (p<0.001). Conclusions Public stigma and multidimensional poverty linked to SMI are pervasive and intertwined. In particular for low caste and women, it is a strong predictor of poverty. Exclusion from employment linked to negative attitudes and lack of income are the highest contributors to multidimensional poverty, increasing the burden for the family. Mental health professionals need to be aware of and address these issues. PMID:25712818

A Case–Control Study on the Origin of Atypical Scrapie in Sheep, France

PubMed Central

Morignat, Eric; Ducrot, Christian; Calavas, Didier

2009-01-01

A matched case–control study (95 cases and 220 controls) was designed to study risk factors for atypical scrapie in sheep in France. We analyzed contacts with animals from other flocks, lambing and feeding practices, and exposure to toxic substances. Data on the prnp genotype were collected for some case and control animals and included in a complementary analysis. Sheep dairy farms had a higher risk for scrapie (odds ratio [OR] 15.1, 95% confidence interval [CI] 3.3–69.7). Lower risk was associated with organic farms (OR 0.15, 95% CI 0.02–1.26), feeding corn silage (OR 0.16, 95% CI 0.05–0.53), and feeding vitamin and mineral supplements (OR 0.6, 95% CI 0.32–1.14). Genetic effects were quantitatively important but only marginally changed estimates of other variables. We did not find any risk factor associated with an infectious origin of scrapie. Atypical scrapie could be a spontaneous disease influenced by genetic and metabolic factors. PMID:19402956

A three-dimensional soft tissue analysis of Class III malocclusion: a case-controlled cross-sectional study.

PubMed

Johal, Ama; Chaggar, Amrit; Zou, Li Fong

2018-03-01

The present study used the optical surface laser scanning technique to compare the facial features of patients aged 8-18 years presenting with Class I and Class III incisor relationship in a case-control design. Subjects with a Class III incisor relationship, aged 8-18 years, were age and gender matched with Class I control and underwent a 3-dimensional (3-D) optical surface scan of the facial soft tissues. Landmark analysis revealed Class III subjects displayed greater mean dimensions compared to the control group most notably between the ages of 8-10 and 17-18 years in both males and females, in respect of antero-posterior (P = 0.01) and vertical (P = 0.006) facial dimensions. Surface-based analysis, revealed the greatest difference in the lower facial region, followed by the mid-face, whilst the upper face remained fairly consistent. Significant detectable differences were found in the surface facial features of developing Class III subjects.

Breast Reference Set Application: GeorgeTuszynski-Temple (2012) — EDRN Public Portal

Cancer.gov

As recommended by the review committee, we will analyze 30 invasive cancer cases and 30 benign controls from the EDRN breast reference set. Cases and controls should be selected that are Caucasian and post-menopausal. It is suggested that the Caucasian cases and controls match as closely as possible in regards to age and body mass index.

Forced diuresis with matched hydration in reducing acute kidney injury during transcatheter aortic valve implantation (Reduce-AKI): study protocol for a randomized sham-controlled trial

PubMed Central

2014-01-01

Background Acute kidney injury (AKI) is observed in up to 41% of patients undergoing transcatheter aortic valve implantation (TAVI) and is associated with increased risk for mortality. The aim of the present study is to evaluate whether furosemide-induced diuresis with matched isotonic intravenous hydration using the RenalGuard system reduces AKI in patients undergoing TAVI. Methods/Design Reduce-AKI is a randomized sham-controlled study designed to examine the effect of an automated matched hydration system in the prevention of AKI in patients undergoing TAVI. Patients will be randomized in a 1:1 fashion to the RenalGuard system (active group) versus non-matched saline infusion (sham-controlled group). Both arms receive standard overnight saline infusion and N-acetyl cysteine before the procedure. Discussion The Reduce-AKI trial will investigate whether the use of automated forced diuresis with matched saline infusion is an effective therapeutic tool to reduce the occurrence of AKI in patients undergoing TAVI. Trial registration Clinicaltrials.gov: NCT01866800, 30 April 30 2013. PMID:24986373

Selection of Reference Gene Expression in a Schizophrenia Brain Cohort

PubMed Central

Weickert, Cynthia Shannon; Sheedy, Donna; Rothmond, Debora A.; Dedova, Irina; Fung, Samantha; Garrick, Therese; Wong, Jenny; Harding, Antony J.; Sivagnanansundaram, Sinthuja; Hunt, Clare; Duncan, Carlotta; Sundqvist, Nina; Tsai, Shan-Yuan; Anand, Jasna; Draganic, Daren; Harper, Clive

2010-01-01

Objective To conduct postmortem human brain research into the neuropathological basis of schizophrenia, it is critical to establish cohorts that are well-characterised and well-matched. Our objective was to determine if specimen characteristics, including: diagnosis, age, postmortem interval (PMI), brain acidity (pH), and/or the agonal state of the subject at death related to RNA quality, and to determine the most appropriate reference gene mRNAs. Methods We selected a matched cohort of 74 cases (37 schizophrenia / schizoaffective disorder cases and 37 controls cases). Middle frontal gyrus tissue was pulverised, tissue pH was measured, RNA isolated for cDNA from each case, and RNA integrity number (RIN) measurements were assessed. Using RT-PCR, we measured nine housekeeper genes and calculated a geomean in each diagnostic group. Results We found that the RINs were very good (mean 7.3) and all nine housekeeper control genes were significantly correlated with RIN. Seven of nine housekeeper genes were also correlated with pH, and two clinical variables, agonal state and duration of illness did have an effect on some control mRNAs. No major impact of PMI or freezer time on housekeeper mRNAs was detected. Our results show that people with schizophrenia had significantly less PPIA, and SDHA and tended to have less GUSB and B2M mRNA suggesting that these control genes may not be good candidates for normalisation. Conclusions In our cohort, less than 10% variability in RIN values was detected and the diagnostic groups were well matched overall. Our cohort was adequately powered (0.80–0.90) to detect mRNA differences (25%) due to disease. Our study suggests that multiple factors should be considered in mRNA expression studies of human brain tissues. When schizophrenia cases are adequately matched to control cases subtle differences in gene expression can be reliably detected. PMID:20073568

Factors influencing tackle injuries in rugby union football

PubMed Central

Garraway, W. M.; Lee, A. J.; Macleod, D. A.; Telfer, J. W.; Deary, I. J.; Murray, G. D.

1999-01-01

OBJECTIVES: To assess the influence of selected aspects of lifestyle, personality, and other player related factors on injuries in the tackle. To describe the detailed circumstances in which these tackles occurred. METHODS: A prospective case-control study was undertaken in which the tackling and tackled players ("the cases") involved in a tackle injury were each matched with "control" players who held the same respective playing positions in the opposing teams. A total of 964 rugby matches involving 71 senior clubs drawn from all districts of the Scottish Rugby Union (SRU) were observed by nominated linkmen who administered self report questionnaires to the players identified as cases and controls. Information on lifestyle habits, match preparation, training, and coaching experience was obtained. A validated battery of psychological tests assessed players' trait anger and responses to anger and hostility. The circumstances of the tackles in which injury occurred were recorded by experienced SRU coaching staff in interviews with involved players after the match. RESULTS: A total of 71 tackle injury episodes with correct matching of cases and controls were studied. The following player related factors did not contribute significantly to tackle injuries: alcohol consumption before the match, feeling "below par" through minor illness, the extent of match preparation, previous coaching, or practising tackling. Injured and non- injured players in the tackle did not differ in their disposition toward, or expression of, anger or hostility. Some 85% of tackling players who were injured were three quarters, and 52% of injuries occurred when the tackle came in behind the tackled player or within his peripheral vision. Either the tackling or tackled player was sprinting or running in all of these injury episodes. One third of injuries occurred in differential speed tackles--that is, when one player was travelling much faster than the other at impact. The player with the lower momentum was injured in 80% of these cases. Forceful or crunching tackles resulting in injury mostly occurred head on or within the tackled player's side vision. CONCLUSIONS: Attention should be focused on high speed tackles going in behind the tackled player's line of vision. Comparative information on the circumstances of the vast majority of tackles in which no injury occurs is required before any changes are considered to reduce injuries in the tackle. 


 PMID:10027056

XPAT: a toolkit to conduct cross-platform association studies with heterogeneous sequencing datasets.

PubMed

Yu, Yao; Hu, Hao; Bohlender, Ryan J; Hu, Fulan; Chen, Jiun-Sheng; Holt, Carson; Fowler, Jerry; Guthery, Stephen L; Scheet, Paul; Hildebrandt, Michelle A T; Yandell, Mark; Huff, Chad D

2018-04-06

High-throughput sequencing data are increasingly being made available to the research community for secondary analyses, providing new opportunities for large-scale association studies. However, heterogeneity in target capture and sequencing technologies often introduce strong technological stratification biases that overwhelm subtle signals of association in studies of complex traits. Here, we introduce the Cross-Platform Association Toolkit, XPAT, which provides a suite of tools designed to support and conduct large-scale association studies with heterogeneous sequencing datasets. XPAT includes tools to support cross-platform aware variant calling, quality control filtering, gene-based association testing and rare variant effect size estimation. To evaluate the performance of XPAT, we conducted case-control association studies for three diseases, including 783 breast cancer cases, 272 ovarian cancer cases, 205 Crohn disease cases and 3507 shared controls (including 1722 females) using sequencing data from multiple sources. XPAT greatly reduced Type I error inflation in the case-control analyses, while replicating many previously identified disease-gene associations. We also show that association tests conducted with XPAT using cross-platform data have comparable performance to tests using matched platform data. XPAT enables new association studies that combine existing sequencing datasets to identify genetic loci associated with common diseases and other complex traits.

An overview of the impact of rare disease characteristics on research methodology.

PubMed

Whicher, Danielle; Philbin, Sarah; Aronson, Naomi

2018-01-19

About 30 million individuals in the United States are living with a rare disease, which by definition have a prevalence of 200,000 or fewer cases in the United States ([National Organization for Rare Disorders], [About NORD], [2016]). Disease heterogeneity and geographic dispersion add to the difficulty of completing robust studies in small populations. Improving the ability to conduct research on rare diseases would have a significant impact on population health. The purpose of this paper is to raise awareness of methodological approaches that can address the challenges to conducting robust research on rare diseases. We conducted a landscape review of available methodological and analytic approaches to address the challenges of rare disease research. Our objectives were to: 1. identify algorithms for matching study design to rare disease attributes and the methodological approaches applicable to these algorithms; 2. draw inferences on how research communities and infrastructure can contribute to the efficiency of research on rare diseases; and 3. to describe methodological approaches in the rare disease portfolio of the Patient-Centered Outcomes Research Institute (PCORI), a funder promoting both rare disease research and research infrastructure. We identified three algorithms for matching study design to rare disease or intervention characteristics (Gagne, et.al, BMJ 349:g6802, 2014); (Gupta, et.al, J Clin Epidemiol 64:1085-1094, 2011); (Cornu, et. al, Orphet J Rare Dis 8:48,2012) and summarized the applicable methodological and analytic approaches. From this literature we were also able to draw inferences on how an effective research infrastructure can set an agenda, prioritize studies, accelerate accrual, catalyze patient engagement and terminate poorly performing studies. Of the 24 rare disease projects in the PCORI portfolio, 11 are randomized controlled trials (RCTs) using standard designs. Thirteen are observational studies using case-control, prospective cohort, or natural history designs. PCORI has supported the development of 9 Patient-Powered Research Networks (PPRNs) focused on rare diseases. Matching research design to attributes of rare diseases and interventions can facilitate the completion of RCTs that are adequately powered. An effective research infrastructure can improve efficiency and avoid waste in rare disease research. Our review of the PCORI research portfolio demonstrates that it is feasible to conduct RCTs in rare disease. However, most of these studies are using standard RCT designs. This suggests that use of a broader array of methodological approaches to RCTs --such as adaptive trials, cross-over trials, and early escape designs can improve the productivity of robust research in rare diseases.

rhBMP-2 protects against reoperation for pseudoarthrosis and/or instrumentation failure: A matched case-control study of 448 patients.

PubMed

Macki, Mohamed; Syeda, Sbaa; Kerezoudis, Panagiotis; Bydon, Ali; Witham, Timothy F; Sciubba, Daniel M; Wolinsky, Jean-Paul; Bydon, Mohamad; Gokaslan, Ziya

2016-10-01

The objective of this independent study is to determine the impact of recombinant human bone morphogenetic protein 2 (rhBMP-2) on reoperation for pseudarthrosis and/or instrumentation failure. A nested case-control study of first-time posterolateral, instrumented fusion of the lumbar spine for degenerative spinal disease was undertaken. Cases of reoperation for pseudoarthrosis and/or instrumentation failure were assigned to controls, who did not experience the primary outcome measure at the time of reoperation. Cases and controls were matched on number of interspaces fused and inclusion of interbody. Predictors of reoperation for pseudoarthrosis and/or instrumentation failure were assessed with a conditional logistical regression controlling for rhBMP-2, age, obesity, and smoking. Of the 448 patients, 155 cases of reoperation for pseudoarthrosis and/or instrumentation were matched with 293 controls. Twenty-six percent of first-time surgeries included rhBMP-2, which was statistically more commonly used in the control cohort (33.11%) versus the case cohort (12.90%) (Unadjusted odds ratio [ORunadj]=0.28) (95% confidence interval [CI]: 0.16-0.49). Following a multivariate analysis controlling for age, obesity, and smoking, the rhBMP-2 recipients incurred a 73% lower odds of reoperation for pseudoarthrosis and/or instrumentation failure (95% CI, 0.15-0.48). Neither sarcomatous nor osseous neoplasm was detected in the study population. Mean follow up did not differ between the cases (81.57±standard deviation [SD] 4.98months) versus controls (74.75±2.49month) (ORunadj=1.01) (95% CI: 1.00-1.01). rhBMP-2 in lumbar fusion constructs protects against reoperation for pseudoarthrosis and/or instrumentation failure. However, the decision to include fusion supplements should be weighted between surgical determinants and clinical outcomes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Endoscopic detection rate of sessile serrated lesions in Lynch syndrome patients is comparable with an age- and gender-matched control population: case-control study with expert pathology review.

PubMed

Vleugels, Jasper L A; Sahin, Husna; Hazewinkel, Yark; Koens, Lianne; van den Berg, Jose G; van Leerdam, Monique E; Dekker, Evelien

2018-05-01

Carcinogenesis in Lynch syndrome involves fast progression of adenomas to colorectal cancer (CRC) because of microsatellite instability. The role of sessile serrated lesions (SSLs) and the serrated neoplasia pathway in these patients is unknown. The aim of this matched case-control study was to compare endoscopic detection rates and distribution of SSLs in Lynch syndrome patients with a matched control population. We collected data of Lynch syndrome patients with a proven germline mutation who underwent colonoscopy between January 2011 and April 2016 in 2 tertiary referral hospitals. Control subjects undergoing elective colonoscopy from 2011 and onward for symptoms or surveillance were selected from a prospectively collected database. Patients were matched 1:1 for age, gender, and index versus surveillance colonoscopy. An expert pathology review of serrated polyps was performed. The primary outcomes included the detection rates and distribution of SSLs. We identified 321 patients with Lynch syndrome who underwent at least 1 colonoscopy. Of these, 223 Lynch syndrome patients (mean age, 49.3; 59% women; index colonoscopy, 56%) were matched to 223 control subjects. SSLs were detected in 7.6% (95% confidence interval, 4.8-11.9) of colonoscopies performed in Lynch syndrome patients and in 6.7% (95% confidence interval, 4.1-10.8) of control subjects (P = .86). None of the detected SSLs in Lynch syndrome patients contained dysplasia. The detection rate of SSLs in Lynch syndrome patients undergoing colonoscopy is comparable with a matched population. These findings suggest that the role of the serrated neoplasia pathway in CRC development in Lynch syndrome seems to be comparable with that in the general population. Copyright © 2018 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

Using case study within a sequential explanatory design to evaluate the impact of specialist and advanced practice roles on clinical outcomes: the SCAPE study.

PubMed

Lalor, Joan G; Casey, Dympna; Elliott, Naomi; Coyne, Imelda; Comiskey, Catherine; Higgins, Agnes; Murphy, Kathy; Devane, Declan; Begley, Cecily

2013-04-08

The role of the clinical nurse/midwife specialist and advanced nurse/midwife practitioner is complex not least because of the diversity in how the roles are operationalised across health settings and within multidisciplinary teams. This aim of this paper is to use The SCAPE Study: Specialist Clinical and Advanced Practitioner Evaluation in Ireland to illustrate how case study was used to strengthen a Sequential Explanatory Design. In Phase 1, clinicians identified indicators of specialist and advanced practice which were then used to guide the instrumental case study design which formed the second phase of the larger study. Phase 2 used matched case studies to evaluate the effectiveness of specialist and advanced practitioners on clinical outcomes for service users. Data were collected through observation, documentary analysis, and interviews. Observations were made of 23 Clinical Specialists or Advanced Practitioners, and 23 matched clinicians in similar matched non-postholding sites, while they delivered care. Forty-one service users, 41 clinicians, and 23 Directors of Nursing or Midwifery were interviewed, and 279 service users completed a survey based on the components of CS and AP practice identified in Phase 1. A coding framework, and the generation of cross tabulation matrices in NVivo, was used to make explicit how the outcome measures were confirmed and validated from multiple sources. This strengthened the potential to examine single cases that seemed 'different', and allowed for cases to be redefined. Phase 3 involved interviews with policy-makers to set the findings in context. Case study is a powerful research strategy to use within sequential explanatory mixed method designs, and adds completeness to the exploration of complex issues in clinical practice. The design is flexible, allowing the use of multiple data collection methods from both qualitative and quantitative paradigms. Multiple approaches to data collection are needed to evaluate the impact of complex roles and interventions in health care outcomes and service delivery. Case study design is an appropriate methodology to use when study outcomes relate to clinical practice.

Rate of return to pitching and performance after Tommy John surgery in Major League Baseball pitchers.

PubMed

Erickson, Brandon J; Gupta, Anil K; Harris, Joshua D; Bush-Joseph, Charles; Bach, Bernard R; Abrams, Geoffrey D; San Juan, Angielyn M; Cole, Brian J; Romeo, Anthony A

2014-03-01

Medial ulnar collateral ligament (UCL) reconstruction is a common procedure performed on Major League Baseball (MLB) pitchers in the United States. To determine (1) the rate of return to pitching (RTP) in the MLB after UCL reconstruction, (2) the RTP rate in either the MLB and minor league combined, (3) performance after RTP, and (4) the difference in the RTP rate and performance between pitchers who underwent UCL reconstruction and matched controls without UCL injuries. Cohort study; Level of evidence, 3. Major League Baseball pitchers with symptomatic medial UCL deficiency who underwent UCL reconstruction were evaluated. All player, elbow, and surgical demographic data were analyzed. Controls matched by age, body mass index, position, handedness, and MLB experience and performance were selected from the MLB during the same years as those undergoing UCL reconstruction. An "index year" was designated for controls, analogous to the UCL reconstruction year in cases. Return to pitching and performance measures in the MLB were compared between cases and controls. Student t tests were performed for analysis of within-group and between-group variables, respectively. A total of 179 pitchers with UCL tears who underwent reconstruction met the inclusion criteria and were analyzed. Of these, 148 pitchers (83%) were able to RTP in the MLB, and 174 pitchers were able to RTP in the MLB and minor league combined (97.2%), while only 5 pitchers (2.8%) were never able to RTP in either the MLB or minor league. Pitchers returned to the MLB at a mean 20.5 ± 9.72 months after UCL reconstruction. The length of career in the MLB after UCL reconstruction was 3.9 ± 2.84 years, although 56 of these patients were still currently actively pitching in the MLB at the start of the 2013 season. The revision rate was 3.9%. In the year before UCL reconstruction, pitching performance declined significantly in the cases versus controls in the number of innings pitched, games played, and wins and the winning percentage (P < .05). After surgery, pitchers showed significantly improved performance versus before surgery (fewer losses, a lower losing percentage, lower earned run average [ERA], threw fewer walks, and allowed fewer hits, runs, and home runs) (P < .05). Comparisons between cases and controls for the time frame after UCL reconstruction (cases) or the index year (controls) demonstrated that cases had significantly (P < .05) fewer losses per season and a lower losing percentage. In addition, cases had a significantly lower ERA and allowed fewer walks and hits per inning pitched. There is a high rate of RTP in professional baseball after UCL reconstruction. Performance declined before surgery and improved after surgery. When compared with demographic-matched controls, patients who underwent UCL reconstruction had better results in multiple performance measures. Reconstruction of the UCL allows for a predictable and successful return to the MLB.

Performance and Return to Sport After Sports Hernia Surgery in NFL Players

PubMed Central

Jack, Robert A.; Evans, David C.; Echo, Anthony; McCulloch, Patrick C.; Lintner, David M.; Varner, Kevin E.; Harris, Joshua D.

2017-01-01

Background: Recognition, diagnosis, and treatment of athletic pubalgia (AP), also known as sports hernia, once underrecognized and undertreated in professional football, are becoming more common. Surgery as the final treatment for sports hernia when nonsurgical treatment fails remains controversial. Given the money involved and popularity of the National Football League (NFL), it is important to understand surgical outcomes in this patient population. Hypothesis: After AP surgery, players would: (1) return to sport (RTS) at a greater than 90% rate, (2) play fewer games for fewer years than matched controls, (3) have no difference in performance compared with before AP surgery, and (4) have no difference in performance versus matched controls. Study Design: Cohort study; Level of evidence, 3. Methods: Internet-based injury reports identified players who underwent AP surgery from January 1996 to August 2015. Demographic and performance data were collected for each player. A 1:1 matched control group and an index year analog were identified. Control and case performance scores were calculated using a standardized scoring system. Groups were compared using paired Student t tests. Results: Fifty-six NFL players (57 AP surgeries) were analyzed (mean age, 28.2 ± 3.1 years; mean years in NFL at surgery, 5.4 ± 3.2). Fifty-three players were able to RTS. Controls were in the NFL longer (P < .05) than players who underwent AP surgery (3.8 ± 2.4 vs 3.2 ± 2.1 years). Controls played more games per season (P < .05) than post-AP players (14.0 ± 2.3 vs 12.0 ± 3.4 games per season). There was no significant (P > .05) difference in pre- versus post-AP surgery performance scores and no significant (P > .05) difference in postoperative performance scores versus controls post-index. Conclusion: There was a high RTS rate after AP surgery without a significant difference in postoperative performance, though career length and games per season after AP surgery were significantly less than that of matched controls. PMID:28451612

Comparison of ultra-congruent mobile- and fixed-bearing navigation-assisted total knee arthroplasty with minimum 5-year follow-up.

PubMed

Kim, Seong Hwan; Lim, Jung-Won; Ko, Young-Bong; Song, Min-Gu; Lee, Han-Jun

2016-11-01

The purpose of this study was to compare the midterm outcomes between fixed and mobile ultra-congruent (UC) bearings in total knee arthroplasty (TKA). This is a retrospective matched-pairs case-control study of patients who underwent primary navigation-assisted TKA with a minimum 5-year follow-up. A total of 182 cases involved the fixed UC bearing system as Group 1 and 101 cases involved mobile UC bearing system group as Group 2. After 1:1 matching, 73 knees in each group were enrolled. Clinical and radiographic outcomes were evaluated. The overall survival was 143 of 146 cases (97.9 %) at final follow-up, and 72 of 73 cases (96.3 %) in Group 1 and 71 of 73 cases (95.8 %) in Group 2 at final follow-up based on an endpoint of revision surgery. The reasons of revision TKA were periprosthetic fracture in Group 1, infection and bearing dislocation in Group 2. There was no statistical difference in Hospital for Special Surgery (HSS) scores, Knee Society Scores (KSS), WOMAC index score evaluations between groups. This study demonstrated that the fixed-bearing UC prosthesis could provide satisfactory performance compared with that of the mobile-bearing UC prosthesis with minimum 5-year follow-up. The fixed-bearing UC prosthesis could be considered in navigation-assisted TKA with theoretical advantages of UC design. IV.

Leveraging public health's participation in a Health Information Exchange to improve communicable disease reporting.

PubMed

Painter, Ian; Revere, Debra; Gibson, P Joseph; Baseman, Janet

2017-01-01

Infectious diseases can appear and spread rapidly. Timely information about disease patterns and trends allows public health agencies to quickly investigate and efficiently contain those diseases. But disease case reporting to public health has traditionally been paper-based, resulting in somewhat slow, burdensome processes. Fortunately, the expanding use of electronic health records and health information exchanges has created opportunities for more rapid, complete, and easily managed case reporting and investigation. To assess how this new service might impact the efficiency and quality of a public health agency's case investigations, we compared the timeliness of usual case investigation to that of case investigations based on case report forms that were partially pre-populated with electronic data. Between September 2013-March 2014, chlamydia disease report forms for certain clinics in Indianapolis were electronically pre-populated with clinical, lab and patient data available through the Indiana Health Information Exchange, then provided to the patient’s doctor. Doctors could then sign the form and deliver it to public health for investigation and population-level disease tracking. Methods: We utilized a novel matched case analysis of timeliness changes in receipt and processing of communicable disease report forms. Each Chlamydia cases reported with the pre-populated form were matched to cases reported in usual ways. We assessed the time from receipt of the case at the public health agency: 1) inclusion of the case into the public health surveillance system and 2) to close to case. A hierarchical random effects model was used to compare mean difference in each outcome between the target cases and the matched cases, with random intercepts for case. Twenty-one Chlamydia cases were reported to the public health agency using the pre-populated form. Sixteen of these pre-populated form cases were matched to at least one other case, with a mean of 23 matches per case. The mean Reporting Lag for the pre-populated form cases was 2.5 days, which was 2.7 days shorter than the mean Reporting Lag for the matched controls (p = <0.001). The mean time to close a pre-populated form case was 4.7 days, which was 0.2 days shorter than time to close for the matched controls (p = 0.792). Use of pre-populated forms significantly decreased the time it took for the local public health agency to begin documenting and closing chlamydia case investigations. Thoughtful use of electronic health data for case reporting may decrease the per-case workload of public health agencies, and improve the timeliness of information about the pattern and spread of disease.

Anorexia nervosa versus bulimia nervosa: differences based on retrospective correlates in a case-control study.

PubMed

Machado, Bárbara C; Gonçalves, Sónia F; Martins, Carla; Brandão, Isabel; Roma-Torres, António; Hoek, Hans W; Machado, Paulo P

2016-06-01

This study is the result of two Portuguese case-control studies that examined the replication of retrospective correlates and preceding life events in anorexia nervosa (AN) and bulimia nervosa (BN) development. This study aims to identify retrospective correlates that distinguish AN and BN METHOD: A case-control design was used to compare a group of women who met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for AN (N = 98) and BN (N = 79) with healthy controls (N = 86) and with other psychiatric disorders (N = 68). Each control group was matched with AN patients regarding age and parental social categories. Risk factors were assessed by interviewing each person with the Oxford Risk Factor Interview. Compared to AN, women with BN reported significantly higher rates of paternal high expectations, excessive family importance placed on fitness/keeping in shape, and negative consequences due to adolescent overweight and adolescent objective overweight. Overweight during adolescence emerged as the most relevant retrospective correlate in the distinction between BN and AN participants. Family expectations and the importance placed on keeping in shape were also significant retrospective correlates in the BN group.

Maternal use of household pesticides during pregnancy and risk of neuroblastoma in offspring. A pooled analysis of the ESTELLE and ESCALE French studies (SFCE).

PubMed

Rios, Paula; Bailey, Helen D; Lacour, Brigitte; Valteau-Couanet, Dominique; Michon, Jean; Bergeron, Christophe; Boutroux, Hélène; Defachelles, Anne-Sophie; Gambart, Marion; Sirvent, Nicolas; Thebaud, Estelle; Ducassou, Stéphane; Orsi, Laurent; Clavel, Jacqueline

2017-10-01

Neuroblastoma (NB) is an embryonic tumor that occurs almost exclusively in infancy and early childhood. While considerable evidence suggests that it may be initiated during embryonic development, the etiology of NB is still unknown. The aim of this study was to explore whether there is an association between maternal use of household pesticides during pregnancy and the risk of NB in the offspring. We conducted a pooled analysis of two French national-based case-control studies. The mothers of 357 NB cases and 1,783 controls younger than 6 years, frequency-matched by age and gender, responded to a telephone interview that focused on sociodemographic and perinatal characteristics, childhood environment, and life-style. Unconditional logistic regression was used to estimate pooled odds ratios and 95% confidence intervals. After controlling for matching variables, study of origin, and potential confounders, the maternal use of any type of pesticide during pregnancy was associated with NB (OR 1.5 [95% CI 1.2-1.9]). The most commonly used type of pesticides were insecticides and there was a positive association with their use alone (OR 1.4 [95% CI 1.1-1.9]) or with other pesticides (OR 2.0 [95% CI 1.1-3.4]). Although there is the potential for recall bias due to the study design, our findings add to the evidence of an association between the household use of pesticides and NB. Until a better study design can be found, our findings add yet another reason why to advise pregnant women to limit pesticide exposure during the periconceptional period.

Pharmaceutical industry research and cost savings in community-acquired pneumonia.

PubMed

Kessler, Lori A; Waterer, Grant W; Barca, Robin; Wunderink, Richard G

2002-09-01

To provide financial justification for continuing pharmaceutical research in an environment that has met with increasing resistance from insurance carriers to paying for the care of patients enrolled in research studies. Matched case-control study of patients enrolled into inpatient community-acquired pneumonia (CAP) pharmaceutical research protocols. Case patients were enrolled into a CAP pharmaceutical research trial. Control patients were obtained from a prospective cohort study of CAP. Cases were matched to controls on the basis of age, sex, pneumonia severity index (PSI) grade, and comorbid illnesses as measured by the PSI and Acute Physiologic and Chronic Health Evaluation II (APACHE II) scoring systems. Financial data were obtained from hospital billing records. Twenty-five cases were identified and matched to appropriate controls. There was no statistically significant difference in mean PSI and APACHE II scores between cases and controls. There was a significant reduction in the total charges for hospital care of patients enrolled into a pharmaceutical industry trial ($6267 vs $9979; P = .03). As expected, the most dramatic reduction was in pharmacy charges ($642 vs $1797; P = .002), but there were trends toward lower charges in all cost subgroups. Interestingly, there was also a strong trend toward reduced length of hospital stay associated with enrollment in a pharmaceutical trial (4.5 vs 6.0 days; P = .06). Enrollment in a pharmaceutical research protocol results in significant cost savings in patients admitted to the hospital with CAP and may lead to earlier hospital discharge.

Association between HIV status and depressive symptoms among children and adolescents in the Southern Highlands Zone, Tanzania: A case-control study.

PubMed

Lwidiko, Abraham; Kibusi, Stephen Matthew; Nyundo, Azan; Mpondo, Bonaventura C T

2018-01-01

Children and adolescents continue to have HIV/AIDS in southern Saharan Africa. Scaling up of HIV services has significantly improved access to ARV and consequently improved on morbidity and mortality related to HIV/AIDS including opportunistic infection. Despite the above efforts, non-communicable conditions including mental disorders such as depression have been observed to contribute to the burden of disabilities about which little is documented. This study, therefore, aimed to determine the magnitude of depressive symptoms and the associated factors among HIV-infected children and adolescents. The study was a matched case-control design involving 300 cases of HIV-infected children matched by age and sex against 600 uninfected controls. Systematic sampling technique was used to select the cases while multistage sampling technique was employed to identify villages/ streets purposive and sampling technique was employed to obtain participants from households. The overall prevalence of depressive symptoms among the cohort of 900 participants was found to be 12.9%, with 27% of HIV-infected and 5.8% of HIV-uninfected children and adolescents screened positive for depressive symptoms. Multiple logistic regression revealed that being HIV-infected (AOR 1.96(1.11-3.45)), residing in a rural setting (AOR 0.61(0.39-0.96)) and history of childhood deprivation (AOR 4.76 (2.79-8.13)) were significantly associated with depressive symptoms. HIV infected adolescents are more affected by depression compared to non-infected counterparts. Childhood deprivation was significantly associated with presence of depressive symptoms. Integration of mental health evaluation and treatment into the HIV care provided for adolescents can be beneficial. More studies to delineate factors associated with depressed adolescents with HIV may add value to the body of knowledge and overall improvement of care.

The effect of past antibiotic exposure on diabetes risk

PubMed Central

Boursi, Ben; Mamtani, Ronac; Haynes, Kevin; Yang, Yu-Xiao

2015-01-01

Objective Gut microbiota influence metabolic pathways relevant to the pathogenesis of obesity, insulin-resistance and diabetes. Antibiotic therapy can alter the microbiota and is commonly used in western countries. We sought to evaluate whether past antibiotic exposure increases diabetes risk. Research design and methods We conducted a nested case-control study using a large population-based database from the United Kingdom (UK). Cases were defined as those with incident diagnosis of diabetes. For every case, 4 eligible controls matched on age, sex, practice-site, and duration of follow-up before index-date were selected using incidence-density sampling. Exposure of interest was antibiotic therapy >1 year before index-date. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression. The risk was adjusted for body mass index (BMI), smoking, last glucose level and number of infections before index-date, as well as past medical history of coronary artery disease and hyperlipidemia. Results The study included 208,002 diabetic cases and 815,576 matched controls. Exposure to a single antibiotic prescription was not associated with higher adjusted diabetes risk. Treatment with 2–5 antibiotic courses was associated with increase in diabetic risk for penicillin, cephalosporins, macrolides and quinolones with adjusted OR ranging from 1.08 (95%CI 1.05–1.11) for penicillin to 1.15 (95%CI 1.08–1.23) for quinolones. The risk increased with the number of antibiotic courses and reached 1.37 (95%CI 1.19–1.58) for >5 courses of quinolones. There was no association between exposure to anti-virals and anti-fungals and diabetes risk. Conclusions Exposure to certain antibiotic groups increases diabetes risk. PMID:25805893

Correlation of CpG Island Methylation of the Cytochrome P450 2E1/2D6 Genes with Liver Injury Induced by Anti-Tuberculosis Drugs: A Nested Case-Control Study.

PubMed

Zhang, Jinling; Zhu, Xuebin; Li, Yuhong; Zhu, Lingyan; Li, Shiming; Zheng, Guoying; Ren, Qi; Xiao, Yonghong; Feng, Fumin

2016-08-01

This study investigated the role of CpG island methylation of the CYP2E1 and CYP2D6 genes in liver injury induced by anti-TB drugs from an epigenetic perspective in a Chinese cohort. A 1:1 matched nested case-control study design was applied. Pulmonary tuberculosis (TB) patients, who underwent standard anti-TB therapy and developed liver injury were defined as cases, while those who did not develop liver injury were defined as control. The two groups were matched in terms of sex, treatment regimen, and age. In 114 pairs of cases, CpG island methylation levels of the CYP2E1 and CYP2D6 genes in plasma cell-free DNA were found to be significantly correlated with the occurrence of anti-TB drug-induced liver injury (ADLI), with odds ratio (OR) values of 2.429 and 3.500, respectively (p < 0.01). Moreover, through multivariate logistic regression analysis, CpG island methylation of the CYP2E1 and CYP2D6 genes in plasma cell-free DNA were found to be significantly correlated with the occurrence of ADLI, with adjusted OR values of 4.390 (95% confidence interval (CI): 1.982-9.724) and 9.193 (95% CI: 3.624-25.888), respectively (p < 0.001). These results suggest that aberrantly elevated methylation of CpG islands of the CYP2E1 and CYP2D6 genes in plasma cell-free DNA may increase the risk of ADLI in Chinese TB patients.

Is gravidity 4+ a risk factor for oral clefts? A case-control study in eight South american countries using structural equation modeling.

PubMed

Gili, Juan Antonio; Poletta, Fernando Adrián; Campaña, Hebe; Comas, Belén; Pawluk, Mariela; Rittler, Monica; López-Camelo, Jorge Santiago

2013-09-01

Background : There is disagreement about the association between cleft lip with or without cleft palate and multigravidity, which could be explained by differences of adjusting for maternal age, Amerindian ancestry, and socioeconomic status. Objective : The aim was to evaluate gravidity 4+ (four or more gestations) as a risk factor for cleft lip with or without cleft palate in South America. Design : We used a matched (1:1) case-control study with structural equation modeling for related causes. Data were obtained from 1,371,575 consecutive newborn infants weighing ≥500 g who were born in the hospitals of the Estudio Colaborativo Latinoamericano de Malformaciones Congénitas (ECLAMC) network between 1982 and 1999. There were a total of 1,271 cases with cleft lip with or without cleft palate (excluding midline and atypical cleft lip with or without cleft palate). A total of 1,227 case-control pairs were obtained, matched by maternal age, newborn gender, and year and place of birth. Potential confounders and intermediary variables were analyzed with structural equation modeling. Results : The crude risk of gravidity 4+ was 1.41 and the 95% confidence interval was 1.14 to 1.61. When applying structural equation modeling, the effect of multigravidity on the risk of cleft lip with or without cleft palate was 1.22 and the 95% confidence interval was 0.91 to 1.39. Conclusions : Multigravid mothers (more than four gestations) showed no greater risk of bearing children who had cleft lip with or without cleft palate than mothers with two or three births. Therefore, the often observed and reported association between multigravidity and oral clefts likely reflects the effect of other risk factors related to low socioeconomic status in South American populations.

Retrospective multicenter matched case-control study on the risk factors for narcolepsy with special focus on vaccinations (including pandemic influenza vaccination) and infections in Germany.

PubMed

Oberle, Doris; Pavel, Jutta; Mayer, Geert; Geisler, Peter; Keller-Stanislawski, Brigitte

2017-06-01

Studies associate pandemic influenza vaccination with narcolepsy. In Germany, a retrospective, multicenter, matched case-control study was performed to identify risk factors for narcolepsy, particularly regarding vaccinations (seasonal and pandemic influenza vaccination) and infections (seasonal and pandemic influenza) and to quantify the detected risks. Patients with excessive daytime sleepiness who had been referred to a sleep center between April 2009 and December 2012 for multiple sleep latency test (MSLT) were eligible. Case report forms were validated according to the criteria for narcolepsy defined by the Brighton Collaboration (BC). Confirmed cases of narcolepsy (BC level of diagnostic certainty 1-4a) were matched with population-based controls by year of birth, gender, and place of residence. A second control group was established including patients in whom narcolepsy was definitely excluded (test-negative controls). A total of 103 validated cases of narcolepsy were matched with 264 population-based controls. The second control group included 29 test-negative controls. A significantly increased odd ratio (OR) to develop narcolepsy (crude OR [cOR] = 3.9, 95% confidence interval [CI] = 1.8-8.5; adjusted OR [aOR] = 4.5, 95% CI = 2.0-9.9) was detected in individuals immunized with pandemic influenza A/H1N1/v vaccine prior to symptoms onset as compared to nonvaccinated individuals. Using test-negative controls, in individuals immunized with pandemic influenza A/H1N1/v vaccine prior to symptoms onset, a nonsignificantly increased OR of narcolepsy was detected when compared to nonvaccinated individuals (whole study population, BC levels 1-4a: cOR = 1.9, 95% CI = 0.5-6.9; aOR = 1.8, 95% CI = 0.3-10.1). The findings of this study support an increased risk for narcolepsy after immunization with pandemic influenza A/H1N1/v vaccine. Copyright © 2017 Elsevier B.V. All rights reserved.

Predictors of early neurological deterioration after ischaemic stroke: a case-control study.

PubMed

Barber, Mark; Wright, Fiona; Stott, David J; Langhorne, Peter

2004-01-01

Early neurological deterioration after ischaemic stroke (stroke in progression) is reported to be common and associated with poor outcome or death. The causes of progressing stroke are, however, uncertain. To determine whether prior drug treatment (with anticoagulant or antiplatelet agents) or early adverse physiological features (pyrexia, hypoxia, dehydration or hyperglycaemia) are associated with progressing ischaemic stroke. The study used a case-control design. From a database of 873 consecutive acute stroke admissions, 196 cases of progressing ischaemic stroke (defined by point deterioration in components of the Scandinavian Stroke Scale or death over the first 72 h after hospital admission) were matched to 196 controls on the basis of age and stroke type. Univariate and conditional logistic regression techniques were used to explore predictors of progressing stroke. Cases and controls were well matched for baseline stroke severity. Warfarin use prior to admission was associated with a reduced risk of progressing stroke [odds ratio (OR) 0.10, p = 0.005]. Prior antiplatelet use was not related. A previous history of diabetes (OR 2.11, p = 0.039) and elevated systolic blood pressure on admission (OR 1.01 for each 1 mm Hg rise, p = 0.017) predicted progressing stroke. Although there were no differences in time to presentation or to brain imaging, a visible causative lesion on CT scanning was more common in the progressing stroke group (OR 2.30, p = 0.022). We found no evidence that adverse physiological features were associated with progressing stroke. Outcomes were worse in the progressing stroke group with 70% being dead or dependent by 30 days compared to 55% in the control group (p = 0.002). Prior warfarin use may be protective against progressing ischaemic stroke. A previous history of diabetes along with elevated admission systolic blood pressure predict deterioration. We found no evidence for an association between adverse physiological features and progressing stroke. Copyright 2004 S. Karger AG, Basel

77 FR 18216 - Applications for New Awards; Investing in Innovation Fund, Scale-Up Grants

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-27

... evaluation and prevents even the appearance of a conflict of interest. Interrupted time series design \\8... findings. \\8\\ A single subject or single case design is an adaptation of an interrupted time series design... matched comparison group designs (as defined in this notice), interrupted time series designs (as defined...

Psychosocial and Psychiatric Factors Associated with Adolescent Suicide: A Case-Control Psychological Autopsy Study

ERIC Educational Resources Information Center

Portzky, Gwendolyn; Audenaert, Kurt; van Heeringen, Kees

2009-01-01

This study aimed at the investigation of psychosocial and psychiatric risk factors of adolescent suicide by means of a case-control psychological autopsy study. Relatives and other informants of 19 suicide victims and 19 matched psychiatric controls were interviewed by means of a semi-structured interview schedule. Psychiatric controls included…

An approach to checking case-crossover analyses based on equivalence with time-series methods.

PubMed

Lu, Yun; Symons, James Morel; Geyh, Alison S; Zeger, Scott L

2008-03-01

The case-crossover design has been increasingly applied to epidemiologic investigations of acute adverse health effects associated with ambient air pollution. The correspondence of the design to that of matched case-control studies makes it inferentially appealing for epidemiologic studies. Case-crossover analyses generally use conditional logistic regression modeling. This technique is equivalent to time-series log-linear regression models when there is a common exposure across individuals, as in air pollution studies. Previous methods for obtaining unbiased estimates for case-crossover analyses have assumed that time-varying risk factors are constant within reference windows. In this paper, we rely on the connection between case-crossover and time-series methods to illustrate model-checking procedures from log-linear model diagnostics for time-stratified case-crossover analyses. Additionally, we compare the relative performance of the time-stratified case-crossover approach to time-series methods under 3 simulated scenarios representing different temporal patterns of daily mortality associated with air pollution in Chicago, Illinois, during 1995 and 1996. Whenever a model-be it time-series or case-crossover-fails to account appropriately for fluctuations in time that confound the exposure, the effect estimate will be biased. It is therefore important to perform model-checking in time-stratified case-crossover analyses rather than assume the estimator is unbiased.

Nitrate in drinking water and risk of death from pancreatic cancer in Taiwan.

PubMed

Yang, Chun-Yuh; Tsai, Shang-Shyue; Chiu, Hui-Fen

2009-01-01

The relationship between nitrate levels in drinking water and risk of pancreatic cancer development remains inconclusive. A matched case-control and nitrate ecology study was used to investigate the association between mortality attributed to pancreatic cancer and nitrate exposure from Taiwan's drinking water. All pancreatic cancer deaths of Taiwan residents from 2000 through 2006 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to the cases by gender, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each case. Data on nitrate-nitrogen (NO(3)-N) levels of drinking water throughout Taiwan were collected from Taiwan Water Supply Corporation (TWSC). The municipality of residence for cancer cases and controls was assumed to be the source of the subject's nitrate exposure via drinking water. The adjusted odds ratios and confidence limits for pancreatic cancer death for those with high nitrate levels in their drinking water, as compared to the lowest tertile, were 1.03 (0.9-1.18) and 1.1 (0.96-1.27), respectively. The results of the present study show that there was no statistically significant association between the levels of nitrate in drinking water and increased risk of death from pancreatic cancer.

Phenoxy herbicides and chlorophenols: a case control study on soft tissue sarcoma and malignant lymphoma.

PubMed Central

Smith, J. G.; Christophers, A. J.

1992-01-01

A case control study on patients with soft tissue sarcoma and malignant lymphoma was undertaken to test whether there was any association between these diseases and past exposure to chlorinated phenoxy acid herbicides or chlorophenols. It was carried out over the period 1982-1988 in Victoria, Australia. Thirty males with soft tissue sarcoma and 52 males with malignant lymphoma were matched by age, place of residence and sex with one population control and one cancer control each. Exposure was assessed by personal interviews conducted by an occupational hygienist. Exposures within 5 years prior to diagnosis of each matched case were ignored, both for the cases and their matched controls. The estimated relative risks for definite or probable exposure to chlorinated phenoxy compounds or chlorophenols for at least 1 day were 1.0 (95% confidence interval (CI): 0.3-3.1) for soft tissue sarcoma and 1.5 (95% CI: 0.6-3.7) for malignant lymphoma. When the criterion for exposure was raised to more than 30 days, the estimated relative risks were 2.0 (95% CI: 0.5-8.0) for soft tissue sarcoma and 2.7 (95% CI: 0.7-9.6) for malignant lymphoma. Additional analyses were carried out for exposure of at least 1 day to phenoxy herbicides alone or chlorophenols alone. None of the estimated relative risks was significantly greater than unity. PMID:1558802

Hospitalization Costs of Total Knee Arthroplasty With a Continuous Femoral Nerve Block Provided Only in the Hospital Versus on an Ambulatory Basis: A Retrospective, Case-Control, Cost-Minimization Analysis

PubMed Central

Ilfeld, Brian M.; Mariano, Edward R.; Williams, Brian A.; Woodard, Jennifer N.; Macario, Alex

2007-01-01

Background and Objectives Following total knee arthroplasty (TKA), hospitalization may be shortened by allowing patients to return home with a continuous femoral nerve block (CFNB). This study quantified the hospitalization costs for 10 TKA patients receiving ambulatory CFNB versus a matched cohort of 10 patients who received CFNB only during hospitalization. Methods We examined the medical records (n=125) of patients who underwent a unilateral, primary, tricompartment TKA with a postoperative CFNB by one surgeon at one institution in an 18-month period beginning January 2004. Each of the ten patients discharged home with an ambulatory CFNB (cases) was matched with a patient with a hospital-only CFNB (controls) for age, gender, body mass index, and health status. Financial data were extracted from the hospital micro-costing database. Results Nine patients with ambulatory CFNB (cases) were discharged home on postoperative day (POD) 1, and one on POD 4. Of the controls, 3 were discharged home on POD 3, 6 on POD 4, and 1 on POD 5. The median (range) costs of hospitalization (excluding implant and professional fees) was $5,292 (4,326 – 7,929) for ambulatory cases, compared with $7,974 (6,931 – 9,979) for inpatient controls (difference=$2,682, 34% decrease, P<0.001). The total charges for hospitalization, the implant, and professional fees was $33,646 (31,816 – 38,468) for cases, compared with $39,100 (36,096 – 44,098) for controls (difference=$5,454, 14% decrease, P<0.001). Conclusions This study provides evidence that ambulatory CFNB for selected patients undergoing TKA has the potential to reduce hospital length-of-stay and associated costs and charges. However, the current study has significant inherent limitations based on the study design. Additional research is required to replicate these results in a prospective, randomized, controlled trial and to determine whether any savings exceed additional CFNB costs such as from complications, having caregivers provide care at home, and additional hospital/health-care provider visits. PMID:17196492

Descriptive epidemiology and natural history of idiopathic venous thromboembolism in U.S. active duty enlisted personnel, 1998-2007.

PubMed

Freeman, Randall J; Li, Yuanzhang; Niebuhr, David W

2011-05-01

The estimated incidence of idiopathic venous thromboembolism (IVTE) cases in the United States ranges from 24,000 to 282,000/year. This analysis explores the incidence and prevalence of IVTE in the military and if cases experience increased attrition. The Defense Medical Surveillance System was searched for incident IVTE cases from 1998 through 2007. Enlisted cases were each matched to 3 controls. Kaplan-Meier survival analysis and Cox proportional hazard modeling were performed. We matched 463 cases to 1,389 controls. Outpatient IVTE rates have increased markedly from 1998 through 2007. Cases of all-cause attrition risk (0.56 [95% CI = 0.44, 0.72]) and rates were significantly less than controls (p < 0.0001), and cases of medical attrition risk (1.64 [95% CI = 1.13, 2.37]) and rates were significantly higher (p < 0.01). Increasing rates with lower attrition suggests increasing case prevalence. Health care providers must maintain a high index of suspicion for venous thromboembolism to minimize adverse sequelae affecting health, unit readiness, and medical costs.

Investigation of a Guillain-Barré syndrome cluster in the Republic of Fiji.

PubMed

Pastula, Daniel M; Khan, Aalisha Sahu; Sharp, Tyler M; Biaukula, Viema L; Naivalu, Taina K; Rafai, Eric; Ermias Belay; Staples, J Erin; Fischer, Marc; Kosoy, Olga I; Laven, Janeen J; Bennett, Elizabeth J; Jenney, Adam W J; Naidu, Ravi Narayan; Lanciotti, Robert S; Galloway, Renee L; Nilles, Eric J; Sejvar, James J; Kama, Mike

2017-01-15

In 2014, we investigated a cluster of Guillain-Barre syndrome (GBS) in Fiji that occurred during a dengue epidemic. We designed a case-control study to determine the etiology. Cases were patients meeting Brighton Collaboration criteria for GBS with onset from February 2014 to May 2014. Controls were persons without symptoms of GBS who were matched by age group and location. We collected information on demographics and potential exposures. Serum samples were tested for evidence of recent arboviral or Leptospira spp. infections. Nine cases of GBS were identified for an incidence of five cases per 100,000 population/year. Median age of cases was 27years (range: 0.8-52); five (56%) were male. Six (67%) reported an acute illness prior to GBS onset. Among the 9 cases and 28 controls enrolled, odds ratios for reported exposures or antibodies against various arboviruses or Leptospira spp. were not statistically significant. No clear etiologies were identified for this unusual GBS cluster. There was a temporal association between the GBS cluster and a dengue epidemic, but we were unable to substantiate an epidemiologic or laboratory association. Further study is needed to explore potential associations between arboviral infections and GBS. Copyright © 2016. Published by Elsevier B.V.

Natural history and clinical detection of undiagnosed coeliac disease in a North American community.

PubMed

Hujoel, I A; Van Dyke, C T; Brantner, T; Larson, J; King, K S; Sharma, A; Murray, J A; Rubio-Tapia, A

2018-05-01

Coeliac disease is a substantially underdiagnosed disorder, with clinical testing currently guided by case finding. To determine the presence of indications for diagnostic testing and frequency of clinical testing in undiagnosed coeliac disease. This was a case-control study of adults without prior diagnosis of coeliac disease. Undiagnosed cases were identified through sequential serology, and unaffected age- and gender-matched controls were selected. Medical records were systematically reviewed for indications for and evidence of clinical testing. Of 47 557 adults, 408 cases of undiagnosed coeliac disease were identified. 408 serology negative matched controls were selected. Eight-matched pairs were excluded, leading to 800 included individuals (61% female; median age 44.2 years). The odds of any indication for clinical testing were similar among undiagnosed coeliac disease and controls (odds ratio (OR) 1.18; 95% CI: 0.85-1.63, P = 0.32). Most individual indications were not associated with serologic status. Exceptions to this include hypothyroidism, which was more likely in cases of undiagnosed coeliac disease, and dyspepsia and chronic diarrhoea, which were less likely. Cases of undiagnosed coeliac disease were more likely to develop osteoporosis (P = 0.005), dermatitis herpetiformis (P = 0.006), chronic fatigue (P = 0.033), thyroiditis (P = 0.003), autoimmune diseases (P = 0.008), and have a family member diagnosed with coeliac disease (P = 0.001). This study strongly suggests that current case finding is not effective in detecting undiagnosed coeliac disease. Individuals with undiagnosed coeliac disease were more likely than controls to develop indications for testing overtime. A more effective method for detection of coeliac disease is needed. © 2018 John Wiley & Sons Ltd and Mayo Foundation.

Systemic Lupus Erythematosus is Associated with Uranium Exposure in a Community Living Near a Uranium Processing Plant: A Nested Case-Control Study

PubMed Central

Lu-Fritts, Pai-Yue; Kottyan, Leah C.; James, Judith A.; Xie, Changchung; Buckholz, Jeanette M.; Pinney, Susan M.; Harley, John B.

2014-01-01

Objective Explore the hypothesis that cases of SLE will be found more frequently in community members with high prior uranium exposure in the Fernald Community Cohort (FCC). Methods A nested case control study was performed. The FCC is a volunteer population that lived near a uranium ore processing plant in Fernald, Ohio, USA during plant operation and members were monitored for 18 years. Uranium plant workers were excluded. SLE cases were identified using American College of Rheumatology classification criteria, laboratory testing, and medical record review. Each case was matched to four age-, race-, and sex-matched controls. Sera from potential cases and controls were screened for autoantibodies. Cumulative uranium particulate exposure was calculated using a dosimetry model. Logistic regression with covariates was used to calculate odds ratios (OR) with 95% confidence intervals (CI). Results The FCC includes 4,187 individuals with background uranium exposure, 1,273 with moderate exposure, and 2,756 with higher exposure. SLE was confirmed in 23 of 31 individuals with a lupus ICD9 code, and in 2 of 43 other individuals prescribed hydroxychloroquine. The female:male ratio was 5.25:1. Of the 25 SLE cases, 12 were in the higher exposure group. SLE was associated with higher uranium exposure (OR 3.92, 95% CI 1.131-13.588, p = 0.031). Conclusion High uranium exposure is associated with SLE relative to matched controls in this sample of uranium exposed individuals. Potential explanations for this relationship include possible autoimmune or estrogen effects of uranium, somatic mutation, epigenetic effects, or effects of some other unidentified accompanying exposure. PMID:25103365

Retinal Detachment Associated with AIDS-Related Cytomegalovirus Retinitis: Risk Factors in a Resource-Limited Setting

PubMed Central

Yen, Michael; Chen, Jenny; Ausayakhun, Somsanguan; Kunavisarut, Paradee; Vichitvejpaisal, Pornpattana; Ausayakhun, Sakarin; Jirawison, Choeng; Shantha, Jessica; Holland, Gary N; Heiden, David; Margolis, Todd P; Keenan, Jeremy D

2014-01-01

Purpose To determine risk factors predictive of retinal detachment in patients with cytomegalovirus (CMV) retinitis in a setting with limited access to ophthalmic care. Design Case-control study. Methods Sixty-four patients with CMV retinitis and retinal detachment were identified from the Ocular Infectious Diseases and Retina Clinics at Chiang Mai University. Three control patients with CMV retinitis but no retinal detachment were selected for each case, matched by calendar date. The medical records of each patient were reviewed, with patient-level and eye-level features recorded for the clinic visit used to match cases and controls, and also for the initial clinic visit at which CMV retinitis was diagnosed. Risk factors for retinal detachment were assessed separately for each of these time points using multivariate conditional logistic regression models that included 1 eye from each patient. Results Patients with a retinal detachment were more likely than controls to have low visual acuity (OR, 1.24 per line of worse vision on the logMAR scale; 95%CI, 1.16-1.33) and bilateral disease (OR, 2.12; 95%CI, 0.92-4.90). Features present at the time of the initial diagnosis of CMV retinitis that predicted subsequent retinal detachment included bilateral disease (OR, 2.68; 95%CI, 1.18-6.08) and lesion size (OR, 2.64 per 10% increase in lesion size; 95%CI, 1.41-4.94). Conclusion Bilateral CMV retinitis and larger lesion sizes, each of which is a marker of advanced disease, were associated with subsequent retinal detachment. Earlier detection and treatment may reduce the likelihood that patients with CMV retinitis develop a retinal detachment. PMID:25448999

Association between age and high-risk human papilloma virus in Mexican oral cancer patients.

PubMed

González-Ramírez, I; Irigoyen-Camacho, M E; Ramírez-Amador, V; Lizano-Soberón, M; Carrillo-García, A; García-Carrancá, A; Sánchez-Pérez, Y; Méndez-Martínez, R; Granados-García, M; Ruíz-Godoy, Lm; García-Cuellar, Cm

2013-11-01

Studies reporting low prevalence of HPV in OSCC with declining age at presentation are increasing. The aim of this study was to determine the prevalence of HPV in a group of OSCC cases and controls in a Mexican population. The matched case-control study included 80 OSCC cases and 320 controls. HPV/DNA presence was evaluated through PCR amplification using three sets of consensus primers for the L1 gene. A conditional logistic regression analysis was carried out for the matched OSCC cases and controls. Interactions between risk factors and OCSS were tested in the construction process of the models. HPV prevalence was 5% in OSCC cases and 2.5% in controls. HPV-detected types were 16, 18 and 56. According to conditional logistics regression model, an association was detected between HR-HPV and OSCC. All HR-HPV-positive OSCC cases corresponded to young patients (<45 years), non-smokers and non-alcohol drinkers. The HR-HPV can be a contributing factor to oral carcinogenesis, especially in younger individuals without known risk factors such as tobacco and alcohol. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The Ethnic/Racial Variations of Intracerebral Hemorrhage (ERICH) Study Protocol

PubMed Central

Woo, Daniel; Rosand, Jonathan; Kidwell, Chelsea; McCauley, Jacob L.; Osborne, Jennifer; Brown, Mark W.; West, Sandra E.; Rademacher, Eric W.; Waddy, Salina; Roberts, Jamie N.; Koch, Sebastian; Gonzales, Nicole R.; Sung, Gene; Kittner, Steven J.; Birnbaum, Lee; Frankel, Michael; Daniel Testai, Fernando; Hall, Christiana E.; Elkind, Mitchell S. V.; Flaherty, Matthew; Coull, Bruce; Chong, Ji Y.; Warwick, Tanya; Malkoff, Marc; James, Michael L.; Ali, Latisha K.; Worrall, Bradford B.; Jones, Floyd; Watson, Tiffany; Leonard, Anne; Martinez, Rebecca; Sacco, Ralph I; Langefeld, Carl D.

2013-01-01

Background and Purpose Epidemiologic studies of intracerebral hemorrhage (ICH) have consistently demonstrated variation in incidence, location, age at presentation, and outcomes among non-Hispanic white, black, and Hispanic populations. We report here the design and methods for this large, prospective, multi-center case-control study of ICH. Methods The ERICH study is a multi-center, prospective case-control study of ICH. Cases are identified by hot-pursuit and enrolled using standard phenotype and risk factor information and include neuroimaging and blood sample collection. Controls are centrally identified by random digit dialing to match cases by age (+/−5 years), race, ethnicity, gender and metropolitan region. Results As of March 22, 2013, 1,655 cases of ICH had been recruited into the study which is 101.5% of the target for that date and 851 controls had been recruited which is 67.2% of the target for that date (1,267 controls) for a total of 2,506 subjects which is 86.5% of the target for that date (2,897 subjects). Of the 1,655 cases enrolled, 1,640 cases had the case interview entered into the database of which 628 (38%) were non-Hispanic black, 458 (28%) were non-Hispanic white and 554 (34%) were Hispanic. Of the 1,197 cases with imaging submitted, 876 (73.2%) had a 24 hour follow-up CT available In addition to CT imaging, 607 cases have had MRI evaluation. Conclusion The ERICH study is a large, case-control study of ICH with particular emphasis on recruitment of minority populations for the identification of genetic and epidemiologic risk factors for ICH and outcomes after ICH. PMID:24021679

Psychosocial Characteristics of Children with Central Disorders of Hypersomnolence Versus Matched Healthy Children

PubMed Central

Avis, Kristin T.; Shen, Jiabin; Weaver, Patrick; Schwebel, David C.

2015-01-01

Background: Hypersomnia of central origin from narcolepsy or idiopathic hypersomnia (IHS) is characterized by pathological levels of excessive daytime sleepiness (EDS). Central hypersomnia has historically been underdiagnosed and poorly understood, especially with respect to its impact on daytime functioning and quality of life in children. Objective: Describe the psychosocial adjustment of children treated for narcolepsy or IHS on school performance, quality of life, and physical/extracurricular activities. Methods: Using a matched case control design, we compared child self- and parent-reported data from thirty-three 8- to 16-year-olds with an established diagnosis of narcolepsy or IHS, according to ICSD-2 criteria, to that of 33 healthy children matched by age, race/ethnicity, gender, and household income. Assessments evaluated academic performance, quality of life and wellness, sleepiness, and participation in extracurricular activities. Results: Compared to healthy controls, children with central hypersomnia had poorer daytime functioning in multiple domains. Children with hypersomnia missed more days of school and had lower grades than healthy controls. Children with hypersomnia had poorer quality of life by both parent and child report. Children with hypersomnia were significantly sleepier, had higher BMI, and were more likely to report a history of recent injury. Finally, children with hypersomnia engaged in fewer after-school activities than healthy controls. Conclusions: A range of significant psychosocial consequences are reported in children with hypersomnia even after a diagnosis has been made and treatments initiated. Health care professionals should be mindful of the psychosocial problems that may present in children with hypersomnia over the course of treatment. Citation: Avis KT, Shen J, Weaver P, Schwebel DC. Psychosocial characteristics of children with central disorders of hypersomnolence versus matched healthy children. J Clin Sleep Med 2015;11(11):1281–1288. PMID:26285115

Chronic Rhinosinusitis Associated with Erectile Dysfunction: A Population-Based Study.

PubMed

Tai, Shu-Yu; Wang, Ling-Feng; Tai, Chih-Feng; Huang, Yu-Ting; Chien, Chen-Yu

2016-08-31

Few studies have investigated the relationship between chronic rhinosinusitis (CRS) and erectile dysfunction (ED). This case-control study aimed to investigate the association between CRS and the risk of ED in a large national sample. Tapping Taiwan's National Health Insurance Research Database, we identified people 30 years or older with a new primary diagnosis of CRS between 1996 and 2007. The cases were compared with sex- and age-matched controls. We identified 14 039 cases and recruited 140 387 matched controls. Both groups were followed up in the same database until the end of 2007 for instances of ED. Of those with CRS, 294 (2.1%) developed ED during a mean (SD) follow-up of 3.20 (2.33) years, while 1 661 (1.2%) of the matched controls developed ED, mean follow up 2.97 (2.39) years. Cox regression analyses were performed adjusting for sex, age, insurance premium, residence, hypertension, hyperlipidemia, diabetes, obesity, coronary heart disease, chronic kidney disease, chronic obstructive pulmonary disease, asthma, allergic rhinitis, arrhythmia, ischemic stroke, intracerebral hemorrhage, and medications. CRS was revealed to be an independent predictor of ED in the fully adjusted model (HR = 1.51; 95% CI = 1.33-1.73; P < 0.0001).

Effects of a psychosocial intervention on survival among patients with stage I breast and prostate cancer: a matched case-control study.

PubMed

Shrock, D; Palmer, R F; Taylor, B

1999-05-01

Psychosocial factors have been linked to the development and progression of cancer and shown to be relevant in cancer care. However, the evidence that psychosocial interventions affect cancer survival is less conclusive. Few methodologically sound studies have addressed this issue. To investigate the effects of a 6-week psychosocial intervention on survival among patients with stage I breast and prostate cancer. Matched case-control. 3 rural hospitals or cancer centers in central Pennsylvania. 21 breast and 29 prostate stage I cancer patients (treatment group) matched with 74 breast and 65 prostate stage I cancer patients from the same hospitals who did not receive the intervention (control group). Six 2-hour health psychology classes conducted by a licensed staff psychologist. Survival time was compared between the 2 groups and with national norms. The intervention group lived significantly longer than did matched controls. At 4- to 7-year follow-up (median = 4.2 years), none of the breast cancer patients in the intervention group died, whereas 12% of those in the control group died. Twice as many matched-control prostate cancer patients died compared with those in the intervention group (28% vs 14%). Control group survival was similar to national norms. These results are consistent with prior clinical trials and suggest that short-term psychosocial interventions that encourage the expression of emotions, provide social support, and teach coping skills can influence survival among cancer patients. However, self-selection bias cannot be ruled out as an alternative explanation for the results. These interventions merit further consideration and research.

A direct approach to the design of linear multivariable systems

NASA Technical Reports Server (NTRS)

Agrawal, B. L.

1974-01-01

Design of multivariable systems is considered and design procedures are formulated in the light of the most recent work on model matching. The word model matching is used exclusively to mean matching the input-output behavior of two systems. The term is used in the frequency domain to indicate the comparison of two transfer matrices containing transfer functions as elements. Design methods where non-interaction is not used as a criteria were studied. Two design methods are considered. The first method of design is based solely upon the specification of generalized error coefficients for each individual transfer function of the overall system transfer matrix. The second design method is called the pole fixing method because all the system poles are fixed at preassigned positions. The zeros of terms either above or below the diagonal are partially fixed via steady state error coefficients. The advantages and disadvantages of each method are discussed and an example is worked to demonstrate their uses. The special cases of triangular decoupling and minimum constraints are discussed.

Pulmonary Tuberculosis Is Associated With Biomass Fuel Use Among Rural Women in Pakistan: An Age- and Residence-Matched Case-Control Study.

PubMed

Rabbani, Unaib; Sahito, Ambreen; Nafees, Asaad Ahmed; Kazi, Ambreen; Fatmi, Zafar

2017-04-01

Facility-based, age- and residential area-matched case-control study was conducted in Sindh, Pakistan to determine association between biomass fuel use for cooking and pulmonary tuberculosis (TB). Cases were women with pulmonary TB, and controls were those suffering from other diseases. Current users of biomass fuel were at higher risk of pulmonary TB (adjusted matched odds ratio [mOR] = 3.0; 95% CI = 1.1-4.9) compared with nonusers. In comparison with former biomass users (women not using biomass for >10 years), recent biomass users (women who switched from biomass to nonbiomass ≤10 years ago), and current (lifetime) users were at a higher risk in a dose-response manner (adjusted mOR = 2.8, 95% CI = 0.9-8.2 and adjusted mOR = 3.9, 95% CI = 1.4-10.7, respectively). Population attributable fraction for TB related to biomass fuel use was 40.6% (95% CI = 35.5%-45.7%). This study strengthens the evidence that biomass fuel use for cooking is associated with pulmonary TB and risk increases with duration of exposure.

Adverse childhood experiences and suicide attempts among those with mental and substance use disorders.

PubMed

Choi, Namkee G; DiNitto, Diana M; Marti, C Nathan; Segal, Steven P

2017-07-01

Using the 2012-2013 National Epidemiologic Survey on Alcohol and Related Conditions data, we examined the associations of ten types of adverse childhood experiences (ACEs) with (1) lifetime suicide attempts and (2) number and age of attempts among U.S. adults aged 18+. In a case-control design, suicide attempters (5.14% of the full sample) were matched with never attempters (matched sample N=3912) on nine mental and substance use disorders. ACE rates were higher among attempters (3.30 [SE=0.07]) than their matched controls (2.19 [SE=0.06]). Results from multivariable logistic regression analyses showed that sexual abuse and parental/other family member's mental illness were associated with increased odds of having attempted suicide among both genders, and emotional neglect was also a factor for men. Population attributable risk fractions for sexual abuse were 25.75% for women and 8.56% for men. Sexual abuse and a higher number of ACEs were also related to repeated suicide attempts. A higher number of ACEs was associated with a younger first attempt age. Gay/bisexual orientation in men and the lack of college education in both genders were significant covariates. In conclusion, this study underscores that ACEs are significantly associated with lifetime suicide attempts even when mental and substance use disorders are controlled. Copyright © 2017 Elsevier Ltd. All rights reserved.

Anthrax Vaccine and the Risk of Rheumatoid Arthritis and Systemic Lupus Erythematosus in the U.S. Military: A Case-Control Study.

PubMed

Bardenheier, Barbara H; Duffy, Jonathan; Duderstadt, Susan K; Higgs, Jay B; Keith, Michael P; Papadopoulos, Patricia J; Gilliland, William R; McNeil, Michael M

2016-10-01

U.S. military personnel assigned to areas deemed to be at high risk for anthrax attack receive Anthrax Vaccine Adsorbed (AVA). Few cases of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) have been reported in persons who received AVA. Using a matched case-control study design, we assessed the relationship of RA and SLE with AVA vaccination using the Defense Medical Surveillance System. We identified potential cases using International Classification of Diseases, 9th Revision, Clinical Modification codes and confirmed cases with medical record review and rheumatologist adjudication. Using conditional logistic regression, we estimated odds ratios (OR) for AVA exposure during time intervals ranging from 90 to 1,095 days before disease onset. Among 77 RA cases, 13 (17%) had ever received AVA. RA cases were no more likely than controls to have received AVA when looking back 1,095 days (OR: 1.03; 95% confidence interval [CI]: 0.48-2.19) but had greater odds of exposure in the prior 90 days (OR: 3.93; 95% CI: 1.08-14.27). Among the 39 SLE cases, 5 (13%) had ever received AVA; no significant difference in receipt of AVA was found when compared with controls (OR: 0.91; 95% CI: 0.26-3.25). AVA was associated with recent onset RA, but did not increase the risk of developing RA in the long term. Reprint & Copyright © 2016 Association of Military Surgeons of the U.S.

77 FR 11087 - Applications for New Awards; Investing in Innovation Fund, Development Grants

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-24

... prevents even the appearance of a conflict of interest. Interrupted time series design \\8\\ means a type of.... \\8\\ A single subject or single case design is an adaptation of an interrupted time series design that... matched comparison group designs (as defined in this notice), interrupted time series designs (as defined...

75 FR 12072 - Office of Innovation and Improvement; Overview Information: Investing in Innovation Fund; Notice...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-12

... matched comparison group designs (as defined in this notice), interrupted time series designs (as defined... reading skills administered in the same way to both groups). Interrupted time series design \\3\\ means a... findings. \\3\\ A single subject or single case design is an adaptation of an interrupted time series design...

Epidemiology of autistic disorder in Bahrain: prevalence and obstetric and familial characteristics.

PubMed

Al-Ansari, A M; Ahmed, M M

2013-09-01

European and North American studies show that the prevalence of autistic disorder is inccreasing. This study was performed to identify the prevalence of autistic disorder in Bahrain, and determine some of the demographic and family characteristics. Using a case-control design, 100 children who received a diagnosis of autistic disorder according to DSM-IV-TR during the period 2000-2010 were selected. An equal numberofcontrols who had received a diagnosis of nocturnal enuresis and no psychopathology were selected, matched for sex and age group. The prevalence of autistic disorder was estimated as 4.3 per 10,000 population, with a male:female sex ratio of 4:1. Significantly more cases than controls were delivered by caesarean section and had mothers who suffered prenatal complications. The prevalence estimate in Bahrain is comparable to previous reports using similar methods. Obstetric complications and caesarean section delivery may be associated with autistic disorder.

Cerebral malaria and sequelar epilepsy: first matched case-control study in Gabon.

PubMed

Ngoungou, Edgard Brice; Koko, Jean; Druet-Cabanac, Michel; Assengone-Zeh-Nguema, Yvonne; Launay, Marylène Ndong; Engohang, Edouard; Moubeka-Mounguengui, Martine; Kouna-Ndouongo, Philomène; Loembe, Paul-Marie; Preux, Pierre-Marie; Kombila, Maryvonne

2006-12-01

Cerebral malaria (CM) is suspected to be a potential cause of epilepsy in tropical areas. The purpose of this article was to evaluate the relationship between CM and epilepsy in Gabon. A matched case-control study was carried out on a sample of subjects aged six months to 25 years and hospitalized between 1990 and 2004 in three hospitals in Libreville, Gabon. Cases were defined as patients suffering from epilepsy and confirmed by a neurologist. Controls were defined as patients without epilepsy. The exposure of interest was CM according to WHO criteria. In total, 296 cases and 296 controls were included. Of these, 36 (26 cases and 10 controls) had a CM history. The adjusted odds ratio (aOR) to develop epilepsy after CM was 3.9 [95% CI: 1.7-8.9], p<0.001. Additional risk factors were identified: family history of epilepsy: aOR=6.0 [95% CI: 2.6-14.1], p<0.0001, and febrile convulsions: aOR=9.2 [95% CI 4.0-21.1], p<0.0001. This first case-control study on that issue suggests that epilepsy-related CM is an underrecognized problem. It emphasizes the need for further studies to better evaluate the role of convulsions during CM.

The Effect of Latent Binary Variables on the Uncertainty of the Prediction of a Dichotomous Outcome Using Logistic Regression Based Propensity Score Matching.

PubMed

Szekér, Szabolcs; Vathy-Fogarassy, Ágnes

2018-01-01

Logistic regression based propensity score matching is a widely used method in case-control studies to select the individuals of the control group. This method creates a suitable control group if all factors affecting the output variable are known. However, if relevant latent variables exist as well, which are not taken into account during the calculations, the quality of the control group is uncertain. In this paper, we present a statistics-based research in which we try to determine the relationship between the accuracy of the logistic regression model and the uncertainty of the dependent variable of the control group defined by propensity score matching. Our analyses show that there is a linear correlation between the fit of the logistic regression model and the uncertainty of the output variable. In certain cases, a latent binary explanatory variable can result in a relative error of up to 70% in the prediction of the outcome variable. The observed phenomenon calls the attention of analysts to an important point, which must be taken into account when deducting conclusions.

Freshman year mental health symptoms and level of adaptation as predictors of Internet addiction: a retrospective nested case-control study of male Chinese college students.

PubMed

Yao, Bin; Han, Wei; Zeng, Lingxia; Guo, Xiong

2013-12-15

A retrospective nested case-control study was designed to explore whether freshman year mental health status and level of adaptation are predictors of Internet addiction. The study cohort was 977 college students at a university in northwest China. In the first college year, the students' mental health status and adaptation level were assessed using the Chinese College Student Mental Health Scale (CCSMHS) and the Chinese College Student Adjustment Scale (CCSAS). In the following 1-3 years, 62 Internet-addicted subjects were identified using Young's 8-item diagnostic questionnaire. Controls were matched for demographic characteristics. Using logistic regression analysis, freshman year mental health status, including factors such as somatization, anxiety, depression and self-contempt, and freshman year adaptive problems were found to be causal factors and predictors of Internet addiction. Freshman with features of depression, learning maladaptation and dissatisfaction could be an important target-intervention population for reducing Internet addiction. © 2013 Elsevier Ireland Ltd. All rights reserved.

Efficacy of a Self-expanding Tract Sealant Device in the Reduction of Pneumothorax and Chest Tube Placement Rates After Percutaneous Lung Biopsy: A Matched Controlled Study Using Propensity Score Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahrar, Judy U., E-mail: judy.ahrar@mdanderson.org; Gupta, Sanjay; Ensor, Joe E.

PurposeTo evaluate the use of a self-expanding tract sealant device (BioSentry™) on the rates of pneumothorax and chest tube insertion after percutaneous lung biopsy.Materials and MethodsIn this retrospective study, we compared 318 patients who received BioSentry™ during percutaneous lung biopsy (treated group) with 1956 patients who did not (control group). Patient-, lesion-, and procedure-specific variables, and pneumothorax and chest tube insertion rates were recorded. To adjust for potential selection bias, patients in the treated group were matched 1:1 to patients in the control group using propensity score matching based on the above-mentioned variables. Patients were considered a match if themore » absolute difference in their propensity scores was ≤equal to 0.02.ResultsBefore matching, the pneumothorax and chest tube rates were 24.5 and 13.1% in the control group, and 21.1 and 8.5% in the treated group, respectively. Using propensity scores, a match was found for 317 patients in the treatment group. Chi-square contingency matched pair analysis showed the treated group had significantly lower pneumothorax (20.8 vs. 32.8%; p = 0.001) and chest tube (8.2 vs. 20.8%; p < 0.0001) rates compared to the control group. Sub-analysis including only faculty who had >30 cases of both treatment and control cases demonstrated similar findings: the treated group had significantly lower pneumothorax (17.6 vs. 30.2%; p = 0.002) and chest tube (7.2 vs. 18%; p = 0.001) rates.ConclusionsThe self-expanding tract sealant device significantly reduced the pneumothorax rate, and more importantly, the chest tube placement rate after percutaneous lung biopsy.« less

Early Neuropsychological Tests as Correlates of Productivity 1 Year after Traumatic Brain Injury: A Preliminary Matched Case-Control Study

ERIC Educational Resources Information Center

Ryu, Won Hyung A.; Cullen, Nora K.; Bayley, Mark T.

2010-01-01

This study explored the relative strength of five neuropsychological tests in correlating with productivity 1 year after traumatic brain injury (TBI). Six moderate-to-severe TBI patients who returned to work at 1-year post-injury were matched with six controls who were unemployed after 1 year based on age, severity of injury, and Functional…

Trivalent inactivated influenza vaccine is not associated with sickle cell crises in children.

PubMed

Hambidge, Simon J; Ross, Colleen; Glanz, Jason; McClure, David; Daley, Matthew F; Xu, Stan; Shoup, Jo Ann; Narwaney, Komal; Baggs, James; Weintraub, Eric

2012-01-01

Children with sickle cell disease are considered at high risk for complications from influenza infection and are recommended to receive annual influenza vaccination. However, data on the safety of influenza vaccination in children with sickle cell anemia are sparse. Using a retrospective cohort of children aged 6 months to 17 years in 8 managed care organizations that comprise the Vaccine Safety Datalink and who had a diagnosis of sickle cell anemia from 1999 to 2006, we conducted matched case-control and self-controlled case series studies to examine the association of trivalent inactivated influenza vaccination with hospitalization for sickle cell crisis in the 2 weeks after vaccination. From an original pool of 1085 pediatric subjects with a diagnosis of sickle cell anemia, we identified 179 children with at least 1 sickle cell crisis during any influenza season (October 1-March 31). In the matched case-control study (matching on age category, gender, Vaccine Safety Datalink site, and season), the odds ratio of hospitalization for a crisis in vaccinated compared with unvaccinated children was not significant: 1.3 (95% confidence interval 0.8-2.2). In the self-controlled case series study of hospitalized cases, the incident rate ratio for hospitalization with sickle cell crisis in the 2 weeks after trivalent inactivated influenza vaccination was also not significant: 1.2 (95% confidence interval 0.75-1.95). This large cohort study did not find an association of influenza vaccination and hospitalization for sickle cell crises in children with sickle cell anemia.

Binational outbreak of Guillain-Barré syndrome associated with Campylobacter jejuni infection, Mexico and USA, 2011.

PubMed

Jackson, B R; Zegarra, J Alomía; López-Gatell, H; Sejvar, J; Arzate, F; Waterman, S; Núñez, A Sánchez; López, B; Weiss, J; Cruz, R Quintero; Murrieta, D Y López; Luna-Gierke, R; Heiman, K; Vieira, A R; Fitzgerald, C; Kwan, P; Zárate-Bermúdez, M; Talkington, D; Hill, V R; Mahon, B

2014-05-01

In June 2011, a cluster of suspected cases of Guillain-Barré syndrome (GBS), which can follow Campylobacter jejuni infection, was identified in San Luis Río Colorado (SLRC), Sonora, Mexico and Yuma County, Arizona, USA. An outbreak investigation identified 26 patients (18 from Sonora, eight from Arizona) with onset of GBS 4 May-21 July 2011, exceeding the expected number of cases (n = 1-2). Twenty-one (81%) patients reported antecedent diarrhoea, and 61% of 18 patients tested were seropositive for C. jejuni IgM antibodies. In a case-control study matched on age group, sex, ethnicity, and neighbourhood of residence, all Arizona GBS patients travelled to SLRC during the exposure period vs. 45% of matched controls (matched odds ratio 8·1, 95% confidence interval 1·5-∞). Exposure information and an environmental assessment suggested that GBS cases resulted from a large outbreak of C. jejuni infection from inadequately disinfected tap water in SLRC. Binational collaboration was essential in investigating this cross-border GBS outbreak, the first in mainland North America since 1976.

Effectiveness of 7-valent pneumococcal conjugate vaccine in the prevention of invasive pneumococcal disease in children aged 7-59 months. A matched case-control study.

PubMed

Domínguez, Angela; Ciruela, Pilar; García-García, Juan José; Moraga, Fernando; de Sevilla, Mariona F; Selva, Laura; Coll, Francis; Muñoz-Almagro, Carmen; Planes, Ana María; Codina, Gemma; Jordán, Iolanda; Esteva, Cristina; Hernández, Sergi; Soldevila, Núria; Cardeñosa, Neus; Batalla, Joan; Salleras, Luis

2011-11-08

The aim of this study was to evaluate the effectiveness of the administration of the 7-valent pneumococcal conjugate vaccine in a region with an intermediate vaccination coverage. A matched case-control study was carried out in children aged 7-59 months with invasive pneumococcal disease (IPD) admitted to two university hospitals in Catalonia. Three controls matched for hospital, age, sex, date of hospitalization and underlying disease were selected for each case. Information on the vaccination status of cases and controls was obtained from the vaccination card, the child's health card, the hospital medical record or the vaccination register of the primary healthcare center where the child was attended for non-severe conditions. A conditional logistic regression analysis was made to control for the effect of possible confounding variables. The adjusted vaccination effectiveness of the complete vaccination schedule (3 doses at 2, 4 and 6 months and a fourth dose at 15 months, 2 doses at least two months apart in children aged 12-23 months or a single dose in children aged >24 months) in preventing IPD caused by vaccine serotypes was 93.7% (95% CI 51.8-99.2). It was not effective in preventing cases caused by non-vaccine serotypes. The results of this study carried out in a population with intermediate vaccination coverage confirm those of other observational studies showing high levels of effectiveness of routine 7-valent pneumococcal conjugate vaccination. Copyright © 2011 Elsevier Ltd. All rights reserved.

Vitamin D and Fracture Risk in Early Childhood: A Case-Control Study

PubMed Central

Anderson, Laura N.; Heong, Sze Wing; Chen, Yang; Thorpe, Kevin E.; Adeli, Khosrow; Howard, Andrew; Sochett, Etienne; Birken, Catherine S.; Parkin, Patricia C.; Maguire, Jonathon L.; Abdullah, Kawsari; Anderson, Laura N.; Birken, Catherine S.; Borkhoff, Cornelia M.; Carsley, Sarah; Chen, Yang; Katz-Lavigne, Mikael; Kavikondala, Kanthi; Kowal, Christine; Maguire, Jonathon L.; Mason, Dalah; Omand, Jessica; Parkin, Patricia C.; Persaud, Navindra; van den Heuvel, Meta; Baker, Jillian; Barozzino, Tony; Bonifacio, Joey; Campbell, Douglas; Cheema, Sohail; Chisamore, Brian; Danayan, Karoon; Das, Paul; Derocher, Mary Beth; Do, Anh; Dorey, Michael; Freeman, Sloane; Fung, Keewai; Guiang, Charlie; Handford, Curtis; Hatch, Hailey; Jacobson, Sheila; Kiran, Tara; Knowles, Holly; Kwok, Bruce; Lakhoo, Sheila; Lam-Antoniades, Margarita; Lau, Eddy; Leung, Fok-Han; Loo, Jennifer; Mahmoud, Sarah; Moodie, Rosemary; Morinis, Julia; Naymark, Sharon; Neelands, Patricia; Owen, James; Peer, Michael; Perlmutar, Marty; Persaud, Navindra; Pinto, Andrew; Porepa, Michelle; Ramji, Nasreen; Ramji, Noor; Rosenthal, Alana; Saunderson, Janet; Saxena, Rahul; Sgro, Michael; Shepherd, Susan; Smiltnieks, Barbara; Taylor, Carolyn; Weisdors, Thea; Wijayasinghe, Sheila; Wong, Peter; Ying, Ethel; Young, Elizabeth

2017-01-01

Abstract The objective of this study was to evaluate the association of vitamin D intake and serum levels with fracture risk in children under 6 years of age. A case-control study was conducted in Toronto, Ontario, Canada. Cases were recruited from the fracture clinic at the Hospital for Sick Children, and matched controls were obtained from the TARGet Kids! primary-care research network. Controls were matched to cases on age, sex, height, and season. Fracture risk was estimated from conditional logistic regression, with adjustment for skin type, fracture history, waist circumference, outdoor free play, neighborhood income, soda consumption, and child's birth weight. A total of 206 cases were recruited during May 2009–April 2013 and matched to 343 controls. Serum 25-hydroxyvitamin D concentration (per 10-nmol/L increment: adjusted odds ratio (aOR) = 0.95, 95% confidence interval (CI): 0.88, 1.03) and intake of cow's milk (<2 cups/day vs. 2 cups/day: aOR = 0.95 (95% CI: 0.60, 1.52); >2 cups/day vs. 2 cups/day: aOR = 1.39 (95% CI: 0.85, 2.23)) were not significantly associated with reduced odds of fracture. A statistically significant association was observed between child use of vitamin D supplements and decreased odds of fracture (yes vs. no: aOR = 0.42, 95% CI: 0.25, 0.69). Vitamin D supplementation, but not serum 25-hydroxyvitamin D level or milk intake, was associated with reduced fracture risk among these healthy young children. PMID:28459987

Demographic and socio-economic determinants of post-neonatal deaths in a special project area of rural northern India.

PubMed

Kabir, Zubair

2003-07-01

The demographic and socio-economic determinants of post-neonatal deaths (n = 475) in a special project area of rural northern India (Ballabgarh) were ascertained from 1991 to 1999 using the electronic database system of the project area for data extraction, and were compared with the eligible living children of the same age using a matched population-based case-control study design. Similar determinants were also ascertained in neonatal deaths (n = 212) using the same study design. After controlling for the potential confounders using conditional logistic regression analyses, lower caste (a proxy measure for low socio-economic conditions in rural India) was found to be significantly associated with higher post-neonatal deaths (OR = 2.21). Higher maternal age (>30 years) and fathers' lower educational levels were significantly associated with higher neonatal deaths, in addition to higher post-neonatal deaths in the same area.

Febrile infectious childhood diseases in the history of cancer patients and matched controls.

PubMed

Albonico, H U; Bräker, H U; Hüsler, J

1998-10-01

The present study was designed to investigate the hypothesis that febrile infectious childhood diseases (FICDs) are associated with a lower cancer risk in adulthood, since biographical considerations are of great importance in anthroposophic medicine. Cancer patients and control patients of 35 anthroposophic general practitioners in Switzerland were matched with respect to gender, age and physician. All patients completed a questionnaire on their FICD. We collected 424 cases; of these we could analyze 379 matched pairs. The study consistently revealed a lower cancer risk for patients with a history of FICD. The strongest associations were found between patients with non-breast cancers and rubella respectively chickenpox. A strong association was also found with the overall number of FICD both 'classical' (measles, mumps, rubella, pertussis, scarlet-fever and chickenpox) and 'other'. None of these associations was apparent for patients with breast cancer. Unexpectedly, we found that cancer was diagnosed significantly earlier in life in cancer patients with a history of FICD compared to those without FICD. Our retrospective study showed a significant association between FICD and the risk of developing cancer. The number of FICD decreased the cancer risk, in particular for non-breast cancers. The relationship with tumor site seems to be important also, but can only be addressed in a larger study.

Substantially Higher and Earlier Occurrence of Anti-Tuberculosis Drug-Related Adverse Reactions in HIV Coinfected Tuberculosis Patients: A Matched-Cohort Study.

PubMed

Matono, Takashi; Nishijima, Takeshi; Teruya, Katsuji; Morino, Eriko; Takasaki, Jin; Gatanaga, Hiroyuki; Kikuchi, Yoshimi; Kaku, Mitsuo; Oka, Shinichi

2017-11-01

Little information exists on the frequency, severity, and timing of first-line anti-tuberculosis drug-related adverse events (TB-AEs) in HIV-tuberculosis coinfected (HIV-TB) patients in the antiretroviral therapy (ART) era. This matched-cohort study included HIV-TB patients as cases and HIV-uninfected tuberculosis (non-HIV-TB) patients as controls. Tuberculosis was culture-confirmed in both groups. Cases were matched to controls in a 1:4 ratio on age, sex, and year of diagnosis. TB-AEs were defined as Grade 2 or higher requiring drug discontinuation/regimen change. From 2003 to 2015, 94 cases and 376 controls were analyzed (95% men, 98% Asians). Standard four-drug combination therapy was initiated in 91% of cases and 89% of controls (p = 0.45). Cases had a higher frequency of TB-AE [51% (48/94) vs. 10% (39/376), p < 0.001]. Their major TB-AEs were fever (19%), rash (11%), and neutropenia (11%). TB-AEs were more severe in cases [Grade 3 or higher: cases (71%, 34/48) vs. controls (49%, 19/39), p < 0.001]. The time from treatment initiation to TB-AE was shorter in cases [median 18 (interquartile range 12-28) vs. 27 (15-57) days, p = 0.027], and 73% of TB-AEs in cases occurred within 4 weeks of starting anti-tuberculosis treatment. HIV infection was an independent risk factor for TB-AEs in the multivariate Cox analysis [adjusted HR (aHR): 6.96; 95% confidence interval: 3.93-12.3]. TB-AEs occurred more frequently in HIV-TB than in non-HIV-TB patients, and were more severe. The majority of TB-AEs occurred within 4 weeks of initiating anti-tuberculosis treatment. Because TB-AEs may delay ART initiation, careful monitoring during this period is warranted in coinfected patients.

Cumulative exposure to biologics and risk of cancer in psoriasis patients: A meta-analysis of Psonet studies from Israel, Italy, Spain, United Kingdom and Republic of Ireland.

PubMed

Garcia-Doval, I; Descalzo, M A; Mason, K J; Cohen, A D; Ormerod, A D; Gómez-García, F J; Cazzaniga, S; Feldhamer, I; Ali, H; Herrera-Acosta, E; Griffiths, C E M; Stern, R; Naldi, L

2018-05-03

Cancer risk following long-term exposure to systemic immunomodulatory therapies in psoriasis patients is possible. To assess a dose-response relationship between cumulative length of exposure to biologic therapy and risk of cancer. Four national studies (a healthcare database from Israel, and prospective cohorts form Italy, Spain and UK/ROI) collaborating through Psonet (European Registry of Psoriasis) participated in these nested case-control studies, including nearly 60.000 person-years of observation. Cases were patients who developed an incident cancer. Patients with previous cancers and benign or in-situ tumours were excluded. Four cancer-free controls were matched to each case on year of birth, gender, geographic area, and registration year. Follow-up for controls was censored at the date of cancer diagnosis for the matched case. Conditional logistic regression was performed by each registry. Results were pooled using random effects meta-analysis. 728 cases and 2671 controls were identified. After matching, differences between cases and controls were present for the Charlson comorbidity index in all three registries, and in the prevalence of previous exposure to psoralen-ultraviolet-A (PUVA) and smoking (BADBIR only). The risk of first cancers was not significantly associated with cumulative exposure to biologics (adjusted odds ratio per year of exposure 1.02; 95%CI 0.92, 1.13). Results were similar if squamous and basal cell carcinomas were included in the outcome. Cumulative length of exposure to biologic therapies of psoriasis patients in real-world clinical practice does not appear to be linked to a higher risk of cancer after several years of use. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Case-Based Multi-Sensor Intrusion Detection

NASA Astrophysics Data System (ADS)

Schwartz, Daniel G.; Long, Jidong

2009-08-01

Multi-sensor intrusion detection systems (IDSs) combine the alerts raised by individual IDSs and possibly other kinds of devices such as firewalls and antivirus software. A critical issue in building a multi-sensor IDS is alert-correlation, i.e., determining which alerts are caused by the same attack. This paper explores a novel approach to alert correlation using case-based reasoning (CBR). Each case in the CBR system's library contains a pattern of alerts raised by some known attack type, together with the identity of the attack. Then during run time, the alert streams gleaned from the sensors are compared with the patterns in the cases, and a match indicates that the attack described by that case has occurred. For this purpose the design of a fast and accurate matching algorithm is imperative. Two such algorithms were explored: (i) the well-known Hungarian algorithm, and (ii) an order-preserving matching of our own device. Tests were conducted using the DARPA Grand Challenge Problem attack simulator. These showed that the both matching algorithms are effective in detecting attacks; but the Hungarian algorithm is inefficient; whereas the order-preserving one is very efficient, in fact runs in linear time.

Influenza vaccine effectiveness estimates in the Dutch population from 2003 to 2014: The test-negative design case-control study with different control groups.

PubMed

van Doorn, Eva; Darvishian, Maryam; Dijkstra, Frederika; Donker, Gé A; Overduin, Pieter; Meijer, Adam; Hak, Eelko

2017-05-15

Information about influenza vaccine effectiveness (IVE) is important for vaccine strain selection and immunization policy decisions. The test-negative design (TND) case-control study is commonly used to obtain IVE estimates. However, the definition of the control patients may influence IVE estimates. We have conducted a TND study using the Dutch Sentinel Practices of NIVEL Primary Care Database which includes data from patients who consulted the General Practitioner (GP) for an episode of acute influenza-like illness (ILI) or acute respiratory infection (ARI) with known influenza vaccination status. Cases were patients tested positive for influenza virus. Controls were grouped into those who tested (1) negative for influenza virus (all influenza negative), (2) negative for influenza virus, but positive for respiratory syncytial virus, rhinovirus or enterovirus (non-influenza virus positive), and (3) negative for these four viruses (pan-negative). We estimated the IVE over all epidemic seasons from 2003/2004 through 2013/2014, pooled IVE for influenza vaccine partial/full matched and mismatched seasons and the individual seasons using generalized linear mixed-effect and multiple logistic regression models. The overall IVE adjusted for age, GP ILI/ARI diagnosis, chronic disease and respiratory allergy was 35% (95% CI: 15-48), 64% (95% CI: 49-75) and 21% (95% CI: -1 to 39) for all influenza negative, non-influenza virus positive and pan-negative controls, respectively. In both the main and subgroup analyses IVE estimates were the highest using non-influenza virus positive controls, likely due to limiting inclusion of controls without laboratory-confirmation of a virus causing the respiratory disease. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Use of Benzodiazepine Receptor Agonists and Risk of Respiratory Failure in Patients with Chronic Obstructive Pulmonary Disease: A Nationwide Population-Based Case-Control Study

PubMed Central

Chen, Su-Jung; Yeh, Chiu-Mei; Chao, Tze-Fan; Liu, Chia-Jen; Wang, Kang-Ling; Chen, Tzeng-Ji; Chou, Pesus; Wang, Fu-Der

2015-01-01

Study Objectives: Insomnia is prevalent in patients with chronic obstructive pulmonary disease (COPD), and benzodiazepine receptor agonists (BZRAs) are the most commonly used drugs despite their adverse effects on respiratory function. The aim of this study was to investigate whether the use of BZRAs was associated with an increased risk of respiratory failure (RF) in COPD patients. Design: Matched case-control study. Setting: National Health Insurance Research Database (NHIRD) in Taiwan. Participants: The case group consisted of 2,434 COPD patients with RF, and the control group consisted of 2,434 COPD patients without RF, matched for age, sex, and date of enrollment. Measurements and Results: Exposure to BZRAs during the 180-day period preceding the index date was analyzed and compared in the case and control groups. Conditional logistic regression was performed, and the use of BZRAs was associated with an increased risk of RF (adjusted odds ratio [aOR] 1.56, 95% confidence interval [CI] 1.14–2.13). In subgroup analysis, we found that the benzodiazepine (BZD) users had a higher risk of RF (aOR 1.58, 95% CI 1.14–2.20), whereas the risk in non-benzodiazepine (non-BZD) users was insignificant (aOR 0.85, 95% CI 0.51–1.44). A greater than 2-fold increase in risk was found in those who received two or more kinds of BZRAs and those using a combination of BZD and non-BZD medications. Conclusions: The use of benzodiazepine receptor agonists was a significant risk factor for respiratory failure in patients with chronic obstructive pulmonary disease (COPD). Compared to benzodiazepine, the prescription of non-benzodiazepine may be safer for the management of insomnia in COPD patients. Citation: Chen SJ, Yeh CM, Chao TF, Liu CJ, Wang KL, Chen TJ, Chou P, Wang FD. The use of benzodiazepine receptor agonists and risk of respiratory failure in patients with chronic obstructive pulmonary disease: a nationwide population-based case-control study. SLEEP 2015;38(7):1045–1050. PMID:25669186

Endemic cryptosporidiosis and exposure to municipal tap water in persons with acquired immunodeficiency syndrome (AIDS): A case-control study

PubMed Central

Aragón, Tomás J; Novotny, Suzanne; Enanoria, Wayne; Vugia, Duc J; Khalakdina, Asheena; Katz, Mitchell H

2003-01-01

Background In persons with acquired immunodeficiency syndrome (AIDS), Cryptosporidium parvum causes a prolonged, severe diarrheal illness to which there is no effective treatment, and the risk of developing cryptosporidiosis from drinking tap water in non-outbreak settings remains uncertain. To test the hypothesis that drinking tap water was associated with developing cryptosporidiosis, we conducted a matched case-control study among persons with AIDS in San Francisco. Methods Among patients reported to the San Francisco AIDS Registry from May 1996 through September 1998, we compared patients who developed cryptosporidiosis to those who did not. Cases were individually matched to controls based on age, sex, race/ethnicity, CD4+ T lymphocyte count, date of CD4+ count, and date of case diagnosis. Population attributable fractions (PAFs) were calculated. Results The study consisted of 49 cases and 99 matched controls. In the multivariable analysis with adjustments for confounders, tap water consumption inside and outside the home at the highest exposure categories was associated with the occurrence of cryptosporidiosis (inside the home: odds ratio (OR), 6.76; 95% CI 1.37–33.5, and outside the home: OR 3.16; 95% CI 1.23–8.13). The PAF was 85%; that is, the proportion of cases of cryptosporidiosis in San Francisco AIDS patients attributable to tap water consumption could have been as high as 85%. Conclusions Although the results from this observational study cannot be considered definitive, until there is more data, we recommend persons with AIDS, especially those with compromised immune systems, consider avoiding tap water. PMID:12515584

Non-tuberculous mycobacterial bloodstream infections in patients with indwelling vascular catheters - the role of sickle cell anaemia.

PubMed

Edun, Babatunde; Shah, Ansal; Durkin, Martin; Whitmire, Melanie; Williams, Shanetta Patterson; Albrecht, Helmut; Al-Hasan, Majdi; Weissman, Sharon

2017-05-01

Few studies have examined risk factors for nontuberculous mycobacteria (NTM) bloodstream infections (BSI) involving indwelling vascular catheters (IDVC). Sickle cell anaemia (HbSS/SC) is known to affect several aspects of the immune system leading to relative immune deficiency. The purpose of this retrospective nested case-control study was to determine if HbSS/SC is a risk factor for NTM BSI among individuals with IDVCs. All NTM IDVC infections (cases) at two tertiary hospitals from 2008 to 2014 were reviewed. Cases were matched 2:1 with controls who had IDVC infections due to organisms other than NTM. Matching criteria included age within 10 years and IDVC infection within three months of index case. Logistic regression was used to identify risk factors for IDVC infection due to NTM. Nineteen NTM BSIs were identified. Three cases were excluded because they did not have IDVCs at the time their BSI was identified. Sixteen cases of NTM IDVC infection were matched to 32 controls with IDVC infections due to other organisms. The mean age of patients with IDVC infections was 48.5 years and 28 (58%) were male. Compared to the control group those with NTM BSI were more likely to have HbSS/SC 38% (6/16) versus 6% (2/32) (p = .006). IDVCs are a risk factor for NTM BSI. Sickle cell anaemia appears to be a risk factor for IDVC infections due to NTM. This study is limited by the small sample size. A larger study is needed to further investigate the association between HbSS/SC and NTM IDVC infections.

Endemic cryptosporidiosis and exposure to municipal tap water in persons with acquired immunodeficiency syndrome (AIDS): a case-control study.

PubMed

Aragón, Tomás J; Novotny, Suzanne; Enanoria, Wayne; Vugia, Duc J; Khalakdina, Asheena; Katz, Mitchell H

2003-01-06

In persons with acquired immunodeficiency syndrome (AIDS), Cryptosporidium parvum causes a prolonged, severe diarrheal illness to which there is no effective treatment, and the risk of developing cryptosporidiosis from drinking tap water in non-outbreak settings remains uncertain. To test the hypothesis that drinking tap water was associated with developing cryptosporidiosis, we conducted a matched case-control study among persons with AIDS in San Francisco. Among patients reported to the San Francisco AIDS Registry from May 1996 through September 1998, we compared patients who developed cryptosporidiosis to those who did not. Cases were individually matched to controls based on age, sex, race/ethnicity, CD4+ T lymphocyte count, date of CD4+ count, and date of case diagnosis. Population attributable fractions (PAFs) were calculated. The study consisted of 49 cases and 99 matched controls. In the multivariable analysis with adjustments for confounders, tap water consumption inside and outside the home at the highest exposure categories was associated with the occurrence of cryptosporidiosis (inside the home: odds ratio (OR), 6.76; 95% CI 1.37-33.5, and outside the home: OR 3.16; 95% CI 1.23-8.13). The PAF was 85%; that is, the proportion of cases of cryptosporidiosis in San Francisco AIDS patients attributable to tap water consumption could have been as high as 85%. Although the results from this observational study cannot be considered definitive, until there is more data, we recommend persons with AIDS, especially those with compromised immune systems, consider avoiding tap water.

Improved Body Mass Index Measures Following a Middle School-Based Obesity Intervention--The MATCH Program

ERIC Educational Resources Information Center

Lazorick, Suzanne; Fang, Xiangming; Hardison, George T.; Crawford, Yancey

2015-01-01

Background: Motivating Adolescents with Technology to CHOOSE Health™ (MATCH) is an educational and behavioral intervention in seventh grade. Methods: Teachers in 2 schools delivered the MATCH curriculum, with 1 control school. Using a quasi-experimental design, outcome measures included lessons completed, body mass index (BMI), BMI z-score (zBMI),…

Singing ability is rooted in vocal-motor control of pitch.

PubMed

Hutchins, Sean; Larrouy-Maestri, Pauline; Peretz, Isabelle

2014-11-01

The inability to vocally match a pitch can be caused by poor pitch perception or by poor vocal-motor control. Although previous studies have tried to examine the relationship between pitch perception and vocal production, they have failed to control for the timbre of the target to be matched. In the present study, we compare pitch-matching accuracy with an unfamiliar instrument (the slider) and with the voice, designed such that the slider plays back recordings of the participant's own voice. We also measured pitch accuracy in singing a familiar melody ("Happy Birthday") to assess the relationship between single-pitch-matching tasks and melodic singing. Our results showed that participants (all nonmusicians) were significantly better at matching recordings of their own voices with the slider than with their voice, indicating that vocal-motor control is an important limiting factor on singing ability. We also found significant correlations between the ability to sing a melody in tune and vocal pitch matching, but not pitch matching on the slider. Better melodic singers also tended to have higher quality voices (as measured by acoustic variables). These results provide important evidence about the role of vocal-motor control in poor singing ability and demonstrate that single-pitch-matching tasks can be useful in measuring general singing abilities.

The utility of the Kohlman Evaluation of Living Skills test is associated with substantiated cases of elder self-neglect.

PubMed

Pickens, Sabrina; Naik, Aanand D; Burnett, Jason; Kelly, P A; Gleason, Mary; Dyer, Carmel B

2007-03-01

Self-neglect is the most prevalent finding among cases reported to Adult Protective Services (APS) and is characterized by an inability to meet one's own basic needs. The Kohlman evaluation of living skills (KELS) has been validated in geriatric populations to assess performance with both instrumental and basic activities of daily living and as an assessment tool for the capacity to live independently; therefore, the purpose of this analysis was to compare the scores of the KELS between substantiated cases of self-neglect and matched community-dwelling elders. This is a cross-sectional pilot study of 50 adults aged 65 years and older who were recruited from APS as documented cases of self-neglect and 50 control participants recruited from Harris County Hospital District outpatient clinics. Control participants were matched for age, race, gender, and ZIP code. A geriatric nurse practitioner (NP)-led team administered a comprehensive geriatric assessment in homes of all study participants. The assessment included the KELS and mini-mental state examination (MMSE) tests. Chi-square analyses were used to determine if cases of self-neglect were significantly more likely to fail the KELS test than matched controls. The analyses revealed that self-neglectors were significantly more likely to fail the KELS than non-self-neglectors (50% vs. 30%, p = .025). When stratified by MMSE scores, self-neglectors with intact cognitive function remained significantly more likely to fail the KELS compared to matched, cognitively intact controls (45% vs. 17%, p = .013). Abnormal results using an in-home KELS test were significantly associated with substantiated cases of self-neglect. There is currently no gold-standard measure for identifying capacity with self-care behaviors among cases of self-neglect. As a result, self-neglect may remain unidentified in many clinical settings. The KELS provides clinicians with an objective measure of an individual's capacity and performance with everyday life-supporting tasks and thus, provides information that can help NPs identify elders at risk for self-neglect. These findings suggest that the KELS test has significant utility as part of a comprehensive geriatric assessment to aid clinicians in suspected cases of self-neglect.

The psychosocial work environment is associated with risk of stroke at working age.

PubMed

Jood, Katarina; Karlsson, Nadine; Medin, Jennie; Pessah-Rasmussen, Hélène; Wester, Per; Ekberg, Kerstin

2017-07-01

Objective The aim of this study was to explore the relation between the risk of first-ever stroke at working age and psychological work environmental factors. Methods A consecutive multicenter matched 1:2 case-control study of acute stroke cases (N=198, age 30-65 years) who had been working full-time at the time of their stroke and 396 sex- and age-matched controls. Stroke cases and controls answered questionnaires on their psychosocial situation during the previous 12 months. The psychosocial work environment was assessed using three different measures: the job-control-demand model, the effort-reward imbalance (ERI) score, and exposures to conflict at work. Results Among 198 stroke cases and 396 controls, job strain [odds ratio (OR) 1.30, 95% confidence interval (95% CI) 1.05-1.62], ERI (OR 1.28, 95% CI 1.01-1.62), and conflict at work (OR 1.75, 95% CI 1.07-2.88) were independent risk factors of stroke in multivariable regression models. Conclusions Adverse psychosocial working conditions during the past 12 months were more frequently observed among stroke cases. Since these factors are presumably modifiable, interventional studies targeting job strain and emotional work environment are warranted.

Alterations in the Immune Cell Composition in Premalignant Breast Tissue that Precede Breast Cancer Development.

PubMed

Degnim, Amy C; Hoskin, Tanya L; Arshad, Muhammad; Frost, Marlene H; Winham, Stacey J; Brahmbhatt, Rushin A; Pena, Alvaro; Carter, Jodi M; Stallings-Mann, Melody L; Murphy, Linda M; Miller, Erin E; Denison, Lori A; Vachon, Celine M; Knutson, Keith L; Radisky, Derek C; Visscher, Daniel W

2017-07-15

Purpose: Little is known about the role of the immune system in the earliest stages of breast carcinogenesis. We studied quantitative differences in immune cell types between breast tissues from normal donors and those from women with benign breast disease (BBD). Experimental Design: A breast tissue matched case-control study was created from donors to the Susan G. Komen for the Cure Tissue Bank (KTB) and from women diagnosed with BBD at Mayo Clinic (Rochester, MN) who either subsequently developed cancer (BBD cases) or remained cancer-free (BBD controls). Serial tissue sections underwent immunostaining and digital quantification of cell number per mm 2 for CD4 + T cells, CD8 + T cells, CD20 + B cells, and CD68 + macrophages and quantification of positive pixel measure for CD11c (dendritic cells). Results: In 94 age-matched triplets, BBD lobules showed greater densities of CD8 + T cells, CD11c + dendritic cells, CD20 + B cells, and CD68 + macrophages compared with KTB normals. Relative to BBD controls, BBD cases had lower CD20 + cell density ( P = 0.04). Nearly 42% of BBD cases had no CD20 + B cells in evaluated lobules compared with 28% of BBD controls ( P = 0.02). The absence of CD20 + cells versus the presence in all lobules showed an adjusted OR of 5.7 (95% confidence interval, 1.4-23.1) for subsequent breast cancer risk. Conclusions: Elevated infiltration of both innate and adaptive immune effectors in BBD tissues suggests an immunogenic microenvironment. The reduced B-cell infiltration in women with later breast cancer suggests a role for B cells in preventing disease progression and as a possible biomarker for breast cancer risk. Clin Cancer Res; 23(14); 3945-52. ©2017 AACR . ©2017 American Association for Cancer Research.

“I Wasted 3 Years, Thinking It’s Not a Problem”: Patient and Health System Delays in Diagnosis of Leprosy in India: A Mixed-Methods Study

PubMed Central

Govindarajulu, Srinivas; Isaakidis, Petros; Shewade, Hemant Deepak; Rokade, Vasudev; Singh, Rajbir; Kamble, Sanjeev

2017-01-01

Background Worldwide, leprosy is one of the major causes of preventable disability. India contributes to 60% of global leprosy burden. With increasing numbers of leprosy with grade 2 disability (visible disability) at diagnosis, we aimed to determine risk factors associated with grade 2 disability among new cases and explore patients and providers’ perspectives into reasons for late presentation. Methodology/Principal Findings This was an explanatory mixed-methods study where the quantitative component, a matched case-control design, was followed by a qualitative component. A total of 70 cases (grade 2 disability) and 140 controls (grade 0) matched for age and sex were randomly sampled from new patients registered between January 2013-January 2015 in three districts of Maharashtra (Mumbai, Thane and Amaravati) and interviewed using a structured close ended questionnaire. Eight public health care providers involved in leprosy care and 7 leprosy patients were purposively selected (maximum variation sampling) and interviewed using a structured open-ended interview schedule. Among cases, overall median (IQR) diagnosis delay in months was 17.9(7–30); patient and health system delay was 7(4–16.5) and 5.5(0.9–12.5) respectively; this was significantly higher than the delay in controls. Reasons for delayed presentation identified by the quantitative and qualitative data were: poor awareness of leprosy symptoms, first health care provider visited being private practitioners who were not aware about provision of free leprosy treatment at public health care facilities, reduced engagement and capacity of the general health care system in leprosy control. Conclusions Raising awareness in communities and health care providers regarding early leprosy symptoms, engagement of private health care provider in early leprosy diagnosis and increasing capacity of general health system staff, especially targeting high endemic areas that are hotspots for leprosy transmission may help in reducing diagnosis delays. PMID:28081131

"I Wasted 3 Years, Thinking It's Not a Problem": Patient and Health System Delays in Diagnosis of Leprosy in India: A Mixed-Methods Study.

PubMed

Muthuvel, Thirumugam; Govindarajulu, Srinivas; Isaakidis, Petros; Shewade, Hemant Deepak; Rokade, Vasudev; Singh, Rajbir; Kamble, Sanjeev

2017-01-01

Worldwide, leprosy is one of the major causes of preventable disability. India contributes to 60% of global leprosy burden. With increasing numbers of leprosy with grade 2 disability (visible disability) at diagnosis, we aimed to determine risk factors associated with grade 2 disability among new cases and explore patients and providers' perspectives into reasons for late presentation. This was an explanatory mixed-methods study where the quantitative component, a matched case-control design, was followed by a qualitative component. A total of 70 cases (grade 2 disability) and 140 controls (grade 0) matched for age and sex were randomly sampled from new patients registered between January 2013-January 2015 in three districts of Maharashtra (Mumbai, Thane and Amaravati) and interviewed using a structured close ended questionnaire. Eight public health care providers involved in leprosy care and 7 leprosy patients were purposively selected (maximum variation sampling) and interviewed using a structured open-ended interview schedule. Among cases, overall median (IQR) diagnosis delay in months was 17.9(7-30); patient and health system delay was 7(4-16.5) and 5.5(0.9-12.5) respectively; this was significantly higher than the delay in controls. Reasons for delayed presentation identified by the quantitative and qualitative data were: poor awareness of leprosy symptoms, first health care provider visited being private practitioners who were not aware about provision of free leprosy treatment at public health care facilities, reduced engagement and capacity of the general health care system in leprosy control. Raising awareness in communities and health care providers regarding early leprosy symptoms, engagement of private health care provider in early leprosy diagnosis and increasing capacity of general health system staff, especially targeting high endemic areas that are hotspots for leprosy transmission may help in reducing diagnosis delays.

Benefits of Matching Domain Structure for Planning Software: The Right Stuff

NASA Technical Reports Server (NTRS)

Billman, Dorrit Owen; Arsintescu, Lucica; Feary, Michael S.; Lee, Jessica Chia-Rong; Smith, Asha Halima; Tiwary, Rachna

2011-01-01

We investigated the role of domain structure in software design. We compared 2 planning applications, for a Mission Control group (International Space Station), and measured users speed and accuracy. Based on our needs analysis, we identified domain structure and used this to develop new prototype software that matched domain structure better than the legacy system. We took a high-fidelity analog of the natural task into the laboratory and found (large) periformance differences, favoring the system that matched domain structure. Our task design enabled us to attribute better periormance to better match of domain structure. We ran through the whole development cycle, in miniature, from needs analysis through design, development, and evaluation. Doing so enabled inferences not just about the particular systems compared, but also provided evidence for the viability of the design process (particularly needs analysis) that we are exploring.

Trimethoprim-sulfamethoxazole induced hyperkalaemia in elderly patients receiving spironolactone: nested case-control study

PubMed Central

Gomes, Tara; Mamdani, Muhammad M; Yao, Zhan; Hellings, Chelsea; Garg, Amit X; Weir, Matthew A; Juurlink, David N

2011-01-01

Objectives To characterise the risk of admission to hospital for hyperkalaemia in elderly patients treated with trimethoprim-sulfamethoxazole in combination with spironolactone. Design Population based nested case-control study. Setting Ontario, Canada, from 1 April 1992 to 1 March 2010. Participants Cases were residents of Ontario aged 66 years or above receiving chronic treatment with spironolactone and admitted to hospital with hyperkalaemia within 14 days of receiving a prescription for either trimethoprim-sulfamethoxazole, amoxicillin, norfloxacin, or nitrofurantoin. Up to four controls for each case were identified from the same cohort, matched on age, sex, and presence or absence of chronic kidney disease and diabetes, and required to have received one of the study antibiotics within 14 days before the case’s index date. Main outcome measures Odds ratio for association between admission to hospital with hyperkalaemia and receipt of a study antibiotic in the preceding 14 days, adjusted for conditions and drugs that may influence risk of hyperkalaemia. Results During the 18 year study period, 6903 admissions for hyperkalaemia were identified, 306 of which occurred within 14 days of antibiotic use. Of these, 248 (81%) cases were matched to 783 controls. 10.8% (17 859/165 754) of spironolactone users received at least one prescription for trimethoprim-sulfamethoxazole. Compared with amoxicillin, prescription of trimethoprim-sulfamethoxazole was associated with a marked increase in the risk of admission to hospital for hyperkalaemia (adjusted odds ratio 12.4, 95% confidence interval 7.1 to 21.6). The population attributable fraction was 59.7%, suggesting that approximately 60% of all cases of hyperkalaemia in older patients taking spironolactone and treated with an antibiotic for a urinary tract infection could be avoided if trimethoprim-sulfamethoxazole was not prescribed. Treatment with nitrofurantoin was also associated with an increase in the risk of hyperkalaemia (adjusted odds ratio 2.4, 1.3 to 4.6), but no such risk was found with norfloxacin (adjusted odds ratio 1.6, 0.8 to 3.4) Conclusions Among older patients receiving spironolactone, treatment with trimethoprim-sulfamethoxazole was associated with a major increase in the risk of admission to hospital for hyperkalaemia. This drug combination should be avoided when possible. PMID:21911446

Humidifier Disinfectants Are a Cause of Lung Injury among Adults in South Korea: A Community-Based Case-Control Study

PubMed Central

Kwon, Geun-Yong; Gwack, Jin; Park, Young-Joon; Youn, Seung-Ki; Kwon, Jun-Wook; Yang, Byung-Guk; Lee, Moo-Song; Jung, Miran; Lee, Hanyi; Jun, Byung-Yool; Lim, Hyun-Sul

2016-01-01

Backgrounds An outbreak of lung injury among South Korean adults was examined in a hospital-based case-control study, and the suspected cause was exposure to humidifier disinfectant (HD). However, a case-control study with community-dwelling controls was needed to validate the previous study’s findings, and to confirm the exposure-response relationship between HD and lung injury. Methods Each case of lung injury was matched with four community-dwelling controls, according to age (±3 years), sex, residence, and history of childbirth since 2006 (for women). Environmental risk factors, which included type and use of humidifier and HD, were investigated using a structured questionnaire during August 2011. The exposure to HD was calculated for both cases and controls, and the corresponding risks of lung injury were compared. Results Among 28 eligible cases, 16 patients agreed to participate, and 60 matched controls were considered eligible for this study. The cases were more likely to have been exposed to HD (odds ratio: 116.1, 95% confidence interval: 6.5–2,063.7). All cases were exposed to HDs containing polyhexamethyleneguanidine phosphate, and the risk of lung injury increased with the cumulative exposure, duration of exposure, and exposure per day. Conclusions This study revealed a statistically significant exposure-response relationship between HD and lung injury. Therefore, continuous monitoring and stricter evaluation of environmental chemicals’ safety should be conducted. PMID:26990641

Modeling Interactions Between Flexible Flapping Wing Spars, Mechanisms, and Drive Motors

DTIC Science & Technology

2011-09-01

of dynamical equations is presented that allow micro air vehicle (MAV) or- nithopter designers to match drive motors to loads produced by flexible...aeroelastic systems is presented. One potential use for such a model is to serve as the basis for a vehicle design tool that matches drive motors to loads...friction. ∗Senior Aerospace Engineer, Control Design and Analysis Branch, 2210 Eighth Street, Ste. 21, Air Force Research Labora- tory, WPAFB, OH 45433

Performance Evaluation of Passive Haptic Feedback for Tactile HMI Design in CAVEs.

PubMed

Lassagne, Antoine; Kemeny, Andras; Posselt, Javier; Merienne, Frederic

2018-01-01

This article presents a comparison of different haptic systems, which are designed to simulate flat Human Machine Interfaces (HMIs) like touchscreens in virtual environments (VEs) such as CAVEs, and their respective performance. We compare a tangible passive transparent slate to a classic tablet and a sensory substitution system. These systems were tested during a controlled experiment. The performance and impressions from 20 subjects were collected to understand more about the modalities in the given context. The results show that the preferences of the subjects are strongly related to the use-cases and needs. In terms of performance, passive haptics proved to be significantly useful, acting as a space reference and a real-time continuous calibration system, allowing subjects to have lower execution durations and relative errors. Sensory substitution induced perception drifts during the experiment, causing significant performance disparities, demonstrating the low robustness of perception when spatial cues are insufficiently available. Our findings offer a better understanding on the nature of perception drifts and the need of strong multisensory spatial markers for such use-cases in CAVEs. The importance of a relevant haptic modality specifically designed to match a precise use-case is also emphasized.

Music evoked autobiographical memory after severe acquired brain injury: preliminary findings from a case series.

PubMed

Baird, A; Samson, S

2014-01-01

Music evoked autobiographical memories (MEAMs) have been characterised in the healthy population, but not, to date, in patients with acquired brain injury (ABI). Our aim was to investigate music compared with verbal evoked autobiographical memories. Five patients with severe ABI and matched controls completed the experimental music (MEAM) task (a written questionnaire) while listening to 50 "Number 1 Songs of the Year" (from 1960 to 2010). Patients also completed the Autobiographical Memory Interview (AMI) and a standard neuropsychological assessment. With the exception of Case 5, who reported no MEAMs and no autobiographical incidents on the AMI and who also had impaired pitch perception, the range of frequency and type of MEAMs in patients was broadly in keeping with their matched controls. The relative preservation of MEAMs in four cases was particularly noteworthy given their impaired verbal and/or visual anterograde memory, and in three cases, autobiographical memory impairment. The majority of MEAMs in both cases and matched controls were of a person/people or a period of life. In three patients music was more efficient at evoking autobiographical memories than the AMI verbal prompts. This is the first study of MEAMs after ABI. The findings suggest that music is an effective stimulus for eliciting autobiographical memories, and may be beneficial in the rehabilitation of autobiographical amnesia, but only in patients without a fundamental deficit in autobiographical recall memory and intact pitch perception.

Association of rs1344706 in the ZNF804A gene with schizophrenia in a case/control sample from Indonesia.

PubMed

Schwab, Sibylle G; Kusumawardhani, Agung A A A; Dai, Nan; Qin, WenWen; Wildenauer, Mutiara D B; Agiananda, Feranindhya; Amir, Nurmiati; Antoni, Ronald; Arsianti, Tiana; Asmarahadi, Asmarahadi; Diatri, Hervita; Djatmiko, Prianto; Irmansyah, Irmansyah; Khalimah, Siti; Kusumadewi, Irmia; Kusumaningrum, Profitasari; Lukman, Petrin R; Mustar, Lukman; Nasrun, Martina W; Naswati, Safyuni; Prasetiyawan, Prasetiyawan; Semen, Gerald M; Siste, Kristiana; Tobing, Heriani; Widiasih, Natalia; Wiguna, Tjhin; Wulandari, Widayanti Dewi; Benyamin, Beben; Wildenauer, Dieter B

2013-06-01

Association of rs1344706 in the ZNF804A gene (2q32.1) with schizophrenia was first reported in a genome wide scan conducted in a sample of 479 cases and replicated in 6666 cases. Subsequently, evidence by replication was obtained in several samples with European- and Asian ancestral background. We report ascertainment, clinical characterization, quality control, and determination of ancestral background of a case control sample from Indonesia, comprising 1067 cases and 1111 ancestry matched controls. Genotyping was performed using a fluorescence-based allelic discrimination assay (TaqMan SNP genotyping assay) and a newly designed PCR-RFLP assay for confirmation of rs1344706 genotypes. We confirmed association of the T-allele of rs1344706 with schizophrenia in a newly ascertained sample from Indonesia with Southeast Asian ancestral background (P=0.019, OR=1.155, 95%, CI 1.025-1.301). In addition, we studied several SNPs in the vicinity of rs1344706, for which nominally significant results had been reported. None of the association P values of the additional SNPs exceeded that of rs1344706. We provide additional evidence for association of the ZNF804A gene with schizophrenia. We conclude that rs1344706 or a yet unknown polymorphism in linkage disequilibrium is also involved in conferring susceptibility to schizophrenia in samples with different (Asian) ancestral backgrounds. Copyright © 2013 Elsevier B.V. All rights reserved.

Effectiveness of one dose of mumps vaccine against clinically diagnosed mumps in Guangzhou, China, 2006–2012

PubMed Central

Fu, Chuanxi; Xu, Jianxiong; Cai, Yuanjun; He, Qing; Zhang, Chunhuan; Chen, Jian; Dong, Zhiqiang; Hu, Wensui; Wang, Hui; Zhu, Wei; Wang, Ming

2013-01-01

Although mumps-containing vaccines were introduced in China in 1990s, mumps continues to be a public health concern due to the lack of decline in reported mumps cases. To assess the mumps vaccine effectiveness (VE) in Guangzhou, China, we performed a 1:1 matched case-control study. Among children in Guangzhou aged 8 mo to 12 y during 2006 to 2012, we matched one healthy child to each child with clinically diagnosed mumps. Cases with clinically diagnosed mumps were identified from surveillance sites system and healthy controls were randomly sampled from the Children’s Expanded Programmed Immunization Administrative Computerized System in Guangzhou. Conditional logistic regression was used to calculate VE. We analyzed the vaccination information for 1983 mumps case subjects and 1983 matched controls and found that the overall VE for 1 dose of mumps vaccine, irrespective of the manufacture, was 53.6% (95% confidence interval [CI], 41.0–63.5%) to children aged 8 mo to 12 y. This post-marketing mumps VE study found that immunization with one dose of the mumps vaccine confers partial protection against mumps disease. Evaluation of the VE for the current mumps vaccines, introduction of a second dose of mumps vaccine, and assessment of modifications to childhood immunization schedules is essential. PMID:23955378

Effectiveness of one dose of mumps vaccine against clinically diagnosed mumps in Guangzhou, China, 2006-2012.

PubMed

Fu, Chuanxi; Xu, Jianxiong; Cai, Yuanjun; He, Qing; Zhang, Chunhuan; Chen, Jian; Dong, Zhiqiang; Hu, Wensui; Wang, Hui; Zhu, Wei; Wang, Ming

2013-12-01

Although mumps-containing vaccines were introduced in China in 1990s, mumps continues to be a public health concern due to the lack of decline in reported mumps cases. To assess the mumps vaccine effectiveness (VE) in Guangzhou, China, we performed a 1:1 matched case-control study. Among children in Guangzhou aged 8 mo to 12 y during 2006 to 2012, we matched one healthy child to each child with clinically diagnosed mumps. Cases with clinically diagnosed mumps were identified from surveillance sites system and healthy controls were randomly sampled from the Children's Expanded Programmed Immunization Administrative Computerized System in Guangzhou. Conditional logistic regression was used to calculate VE. We analyzed the vaccination information for 1983 mumps case subjects and 1983 matched controls and found that the overall VE for 1 dose of mumps vaccine, irrespective of the manufacture, was 53.6% (95% confidence interval [CI], 41.0-63.5%) to children aged 8 mo to 12 y. This post-marketing mumps VE study found that immunization with one dose of the mumps vaccine confers partial protection against mumps disease. Evaluation of the VE for the current mumps vaccines, introduction of a second dose of mumps vaccine, and assessment of modifications to childhood immunization schedules is essential.

Maternal and paternal occupational exposures and hepatoblastoma: results from the HOPE study through the Children's Oncology Group.

PubMed

Janitz, Amanda E; Ramachandran, Gurumurthy; Tomlinson, Gail E; Krailo, Mark; Richardson, Michaela; Spector, Logan

2017-07-01

Little is known about the etiology of hepatoblastoma. We aimed to confirm the results of a previous study evaluating the association between parental occupational exposures and hepatoblastoma. In our case-control study, we identified cases (n=383) from the Children's Oncology Group and controls from birth certificates (n=387), which were frequency matched to cases on year and region of birth, sex, and birth weight. Occupational exposure in the year before and during the index pregnancy was collected through maternal interview and analyzed using unconditional logistic regression. The odds of both paternal and maternal "Likely" exposure to paints was elevated among cases compared with controls (paternal odds ratio (OR): 1.71, 95% confidence interval (CI): 1.04, 2.81; maternal OR: 3.29, 95% CI: 0.32, 33.78) after adjustment for matching factors and the confounding factors of maternal race (maternal only) and household income. In addition, paternal exposure to other chemicals was also elevated when adjusting for matching factors only (OR: 1.53, 95% CI: 1.02, 2.30). The results of our study provide further evidence of an association between parental occupation and hepatoblastoma. These results warrant further investigation of the etiologically relevant timing of occupational exposure to fumes and chemicals related to hepatoblastoma.

Campylobacteriosis in New Zealand: results of a case-control study.

PubMed

Eberhart-Phillips, J; Walker, N; Garrett, N; Bell, D; Sinclair, D; Rainger, W; Bates, M

1997-12-01

To identify and assess the contributions of major risk factors for campylobacteriosis in New Zealand. Case-control study. Home interviews were conducted over nine months using a standardised questionnaire to assess recent food consumption and other exposures. Four centres in New Zealand with high notification rates of campylobacter infections--Auckland, Hamilton, Wellington, and Christchurch. Case patients were 621 people notified between 1 June 1994 and 28 February 1995 as having campylobacter infection. Control subjects were selected randomly from telephone directories, and were matched 1:1 with case patients in relation to sex, age group, and home telephone prefix. Risk of campylobacteriosis was strongly associated with recent consumption of raw or undercooked chicken (matched odds ratio 4.52, 95% confidence interval 2.88, 7.10). There was also an increased risk with chicken eaten in restaurants (matched odds ratio 3.85; 2.52, 5.88). Recent consumption of baked or roasted chicken seemed to be protective. Campylobacteriosis was also associated with recent overseas travel, rainwater as a source of water at home, consumption of raw dairy products, and contact with puppies and cattle, particularly calves. Improperly cooked chicken seems to be associated with a large proportion of campylobacteriosis in New Zealand. Thorough cooking of chicken in homes and restaurants could reduce considerably the incidence of this disease.

Energy Efficient Engine: High-pressure compressor test hardware detailed design report

NASA Technical Reports Server (NTRS)

Howe, David C.; Marchant, R. D.

1988-01-01

The objective of the NASA Energy Efficient Engine program is to identify and verify the technology required to achieve significant reductions in fuel consumption and operating cost for future commercial gas turbine engines. The design and analysis is documented of the high pressure compressor which was tested as part of the Pratt and Whitney effort under the Energy Efficient Engine program. This compressor was designed to produce a 14:1 pressure ratio in ten stages with an adiabatic efficiency of 88.2 percent in the flight propulsion system. The corresponding expected efficiency for the compressor component test rig is 86.5 percent. Other performance goals are a surge margin of 20 percent, a corrected flow rate of 35.2 kg/sec (77.5 lb/sec), and a life of 20,000 missions and 30,000 hours. Low loss, highly loaded airfoils are used to increase efficiency while reducing the parts count. Active clearance control and case trenches in abradable strips over the blade tips are included in the compressor component design to further increase the efficiency potential. The test rig incorporates variable geometry stator vanes in all stages to permit maximum flexibility in developing stage-to-stage matching. This provision precluded active clearance control on the rear case of the test rig. Both the component and rig designs meet or exceed design requirements with the exception of life goals, which will be achievable with planned advances in materials technology.

Statins and Risk of Lower Limb Revision Surgery: The Influence of Differences in Study Design Using Electronic Health Records From the United Kingdom and Denmark

PubMed Central

Lalmohamed, Arief; van Staa, Tjeerd P.; Vestergaard, Peter; Leufkens, Hubertus G. M.; de Boer, Anthonius; Emans, Pieter; Cooper, Cyrus; de Vries, Frank

2016-01-01

Abstract Previous observational studies on statins have shown variable results based on the methodology used. Our objective was to study the association between statins and orthopedic implant failure and to explore the influence of methodological differences in study design. Our study base consisted of patients with a primary total joint replacement in Denmark and the United Kingdom (n = 189,286; 1987–2012). We used 4 study designs: 1) case-control (each patient with revision surgery matched to 4 controls), 2) time-dependent cohort (postoperative statin use as a time-varying exposure variable), 3) immortal time cohort (misclassifying the time postoperatively before statin use), and 4) time-exclusion cohort (excluding the time postoperatively before statin use). Cox proportional hazards models and logistic regression were used to estimate incidence rate ratios. In the time-dependent cohort design, statin use was associated with a decreased risk of revision surgery (adjusted incidence rate ratio (IRR) = 0.90, 95% confidence interval (CI): 0.85, 0.96), which was similar to our case-control results (IRR = 0.87, 95% CI: 0.81, 0.93). In contrast, both time-fixed cohort designs yielded substantially lower risk estimates (IRR = 0.36 (95% CI: 0.34, 0.38) and IRR = 0.65 (95% CI: 0.63, 0.68), respectively). We discourage the use of time-fixed cohort studies, which may falsely suggest protective effects. The simple choice of how to classify exposure can substantially change results from biologically plausible to implausible. PMID:27317693

Upper gastrointestinal bleeding caused by severe esophagitis: a unique clinical syndrome.

PubMed

Guntipalli, Prathima; Chason, Rebecca; Elliott, Alan; Rockey, Don C

2014-12-01

We have recognized a unique clinical syndrome in patients with upper gastrointestinal bleeding who are found to have severe esophagitis. We aimed to more clearly describe the clinical entity of upper gastrointestinal bleeding in patients with severe esophagitis. We conducted a retrospective matched case-control study designed to investigate clinical features in patients with carefully defined upper gastrointestinal bleeding and severe esophagitis. Patient data were captured prospectively via a Gastrointestinal Bleeding Healthcare Registry, which collects data on all patients admitted with gastrointestinal bleeding. Patients with endoscopically documented esophagitis (cases) were matched with randomly selected controls that had upper gastrointestinal bleeding caused by other lesions. Epidemiologic features in patients with esophagitis were similar to those with other causes of upper gastrointestinal bleeding. However, hematemesis was more common in patients with esophagitis 86% (102/119) than in controls 55% (196/357) (p < 0.0001), while melena was less common in patients with esophagitis 38% (45/119) than in controls 68% (244/357) (p < 0.0001). Additionally, the more severe the esophagitis, the more frequent was melena. Patients with esophagitis had less abnormal vital signs, lesser decreases in hematocrit, and lesser increases in BUN. Both pre- and postRockall scores were lower in patients with esophagitis compared with controls (p = 0.01, and p < 0.0001, respectively). Length of hospital stay (p = 0.002), rebleeding rate at 42 days (p = 0.0007), and mortality were less in patients with esophagitis than controls. Finally, analysis of patients with esophagitis and cirrhosis suggested that this group of patients had more severe bleeding than those without cirrhosis. We have described a unique clinical syndrome in patients with upper gastrointestinal bleeding who have erosive esophagitis. This syndrome is manifest by typical clinical features and is associated with favorable outcomes.

Epstein-Barr Virus and Gastric Cancer Risk: A Meta-analysis With Meta-regression of Case-control Studies.

PubMed

Bae, Jong-Myon; Kim, Eun Hee

2016-03-01

Research on how the risk of gastric cancer increases with Epstein-Barr virus (EBV) infection is lacking. In a systematic review that investigated studies published until September 2014, the authors did not calculate the summary odds ratio (SOR) due to heterogeneity across studies. Therefore, we include here additional studies published until October 2015 and conduct a meta-analysis with meta-regression that controls for the heterogeneity among studies. Using the studies selected in the previously published systematic review, we formulated lists of references, cited articles, and related articles provided by PubMed. From the lists, only case-control studies that detected EBV in tissue samples were selected. In order to control for the heterogeneity among studies, subgroup analysis and meta-regression were performed. In the 33 case-control results with adjacent non-cancer tissue, the total number of test samples in the case and control groups was 5280 and 4962, respectively. In the 14 case-control results with normal tissue, the total number of test samples in case and control groups was 1393 and 945, respectively. Upon meta-regression, the type of control tissue was found to be a statistically significant variable with regard to heterogeneity. When the control tissue was normal tissue of healthy individuals, the SOR was 3.41 (95% CI, 1.78 to 6.51; I-squared, 65.5%). The results of the present study support the argument that EBV infection increases the risk of gastric cancer. In the future, age-matched and sex-matched case-control studies should be conducted.

Case-control study of renal cell carcinoma in relation to occupation, smoking, and alcohol consumption

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brownson, R.C.

1988-05-01

A case-control study based on data from a cancer registry was conducted to evaluate the effects of smoking, alcohol use, and occupation on renal cell cancer risk. Information was obtained for 326 male and female cases and 978 age- and sex-matched controls. Elevated risks were identified for cigarette smokers and for men employed as truck drivers. No relationship between alcohol consumption and renal cancer was observed.

Clinical, virologic, and immunologic outcomes in lymphoma survivors and in cancer-free, HIV-1-infected patients: a matched cohort study.

PubMed

Spagnuolo, Vincenzo; Travi, Giovanna; Galli, Laura; Cossarini, Francesca; Guffanti, Monica; Gianotti, Nicola; Salpietro, Stefania; Lazzarin, Adriano; Castagna, Antonella

2013-08-01

The objective of this study was to compare immunologic, virologic, and clinical outcomes between living human immunodeficiency virus (HIV)-infected individuals who had a diagnosis of lymphoma versus outcomes in a control group of cancer-free, HIV-infected patients. In this matched cohort study, patients in the case group were survivors of incident lymphomas that occurred between 1997 and June 2010. Controls were living, cancer-free, HIV-infected patients who were matched to cases at a 4:1 ratio by age, sex, nadir CD4 cell count, and year of HIV diagnosis. The date of lymphoma diagnosis served as the baseline in cases and in the corresponding controls. In total, 62 patients (cases) who had lymphoma (20 with Hodgkin disease [HD] and 42 with non-Hodgkin lymphoma [NHL]) were compared with 211 controls. The overall median follow-up was 4.8 years (interquartile range, 2.0-7.9 years). The CD4 cell count at baseline was 278 cells/mm³ (interquartile range, 122-419 cells/mm³) in cases versus 421 cells/mm³ (interquartile range, 222-574 cells/mm³) in controls (P = .003). At the last available visit, the CD4 cell count was 412 cells/mm³ (range, 269-694 cells/mm³) in cases versus 518 cells/mm³ (interquartile range, 350-661 cells/mm³) in controls (P = .087). The proportion of patients who achieved virologic success increased from 30% at baseline to 74% at the last available visit in cases (P = .008) and from 51% to 81% in controls (P = .0286). Patients with HD reached higher CD4 cell counts at their last visit than patients with NHL (589 cells/mm³ [range, 400-841 cells/mm³] vs 332 cells/mm³ [interquartile range, 220-530 cells/mm³], respectively; P = .003). Virologic success was similar between patients with HD and patients with NHL at the last visit. Forty cases (65%) and 76 controls (36%) experienced at least 1 clinical event after baseline (P < .0001); cases were associated with a shorter time to occurrence of the first clinical event compared with controls (P < .0001). HIV-infected lymphoma survivors experienced more clinical events than controls, especially during the first year of follow-up, but they reached similar long-term immunologic and virologic outcomes. © 2013 American Cancer Society.

Impact of a Social-Emotional and Character Development Program on School-Level Indicators of Academic Achievement, Absenteeism, and Disciplinary Outcomes: A Matched-Pair, Cluster-Randomized, Controlled Trial

ERIC Educational Resources Information Center

Snyder, Frank; Flay, Brian; Vuchinich, Samuel; Acock, Alan; Washburn, Isaac; Beets, Michael; Li, Kin-Kit

2010-01-01

This article reports the effects of a comprehensive elementary school-based social-emotional and character education program on school-level achievement, absenteeism, and disciplinary outcomes utilizing a matched-pair, cluster-randomized, controlled design. The "Positive Action" Hawai'i trial included 20 racially/ethnically diverse…

Association Between Hospitalization for Pneumonia and Subsequent Risk of Cardiovascular Disease

PubMed Central

Corrales-Medina, Vicente F.; Alvarez, Karina N.; Weissfeld, Lisa A.; Angus, Derek C.; Chirinos, Julio A.; Chang, Chung-Chou H.; Newman, Anne; Loehr, Laura; Folsom, Aaron R.; Elkind, Mitchell S.; Lyles, Mary F.; Kronmal, Richard A.; Yende, Sachin

2015-01-01

IMPORTANCE The risk of cardiovascular disease (CVD) after infection is poorly understood. OBJECTIVE To determine whether hospitalization for pneumonia is associated with an increased short-term and long-term risk of CVD. DESIGN, SETTINGS, AND PARTICIPANTS We examined 2 community-based cohorts: the Cardiovascular Health Study (CHS, n = 5888; enrollment age, ≥65 years; enrollment period, 1989–1994) and the Atherosclerosis Risk in Communities study (ARIC, n = 15 792; enrollment age, 45-64 years; enrollment period, 1987–1989). Participants were followed up through December 31, 2010. We matched each participant hospitalized with pneumonia to 2 controls. Pneumonia cases and controls were followed for occurrence of CVD over 10 years after matching. We estimated hazard ratios (HRs) for CVD at different time intervals, adjusting for demographics, CVD risk factors, subclinical CVD, comorbidities, and functional status. EXPOSURES Hospitalization for pneumonia. MAIN OUTCOMES AND MEASURES Incident CVD (myocardial infarction, stroke, and fatal coronary heart disease). RESULTS Of 591 pneumonia cases in CHS, 206 had CVD events over 10 years after pneumonia hospitalization. Compared with controls, CVD risk among pneumonia cases was highest during the first year after hospitalization and remained significantly higher than among controls through 10 years. In ARIC, of 680 pneumonia cases, 112 had CVD events over 10 years after hospitalization. After the second year, CVD risk among pneumonia cases was not significantly higher than among controls. Pneumonia Cases Controls HR (95% CI) CHS No. of participants 591 1182 CVD events  0-30 d 54 6 4.07 (2.86-5.27)  31-90 d 11 9 2.94 (2.18-3.70)  91 d-1 y 22 55 2.10 (1.59-2.60)  9-10 y 4 12 1.86 (1.18-2.55) ARIC No. of participants 680 1360 CVD events  0-30 d 4 3 2.38 (1.12-3.63)  31-90 d 4 0 2.40 (1.23-3.47)  91 d-1 y 11 8 2.19 (1.20-3.19)  1-2 y 8 7 1.88 (1.10-2.66) CONCLUSIONS AND RELEVANCE Hospitalization for pneumonia was associated with increased short-term and long-term risk of CVD, suggesting that pneumonia may be a risk factor for CVD. PMID:25602997

Open Rotor Tone Shielding Methods for System Noise Assessments Using Multiple Databases

NASA Technical Reports Server (NTRS)

Bahr, Christopher J.; Thomas, Russell H.; Lopes, Leonard V.; Burley, Casey L.; Van Zante, Dale E.

2014-01-01

Advanced aircraft designs such as the hybrid wing body, in conjunction with open rotor engines, may allow for significant improvements in the environmental impact of aviation. System noise assessments allow for the prediction of the aircraft noise of such designs while they are still in the conceptual phase. Due to significant requirements of computational methods, these predictions still rely on experimental data to account for the interaction of the open rotor tones with the hybrid wing body airframe. Recently, multiple aircraft system noise assessments have been conducted for hybrid wing body designs with open rotor engines. These assessments utilized measured benchmark data from a Propulsion Airframe Aeroacoustic interaction effects test. The measured data demonstrated airframe shielding of open rotor tonal and broadband noise with legacy F7/A7 open rotor blades. Two methods are proposed for improving the use of these data on general open rotor designs in a system noise assessment. The first, direct difference, is a simple octave band subtraction which does not account for tone distribution within the rotor acoustic signal. The second, tone matching, is a higher-fidelity process incorporating additional physical aspects of the problem, where isolated rotor tones are matched by their directivity to determine tone-by-tone shielding. A case study is conducted with the two methods to assess how well each reproduces the measured data and identify the merits of each. Both methods perform similarly for system level results and successfully approach the experimental data for the case study. The tone matching method provides additional tools for assessing the quality of the match to the data set. Additionally, a potential path to improve the tone matching method is provided.

Observer-Based Non-PDC Control for Networked T-S Fuzzy Systems With an Event-Triggered Communication.

PubMed

Peng, Chen; Ma, Shaodong; Xie, Xiangpeng

2017-02-07

This paper addresses the problem of an event-triggered non-parallel distribution compensation (PDC) control for networked Takagi-Sugeno (T-S) fuzzy systems, under consideration of the limited data transmission bandwidth and the imperfect premise matching membership functions. First, a unified event-triggered T-S fuzzy model is provided, in which: 1) a fuzzy observer with the imperfect premise matching is constructed to estimate the unmeasurable states of the studied system; 2) a fuzzy controller is designed following the same premise as the observer; and 3) an output-based event-triggering transmission scheme is designed to economize the restricted network resources. Different from the traditional PDC method, the synchronous premise between the fuzzy observer and the T-S fuzzy system are no longer needed in this paper. Second, by use of Lyapunov theory, a stability criterion and a stabilization condition are obtained for ensuring asymptotically stable of the studied system. On account of the imperfect premise matching conditions are well considered in the derivation of the above criteria, less conservation can be expected to enhance the design flexibility. Compared with some existing emulation-based methods, the controller gains are no longer required to be known a priori. Finally, the availability of proposed non-PDC design scheme is illustrated by the backing-up control of a truck-trailer system.

Worker substance use, workplace problems and the risk of occupational injury: a matched case-control study.

PubMed

Spicer, Rebecca S; Miller, Ted R; Smith, Gordon S

2003-07-01

This study examines the tendency toward problem behavior as an explanation for the relationship between problem substance use and occupational injury. The authors used a matched case-control study nested in a cohort of 26,413 workers, in which cases (n = 3,994) were workers suffering an occupational injury. Five controls per case (n = 19,970) were selected from the cohort of workers active on the day of the injury and matched on job type. Conditional logistic regression modeled the association of problem substance use with occupational injury, controlling for problem behaviors and worker characteristics. Problem substance use was indicated indirectly if any of the following were alcohol/drug-involved during the comparison period: Employee Assistance Program visit, excused absence or disciplinary action. Discipline records identified minor (absenteeism) and serious (dishonesty, theft, assault, harassment, disrespect) problem behaviors during the comparison period. The odds of injury among workers with an indicator of problem substance use was 1.35 (p = .015) times greater than the odds among workers without an indicator, controlling for job type and demographics as well as adjusting for exposure. This ratio declined to 1.21 (p = .138) when problem behaviors were also controlled for. Minor and serious problem behaviors were significantly associated with occupational injury (odds ratio [OR] = 1.73, p < .001, and OR = 2.19, p < .001, respectively), controlling for demographics and substance use. The relationship of problem substance use with occupational injury was weak when problem behaviors were controlled for, suggesting that this relationship, observed in previous studies, may be explained by a workers tendency toward problem behaviors. Workplace injury prevention programs should address the expression of problem behaviors as a complement to drug and alcohol deterrent programs.

Cluster Randomized Test-Negative Design (CR-TND) Trials: A Novel and Efficient Method to Assess the Efficacy of Community Level Dengue Interventions.

PubMed

Anders, Katherine L; Cutcher, Zoe; Kleinschmidt, Immo; Donnelly, Christl A; Ferguson, Neil M; Indriani, Citra; O'Neill, Scott L; Jewell, Nicholas P; Simmons, Cameron P

2018-05-07

Cluster randomized trials are the gold standard for assessing efficacy of community-level interventions, such as vector control strategies against dengue. We describe a novel cluster randomized trial methodology with a test-negative design, which offers advantages over traditional approaches. It utilizes outcome-based sampling of patients presenting with a syndrome consistent with the disease of interest, who are subsequently classified as test-positive cases or test-negative controls on the basis of diagnostic testing. We use simulations of a cluster trial to demonstrate validity of efficacy estimates under the test-negative approach. This demonstrates that, provided study arms are balanced for both test-negative and test-positive illness at baseline and that other test-negative design assumptions are met, the efficacy estimates closely match true efficacy. We also briefly discuss analytical considerations for an odds ratio-based effect estimate arising from clustered data, and outline potential approaches to analysis. We conclude that application of the test-negative design to certain cluster randomized trials could increase their efficiency and ease of implementation.

Hyperthyroidism association with SLE, lessons from real-life data--A case-control study.

PubMed

Watad, Abdulla; Cohen, Arnon D; Comaneshter, Doron; Tekes-Manova, Dorit; Amital, Howard

2016-01-01

Despite the frequently encountered association between thyroid disease and systemic lupus erythematosus (SLE) is well known, it is of surprise that only several reports compromised of small population size support this observation. To investigate the association of comorbid SLE and hyperthyroidism. Using the database of the largest health maintenance organization (HMO) in Israel, the Clalit Health Services, we searched for the co-existence of SLE and hyperthyroidism. Patients with SLE were compared with age- and sex-matched controls regarding the prevalence of hyperthyroidism in a case-control study. Chi-square and t-tests were used for univariate analysis and a logistic regression model was used for multivariate analysis. The study included 5018 patients with SLE and 25,090 age- and sex- matched controls. The prevalence of hyperthyroidism in patients with SLE was increased compared with the prevalence in controls (2.59% and 0.91%, respectively, p < 0.001). In a multivariate analysis, SLE was associated with hyperthyroidism (odds ratio 2.52, 95% confidence interval 2.028-3.137). Patients with SLE have a greater prevalence of hyperthyroidism than matched controls. Therefore, physicians treating patients with SLE should be aware of this possibility of this thyroid dysfunction.

Improving Balance in Regression Discontinuity Design by Matching: Estimating the Effect of Academic Probation after the First Year of College

ERIC Educational Resources Information Center

Chi, Olivia L.; Dow, Aaron W.

2014-01-01

This study focuses on how matching, a method of preprocessing data prior to estimation and analysis, can be used to reduce imbalance between treatment and control group in regression discontinuity design. To examine the effects of academic probation on student outcomes, researchers replicate and expand upon research conducted by Lindo, Sanders,…

Mid-Season Influenza Vaccine Effectiveness Estimates for the 2016-2017 Influenza Season (Open Access Publisher’s Version)

DTIC Science & Technology

2017-08-01

controls ; AFHSB used healthy controls (matched to cases by sex, age, date [+/– 3 days] and location). bAFHSB-AF adjusted for age group , month of illness...presented in this report. M E T H O D S The AFHSB–Air Force Satellite Cell (AFHSB-AF) conducted a test-negative case- control study using data from the...ILI). Influenza cases were identified using reverse transcription–polymerase chain reaction (RT-PCR) or viral culture; controls were ILI patients

Blood-Based Biomarkers of Early-Onset Breast Cancer

DTIC Science & Technology

2015-10-01

n=51). The women with early-onset breast cancer were disease and treatment free for at least 6 months at time of blood donation . Cases and controls...were age matched to age at blood donation . 2. KEYWORDS: biomarkers, early-onset breast cancer, expression profiling, risk-assessment, breast cancer...matched controls. This prospectively collected cohort consists of blood donated to blood banks ~15 years ago and subsequently linked to the California

Risk factors for the occurrence of sporadic Salmonella enterica serotype enteritidis infections in children in France: a national case-control study.

PubMed Central

Delarocque-Astagneau, E.; Desenclos, J. C.; Bouvet, P.; Grimont, P. A.

1998-01-01

To determine risk factors associated with the occurrence of sporadic cases of Salmonella enteritidis infections among children in France, we conducted a matched case-control study. Cases were identified between 1 March and 30 September 1995. One hundred and five pairs of cases and controls matched for age and place of residence were interviewed. In the 1-5 years age group, illness was associated with the consumption of raw eggs or undercooked egg-containing foods (OR 2.4, 95% CI 1.2-4.8). Storing eggs more than 2 weeks after purchase was associated with Salmonella enteritidis infection (OR 3.8, 95% CI 1.4-10.2), particularly during the summer period (OR 6.0, 95% CI 1.3-26.8). Cases were more likely to report a case of diarrhoea in the household 10-3 days before the onset of symptoms, particularly in the age group < or = 1 year (P = 0.01). This study confirms the link between eggs and the occurrence of sporadic cases of Salmonella enteritidis among children, highlights the potential role of prolonged egg storage and underlines the role of person-to-person transmission in infants. PMID:10030705

Adopting an Evidence-Based Lifestyle Physical Activity Program: Dissemination Study Design and Methods.

PubMed

Dunn, Andrea L; Buller, David B; Dearing, James W; Cutter, Gary; Guerra, Michele; Wilcox, Sara; Bettinghaus, Erwin P

2012-06-01

BACKGROUND: There is a scarcity of research studies that have examined academic-commercial partnerships to disseminate evidence-based physical activity programs. Understanding this approach to dissemination is essential because academic-commercial partnerships are increasingly common. Private companies have used dissemination channels and strategies to a degree that academicians have not, and declining resources require academicians to explore these partnerships. PURPOSE: This paper describes a retrospective case-control study design including the methods, demographics, organizational decision-making, implementation rates, and marketing strategy for Active Living Every Day (ALED), an evidence-based lifestyle physical activity program that has been commercially available since 2001. Evidence-based public health promotion programs rely on organizations and targeted sectors to disseminate these programs although relatively little is known about organizational-level and sector-level influences that lead to their adoption and implementation. METHODS: Cases (n=154) were eligible if they had signed an ALED license agreement with Human Kinetics (HK), publisher of the program's textbooks and facilitator manuals, between 2001 and 2008. Two types of controls were matched (2:2:1) and stratified by sector and region. Active controls (Control 1; n=319) were organizations that contacted HK to consider adopting ALED. Passive controls (Control 2; n=328) were organizations that received unsolicited marketing materials and did not initiate contact with HK. We used Diffusion of Innovations Theory (DIT) constructs as the basis for developing the survey of cases and controls. RESULTS: Using the multi-method strategy recommended by Dillman, a total of n=801 cases and controls were surveyed. Most organizations were from the fitness sector followed by medical, nongovernmental, governmental, educational, worksite and other sectors with significantly higher response rates from government, educational and medical sectors compared with fitness and other sectors, (p=0.02). More cases reported being involved in the decision to adopt ALED (p<0.0001). Data indicate that a low percentage of controls had ever heard of ALED despite repeated marketing and offering other types of physical activity programs and services. Finally, slightly over half of the adopters reported they had actually implemented the ALED program. CONCLUSION: Dissemination research requires new perspectives and designs to produce valid insights about the results of dissemination efforts. This study design, survey methods and theoretically-based questions can serve as a useful model for other evidence-based public health interventions that are marketed by commercial publishers to better understand key issues related to adoption and implementation of evidence-based programs.

ASRM case insulation design and development

NASA Astrophysics Data System (ADS)

Bell, Matthew S.; Tam, William F. S.

1992-10-01

This paper describes the achievements made on the Advanced Solid Rocket Motor (ASRM) case insulation design and development program. The ASRM case insulation system described herein protects the metal case and joints from direct radiation and hot gas impingement. Critical failure of solid rocket systems is often traceable to failure of the insulation design. The wide ranging accomplishments included the development of a nonasbestos insulation material for ASRM that replaced the existing Redesigned Solid Rocket Motor (RSRM) asbestos-filled nitrile butadiene rubber (NBR) along with a performance gain of 300 pounds, and improved reliability of all the insulation joint designs, i.e., segmented case joint, case-to-nozzle and case-to-igniter joint. The insulation process development program included the internal stripwinding process. This process advancement allowed Aerojet to match to exceed the capability of other propulsion companies.

ASRM case insulation design and development

NASA Technical Reports Server (NTRS)

Bell, Matthew S.; Tam, William F. S.

1992-01-01

This paper describes the achievements made on the Advanced Solid Rocket Motor (ASRM) case insulation design and development program. The ASRM case insulation system described herein protects the metal case and joints from direct radiation and hot gas impingement. Critical failure of solid rocket systems is often traceable to failure of the insulation design. The wide ranging accomplishments included the development of a nonasbestos insulation material for ASRM that replaced the existing Redesigned Solid Rocket Motor (RSRM) asbestos-filled nitrile butadiene rubber (NBR) along with a performance gain of 300 pounds, and improved reliability of all the insulation joint designs, i.e., segmented case joint, case-to-nozzle and case-to-igniter joint. The insulation process development program included the internal stripwinding process. This process advancement allowed Aerojet to match to exceed the capability of other propulsion companies.

The Utility of Case-Control Methods for Health Policy and Planning Analysis: An Illustration from Kinshasa, Zaire.

ERIC Educational Resources Information Center

Mock, Nancy B.; And Others

1993-01-01

The use of case-control methodology as an applied policy/planning research tool in assessing the potential effectiveness of behavioral interventions is studied in connection with diarrhea control in Zaire. Results with 107 matched pairs of children demonstrate the importance of hygiene-related knowledge and the utility of the research approach.…

Accommodation and vergence response gains to different near cues characterize specific esotropias

PubMed Central

Horwood, Anna M; Riddell, Patricia M

2015-01-01

Aim To describe preliminary findings of how the profile of the use of blur, disparity and proximal cues varies between non-strabismic groups and those with different types of esotropia. Design Case control study Methodology A remote haploscopic photorefractor measured simultaneous convergence and accommodation to a range of targets containing all combinations of binocular disparity, blur and proximal (looming) cues. 13 constant esotropes, 16 fully accommodative esotropes, and 8 convergence excess esotropes were compared with age and refractive error matched controls, and 27 young adult emmetropic controls. All wore full refractive correction if not emmetropic. Response AC/A and CA/C ratios were also assessed. Results Cue use differed between the groups. Even esotropes with constant suppression and no binocular vision (BV) responded to disparity in cues. The constant esotropes with weak BV showed trends for more stable responses and better vergence and accommodation than those without any BV. The accommodative esotropes made less use of disparity cues to drive accommodation (p=0.04) and more use of blur to drive vergence (p=0.008) than controls. All esotropic groups failed to show the strong bias for better responses to disparity cues found in the controls, with convergence excess esotropes favoring blur cues. AC/A and CA/C ratios existed in an inverse relationship in the different groups. Accommodative lag of >1.0D at 33cm was common (46%) in the pooled esotropia groups compared with 11% in typical children (p=0.05). Conclusion Esotropic children use near cues differently from matched non-esotropic children in ways characteristic to their deviations. Relatively higher weighting for blur cues was found in accommodative esotropia compared to matched controls. PMID:23978142

Assessing musculoskeletal disorders among municipal waste loaders of Mumbai, India.

PubMed

Salve, Pradeep; Chokhandre, Praveen; Bansod, Dhananjay

2017-10-06

The study aims to assess the impact of municipal waste loading occupation upon developing musculoskeletal disorders (MSDs) and thereby disabilities among waste loaders. Additionally, the study has identified the potential risk factors raising MSDs and disabilities. A cross-sectional case-control design survey was conducted in 6 out of 24 municipal wards of Mumbai during March-September 2015. The study population consisted of municipal waste loaders (N = 180) and a control group (N = 180). The Standardized Modified Nordic questionnaire was adopted to measures the MSDs and thereby disabilities in the past 12 months. A Propensity Score Matching (PSM) method was applied to assess the impact of waste loading occupation on developing MSDs and disabilities. Waste loaders had a significantly higher risk of developing MSDs as well as disabilities than the control group particularly for low back, hip/ thigh upper back and shoulder. Propensity Score Matching results revealed that the MSDs were significantly higher among waste loaders for hip/thigh (22%), low back (19%), shoulder (18%), and upper back (15%) than matched control group. Likewise, MSDs-related disabilities were found to be significantly higher among waste loaders for low back (20%), hip/ thigh (18%) upper back (13%) and shoulder (8%) than the control group. Duration of work, substance use and mental health were found to be the potential psychosocial factors for developing the risk of MSDs and disabilities. The municipal waste loading occupation raised the risk of MSDs and related disabilities among waste loaders compared to the control group. The preventive and curative measures are strongly recommended to minimize the burden of MSDs and disabilities. Int J Occup Med Environ Health 2017;30(6):875-886. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Assessing the prevalence of compromised bone health among overweight and obese African-American breast cancer survivors: a case control study

PubMed Central

Sheean, Patricia; Liang, Huifang; Schiffer, Linda; Arroyo, Claudia; Troy, Karen; Stolley, Melinda

2015-01-01

Purpose Osteoporosis increases the risk of fracture and is often considered a late effect of breast cancer treatment. We examined the prevalence of compromised bone health in a sample of exclusively African-American (AA) breast cancer survivors since bone mineral density (BMD) varies by race/ethnicity in healthy populations. Methods Using a case-control design, AA women in a weight loss intervention previously diagnosed and treated for Stage I-IIIa breast cancer were matched 1:1 on age, race, sex and BMI with non-cancer population controls (n=101 pairs) from NHANES. Questionnaires and dual energy x-ray absorptiometry (DXA) scanning were completed and participants were categorized as having normal bone density, low bone mass or osteoporosis using the WHO definition for femoral neck T-scores. Results The majority of these overweight/obese survivors were 6.6 (± 4.7) years post-diagnosis, had Stage II (n=46) or Stage III (n=16) disease, and treated with chemotherapy (76%), radiation (72%) and/or adjuvant hormone therapies (45%). Mean femoral neck BMD was significantly lower in cases vs. matched non-cancer population controls (0.85 ± 0.15 vs. 0.91 ± 0.14 g/cm2, respectively; p=0.007). However, the prevalence of low bone mass and osteoporosis was low and did not significantly differ between groups (n=101 pairs; p=0.26), even when restricted to those on adjuvant hormone therapies (n=45 pairs; p=0.75). Using conditional logistic regression, controlling for dietary factors and education, the odds of developing compromised bone health in AA breast cancer survivors was insignificant (OR 1.5, 95% CI 0.52, 5.56). Conclusions These null case-control findings challenge the clinical assumption that osteoporosis is highly prevalent among all breast cancer survivors, providing foundational evidence to support differences by race/ethnicity and body weight. Implications for cancer survivors Routine bone density testing and regular patient-provider dialogue is critical in overweight/obese AA breast cancer survivors to ensure that healthy lifestyle factors (e.g., ideal weight, regular weight-bearing exercises, dietary adequacy of calcium and vitamin D) support optimal skeletal health. PMID:25820976

Semiparametric time varying coefficient model for matched case-crossover studies.

PubMed

Ortega-Villa, Ana Maria; Kim, Inyoung; Kim, H

2017-03-15

In matched case-crossover studies, it is generally accepted that the covariates on which a case and associated controls are matched cannot exert a confounding effect on independent predictors included in the conditional logistic regression model. This is because any stratum effect is removed by the conditioning on the fixed number of sets of the case and controls in the stratum. Hence, the conditional logistic regression model is not able to detect any effects associated with the matching covariates by stratum. However, some matching covariates such as time often play an important role as an effect modification leading to incorrect statistical estimation and prediction. Therefore, we propose three approaches to evaluate effect modification by time. The first is a parametric approach, the second is a semiparametric penalized approach, and the third is a semiparametric Bayesian approach. Our parametric approach is a two-stage method, which uses conditional logistic regression in the first stage and then estimates polynomial regression in the second stage. Our semiparametric penalized and Bayesian approaches are one-stage approaches developed by using regression splines. Our semiparametric one stage approach allows us to not only detect the parametric relationship between the predictor and binary outcomes, but also evaluate nonparametric relationships between the predictor and time. We demonstrate the advantage of our semiparametric one-stage approaches using both a simulation study and an epidemiological example of a 1-4 bi-directional case-crossover study of childhood aseptic meningitis with drinking water turbidity. We also provide statistical inference for the semiparametric Bayesian approach using Bayes Factors. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Are vital signs indicative for bacteremia in newborns?

PubMed

Yapıcıoğlu, Hacer; Özlü, Ferda; Sertdemir, Yaşar

2015-01-01

Neonatal systemic infection is a leading cause of morbidity and mortality both in industrialized and developing countries. The aim of this prospective study was to evaluate if vital signs had a predictive power in neonatal sepsis as an early marker. This study was designed as a matched case-control study. Vital signs were monitorized prior to infection in newborns that had healthcare-associated blood stream infection (BSI). Maximum and minimum values of the vital signs (blood pressure, heart rate, respiratory rate and temperature) of the babies at rest were recorded from the nurse observation charts five days prior to clinical sepsis and compared with vital signs of healthy, age-matched babies. Maximum mean heart rates, respiratory rates and systolic blood pressure levels of the patients in BSI group were significantly higher than the control group in the past three days prior to clinical deterioration. Monitoring vital signs closely might be helpful in a newborn infant to define a BSI. In future, a respiratory and blood pressure predictive monitoring system such as heart rate variability index may be developed for newborn patients with sepsis.

Epidemiological study of the characteristics of veterinarians who pursue a research career: part I.

PubMed

Murray, J K; French, N P; Fitzpatrick, J L; Pinchbeck, G L

2005-09-24

This retrospective, matched case-control study compared the characteristics of veterinary surgeons employed in veterinary research with those who had never held a research post. The cases were randomly selected from graduates of veterinary schools in Great Britain or Ireland who were employed at universities or institutes that conduct research and who played a major role in veterinary research projects during 2001 to 2003. The controls were veterinary surgeons who had not held any post that was primarily a research post since they graduated. The cases and controls were matched by year of graduation and data were obtained for 173 matched sets. Graduates who were significantly (P<0.05) more likely to have a career involving research included male graduates, graduates who had completed a summer studentship, graduates who had completed an internship, residency or houseman's programme, graduates who held a veterinary diploma, and graduates who had intended to pursue a career in research or academia when they graduated from veterinary school. A career involving research was significantly (P<0.05) more likely to be associated with full-time employment and a lower salary than a career that did not involve research.

Evaluation of Female Breast Cancer Risk Among the Betel Quid Chewer: A Bio-Statistical Assessment in Assam, India.

PubMed

Rajbongshi, Nijara; Mahanta, Lipi B; Nath, Dilip C

2015-06-01

Breast cancer is the most commonly diagnosed cancer among the female population of Assam, India. Chewing of betel quid with or without tobacco is common practice among female population of this region. Moreoverthe method of preparing the betel quid is different from other parts of the country.So matched case control study is conducted to analyse whetherbetel quid chewing plays a significant role in the high incidence of breast cancer occurrences in Assam. Here, controls are matched to the cases by age at diagnosis (±5 years), family income and place of residence with matching ratio 1:1. Conditional logistic regression models and odd ratios (OR) was used to draw conclusions. It is observed that cases are more habituated to chewing habits than the controls.Further the conditional logistic regression analysis reveals that betel quid chewer faces 2.353 times more risk having breast cancer than the non-chewer with p value 0.0003 (95% CI 1.334-4.150). Though the female population in Assam usually does not smoke, the addictive habits typical to this region have equal effect on the occurrence of breast cancer.

Vehicle Hybrid Braking Control Using Sliding Mode Control

NASA Astrophysics Data System (ADS)

Kasahara, Misawa; Kanai, Yuki; Shiraki, Ryoko; Mori, Yasuchika

Anti-lock brake system and brake-by-wire are proposed in the vehicle control using a brake, and the braking power is expected to be improved more than ever. The researches such as an application to the ABS of Siliding mode control which considered a actuator dynamics and a hybrid control of the brake using model reference adaptive control are done so far. However, in the former case, speed following that becomes a target exists physically impossible situation by saturation of tire frictional force because only speed following is done. In the latter, the model error is caused because the simulation model and the controller design model are different. Therefore, there is a problem that an accurate follow cannot be done. In this paper, the braking control is performed using the sliding mode control which has high robustness for disturbance that fulfils matching conditions. In so doing, it aims at the achievement of optimal braking control to switch wheel speed following to slip ratio following.

Neonatal hypoglycemia in term, nondiabetic pregnancies.

PubMed

DePuy, Amy M; Coassolo, Kara M; Som, Dara A; Smulian, John C

2009-05-01

To define the incidence of hypoglycemia and identify risk factors in neonates from term, singleton, nondiabetic pregnancies. We conducted a matched case-control study of term, singleton infants weighing more than 2500 g in nondiabetic pregnancies. Cases with hypoglycemia (glucose < 50 mg/dL) were identified by International Classification of Diseases, ninth revision, codes. Two controls per case were matched on race, maternal age, and birthweight. Conditional logistic regression analyses were performed. There were 116 cases and 232 controls studied. The incidence density of neonatal hypoglycemia was 24.7 per 1000 infant-days at risk. Hypoglycemia was less commonly associated with later gestational age (odds ratio [OR], 0.66; 95% confidence interval [CI], 0.53-0.85 per week of gestation). Maternal fever during labor was more common with hypoglycemia (OR, 4.08; 95% CI, 1.39-11.79). Public insurance was more than twice as common with hypoglycemia compared with those privately insured (OR, 2.31; 95% CI, 1.17-4.58). Neonatal hypoglycemia was associated with earlier gestational age, intrapartum fever, and public insurance.

Visits on 'lamb-viewing days' at a sheep farm open to the public was a risk factor for Q fever in 2009.

PubMed

Whelan, J; Schimmer, B; de Bruin, A; van Beest Holle, M Robert-du Ry; van der Hoek, W; ter Schegget, R

2012-05-01

Between February and May 2009, 347 laboratory-confirmed cases of acute Q fever were reported in a southern municipal health service region in The Netherlands. Commercial dairy-goat farms were implicated and control measures were initially targeted there. A preliminary investigation also implicated a non-dairy sheep farm, open to the public on 'lamb-viewing days'. This study tested the association between visiting the non-dairy sheep farm and developing Q fever in residents of the region between February and May 2009. A case-control study of 146 cases and 431 address-matched controls was conducted. Multivariable logistic regression analysis confirmed the association between visiting to the sheep farm and Q fever disease (matched odds ratio 43, 95% confidence interval 9-200). Other risk factors were being a smoker, having a past medical history and being aged >40 years. Vaccination of sheep and goats on farms open to the public should help to reduce the number of future human cases.

Biomarkers and bacterial pneumonia risk in patients with treated HIV infection: a case-control study.

PubMed

Bjerk, Sonja M; Baker, Jason V; Emery, Sean; Neuhaus, Jacqueline; Angus, Brian; Gordin, Fred M; Pett, Sarah L; Stephan, Christoph; Kunisaki, Ken M

2013-01-01

Despite advances in HIV treatment, bacterial pneumonia continues to cause considerable morbidity and mortality in patients with HIV infection. Studies of biomarker associations with bacterial pneumonia risk in treated HIV-infected patients do not currently exist. We performed a nested, matched, case-control study among participants randomized to continuous combination antiretroviral therapy (cART) in the Strategies for Management of Antiretroviral Therapy trial. Patients who developed bacterial pneumonia (cases) and patients without bacterial pneumonia (controls) were matched 1∶1 on clinical center, smoking status, age, and baseline cART use. Baseline levels of Club Cell Secretory Protein 16 (CC16), Surfactant Protein D (SP-D), C-reactive protein (hsCRP), interleukin-6 (IL-6), and d-dimer were compared between cases and controls. Cases (n = 72) and controls (n = 72) were 25.7% female, 51.4% black, 65.3% current smokers, 9.7% diabetic, 36.1% co-infected with Hepatitis B/C, and 75.0% were on cART at baseline. Median (IQR) age was 45 (41, 51) years with CD4+ count of 553 (436, 690) cells/mm(3). Baseline CC16 and SP-D were similar between cases and controls, but hsCRP was significantly higher in cases than controls (2.94 µg/mL in cases vs. 1.93 µg/mL in controls; p = 0.02). IL-6 and d-dimer levels were also higher in cases compared to controls, though differences were not statistically significant (p-value 0.06 and 0.10, respectively). In patients with cART-treated HIV infection, higher levels of systemic inflammatory markers were associated with increased bacterial pneumonia risk, while two pulmonary-specific inflammatory biomarkers, CC16 and SP-D, were not associated with bacterial pneumonia risk.

Return to Sport and Performance After Microfracture in the Knees of National Basketball Association Players.

PubMed

Harris, Joshua D; Walton, David M; Erickson, Brandon J; Verma, Nikhil N; Abrams, Geoffrey D; Bush-Joseph, Charles A; Bach, Bernard R; Cole, Brian J

2013-11-01

Use of microfracture in the knees of National Basketball Association (NBA) players is controversial. (1) There would be a high rate of return to sport (RTS) in NBA players following microfracture, (2) players would RTS the season following surgery, (3) preoperative player performance would not be significantly different on RTS, and (4) there would be no significant difference in RTS rate or postoperative performance in players undergoing microfracture in comparison with an age-, position-, NBA experience-, and performance-matched control group. Cohort study; Level of evidence, 3. NBA players undergoing microfracture were evaluated. Age-, body mass index-, position-, NBA experience-, and performance-matched controls were selected from the NBA during the same years as those undergoing microfracture. An index year was selected (controls) to match the number of seasons of NBA experience in microfracture cases. RTS and performance were analyzed and compared between cases and controls. Student t tests were performed for analysis of within- and between-group variables. A total of 41 NBA players underwent microfracture and were compared with 41 demographic- and performance-matched controls. Rate of RTS after microfracture was 73% in the NBA and 83% in professional basketball (NBA, D-league, and International Basketball Federation [FIBA]). Time to RTS in NBA was 9.20 ± 4.88 months. Seventy-one percent (29/41) of players RTS the season following microfracture. Length of NBA career following microfracture (4.10 ± 3.91 years) was not significantly different from controls. After microfracture, case athletes played fewer games per season and with fewer points and steals per game (relative to premicrofracture; P < .05). Performance was better in control (after index year) versus case players (after microfracture) with regard to points per game, games played per season, and field goal and free throw percentage (P < .05). Eighty-three percent of NBA players undergoing microfracture returned to professional basketball. Career length was not significantly different between players undergoing microfracture and controls. However, following microfracture, players competed in fewer games per season with fewer points and steals.

Risk factors for childhood burns: a case-control study of Ghanaian children.

PubMed

Forjuoh, S N; Guyer, B; Strobino, D M; Keyl, P M; Diener-West, M; Smith, G S

1995-04-01

To study risk factors for childhood burns in order to identify possible preventive strategies. Case-control design with pair matching of controls to cases in relation to age, sex, and area of residence. The cases and controls were identified by a community based, multisite survey. The effects of host and socioenvironmental variables reported by mothers were investigated in a multivariate analysis using conditional logistic regression. A developing country setting the Ashanti Region in Ghana. These comprised 610 cases aged 0-5 years who had been burned (as evidenced by a visible scar) and 610 controls with no burn history. The presence of a pre-existing impairment in a child was the strongest risk factor in this population (OR = 6.71; 95% CI 2.78, 16.16). Other significant risk factor included: sibling death from a burn (OR = 4.41; 95% CI 1.16, 16.68); history of burn in a sibling (OR = 1.79; 95% CI 1.24, 2.58); and storage of a flammable substance in the home (OR = 1.51; 95% CI 1.03; 2.21). Maternal education had a protective effect against childhood burns, although this effect was not strong (OR = 0.76; 95% CI 0.55, 1.05). Community programmes to ensure adequate child supervision and general child wellbeing, particularly for those with impairments, as well as parental education about burns are recommended, to reduce childhood burns in this region of Ghana. The public should bed advised against storing flammable substances in the home.

Using Clustering Strategies for Creating Authority Files.

ERIC Educational Resources Information Center

French, James C.; Powell, Allison L.; Schulman, Eric

2000-01-01

Discussion of quality control of data in online bibliographic databases focuses on authority files. Describes approximate string matching, introduces the concept of approximate word matching and clustering, and presents a case study using the Astrophysics Data System (ADS) that shows how to reduce human effort involved in authority work. (LRW)

Mix and match: how to regain your balance.

PubMed

Jupiter, Daniel C

2013-01-01

In retrospective studies, a demographic imbalance often exists between cases and controls. This imbalance may affect outcome, independent of experimental group. We discuss matching methods that allow us to overcome these imbalances. Copyright © 2013 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Central Nervous System Medication Burden and Serious Falls in Older Nursing Home Residents

PubMed Central

Hanlon, Joseph T.; Zhao, Xinhua; Naples, Jennifer G.; Aspinall, Sherrie L.; Perera, Subashan; Nace, David A.; Castle, Nicholas G.; Greenspan, Susan L.; Thorpe, Carolyn T.

2016-01-01

Objectives To examine the association between CNS medication burden and serious falls in those with a recent fall history. Design Nested-case control study; cases matched to four controls by age, gender, and date. Setting US nursing homes Participants 5,556 residents age ≥ 65 with a recent fall history admitted to a nursing home between 1/1–9/30/2010 and followed until discharge, death, or 12/31/2010. Measurements Outcome was serious falls as per Medicare Part A and B ICD/CPT codes. CNS burden, from Medicare Part D data, was calculated by dividing the daily dose of each CNS agent (i.e., specific antidepressants, antiepileptic, antipsychotic, benzodiazepine and opioid receptor agonists) received during the six days prior to the index (outcome) date by the minimum effective geriatric daily dose and summing the results across medications. Results There were 367 cases and 1468 matched controls. Those taking 3+ CNS standardized daily doses were more likely to have a serious fall than those not taking any CNS medications (Adjusted Odds Ratio 1.83; 95% confidence interval 1.35–2.48). There was no significant difference in fall risk for residents taking >0 to <3 CNS standardized daily doses compared to residents taking no CNS medications (Adjusted Odds Ratio 0.85; 95% CI 0.63–1.15). Conclusion CNS medication burden, approximately 3+ standardized daily doses, was associated with an increased risk of serious falls in nursing home residents with recent fall. Clinicians should be vigilant for opportunities to discontinue or decrease the doses of individual CNS medications and/or consider non-pharmacological alternatives. Such interventions that reduce use of CNS medications in nursing homes could reduce fall rates but further research is needed to confirm this. PMID:28152179

Plasma fatty acids, oxylipins, and risk of myocardial infarction: the Singapore Chinese health study

USDA-ARS?s Scientific Manuscript database

Objective: We aimed to examine the prospective association between plasma fatty acids (FAs), oxylipins and risk of acute myocardial infarction (AMI) in a Singapore Chinese population. Methods: A nested case-control study with 744 incident AMI cases and 744 matched controls aged 47-83 years was condu...

Prenatal and Perinatal Risk Factors for Autism in China

ERIC Educational Resources Information Center

Zhang, Xin; Lv, Cong-Chao; Tian, Jiang; Miao, Ru-Juan; Xi, Wei; Hertz-Picciotto, Irva; Qi, Lihong

2010-01-01

We conducted a case-control study using 190 Han children with and without autism to investigate prenatal and perinatal risk factors for autism in China. Cases were recruited through public special education schools and controls from regular public schools in the same region (Tianjin), with frequency matching on sex and birth year. Unadjusted…

The linear shade guide design of Vita 3D-master performs as well as the original design of the Vita 3D-master.

PubMed

Corcodel, N; Rammelsberg, P; Jakstat, H; Moldovan, O; Schwarz, S; Hassel, A J

2010-11-01

Visual tooth colour assessment by use of the Vita 3D-Master(®) (3D; Vita Zahnfabrik, Bad Säckingen, Germany) is well documented. To improve handling, a new linear arrangement of the shade tabs has been introduced (LG; Linearguide 3D-Master(®) ). The purpose of this study was to investigate whether the linear design has an effect on shade matching. Fifty-six students underwent identical, theoretical and practical training, by use of an Internet learning module [Toothguide Training Software(®) (TT)] and a standardised training programme [Toothguide Training Box(®) (TTB)]. Each student then matched 30 randomly chosen shade tabs presented in an intra-oral setting by a standardised device [Toothguide Check Box(®) (TCB)]; 15 matches were made using the 3D and 15 using the LG shade guide system, under a daylight lamp (840 matches for each guide). It was recorded to what extent the presented and selected shade tabs, or the lightness group of the tabs, matched, also the needed time for colour matching. The results showed that 35% of perfect matches were observed for the 3D and 32% for the LG. The lightness group was correct in 59% of cases for 3D and 56% for LG. Mean time needed for matching of tabs and lightness group was no different between groups (no significant difference for any assessment). Within the limitations of the study design, the colour assessment with regard to performance and time needed in shade matching was not different with the LG or the 3D. Therefore, the user should choose which shade tab arrangement is more applicable. © 2010 Blackwell Publishing Ltd.

The High Direct Medical Costs of Prader-Willi Syndrome.

PubMed

Shoffstall, Andrew J; Gaebler, Julia A; Kreher, Nerissa C; Niecko, Timothy; Douglas, Diah; Strong, Theresa V; Miller, Jennifer L; Stafford, Diane E; Butler, Merlin G

2016-08-01

To assess medical resource utilization associated with Prader-Willi syndrome (PWS) in the US, hypothesized to be greater relative to a matched control group without PWS. We used a retrospective case-matched control design and longitudinal US administrative claims data (MarketScan) during a 5-year enrollment period (2009-2014). Patients with PWS were identified by Classification of Diseases, Ninth Revision, Clinical Modification diagnosis code 759.81. Controls were matched on age, sex, and payer type. Outcomes included total, outpatient, inpatient and prescription costs. After matching and application of inclusion/exclusion criteria, we identified 2030 patients with PWS (1161 commercial, 38 Medicare supplemental, and 831 Medicaid). Commercially insured patients with PWS (median age 10 years) had 8.8-times greater total annual direct medical costs than their counterparts without PWS (median age 10 years: median costs $14 907 vs $819; P < .0001; mean costs: $28 712 vs $3246). Outpatient care comprised the largest portion of medical resource utilization for enrollees with and without PWS (median $5605 vs $675; P < .0001; mean $11 032 vs $1804), followed by mean annual inpatient and medication costs, which were $10 879 vs $1015 (P < .001) and $6801 vs $428 (P < .001), respectively. Total annual direct medical costs were ∼42% greater for Medicaid-insured patients with PWS than their commercially insured counterparts, an increase partly explained by claims for Medicaid Waiver day and residential habilitation. Direct medical resource utilization was considerably greater among patients with PWS than members without the condition. This study provides a first step toward quantifying the financial burden of PWS posed to individuals, families, and society. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Obstructive Sleep Apnea Syndrome (OSAS) Increases Pedestrian Injury Risk in Children

PubMed Central

Avis, Kristin T.; Gamble, Karen L.; Schwebel, David C

2014-01-01

Objectives To evaluate pedestrian behavior, including reaction time, impulsivity, risk-taking, attention, and decision-making, in children with obstructive sleep apnea syndrome (OSAS) compared with healthy controls. Study design Using a case control design, sixty 8- to 16-year-olds with newly diagnosed and untreated OSAS engaged in a virtual reality pedestrian environment. Sixty-one healthy children matched using a yoke-control procedure by age, race, gender and household income served as controls. Results Children with OSAS were riskier pedestrians than healthy children of the same age, race, and sex. Children with OSAS waited less time to cross (p<.01). The groups did not differ in looking at oncoming traffic or taking longer to decide to cross. Conclusions Results suggest OSAS may have significant consequences on children’s daytime functioning in a critical domain of personal safety, pedestrian skills. Children with OSAS appeared to have greater impulsivity when crossing streets. Results highlight the need for heightened awareness of the consequences of untreated sleep disorders and identify a possible target for pediatric injury prevention. PMID:25444002

A Genome-Wide Investigation of Autozygosity and Breast Cancer Risk

DTIC Science & Technology

2011-07-01

cases than in controls, using logistic regression methods. Using genome-wide SNP data (525,000 SNPs) on 1,647 non-Hispanic white, early-onset...premenopausal breast cancer cases and 1,556 matched controls we identified over 65,000 individual RoHs and 423 genomic regions harbor RoHs for at least 10...we hypothesize that germline autozygosity is more common in breast cancer cases than in controls. More specifically, we hypothesize that there are

Graphical Models for Quasi-Experimental Designs

ERIC Educational Resources Information Center

Steiner, Peter M.; Kim, Yongnam; Hall, Courtney E.; Su, Dan

2017-01-01

Randomized controlled trials (RCTs) and quasi-experimental designs like regression discontinuity (RD) designs, instrumental variable (IV) designs, and matching and propensity score (PS) designs are frequently used for inferring causal effects. It is well known that the features of these designs facilitate the identification of a causal estimand…

A stratification approach using logit-based models for confounder adjustment in the study of continuous outcomes.

PubMed

Tan, Chuen Seng; Støer, Nathalie C; Chen, Ying; Andersson, Marielle; Ning, Yilin; Wee, Hwee-Lin; Khoo, Eric Yin Hao; Tai, E-Shyong; Kao, Shih Ling; Reilly, Marie

2017-01-01

The control of confounding is an area of extensive epidemiological research, especially in the field of causal inference for observational studies. Matched cohort and case-control study designs are commonly implemented to control for confounding effects without specifying the functional form of the relationship between the outcome and confounders. This paper extends the commonly used regression models in matched designs for binary and survival outcomes (i.e. conditional logistic and stratified Cox proportional hazards) to studies of continuous outcomes through a novel interpretation and application of logit-based regression models from the econometrics and marketing research literature. We compare the performance of the maximum likelihood estimators using simulated data and propose a heuristic argument for obtaining the residuals for model diagnostics. We illustrate our proposed approach with two real data applications. Our simulation studies demonstrate that our stratification approach is robust to model misspecification and that the distribution of the estimated residuals provides a useful diagnostic when the strata are of moderate size. In our applications to real data, we demonstrate that parity and menopausal status are associated with percent mammographic density, and that the mean level and variability of inpatient blood glucose readings vary between medical and surgical wards within a national tertiary hospital. Our work highlights how the same class of regression models, available in most statistical software, can be used to adjust for confounding in the study of binary, time-to-event and continuous outcomes.

Pernicious anemia and colorectal cancer risk - A nested case-control study.

PubMed

Boursi, Ben; Mamtani, Ronac; Haynes, Kevin; Yang, Yu-Xiao

2016-11-01

Hypergastrinemia was shown to stimulate colonic epithelial cell proliferation. To evaluate the association between pernicious anemia (PA), a disease with hypergastrinemia, and colorectal cancer (CRC) risk. We conducted a nested case-control study within a large database from the UK. Cases were defined as all individuals in the cohort with at least one medical code for CRC. Controls were selected based on incidence-density sampling. For each case, up to four eligible controls were matched on age at diagnosis, sex, practice-site, and both duration and calendar time of follow-up. Exposure of interest was diagnosis of PA prior to CRC diagnosis date. The primary analysis was a multivariable conditional logistic regression. Our study included 22,098 CRC cases and 85,969 matched controls. We identified 154 (0.70%) cases and 563 (0.65%) controls with past history of PA. The adjusted OR for the association between PA and CRC risk was 1.02 (95% CI 0.85-1.22). There was no difference in the results after stratification according to sex. In a sensitivity analysis only among individuals without chronic use of proton pump inhibitors (PPIs) the adjusted OR was 1.14 (95% CI 0.90-1.45). There was no association between duration of PA and CRC risk. PA is not associated with higher CRC risk. Copyright © 2016. Published by Elsevier Ltd.

Influence of exercise on serum levels of myoglobin measured by radioimmunoassay.

PubMed

Sabriá, M; Ruibal, A; Rey, C; Foz, M; Domenech, F M

1983-01-01

To determine the influence of exercise on serum levels of myoglobin, serum levels of this protein were determined by RIA in 90 healthy men, divided as follows: (1) Basal control (no exercise) 25 cases; (2) Moderate exercise (after subject had been working for 12 h in Medicine Emergency Service) 19 cases, and (3) Intensive exercise: (a) football professional (45-min match) 10 cases; (b) football amateur (45-min match) 10 cases; (c) basketball professional (45-min match) 10 cases, and (d) basketball professional (90-min training) 16 cases. Our results led us to the following conclusions. (1) Moderate exercise, such as the usual daily work, does not modify myoglobin levels; (2) Myoglobin serum levels after exercise increase in nearly all individuals. They are higher in untrained people; (3) There seems to be a correlation between exercise intensity and increase of myoglobin serum levels, and (4) The detection of serum myoglobin by RIA may have a wide field of application for sport medicine.

Calcified Neurocysticercosis Associates with Hippocampal Atrophy: A Population-Based Study

PubMed Central

Del Brutto, Oscar H.; Salgado, Perla; Lama, Julio; Del Brutto, Victor J.; Campos, Xavier; Zambrano, Mauricio; García, Héctor H.

2015-01-01

Calcified neurocysticercosis has been associated with hippocampal atrophy in patients with refractory epilepsy, but the relevance of this association in the population at large is unknown. We assessed calcified cysticerci and its association with hippocampal atrophy in elderly persons living in Atahualpa, an Ecuadorian village endemic for neurocysticercosis. All Atahualpa residents ≥ 60 years of age were invited to undergo computed tomography/magnetic resonance imaging for neurocysticercosis detection. Twenty-eight (11%) out of 248 enrolled persons had calcified cysticerci (case-patients) and were matched 1:1 by age, sex, and years of education to individuals without neurocysticercosis on computed tomography/magnetic resonance imaging (controls). Four case-patients and none of the controls had epilepsy (P = 0.134). Cognitive performance was similar across both groups. The Scheltens' medial temporal atrophy scale was used for hippocampal rating in case-patients and matched controls without neurocysticercosis. Mean score in the Scheltens' scale was higher in case-patients than in controls (P < 0.001). Atrophic hippocampi were noticed in 19 case-patients and five controls (P = 0.003). Atrophy was bilateral in 11 case-patients and unilateral in eight. All case-patients with unilateral hippocampal atrophy had at least one ipsilateral calcification. This study shows an association between calcified cysticerci and hippocampal atrophy and raises the possibility of an inflammation-mediated hippocampal damage as the responsible mechanism for these findings. PMID:25349375

Depression, anxiety and self-care behaviours of young adults with Type 2 diabetes: results from the International Diabetes Management and Impact for Long-term Empowerment and Success (MILES) Study.

PubMed

Browne, J L; Nefs, G; Pouwer, F; Speight, J

2015-01-01

Young adults with Type 2 diabetes have higher physical morbidity and mortality than other diabetes sub-groups, but differences in psychosocial outcomes have not yet been investigated. We sought to compare depression and anxiety symptoms and self-care behaviours of young adults with Type 2 diabetes with two matched control groups. Using cross-sectional survey data from the Australian and Dutch Diabetes Management and Impact for Long-term Empowerment and Success (MILES) studies, we matched 93 young adults (aged 18-39 years) with Type 2 diabetes (case group) with: (i) 93 older adults ( ≥ 40 years) with Type 2 diabetes (Type 2 diabetes control group; matched on country, gender, education, diabetes duration and insulin use) and (ii) 93 young adults with Type 1 diabetes (Type 1 diabetes control group; matched on country, gender, age and education). Groups were compared with regard to depression symptoms (nine-item Patient Health Questionnaire), anxiety symptoms (seven-item Generalised Anxiety Disorder questionnaire) and frequency of selected self-care behaviours (single item per behaviour). Participants in the case group had higher depression scores (Cohen's d = 0.40) and were more likely to have clinically meaningful depressive symptoms (Cramer's V = 0.23) than those in the Type 2 diabetes control group. Participants in the case group had statistically equivalent depression scores to the Type 1 diabetes control group. The groups did not differ in anxiety scores. Those in the case group were less likely than both control groups to take insulin as recommended (Cramer's V = 0.24-0.34), but there were no significant differences between the groups in oral medication-taking. The case group were less likely than the Type 2 diabetes control group to eat healthily (Cramer's V = 0.16), and less likely than the Type 1 diabetes control group to be physically active (Cramer's V = 0.15). Our results suggest that Type 2 diabetes is as challenging as Type 1 diabetes for young adults and more so than for older adults. Young adults with Type 2 diabetes may require more intensive psychological and self-care support than their older counterparts. © 2014 The Authors. Diabetic Medicine © 2014 Diabetes UK.

Maternal Exposure to Bisphenol-A and Fetal Growth Restriction: A Case-Referent Study

PubMed Central

Burstyn, Igor; Martin, Jonathan W.; Beesoon, Sanjay; Bamforth, Fiona; Li, Qiaozhi; Yasui, Yutaka; Cherry, Nicola M.

2013-01-01

We conducted a case-referent study of the effect of exposure to bisphenol-A on fetal growth in utero in full-term, live-born singletons in Alberta, Canada. Newborns <10 percentile of expected weight for gestational age and sex were individually matched on sex, maternal smoking and maternal age to referents with weight appropriate to gestational age. Exposure of the fetus to bisphenol-A was estimated from maternal serum collected at 15–16 weeks of gestation. We pooled sera across subjects for exposure assessment, stratified on case-referent status and sex. Individual 1:1 matching was maintained in assembling 69 case and 69 referent pools created from 550 case-referent pairs. Matched pools had an equal number of aliquots from individual women. We used an analytical strategy conditioning on matched set and total pool-level values of covariates to estimate individual-level effects. Pools of cases and referents had identical geometric mean bisphenol-A concentrations (0.5 ng/mL) and similar geometric standard deviations (2.3–2.5). Mean difference in concentration between matched pools was 0 ng/mL, standard deviation: 1 ng/mL. Stratification by sex and control for confounding did not suggest bisphenol-A increased fetal growth restriction. Our analysis does not provide evidence to support the hypothesis that bisphenol-A contributes to fetal growth restriction in full-term singletons. PMID:24336026

Psychosocial Characteristics of Children with Central Disorders of Hypersomnolence Versus Matched Healthy Children.

PubMed

Avis, Kristin T; Shen, Jiabin; Weaver, Patrick; Schwebel, David C

2015-11-15

Hypersomnia of central origin from narcolepsy or idiopathic hypersomnia (IHS) is characterized by pathological levels of excessive daytime sleepiness (EDS). Central hypersomnia has historically been underdiagnosed and poorly understood, especially with respect to its impact on daytime functioning and quality of life in children. Describe the psychosocial adjustment of children treated for narcolepsy or IHS on school performance, quality of life, and physical/extracurricular activities. Using a matched case control design, we compared child self- and parent-reported data from thirty-three 8- to 16-year-olds with an established diagnosis of narcolepsy or IHS, according to ICSD-2 criteria, to that of 33 healthy children matched by age, race/ethnicity, gender, and household income. Assessments evaluated academic performance, quality of life and wellness, sleepiness, and participation in extracurricular activities. Compared to healthy controls, children with central hypersomnia had poorer daytime functioning in multiple domains. Children with hypersomnia missed more days of school and had lower grades than healthy controls. Children with hypersomnia had poorer quality of life by both parent and child report. Children with hypersomnia were significantly sleepier, had higher BMI, and were more likely to report a history of recent injury. Finally, children with hypersomnia engaged in fewer after-school activities than healthy controls. A range of significant psychosocial consequences are reported in children with hypersomnia even after a diagnosis has been made and treatments initiated. Health care professionals should be mindful of the psychosocial problems that may present in children with hypersomnia over the course of treatment. © 2015 American Academy of Sleep Medicine.

Bilirubin exposure is associated with neonatal sepsis in the eight days preceding symptoms: a retrospective study.

PubMed

Raimondi, Francesco; Borrelli, Angela Carla; Ferrara, Teresa; Giannattasio, Antonietta; Capasso, Letizia

2017-09-01

To compare levels of bilirubin (using the area under the curve, AUC) in preterm infants before the onset of sepsis with healthy matched-controls. Preterm infants born between January 2011 and December 2015 with late-onset sepsis were enrolled in our retrospective study and were matched with healthy controls (sex, birth weight and gestational age). Levels of bilirubin were registered in the eight days preceding the onset of sepsis and the AUC was calculated for both groups. Eighty-eight neonates (44 cases) were studied. GA and BW did not differ between cases and controls. In cases, we found a higher value of AUC (30.7 versus 22.5; p = 0.021). In our retrospective cohort, we found that the levels of bilirubin and the AUC in the first eight days before the onset of sepsis in preterm infants were significantly higher than the healthy controls. These data suggest that the prolonged exposition to high levels of bilirubin could increase the infection susceptibility in preterm infants.

A client-treatment matching protocol for therapeutic communities: first report.

PubMed

Melnick, G; De Leon, G; Thomas, G; Kressel, D

2001-10-01

The present study is the first report on a client-treatment matching protocol (CMP) to guide admissions to residential and outpatient substance abuse treatment settings. Two cohorts, a field test sample (n = 318) and cross-validation (n = 407) sample were drawn from consecutive admissions to nine geographically distributed multisetting therapeutic communities (TCs). A passive matching design was employed. Clients received the CMP on admission, but agencies were "blind" to the CMP treatment recommendation (i.e., match) and assigned clients to treatment by the usual intake procedures. Bivariate and logistical regression analyses show that positive treatment dispositions (treatment completion or longer retention in treatment)) were significantly higher among the CMP-matched clients. The present findings provide the empirical basis for studies assessing the validity and utility of the CMP with controlled designs. Though limited to TC-oriented agencies, the present research supports the use of objective matching criteria to improve treatment.

A prospective study of Trichomonas vaginalis and prostate cancer risk among African American men.

PubMed

Fowke, Jay H; Han, Xijing; Alderete, J F; Moses, Kelvin A; Signorello, Lisa B; Blot, William J

2016-04-18

African Americans (AA) have a higher prevalence of Trichomonas vaginalis (Tv) infection and a higher prostate (PC) risk. Past studies suggest an association between Tv seropositivity and PC, and therefore we prospectively investigated this association among AA men. Incident PC cases were individually matched to controls in a nested case-control study within the Southern Community Cohort Study (SCCS). Primary analysis included 296 PC cases and 497 race-matched controls. Levels of Tv antibody response were measured by ELISA in serum collected at baseline. Tv antibody response did not significantly differ between cases and controls overall or within AA participants (253 AA cases). There were no significant associations or trends between levels of Tv response and PC risk or the diagnosis of aggressive PC. We found no evidence of a prospective association between baseline Tv infection and PC risk in AA men. Tv infection in men may have substantial health implications in HIV transmission and reproductive outcomes, but may not impact future PC risk in AA men at high-risk for PC. Further efforts need to define past vs. present Tv infection and to separate pathophysiology from PC detection.

Pneumocystis jirovecii pneumonia in systemic autoimmune rheumatic disease: A case-control study.

PubMed

Tadros, Susan; Teichtahl, Andrew J; Ciciriello, Sabina; Wicks, Ian P

2017-06-01

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic fungal infection that affects the immunocompromised. Patients with systemic autoimmune rheumatic disease are increasingly recognised as an at-risk clinical population with a high mortality. This case-control study examined differences in the characteristics and peripheral blood parameters between patients with systemic autoimmune rheumatic disease who developed PJP and gender, age and disease-matched controls. Historical data collected between 2002 and 2013 at the Royal Melbourne Hospital, Australia were reviewed. Cases were defined by having a systemic autoimmune rheumatic disease and a diagnosis of PJP (either a positive toluidine blue O stain or P. jirovecii PCR, with a concurrent respiratory illness that was clinically consistent with PJP). Controls were matched for age, gender and disease in a 4:1 ratio. Peripheral blood results were retrieved from an in-house pathology database. Clinical information including glucocorticoid exposure, PJP prophylaxis, comorbidities and month of admission were retrieved from medical notes. After adjustment for corticosteroid exposure and C-reactive protein, lymphocyte count on admission (0.4 vs. 1.3; p = 0.04) and at nadir (0.2 vs. 0.8 × 10 9 /L; p = 0.05) was significantly lower in cases than in controls. Cases (n = 11) were more frequently Caucasian rather than non-Caucasian (81.8% vs. 65.9%; p = 0.04). In addition, cases more commonly presented in autumn (March to May) than in other seasons (OR = 7.3; 95% CI: 1.4-38.7; p = 0.02). These data demonstrate that patients with systemic autoimmune rheumatic disease who develop PJP have significantly greater lymphopenia than age, gender and disease-matched controls, independent of corticosteroid exposure, as well as a potential ethnicity and seasonal predilection to PJP. This may help to inform prophylactic guidelines for PJP in these patients. Copyright © 2017 Elsevier Inc. All rights reserved.

Association between Use of Exogenous Testosterone Therapy and Risk of Venous Thrombotic Events among Exogenous Testosterone Treated and Untreated Men with Hypogonadism.

PubMed

Li, Hu; Benoit, Karin; Wang, Wei; Motsko, Stephen

2016-04-01

Limited information exists about whether exogenous testosterone therapy is associated with a risk of venous thrombotic events. We investigated via cohort and nested case-control analyses whether exogenous testosterone therapy is associated with the risk of venous thrombotic events in men with hypogonadism. Databases were reviewed to identify men prescribed exogenous testosterone therapy and/or men with a hypogonadism diagnosis. Propensity score 1:1 matching was used to select patients for cohort analysis. Cases (men with venous thrombotic events) were matched 1:4 with controls (men without venous thrombotic events) for the nested case-control analysis. Primary outcome was defined as incident idiopathic venous thrombotic events. Cox regression and conditional logistic regression were used to assess HRs and ORs, respectively. Sensitivity analyses were also performed. A total of 102,650 exogenous testosterone treated and 102,650 untreated patients were included in cohort analysis after matching, and 2,785 cases and 11,119 controls were included in case-control analysis. Cohort analysis revealed a HR of 1.08 for all testosterone treated patients (95% CI 0.91, 1.27, p = 0.378). Case-control analysis resulted in an OR of 1.02 (95% CI 0.92, 1.13, p = 0.702) for current exogenous testosterone therapy exposure and an OR of 0.92 (95% CI 0.82, 1.03, p = 0.145) for past exogenous testosterone therapy exposure. These results remained nonstatistically significant after stratifying by exogenous testosterone therapy administration route and age category. Most sensitivity analyses yielded consistent results. No significant association was found between exogenous testosterone therapy and incidents of idiopathic or overall venous thrombotic events in men with hypogonadism. However, some discrepant findings exist for the association between injectable formulations and the risk of overall venous thrombotic events. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Closed-loop assisted versus manual goal-directed fluid therapy during high-risk abdominal surgery: a case-control study with propensity matching.

PubMed

Rinehart, Joseph; Lilot, Marc; Lee, Christine; Joosten, Alexandre; Huynh, Trish; Canales, Cecilia; Imagawa, David; Demirjian, Aram; Cannesson, Maxime

2015-03-19

Goal-directed fluid therapy strategies have been shown to benefit moderate- to high-risk surgery patients. Despite this, these strategies are often not implemented. The aim of this study was to assess a closed-loop fluid administration system in a surgical cohort and compare the results with those for matched patients who received manual management. Our hypothesis was that the patients receiving closed-loop assistance would spend more time in a preload-independent state, defined as percentage of case time with stroke volume variation less than or equal to 12%. Patients eligible for the study were all those over 18 years of age scheduled for hepatobiliary, pancreatic or splenic surgery and expected to receive intravascular arterial blood pressure monitoring as part of their anesthetic care. The closed-loop resuscitation target was selected by the primary anesthesia team, and the system was responsible for implementation of goal-directed fluid therapy during surgery. Following completion of enrollment, each study patient was matched to a non-closed-loop assisted case performed during the same time period using a propensity match to reduce bias. A total of 40 patients were enrolled, 5 were ultimately excluded and 25 matched pairs were selected from among the remaining 35 patients within the predefined caliper distance. There was no significant difference in fluid administration between groups. The closed-loop group spent a significantly higher portion of case time in a preload-independent state (95 ± 6% of case time versus 87 ± 14%, P =0.008). There was no difference in case mean or final stroke volume index (45 ± 10 versus 43 ± 9 and 45 ± 11 versus 42 ± 11, respectively) or mean arterial pressure (79 ± 8 versus 83 ± 9). Case end heart rate was significantly lower in the closed-loop assisted group (77 ± 10 versus 88 ± 13, P =0.003). In this case-control study with propensity matching, clinician use of closed-loop assistance resulted in a greater portion of case time spent in a preload-independent state throughout surgery compared with manual delivery of goal-directed fluid therapy. ClinicalTrials.gov Identifier: NCT02020863. Registered 19 December 2013.

HLA matching in unrelated donor bone marrow transplantation.

PubMed

Charron, D J

1996-11-01

The availability of an HLA-matched sibling donor in only 30% to 35% of patients requiring allogeneic bone marrow transplantation (BMT) has led to the proposal of unrelated donors as an alternative source of bone marrow. The greater HLA incompatibility, which, although present, was undetected until recently in many unrelated donor BMT cases, has resulted in a higher rate of posttransplant complications and impaired acturial survival when compared with HLA-matched sibling BMT. Molecular HLA typing enables us to evaluate the impact of incompatibility at each locus in the outcome of unrelated donor BMT. The overall retrospective data would recommend that HLA-A, -B and -C allelic molecular matching should be implemented in addition to HLA-DR allelic matching. Further retrospective analysis is needed in order to assess which incompatibility or combinations are better tolerated than others. Only the definitive knowledge at the sequence level of the donor and the recipient HLA allelic diversity involved in controlling the allogeneic immune response will allow us to understand the precise biologic rationale of the graft-versus-host disease. Knowledge and control of the HLA incompatibilities should allow us to offset the detrimental effects of histoincompatibility while developing strategies to take advantage of the beneficial graft-versus-leukemia effect. Also the role of minor histocompatibility antigens remains largely unknown and will require careful evaluation before minor antigens can be used as a selection criterion in BMT. Carefully designed prospective studies will enable us to test the impact of each HLA locus. HLA typing and BMT represent a successful example of productive cooperation between basic and clinical sciences that should be pursued for the improvement of the clinical outcome of unrelated donor BMT.

Intensive cognitive therapy for post-traumatic stress disorder in routine clinical practice: A matched comparison audit.

PubMed

Murray, Hannah; El-Leithy, Sharif; Billings, Jo

2017-11-01

Intensive cognitive therapy for post-traumatic stress disorder (PTSD) has been shown to be as effective as weekly treatment in controlled trials. In this study, outcome data comparing standard and intensive treatments delivered in routine clinical practice were analysed. A consecutive case series of intensive treatment cases were compared to matched control cases who had completed weekly treatment. Both groups showed significant improvements on PTSD and depression measures. The intensive group showed larger PTSD symptomatic improvement. There were differences between the groups in age and time since trauma, suggesting selection biases in who is offered, and/or who chooses intensive treatment. For some individuals, an intensive format may be more effective than weekly treatment. © 2017 The British Psychological Society.

Optimum Design of PIλDμ Controller for an Automatic Voltage Regulator System Using Combinatorial Test Design

PubMed Central

Sahib, Mouayad A.; Gambardella, Luca M.; Afzal, Wasif; Zamli, Kamal Z.

2016-01-01

Combinatorial test design is a plan of test that aims to reduce the amount of test cases systematically by choosing a subset of the test cases based on the combination of input variables. The subset covers all possible combinations of a given strength and hence tries to match the effectiveness of the exhaustive set. This mechanism of reduction has been used successfully in software testing research with t-way testing (where t indicates the interaction strength of combinations). Potentially, other systems may exhibit many similarities with this approach. Hence, it could form an emerging application in different areas of research due to its usefulness. To this end, more recently it has been applied in a few research areas successfully. In this paper, we explore the applicability of combinatorial test design technique for Fractional Order (FO), Proportional-Integral-Derivative (PID) parameter design controller, named as FOPID, for an automatic voltage regulator (AVR) system. Throughout the paper, we justify this new application theoretically and practically through simulations. In addition, we report on first experiments indicating its practical use in this field. We design different algorithms and adapted other strategies to cover all the combinations with an optimum and effective test set. Our findings indicate that combinatorial test design can find the combinations that lead to optimum design. Besides this, we also found that by increasing the strength of combination, we can approach to the optimum design in a way that with only 4-way combinatorial set, we can get the effectiveness of an exhaustive test set. This significantly reduced the number of tests needed and thus leads to an approach that optimizes design of parameters quickly. PMID:27829025

Vitamin D deficiency in first episode psychosis: a case-control study.

PubMed

Crews, Matthieu; Lally, John; Gardner-Sood, Poonam; Howes, Oliver; Bonaccorso, Stefania; Smith, Shubulade; Murray, Robin M; Di Forti, Marta; Gaughran, Fiona

2013-11-01

Vitamin D deficiency is seen in a high proportion of people with established psychotic disorders, but it is not known if this is present at onset of the illness. We set out to examine vitamin D levels in people with their first episode of psychosis (FEP). We conducted a matched case-control study to examine vitamin D levels and rates of vitamin D deficiency in sixty nine patients presenting with their FEP and sixty nine controls matched for age, sex and ethnicity. Differences between groups were tested using student's-t tests, paired t-tests and odds ratios for further analysis. Vitamin D levels were significantly lower in cases than in controls (p<0.001). The odds ratio of being vitamin D deficient was 2.99 in the FEP group relative to the control group. There was no correlation between vitamin D levels and length of hospitalisation in the patient group (r=-0.027, p=0.827). We found higher rates of vitamin D deficiency in people with FEP compared to matched controls. Given that vitamin D is neuroprotective; that developmental vitamin D deficiency may be a risk factor for psychosis, and that incipient psychosis may affect lifestyle factors and diet, future studies are required to examine this association further. In the meantime, there is a need for more widespread testing of vitamin D levels in FEP and for the development of appropriate management strategies. © 2013 Elsevier B.V. All rights reserved.

Childhood leukemia and traffic air pollution in Taiwan: petrol station density as an indicator.

PubMed

Weng, Hsu-Huei; Tsai, Shang-Shyue; Chiu, Hui-Fen; Wu, Trong-Neng; Yang, Chun-Yuh

2009-01-01

To investigate the relationship between traffic air pollution exposure and development of childhood leukemia (14 yr of age or younger), a matched case-control study was conducted using childhood deaths that occurred in Taiwan from 1996 through 2006. Data on all eligible childhood leukemia deaths were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. The control group consisted of children who died from causes other than neoplasms or diseases that were not associated with respiratory complications. The controls were pair matched to the cancer cases by gender, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each case. Data on the number of petrol stations in study municipalities were collected from the two major petroleum supply companies, Chinese Petroleum Corporation (CPC) and Formosa Petrochemical Corporation (FPCC). The petrol station density (per square kilometer) (PSD) for study municipalities was used as an indicator of a subject's exposure to benzene and other hydrocarbons present in evaporative losses of petrol or to air emissions from motor vehicles. The subjects were divided into tertiles according to PSD in their residential municipality. The results showed that there was a significant exposure-response relationship between PSD and the risk of leukemia development in young children after controlling for possible confounders. The findings of this study warrant further investigation of the role of traffic air pollution exposure in the etiology of childhood leukemia.

Risk of non-fatal venous thromboembolism in women using oral contraceptives containing drospirenone compared with women using oral contraceptives containing levonorgestrel: case-control study using United States claims data

PubMed Central

Hernandez, Rohini K

2011-01-01

Objective To compare the risk of non-fatal venous thromboembolism in women receiving oral contraceptives containing drospirenone with that in women receiving oral contraceptives containing levonorgestrel. Design Nested case-control and cohort study. Setting The study was based on information from PharMetrics, a United States based company that collects information on claims paid by managed care plans. Participants The study encompassed all women aged 15 to 44 years who received an oral contraceptive containing either drospirenone or levonorgestrel after 1 January 2002. Cases were women with current use of a study oral contraceptive and a diagnosis of venous thromboembolism in the absence of identifiable clinical risk factors (idiopathic venous thromboembolism). Up to four controls were matched to each case by age and calendar time. Main outcome measures Odds ratios comparing the risk of non-fatal venous thromboembolism in users of the two contraceptives; incidence rates and rate ratios of non-fatal venous thromboembolism for users of each of the study contraceptives. Results 186 newly diagnosed, idiopathic cases of venous thromboembolism were identified in the study population and matched with 681 controls. In the case-control analysis, the conditional odds ratio for venous thromboembolism comparing use of oral contraceptives containing drospirenone with use of those containing levonorgestrel was 2.3 (95% confidence interval 1.6 to 3.2). The incidence rates for venous thromboembolism in the study population were 30.8 (95% confidence interval 25.6 to 36.8) per 100 000 woman years among users of oral contraceptives containing drospirenone and 12.5 (9.61 to 15.9) per 100 000 woman years among users of oral contraceptives containing levonorgestrel. The age adjusted incidence rate ratio for venous thromboembolism for current use of oral contraceptives containing drospirenone compared with those containing levonorgestrel was 2.8 (2.1 to 3.8). Conclusions The risk of non-fatal venous thromboembolism among users of oral contraceptives containing drospirenone seems to be around twice that of users of oral contraceptives containing levonorgestrel, after the effects of potential confounders and prescribing biases have been taken into account. PMID:21511805

Brain-relevant antibodies in first-episode psychosis: a matched case-control study.

PubMed

Gaughran, Fiona; Lally, John; Beck, Katherine; McCormack, Ruaidhri; Gardner-Sood, Poonam; Coutinho, Ester; Jacobson, Leslie; Lang, Bethan; Sainz-Fuertes, Ricardo; Papanastasiou, Evangelos; Di Forti, Marta; Nicholson, Tim; Vincent, Angela; Murray, Robin M

2018-06-01

There has been much recent excitement about the possibility that some cases of psychosis may be wholly due to brain-reactive antibodies, with antibodies to N-methyl-D-aspartate receptor (NMDAR) and the voltage-gated potassium channel (VGKC)-complex reported in a few patients with first-episode psychosis (FEP). Participants were recruited from psychiatric services in South London, UK, from 2009 to 2011 as part of the Genetics and Psychosis study. We conducted a case-control study to examine NMDAR and VGKC-complex antibody levels and rates of antibody positivity in 96 patients presenting with FEP and 98 controls matched for age and sex. Leucine-rich glioma inactiviated-1 (LGI1) and contactin-associated protein (CASPR) antibodies were also measured. Notably, patients with suspicion of organic disease were excluded. VGKC-complex antibodies were found in both cases (n = 3) and controls (n = 2). NMDAR antibody positivity was seen in one case and one control. Either LGI1-Abs or CASPR2-Abs were found in three cases and three controls. Neuronal antibody staining, consistent with the above results or indicating potential novel antigens, was overall positive in four patients but also in six controls. Overall, antibody positivity was at low levels only and not higher in cases than in controls. This case-control study of the prevalence of antibodies in FEP does not provide evidence to support the hypothesis that FEP is associated with an immune-mediated process in a subgroup of patients. Nevertheless, as other bio-clinical factors may influence the effect of such antibodies in a given individual, and patients with organic neurological disease may be misdiagnosed as FEP, the field requires more research to put these findings in context.

Distribution of maternal age and birth order groups in cases with unclassified multiple congenital abnormalities according to the number of component abnormalities: a national population-based case-control study.

PubMed

Csermely, Gyula; Czeizel, Andrew E; Veszprémi, Béla

2015-02-01

Multiple congenital abnormalities are caused by chromosomal aberrations, mutant major genes and teratogens. A minor proportion of these patients are identified as syndromes but the major part belonging to the group of unclassified multiple CAs (UMCAs). The main objective of this study was to evaluate the maternal age and birth order in pregnant women who had offspring affected with UMCA. The strong association between numerical chromosomal aberrations, e.g., Down syndrome and advanced maternal age is well-known and tested here. The Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980 to 1996, yielded a large population-based national data set with 22,843 malformed newborns or fetuses ("informative cases") included 1349 UMCA cases with their 2407 matched controls. Case-control comparison of maternal age and birth order was made for cases with UMCA, stratified by component numbers and their controls. In addition, 834 cases with Down syndrome were compared to 1432 matched controls. The well-known advanced maternal age with the higher risk for Down syndrome was confirmed. The findings of the study suggest that the young age of mothers associates with the higher risk of UMCA, in addition birth order 4 or more associates with the higher risk for UMCA with 2 and 3 component CAs. This study was the first to analyze the possible maternal and birth order effect for cases with UMCA, and the young age and higher birth order associated with a higher risk for UMCA. © 2014 Wiley Periodicals, Inc.

Risk factors for nonspecific low-back pain in Chinese adolescents: a case-control study.

PubMed

Yao, WeiGuang; Luo, ChenLing; Ai, FuZhi; Chen, Qing

2012-05-01

The objective of this study was to gain a basic understanding of the influential factors for nonspecific low-back pain (LBP) among adolescents of southern China. The study was designed as a school-based case control study. Nonspecific LBP is a common health problem in adolescence. Although some behaviors and socio-demographic factors are believed to contribute to the disorder, influential factors of LBP remain undefined. Moreover, until now there is no available information of influential factors for LBP in Chinese adolescents. A total of 1,214 adolescents were involved in the study, including 607 cases with nonspecific LBP and 607 controls without history of nonspecific LBP. A self-administered questionnaire was designed for epidemiological survey to investigate the risk factors for nonspecific LBP. All cases and controls were investigated for their family histories of nonspecific LBP, physical activities, sedentary activities, schoolbag weights, school performances, living conditions, and etc. A 1:1 matched case-control study was conducted on 1,214 adolescents from an elementary school and a secondary school in Guangzhou City, southern China. Family history (odds ratio [OR] 2.57, 95% confidence interval [CI] 1.85-3.58), long duration of carrying schoolbag (OR 1.38, 95% CI 1.11-1.72) and rest position between classes (OR 1.18, 95% CI 1.01-1.39) were positively correlated with self-reported nonspecific LBP. Students regularly playing basketball (OR 1.58, 95% CI 1.09-2.30) was found to be significantly more likely to have LBP. Also, students who feel schoolbag uncomfortable (OR 1.38, 95% CI 1.11-1.72) was found to experience more LBP. Family history, feeling schoolbag uncomfortable, duration of schoolbag carrying, basketball playing and rest position between classes are the major risk factors for nonspecific LBP in adolescents. Wiley Periodicals, Inc.

Embedding an Identity-Matching Task within a Prompting Hierarchy to Facilitate Acquisition of Conditional Discriminations in Children with Autism

PubMed Central

Fisher, Wayne W; Kodak, Tiffany; Moore, James W

2007-01-01

Least-to-most prompting hierarchies (e.g., progressing from verbal to modeled to physical prompts until the target response occurs) may be ineffective when the prompts do not cue the individual to attend to the relevant stimulus dimensions. In such cases, emission of the target response persistently requires one or more of the higher level prompts, a condition called prompt dependence (Clark & Green, 2004). Reinforcement of differential observing responses (DORs) has sometimes been used to ensure that participants attend to the relevant stimulus dimensions in matching-to-sample (MTS) tasks (e.g., Dube & McIlvane, 1999). For 2 participants with autism, we embedded an identity-matching task within a prompting hierarchy as a DOR to increase the likelihood that the participants attended to and discriminated the relevant features of the comparison stimuli in an MTS task. This procedure was compared with a traditional least-to-most prompting hierarchy and a no-reinforcement control condition in a multielement design. Results for both participants indicated that mastery-level acquisition of spoken-word-to-picture relations occurred only under the identity-matching condition. Findings are discussed relative to the use of DORs to facilitate acquisition of conditional discriminations in persons with autism or other conditions who do not attend to the comparison stimuli. PMID:17970262

Embedding an identity-matching task within a prompting hierarchy to facilitate acquisition of conditional discriminations in children with autism.

PubMed

Fisher, Wayne W; Kodak, Tiffany; Moore, James W

2007-01-01

Least-to-most prompting hierarchies (e.g., progressing from verbal to modeled to physical prompts until the target response occurs) may be ineffective when the prompts do not cue the individual to attend to the relevant stimulus dimensions. In such cases, emission of the target response persistently requires one or more of the higher level prompts, a condition called prompt dependence (Clark & Green, 2004). Reinforcement of differential observing responses (DORs) has sometimes been used to ensure that participants attend to the relevant stimulus dimensions in matching-to-sample (MTS) tasks (e.g., Dube & McIlvane, 1999). For 2 participants with autism, we embedded an identity-matching task within a prompting hierarchy as a DOR to increase the likelihood that the participants attended to and discriminated the relevant features of the comparison stimuli in an MTS task. This procedure was compared with a traditional least-to-most prompting hierarchy and a no-reinforcement control condition in a multielement design. Results for both participants indicated that mastery-level acquisition of spoken-word-to-picture relations occurred only under the identity-matching condition. Findings are discussed relative to the use of DORs to facilitate acquisition of conditional discriminations in persons with autism or other conditions who do not attend to the comparison stimuli.

Outcome of renal replacement treatment in patients with diabetes mellitus.

PubMed Central

McMillan, M A; Briggs, J D; Junor, B J

1990-01-01

OBJECTIVE--To compare the outcome of renal replacement treatment in patients with diabetes mellitus and in non-diabetic patients with end stage renal failure. DESIGN--Retrospective comparison of cases and matched controls. SETTING--Renal unit, Western Infirmary, Glasgow, providing both dialysis and renal transplantation. PATIENTS--82 Diabetic patients starting renal replacement treatment between 1979 and 1988, compared with 82 matched non-diabetic controls with renal failure and 39 different matched controls undergoing renal transplantation. MAIN OUTCOME MEASURES--Patient characteristics, history of smoking, prevalence of left ventricular hypertrophy and myocardial ischaemia at start of renal replacement treatment; survival of patients with renal replacement treatment and of patients and allografts with renal transplantation. RESULTS--The overall survival of the diabetic patients during the treatment was 83%, 59%, and 50% at one, three, and five years. Survival was significantly poorer in the diabetic patients than the controls (p less than 0.001). Particularly adverse features for outcome at the start of treatment were increasing age (p less than 0.01) and current cigarette smoking (relative risk (95% confidence interval) 2.28 (0.93 to 4.84), p less than 0.05). Deaths were mainly from cardiac and vascular causes. The incidence of peritonitis in patients on continuous ambulatory peritoneal dialysis was the same in diabetic patients and controls (49% in each group remained free of peritonitis after one year), and the survival of renal allografts was not significantly worse in diabetic patients (p less than 0.5). CONCLUSIONS--Renal replacement treatment may give good results in diabetic patients, although the outlook remains less favourable than for non-diabetic patients because of coexistent, progressive vascular disease, which is more severe in older patients. PMID:2207427

Increased Executive Functioning, Attention, and Cortical Thickness in White-Collar Criminals

PubMed Central

Raine, Adrian; Laufer, William S.; Yang, Yaling; Narr, Katherine L.; Thompson, Paul; Toga, Arthur W.

2011-01-01

Very little is known on white collar crime and how it differs to other forms of offending. This study tests the hypothesis that white collar criminals have better executive functioning, enhanced information processing, and structural brain superiorities compared to offender controls. Using a case-control design, executive functioning, orienting, and cortical thickness was assessed in 21 white collar criminals matched with 21 controls on age, gender, ethnicity, and general level of criminal offending. White collar criminals had significantly better executive functioning, increased electrodermal orienting, increased arousal, and increased cortical gray matter thickness in the ventromedial prefrontal cortex, inferior frontal gyrus, somatosensory cortex, and the temporal-parietal junction compared to controls. Results, while initial, constitute the first findings on neurobiological characteristics of white-collar criminals It is hypothesized that white collar criminals have information-processing and brain superiorities that give them an advantage in perpetrating criminal offenses in occupational settings. PMID:22002326

Increased executive functioning, attention, and cortical thickness in white-collar criminals.

PubMed

Raine, Adrian; Laufer, William S; Yang, Yaling; Narr, Katherine L; Thompson, Paul; Toga, Arthur W

2012-12-01

Very little is known on white-collar crime and how it differs to other forms of offending. This study tests the hypothesis that white-collar criminals have better executive functioning, enhanced information processing, and structural brain superiorities compared with offender controls. Using a case-control design, executive functioning, orienting, and cortical thickness was assessed in 21 white-collar criminals matched with 21 controls on age, gender, ethnicity, and general level of criminal offending. White-collar criminals had significantly better executive functioning, increased electrodermal orienting, increased arousal, and increased cortical gray matter thickness in the ventromedial prefrontal cortex, inferior frontal gyrus, somatosensory cortex, and the temporal-parietal junction compared with controls. Results, while initial, constitute the first findings on neurobiological characteristics of white-collar criminals. It is hypothesized that white-collar criminals have information-processing and brain superiorities that give them an advantage in perpetrating criminal offenses in occupational settings. Copyright © 2011 Wiley Periodicals, Inc.

Micro-scale Spatial Clustering of Cholera Risk Factors in Urban Bangladesh.

PubMed

Bi, Qifang; Azman, Andrew S; Satter, Syed Moinuddin; Khan, Azharul Islam; Ahmed, Dilruba; Riaj, Altaf Ahmed; Gurley, Emily S; Lessler, Justin

2016-02-01

Close interpersonal contact likely drives spatial clustering of cases of cholera and diarrhea, but spatial clustering of risk factors may also drive this pattern. Few studies have focused specifically on how exposures for disease cluster at small spatial scales. Improving our understanding of the micro-scale clustering of risk factors for cholera may help to target interventions and power studies with cluster designs. We selected sets of spatially matched households (matched-sets) near cholera case households between April and October 2013 in a cholera endemic urban neighborhood of Tongi Township in Bangladesh. We collected data on exposures to suspected cholera risk factors at the household and individual level. We used intra-class correlation coefficients (ICCs) to characterize clustering of exposures within matched-sets and households, and assessed if clustering depended on the geographical extent of the matched-sets. Clustering over larger spatial scales was explored by assessing the relationship between matched-sets. We also explored whether different exposures tended to appear together in individuals, households, and matched-sets. Household level exposures, including: drinking municipal supplied water (ICC = 0.97, 95%CI = 0.96, 0.98), type of latrine (ICC = 0.88, 95%CI = 0.71, 1.00), and intermittent access to drinking water (ICC = 0.96, 95%CI = 0.87, 1.00) exhibited strong clustering within matched-sets. As the geographic extent of matched-sets increased, the concordance of exposures within matched-sets decreased. Concordance between matched-sets of exposures related to water supply was elevated at distances of up to approximately 400 meters. Household level hygiene practices were correlated with infrastructure shown to increase cholera risk. Co-occurrence of different individual level exposures appeared to mostly reflect the differing domestic roles of study participants. Strong spatial clustering of exposures at a small spatial scale in a cholera endemic population suggests a possible role for highly targeted interventions. Studies with cluster designs in areas with strong spatial clustering of exposures should increase sample size to account for the correlation of these exposures.

Designing payment for Collaborative Care for Depression in primary care.

PubMed

Bao, Yuhua; Casalino, Lawrence P; Ettner, Susan L; Bruce, Martha L; Solberg, Leif I; Unützer, Jürgen

2011-10-01

To design a bundled case rate for Collaborative Care for Depression (CCD) that aligns incentives with evidence-based depression care in primary care. A clinical information system used by all care managers in a randomized controlled trial of CCD for older primary care patients. We conducted an empirical investigation of factors accounting for variation in CCD resource use over time and across patients. CCD resource use at the patient-episode and patient-month levels was measured by number of care manager contacts and direct patient contact time and analyzed with count data (Poisson or negative binomial) models. Episode-level resource use varies substantially with patient's time in the program. Monthly use declines sharply in the first 6 months regardless of treatment response or remission status, but it remains stable afterwards. An adjusted episode or monthly case rate design better matches payment with variation in resource use compared with a fixed design. Our findings lend support to an episode payment adjusted by number of months receiving CCD and a monthly payment adjusted by the ordinal month. Nonpayment tools including program certification and performance evaluation and reward systems are needed to fully align incentives. © Health Research and Educational Trust.

Deliberate self-harm in Oxford University students, 1993-2005: a descriptive and case-control study.

PubMed

Mahadevan, Su; Hawton, Keith; Casey, Deborah

2010-02-01

Deliberate self-harm (DSH; intentional self-poisoning or self-injury) is a major problem among young people and has been identified as one of the key mental health problems affecting students. Data on DSH presentations to the general hospital in Oxford by Oxford University students were analysed for the 12-year period from 1993 to 2005. The characteristics of the students with DSH were compared with those of age-matched DSH controls in the Oxford City area. Problems with academic work, relationships with family, partners and friends were most likely to contribute to DSH episodes in students. Many experienced problems with psychiatric disorders and social isolation. The frequency of eating disorders was very high in students, and contributed to DSH significantly more often than in controls. Fewer students than controls self-poisoned in the DSH episode, fewer had personality disorder and fewer had problems with physical health, finance, housing and violence. Alcohol consumption in association with DSH and alcohol-related problems were common in both students and controls. Male students had significantly higher suicide intent than controls. Many students were referred to the university counselling service for follow-up, a resource not available to non-student controls. Comparison of university students following DSH with age-matched controls has shown key differences in psychiatric characteristics, problems contributing to DSH and aftercare offered. These findings may help in the design of targeted self-harm prevention and management strategies for students.

Advance Care Planning in an Accountable Care Organization Is Associated with Increased Advanced Directive Documentation and Decreased Costs

PubMed Central

Kim, Minchul; Franciskovich, Chris M.; Weinberg, Jason E.; Svendsen, Jessica D.; Fehr, Linda S.; Funk, Amy; Sawicki, Robert; Asche, Carl V.

2018-01-01

Abstract Background: Advance care planning (ACP) documents patient wishes and increases awareness of palliative care options. Objective: To study the association of outpatient ACP with advanced directive documentation, utilization, and costs of care. Design: This was a case–control study of cases with ACP who died matched 1:1 with controls. We used 12 months of data pre-ACP/prematch and predeath. We compared rates of documentation with logit model regression and conducted a difference-in-difference analysis using generalized linear models for utilization and costs. Setting/subjects: Medicare beneficiaries attributed to a large rural-suburban-small metro multisite accountable care organization from January 2013 to April 2016, with cross reference to ACP facilitator logs to find cases. Measurements: The presence of advance directive forms was verified by chart review. Cost analysis included all utilization and costs billed to Medicare. Results: We matched 325 cases and 325 controls (51.1% female and 48.9% male, mean age 81). 320/325 (98.5%) ACP versus 243/325 (74.8%) of controls had a Healthcare Power of Attorney (odds ratio [OR] 21.6, 95% CI 8.6–54.1) and 172/325(52.9%) ACP versus 145/325 (44.6%) controls had Practitioner Orders for Life Sustaining Treatment (OR 1.40, 95% CI 1.02–1.90) post-ACP/postmatch. Adjusted results showed ACP cases had fewer inpatient admissions (−0.37 admissions, 95% CI −0.66 to −0.08), and inpatient days (−3.66 days, 95% CI −6.23 to −1.09), with no differences in hospice, hospice days, skilled nursing facility use, home health use, 30-day readmissions, or emergency department visits. Adjusted costs were $9,500 lower in the ACP group (95% CI −$16,207 to −$2,793). Conclusions: ACP increases documentation and was associated with a reduction in overall costs driven primarily by a reduction in inpatient utilization. Our data set was limited by small numbers of minorities and cancer patients. PMID:29206564

Mobile phone use and the risk for malignant brain tumors: a case-control study on deceased cases and controls.

PubMed

Hardell, Lennart; Carlberg, Michael; Hansson Mild, Kjell

2010-08-01

We investigated the use of mobile or cordless phones and the risk for malignant brain tumors in a group of deceased cases. Most previous studies have either left out deceased cases of brain tumors or matched them to living controls and therefore a study matching deceased cases to deceased controls is warranted. Recall error is one issue since it has been claimed that increased risks reported in some studies could be due to cases blaming mobile phones as a cause of the disease. This should be of less importance for deceased cases and if cancer controls are used. In this study brain tumor cases aged 20-80 years diagnosed during 1997-2003 that had died before inclusion in our previous studies on the same topic were included. Two control groups were used: one with controls that had died from another type of cancer than brain tumor and one with controls that had died from other diseases. Exposure was assessed by a questionnaire sent to the next-of-kin for both cases and controls. Replies were obtained for 346 (75%) cases, 343 (74%) cancer controls and 276 (60%) controls with other diseases. Use of mobile phones gave an increased risk, highest in the >10 years' latency group yielding odds ratio (OR) = 2.4, and 95% confidence interval (CI) = 1.4-4.1. The risk increased with cumulative number of lifetime hours for use, and was highest in the >2,000 h group (OR = 3.4, 95% CI = 1.6-7.1). No clear association was found for use of cordless phones, although OR = 1.7, 95% CI = 0.8-3.4 was found in the group with >2,000 h of cumulative use. This investigation confirmed our previous results of an association between mobile phone use and malignant brain tumors. Copyright 2010 S. Karger AG, Basel.

Maternal and paternal occupational exposures and hepatoblastoma: results from the HOPE study through the Children’s Oncology Group (COG)

PubMed Central

Janitz, Amanda E.; Ramachandran, Gurumurthy; Tomlinson, Gail E.; Krailo, Mark; Richardson, Michaela; Spector, Logan

2017-01-01

Introduction Little is known about the etiology of hepatoblastoma. We aimed to confirm the results of a previous study evaluating the association between parental occupational exposures and hepatoblastoma. Methods In our case-control study, we identified cases (n=383) from the Children’s Oncology Group and controls from birth certificates (n=387), which were frequency matched to cases on year and region of birth, sex, and birth weight. Occupational exposure in the year prior to and during the index pregnancy was collected through maternal interview and analyzed using unconditional logistic regression. Results The odds of both paternal and maternal “Likely” exposure to paints was elevated among cases compared to controls (Paternal Odds Ratio [OR]: 1.71, 95% Confidence Interval [CI]: 1.04, 2.81; Maternal OR: 3.29, 95% CI: 0.32, 33.78) after adjustment for matching factors and the confounding factors of maternal race (maternal only) and household income. In addition, paternal exposure to other chemicals was also elevated when adjusting for matching factors only (OR: 1.53, 95% CI: 1.02, 2.30). Discussion The results of our study provide further evidence of an association between parental occupation and hepatoblastoma. These results warrant further investigation of the etiologically relevant timing of occupational exposure to fumes and chemicals related to hepatoblastoma. PMID:28272399

A large case-control study reveals a positive association between bisphosphonate use and delayed dental healing and osteonecrosis of the jaw.

PubMed

Borromeo, Gelsomina L; Brand, Caroline; Clement, John G; McCullough, Michael; Crighton, Lisa; Hepworth, Graham; Wark, John D

2014-06-01

This study sought to investigate, using a case-control study design, the association between bisphosphonate therapy and delayed dental healing and osteonecrosis of the jaw. Identification of potential cases of delayed dental healing was by consecutive screening of Specialist Oral and Maxillofacial and Special Needs Dentist clinic records for patients aged older than 50 years, during a 6-month window, in Victoria, Australia. Cases were confirmed by a case adjudication panel blinded to bisphosphonate status. Cases associated with malignancy or local radiotherapy were excluded. Controls were matched for age, sex, and source of dental referral (1:4, n = 160 controls). Variables of interest were dental precipitants, dental clinic type, smoking history, and medical comorbidities. A total of 4212 of 22,358 patients met inclusion criteria, of which 69 were potential cases with 40 (0.95%) confirmed cases. The odds ratio (OR) for developing delayed dental healing when taking an oral bisphosphonate was 13.1 (95% confidence interval [CI] 4.4 to 39.3; p < 0.001). There were no cases associated with intravenous bisphosphonate use. There was some evidence of an interaction with age, sex, and clinic type. When adjusted for smoking, the estimated odds ratio was 11.6 (95% CI 1.9 to 69.4; p = 0.01). There was an association between having another illness and delayed dental healing (OR = 2.3; 95% CI 1.0 to 5.2). A dental precipitant was present in 39 of 40 (97.5%) delayed dental healing cases. An important association between bisphosphonate use and delayed dental healing in the setting of benign bone disease, predominately in individuals with a dental precipitant, has been demonstrated. © 2014 American Society for Bone and Mineral Research.

General Certificate of Secondary Education performance in very low birthweight infants

PubMed Central

Pharoah, P; Stevenson, C; West, C

2003-01-01

Aim: To compare children of very low birth weight with matched controls for their performance in the General Certificate of Secondary Education (GCSE). Methods: GCSE examination results of 167 children of birth weight ⩽1500 g attending mainstream schools and without clinical disability and 167 individually matched classroom controls were analysed. Results: In 143 instances, both children of a matched pair were entered for examination in one or more GCSE subjects. The total points score obtained was greater in the comparison group than in the index cases (difference between means 4.45: 95% CI 0.95 to 7.94; p = 0.01). The mean point score per examination subject was also significantly greater in the comparison group than in the index cases (mean of differences 0.43: 95% CI 0.12 to 0.73; p < 0.01). Conclusions: As the children were closely matched for school and several social variables, factors acting during fetal or early postnatal development of very low birthweight infants probably compromise performance in the GCSE examination to a greater extent than school or childhood social environmental factors. PMID:12651749

Internet-based control recruitment for a case-control study of major risk factors for stroke in Korea: lessons from the experience.

PubMed

Park, Jong-Moo; Cho, Yong-Jin; Lee, Kyung Bok; Park, Tai Hwan; Lee, Soo Joo; Han, Moon-Ku; Ko, Youngchai; Lee, Jun; Cha, Jae-Kwan; Lee, Byung-Chul; Yu, Kyung-Ho; Oh, Mi-Sun; Lee, Ji Sung; Lee, Juneyoung; Bae, Hee-Joon

2014-01-01

This study aimed to estimate the population-attributable risks (PARs) of 9 major risk factors for stroke in Korea through a case-control study and to test the feasibility and validity of internet-based control recruitment. From April 2008 to September 2009, controls were enrolled via internet after providing consent for participation through a web-based survey. The cases included patients who were admitted to the participating centers due to acute stroke or transient ischemic attack within 7 days of onset during the study period. Each control was age- and sex-matched with 2 cases. Adjusted odd ratios, age-standardized prevalence, and PARs were estimated for the 9 major risk factors using the prevalence of risk factors in the control group and the age and sex characteristics from Korea's national census data. In total, 1041 controls were matched to 2082 stroke cases. Because of a shortage of elderly controls in the internet-based recruitment, 248 controls were recruited off-line. The PARs were 23.44%, 10.95%, 51.32%, and 6.35% for hypertension, diabetes, smoking, and stroke history, respectively. Hypercholesterolemia, atrial fibrillation, obesity, coronary heart disease, and a family history of stroke were not associated with stroke. Comparison with education and religion of the control group with that mentioned in the national census data showed a notable difference. The study results imply that internet-based control recruitment for a case-control study requires careful selection of risk factors with high self-awareness and effective strategies to facilitate the recruitment of elderly participants. Copyright © 2014 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Brain activation during neurocognitive testing using functional near-infrared spectroscopy in patients following concussion compared to healthy controls.

PubMed

Kontos, A P; Huppert, T J; Beluk, N H; Elbin, R J; Henry, L C; French, J; Dakan, S M; Collins, M W

2014-12-01

There is no accepted clinical imaging modality for concussion, and current imaging modalities including fMRI, DTI, and PET are expensive and inaccessible to most clinics/patients. Functional near-infrared spectroscopy (fNIRS) is a non-invasive, portable, and low-cost imaging modality that can measure brain activity. The purpose of this study was to compare brain activity as measured by fNIRS in concussed and age-matched controls during the performance of cognitive tasks from a computerized neurocognitive test battery. Participants included nine currently symptomatic patients aged 18-45 years with a recent (15-45 days) sport-related concussion and five age-matched healthy controls. The participants completed a computerized neurocognitive test battery while wearing the fNIRS unit. Our results demonstrated reduced brain activation in the concussed subject group during word memory, (spatial) design memory, digit-symbol substitution (symbol match), and working memory (X's and O's) tasks. Behavioral performance (percent-correct and reaction time respectively) was lower for concussed participants on the word memory, design memory, and symbol match tasks than controls. The results of this preliminary study suggest that fNIRS could be a useful, portable assessment tool to assess reduced brain activation and augment current approaches to assessment and management of patients following concussion.

Gall bladder mucoceles and their association with endocrinopathies in dogs: a retrospective case-control study.

PubMed

Mesich, M L L; Mayhew, P D; Paek, M; Holt, D E; Brown, D C

2009-12-01

To investigate the relationship between endocrinopathies and diagnosis of gall bladder mucocele in dogs via a retrospective case-control study. Records of 78 dogs with a surgical or ultrasonographic diagnosis of gall bladder mucocele were examined for the presence or absence of hyperadrenocorticism, hypothyroidism and diabetes mellitus. Two age- and breed-matched controls for each gall bladder mucocele dog (156 total control dogs) were examined for the same concurrent diseases. A matched case-control analysis was performed using conditional logistic regression. The odds of mucocele in dogs with hyperadrenocorticism were 29 times that of dogs without hyperadrenocorticism (P=0.001; 95 per cent CI 3.8, 219.9). No difference was found between dogs with and without diabetes mellitus. Although a significant association was found between gall bladder mucocele and hypothyroidism, potential observation bias was also identifi ed. Hyperadrenocorticoid dogs that were presented for acute illness with laboratory evidence of hepatobiliary disease should undergo evaluation for the presence of a biliary mucocele. Dogs diagnosed with a gall bladder mucocele should be screened for concurrent hyperadrenocorticism if clinical suspicion exists.

Risk factors for noma disease: a 6-year, prospective, matched case-control study in Niger.

PubMed

Baratti-Mayer, Denise; Gayet-Ageron, Angèle; Hugonnet, Stéphane; François, Patrice; Pittet-Cuenod, Brigitte; Huyghe, Antoine; Bornand, Jacques-Etienne; Gervaix, Alain; Montandon, Denys; Schrenzel, Jacques; Mombelli, Andrea; Pittet, Didier

2013-08-01

Noma is a poorly studied disease that leads to severe facial tissue destruction in children in developing countries, but the cause remains unknown. We aimed to identify the epidemiological and microbiological risk factors associated with noma disease. We did a prospective, matched, case-control study in Niger between Aug 1, 2001, and Oct 31, 2006, in children younger than 12 years to assess risk factors for acute noma. All acute noma cases were included and four controls for each case were matched by age and home village. Epidemiological and clinical data were obtained at study inclusion. We undertook matched-paired analyses with conditional logistic regression models. We included 82 cases and 327 controls. Independent risk factors associated with noma were: severe stunting (odds ratio [OR] 4·87, 95% CI 2·35-10·09) or wasting (2·45, 1·25-4·83); a high number of previous pregnancies in the mother (1·16, 1·04-1·31); the presence of respiratory disease, diarrhoea, or fever in the past 3 months (2·70, 1·35-5·40); and the absence of chickens at home (1·90, 0·93-3·88). After inclusion of microbiological data, a reduced proportion of Fusobacterium (4·63, 1·61-13·35), Capnocytophaga (3·69, 1·48-9·17), Neisseria (3·24, 1·10-9·55), and Spirochaeta in the mouth (7·77, 2·12-28·42), and an increased proportion of Prevotella (2·53, 1·07-5·98), were associated with noma. We identified no specific single bacterial or viral pathogen in cases. Noma is associated with indicators of severe poverty and altered oral microbiota. The predominance of specific bacterial commensals is indicative of a modification of the oral microbiota associated with reduced bacterial diversity. Gertrude Hirzel Foundation. Copyright © 2013 Baratti-Mayer et al. Open Access article distributed under the terms of CC BY-NC-ND. Published by .. All rights reserved.

Prolonged university outbreak of meningococcal disease associated with a serogroup B strain rarely seen in the United States.

PubMed

Mandal, Sema; Wu, Henry M; MacNeil, Jessica R; Machesky, Kimberly; Garcia, Jocelyn; Plikaytis, Brian D; Quinn, Kim; King, Larry; Schmink, Susanna E; Wang, Xin; Mayer, Leonard W; Clark, Thomas A; Gaskell, James R; Messonnier, Nancy E; DiOrio, Mary; Cohn, Amanda C

2013-08-01

College students living in residential halls are at increased risk of meningococcal disease. Unlike that for serogroups prevented by quadrivalent meningococcal vaccines, public health response to outbreaks of serogroup B meningococcal disease is limited by lack of a US licensed vaccine. In March 2010, we investigated a prolonged outbreak of serogroup B disease associated with a university. In addition to case ascertainment, molecular typing of isolates was performed to characterize the outbreak. We conducted a matched case-control study to examine risk factors for serogroup B disease. Five controls per case, matched by college year, were randomly selected. Participants completed a risk factor questionnaire. Data were analyzed using conditional logistic regression. Between January 2008 and November 2010, we identified 13 meningococcal disease cases (7 confirmed, 4 probable, and 2 suspected) involving 10 university students and 3 university-linked persons. One student died. Ten cases were determined to be serogroup B. Isolates from 6 confirmed cases had an indistinguishable pulsed-field gel electrophoresis pattern and belonged to sequence type 269, clonal complex 269. Factors significantly associated with disease were Greek society membership (matched odds ratio [mOR], 15.0; P = .03), >1 kissing partner (mOR, 13.66; P = .03), and attending bars (mOR, 8.06; P = .04). The outbreak was associated with a novel serogroup B strain (CC269) and risk factors were indicative of increased social mixing. Control measures were appropriate but limited by lack of vaccine. Understanding serogroup B transmission in college and other settings will help inform use of serogroup B vaccines currently under consideration for licensure.

The case-control design in veterinary sciences: A survey.

PubMed

Cullen, Jonah N; Sargeant, Jan M; Makielski, Kelly M; O'Connor, Annette M

2016-11-01

The case-control study design is deceptively simple. However, many design considerations influence the estimated effect measure. An investigation of case-control studies in the human health literature suggested that some of these considerations are not described in reports of case-control studies. Our hypothesis was that the majority of veterinary studies labeled as case-controls would be incident density designs, and many would not interpret the effect measure obtained from those studies as the rate ratio rather than the odds ratio. Reference databases were searched for author-designated case-control studies. A survey of 100 randomly selected studies was conducted to examine the different design options described and estimated effect measures. Of the 100 author-identified case-control studies, 83 assessed an exposure-outcome association and, of those, only 54 (65.1%) sampled the study population based on an outcome and would thus be considered case-control designs. Twelve studies were incidence density designs but none used this terminology. Of the studies that reported an odds ratio as the effect measure, none reported on additional considerations that would have enabled a more interpretable result. This survey indicated many case-control-labeled studies were not case-control designs and among case-control studies, key design aspects were not often described. The absence of information about study design elements and underlying assumptions in case-control studies limits the ability to establish the effect measured by the study and the evidentiary value of the study might be underestimated. Copyright © 2016 Elsevier B.V. All rights reserved.

Performance and Return to Sport After Tommy John Surgery Among Major League Baseball Position Players.

PubMed

Jack, Robert A; Burn, Matthew B; Sochacki, Kyle R; McCulloch, Patrick C; Lintner, David M; Harris, Joshua D

2018-06-01

The anterior bundle of the medial ulnar collateral ligament (UCL) is the primary restraint to valgus stress at the elbow and is often injured among overhead throwing athletes. Despite prevention strategies, injuries to the elbow UCL are on the rise. To determine (1) the return-to-sport (RTS) rate of Major League Baseball (MLB) position players after elbow medial UCL reconstruction, (2) postoperative career length and games per season, (3) pre- and postoperative performance, (4) postoperative performance versus matched control players, and (5) whether position players changed positions after UCL reconstruction. Cohort study; Level of evidence, 3. MLB players who underwent elbow UCL reconstruction were identified (cases). Demographic and performance data were collected for each player. Matched controls were identified. RTS in MLB was defined as playing in at least 1 MLB game after UCL reconstruction. Comparisons between case and control groups and pre- and postoperative time points were made via paired samples Student t tests. Thirty-three players (34 surgical procedures) were identified with a mean ± SD age of 30.2 ± 4.2 years and a mean experience in the MLB of 6.3 ± 3.9 years at the time of surgery. Twenty-eight players (84.8%) were able to RTS in MLB at a mean 336.9 ± 121.8 days. However, players ≥30 years old demonstrated a significantly lower RTS rate (53.3%) than players <30 years old (89.4%; P < .05). Catchers had a significantly shorter postoperative career length (2.8 ± 1.8 years) versus matched controls (6.1 ± 1.9 years; P < .05). Outfielders had a significantly lower wins above replacement postoperatively (0.8 ± 0.7) versus preoperatively (1.5 ± 1.1; P < .05). There were no performance differences between cases and matched controls. Twelve players (48%) returned to a different position postoperatively. The RTS rate for MLB position players after elbow UCL reconstruction is similar to that of pitchers. Catchers had a significantly shorter career length than that of matched controls. Outfielders performed worse postoperatively versus preoperatively. There is a high rate of position change after Tommy John surgery for infielders and outfielders.

Muscle Synergies May Improve Optimization Prediction of Knee Contact Forces During Walking

PubMed Central

Walter, Jonathan P.; Kinney, Allison L.; Banks, Scott A.; D'Lima, Darryl D.; Besier, Thor F.; Lloyd, David G.; Fregly, Benjamin J.

2014-01-01

The ability to predict patient-specific joint contact and muscle forces accurately could improve the treatment of walking-related disorders. Muscle synergy analysis, which decomposes a large number of muscle electromyographic (EMG) signals into a small number of synergy control signals, could reduce the dimensionality and thus redundancy of the muscle and contact force prediction process. This study investigated whether use of subject-specific synergy controls can improve optimization prediction of knee contact forces during walking. To generate the predictions, we performed mixed dynamic muscle force optimizations (i.e., inverse skeletal dynamics with forward muscle activation and contraction dynamics) using data collected from a subject implanted with a force-measuring knee replacement. Twelve optimization problems (three cases with four subcases each) that minimized the sum of squares of muscle excitations were formulated to investigate how synergy controls affect knee contact force predictions. The three cases were: (1) Calibrate+Match where muscle model parameter values were calibrated and experimental knee contact forces were simultaneously matched, (2) Precalibrate+Predict where experimental knee contact forces were predicted using precalibrated muscle model parameters values from the first case, and (3) Calibrate+Predict where muscle model parameter values were calibrated and experimental knee contact forces were simultaneously predicted, all while matching inverse dynamic loads at the hip, knee, and ankle. The four subcases used either 44 independent controls or five synergy controls with and without EMG shape tracking. For the Calibrate+Match case, all four subcases closely reproduced the measured medial and lateral knee contact forces (R2 ≥ 0.94, root-mean-square (RMS) error < 66 N), indicating sufficient model fidelity for contact force prediction. For the Precalibrate+Predict and Calibrate+Predict cases, synergy controls yielded better contact force predictions (0.61 < R2 < 0.90, 83 N < RMS error < 161 N) than did independent controls (-0.15 < R2 < 0.79, 124 N < RMS error < 343 N) for corresponding subcases. For independent controls, contact force predictions improved when precalibrated model parameter values or EMG shape tracking was used. For synergy controls, contact force predictions were relatively insensitive to how model parameter values were calibrated, while EMG shape tracking made lateral (but not medial) contact force predictions worse. For the subject and optimization cost function analyzed in this study, use of subject-specific synergy controls improved the accuracy of knee contact force predictions, especially for lateral contact force when EMG shape tracking was omitted, and reduced prediction sensitivity to uncertainties in muscle model parameter values. PMID:24402438

Muscle synergies may improve optimization prediction of knee contact forces during walking.

PubMed

Walter, Jonathan P; Kinney, Allison L; Banks, Scott A; D'Lima, Darryl D; Besier, Thor F; Lloyd, David G; Fregly, Benjamin J

2014-02-01

The ability to predict patient-specific joint contact and muscle forces accurately could improve the treatment of walking-related disorders. Muscle synergy analysis, which decomposes a large number of muscle electromyographic (EMG) signals into a small number of synergy control signals, could reduce the dimensionality and thus redundancy of the muscle and contact force prediction process. This study investigated whether use of subject-specific synergy controls can improve optimization prediction of knee contact forces during walking. To generate the predictions, we performed mixed dynamic muscle force optimizations (i.e., inverse skeletal dynamics with forward muscle activation and contraction dynamics) using data collected from a subject implanted with a force-measuring knee replacement. Twelve optimization problems (three cases with four subcases each) that minimized the sum of squares of muscle excitations were formulated to investigate how synergy controls affect knee contact force predictions. The three cases were: (1) Calibrate+Match where muscle model parameter values were calibrated and experimental knee contact forces were simultaneously matched, (2) Precalibrate+Predict where experimental knee contact forces were predicted using precalibrated muscle model parameters values from the first case, and (3) Calibrate+Predict where muscle model parameter values were calibrated and experimental knee contact forces were simultaneously predicted, all while matching inverse dynamic loads at the hip, knee, and ankle. The four subcases used either 44 independent controls or five synergy controls with and without EMG shape tracking. For the Calibrate+Match case, all four subcases closely reproduced the measured medial and lateral knee contact forces (R2 ≥ 0.94, root-mean-square (RMS) error < 66 N), indicating sufficient model fidelity for contact force prediction. For the Precalibrate+Predict and Calibrate+Predict cases, synergy controls yielded better contact force predictions (0.61 < R2 < 0.90, 83 N < RMS error < 161 N) than did independent controls (-0.15 < R2 < 0.79, 124 N < RMS error < 343 N) for corresponding subcases. For independent controls, contact force predictions improved when precalibrated model parameter values or EMG shape tracking was used. For synergy controls, contact force predictions were relatively insensitive to how model parameter values were calibrated, while EMG shape tracking made lateral (but not medial) contact force predictions worse. For the subject and optimization cost function analyzed in this study, use of subject-specific synergy controls improved the accuracy of knee contact force predictions, especially for lateral contact force when EMG shape tracking was omitted, and reduced prediction sensitivity to uncertainties in muscle model parameter values.

A novel method for biomaterial scaffold internal architecture design to match bone elastic properties with desired porosity.

PubMed

Lin, Cheng Yu; Kikuchi, Noboru; Hollister, Scott J

2004-05-01

An often-proposed tissue engineering design hypothesis is that the scaffold should provide a biomimetic mechanical environment for initial function and appropriate remodeling of regenerating tissue while concurrently providing sufficient porosity for cell migration and cell/gene delivery. To provide a systematic study of this hypothesis, the ability to precisely design and manufacture biomaterial scaffolds is needed. Traditional methods for scaffold design and fabrication cannot provide the control over scaffold architecture design to achieve specified properties within fixed limits on porosity. The purpose of this paper was to develop a general design optimization scheme for 3D internal scaffold architecture to match desired elastic properties and porosity simultaneously, by introducing the homogenization-based topology optimization algorithm (also known as general layout optimization). With an initial target for bone tissue engineering, we demonstrate that the method can produce highly porous structures that match human trabecular bone anisotropic stiffness using accepted biomaterials. In addition, we show that anisotropic bone stiffness may be matched with scaffolds of widely different porosity. Finally, we also demonstrate that prototypes of the designed structures can be fabricated using solid free-form fabrication (SFF) techniques.

Piped water supply interruptions and acute diarrhea among under-five children in Addis Ababa slums, Ethiopia: A matched case-control study.

PubMed

Adane, Metadel; Mengistie, Bezatu; Medhin, Girmay; Kloos, Helmut; Mulat, Worku

2017-01-01

The problem of intermittent piped water supplies that exists in low- and middle-income countries is particularly severe in the slums of sub-Saharan Africa. However, little is known about whether there is deterioration of the microbiological quality of the intermittent piped water supply at a household level and whether it is a factor in reducing or increasing the occurrence of acute diarrhea among under-five children in slums of Addis Ababa. This study aimed to determine the association of intermittent piped water supplies and point-of-use (POU) contamination of household stored water by Escherichia coli (E. coli) with acute diarrhea among under-five children in slums of Addis Ababa. A community-based matched case-control study was conducted from November to December, 2014. Cases were defined as under-five children with acute diarrhea during the two weeks before the survey. Controls were matched by age and neighborhood with cases by individual matching. Data were collected using a pre-tested structured questionnaire and E. coli analysis of water from piped water supplies and household stored water. A five-tube method of Most Probable Number (MPN)/100 ml standard procedure was used for E. coli analysis. Multivariable conditional logistic regression with 95% confidence interval (CI) was used for data analysis by controlling potential confounding effects of selected socio-demographic characteristics. During the two weeks before the survey, 87.9% of case households and 51.0% of control households had an intermittent piped water supply for an average of 4.3 days and 3.9 days, respectively. POU contamination of household stored water by E. coli was found in 83.3% of the case households, and 52.1% of the control households. In a fully adjusted model, a periodically intermittent piped water supply (adjusted matched odds ratio (adjusted mOR) = 4.8; 95% CI: 1.3-17.8), POU water contamination in household stored water by E. coli (adjusted mOR = 3.3; 95% CI: 1.1-10.1), water retrieved from water storage containers using handle-less vessels (adjusted mOR = 16.3; 95% CI: 4.4-60.1), and water retrieved by interchangeably using vessels both with and without handle (adjusted mOR = 5.4; 95% CI: 1.1-29.1) were independently associated with acute diarrhea. We conclude that provision of continuously available piped water supplies and education of caregivers about proper water retrieval methods of household stored water can effectively reduce POU contamination of water at the household level and thereby reduce acute diarrhea among under-five children in slums of Addis Ababa. Promotion of household water treatment is also highly encouraged until the City's water authority is able to deliver continuously available piped water supplies.

Improved Body Mass Index Measures Following a Middle School-Based Obesity Intervention-The MATCH Program.

PubMed

Lazorick, Suzanne; Fang, Xiangming; Hardison, George T; Crawford, Yancey

2015-10-01

Motivating Adolescents with Technology to CHOOSE Health™ (MATCH) is an educational and behavioral intervention in seventh grade. Teachers in 2 schools delivered the MATCH curriculum, with 1 control school. Using a quasi-experimental design, outcome measures included lessons completed, body mass index (BMI), BMI z-score (zBMI), BMI percentile, weight category, and self-reported lifestyle behaviors. We used multiple regression models to compare group results. For the MATCH group (N = 189), teachers provided lessons over 14 weeks; the control group (N = 173) received usual curriculum. Postintervention, the MATCH group had significant decreases in BMI measures compared with the control. In combined overweight and obese participants, the mean (95% confidence interval) zBMI change was -0.05 (-0.07, -0.03) in MATCH and -0.01 (-0.04, 0.02) in control, p = .034 between groups. After 1 year, improvements are sustained: for the overweight subgroup, the mean zBMI decreased from 1.34 to 1.26 post-MATCH, then to 1.26 after 1 year; for the obese subgroup, mean zBMI = 2.16, to 2.13 post-MATCH to 2.08 after 1 year. Self-reported lifestyle behaviors showed no differences. MATCH integrates theory-based strategies into standard curriculum delivered by teachers. No prior middle-school intervention has shown sustained change in BMI measures. MATCH warrants further study as a strategy to address obesity. © 2015, American School Health Association.

Biodemography of Exceptional Longevity: Early-life and Mid-life predictors of Human Longevity

PubMed Central

Gavrilov, Leonid A.; Gavrilova, Natalia S.

2011-01-01

Effects of early-life and middle-life conditions on exceptional longevity are explored in this study using two matched case-control studies. The first study compares 198 validated centenarians born in the United States in 1890-1893 to their shorter-lived siblings. Family histories of centenarians were reconstructed and exceptional longevity validated using early U.S. censuses, Social Security Administration Death Master File, state death indexes, online genealogies and other supplementary data resources. Siblings born to young mothers (<25 years) had significantly higher chances to live to 100 compared to siblings born to older mothers (odds ratio = 2.03, 95% CI = 1.33 - 3.11, P = 0.001) while paternal age and birth order were not associated with exceptional longevity. The second study explores whether people living to 100 and beyond are any different in physical characteristics at young age from their shorter-lived peers. A random representative sample of 240 men born in 1887 and survived to age 100 was selected from the US Social Security Administration database and linked to the US WWI civil draft registration cards collected in 1917 when these men were 30 years old. These validated centenarians were then compared to randomly selected controls matched by calendar year of birth, race and place of draft registration in 1917. It was found that ‘stout’ body build (being in the heaviest 15% of population) was negatively associated with survival to age 100 years. Farmer occupation and large number of children (4+) at age 30 increased the chances of exceptional longevity. Detailed description of dataset development, data cleaning procedure and validation of exceptional longevity is provided for both studies. These results demonstrate that matched case-control design is a useful approach in exploring effects of early-life conditions and middle-life characteristics on exceptional longevity. PMID:22582891

Risk factors associated with asbestos-related diseases: a community-based case–control study

PubMed Central

2013-01-01

Background Asbestos is a first level carcinogen. However, few epidemiological studies analyse the risk and protective factors associated with asbestos-related diseases and follow up these conditions in the general population. Pleural mesothelioma, caused by inhalation of asbestos fibres at work, at home or in the environment, is the most representative asbestos-related disease. The objectives of this study are to analyse the risk and protective factors associated with asbestos-related diseases and to investigate the incidence of new clinical manifestations in patients already diagnosed with some form of ARD. Methods/Design We have designed a matched case–control study with follow up of both cohorts from a population of a health district of the Barcelona province that has been exposed to asbestos for a period of 90 years. Discussion A better understanding of asbestos-related diseases should improve i) the clinical and epidemiological follow up of patients with this condition; ii) the design of new treatment strategies; iii) and the development of preventive activities. At the end of the study, the two cohorts created in this study (affected cases and healthy controls) will constitute the basis for future research. PMID:23915043

Bias with respect to socioeconomic status: A closer look at zip code matching in a pneumococcal vaccine effectiveness study.

PubMed

Link-Gelles, Ruth; Westreich, Daniel; Aiello, Allison E; Shang, Nong; Weber, David J; Holtzman, Corinne; Scherzinger, Karen; Reingold, Arthur; Schaffner, William; Harrison, Lee H; Rosen, Jennifer B; Petit, Susan; Farley, Monica; Thomas, Ann; Eason, Jeffrey; Wigen, Christine; Barnes, Meghan; Thomas, Ola; Zansky, Shelley; Beall, Bernard; Whitney, Cynthia G; Moore, Matthew R

2016-12-01

In 2010, 13-valent pneumococcal conjugate vaccine (PCV13) was introduced in the US for prevention of invasive pneumococcal disease in children. Individual-level socioeconomic status (SES) is a potential confounder of the estimated effectiveness of PCV13 and is often controlled for in observational studies using zip code as a proxy. We assessed the utility of zip code matching for control of SES in a post-licensure evaluation of the effectiveness of PCV13 (calculated as [1-matched odds ratio]*100). We used a directed acyclic graph to identify subsets of confounders and collected SES variables from birth certificates, geo-coding, a parent interview, and follow-up with medical providers. Cases tended to be more affluent than eligible controls (for example, 48.3% of cases had private insurance vs. 44.6% of eligible controls), but less affluent than enrolled controls (52.9% of whom had private insurance). Control of confounding subsets, however, did not result in a meaningful change in estimated vaccine effectiveness (original estimate: 85.1%, 95% CI 74.8-91.9%; adjusted estimate: 82.5%, 95% CI 65.6-91.1%). In the context of a post-licensure vaccine effectiveness study, zip code appears to be an adequate, though not perfect, proxy for individual SES.

Investigation of Geobase Implementation Issues: Case Study of Information Resource Management

DTIC Science & Technology

2004-03-01

case study , ethnography , phenomenological study , and grounded theory . “Of...all the research designs [described] … a grounded theory study is the one that is least likely to begin from a 40 Use this approach if...the treatments explained, the case study method best matches the objectives of this research (Leedy & Ormrod, 2001). Yin’s criteria for

Sexual mixing patterns among social networks of HIV-positive and HIV-negative Beijing men who have sex with men: a multilevel comparison using roundtable network mapping.

PubMed

Ruan, Yuhua; Pan, Stephen W; Chamot, Eric; Qian, Han-Zhu; Li, Dongliang; Li, Qing-Chun; Liang, Hong-Yuan; Spittal, Patricia; Shao, Yiming; Kristensen, Sibylle

2011-08-01

Men who have sex with men (MSM) are of immediate concern in China's HIV epidemic. In 2008, approximately 2.5-6.5% of China's eight million MSM were HIV positive, while MSM represented 11% of all new HIV cases. Two factors that will in-part determine HIV-transmission dynamics among MSM, are sexual mixing patterns and the social networks which shape them. Sexual mixing patterns and social networks of Chinese MSM, however, remain poorly understood with little refined data available. One reason is that stigma discourages disclosure of names and identifiers to researchers. Using an alternative network-mapping approach, matched case-control design, and snowball sampling, this pilot study sought to compare characteristics of social networks of HIV-positive and HIV-negative Beijing MSM at the individual, dyad, and network levels. First, HIV-negative MSM controls were matched to HIV-positive MSM cases based on age, education, residency, and ethnicity. Then, each case or control and their MSM social network convened at a specific time and location with study investigators. Venues included health clinics, karaoke clubs, brothels, and community centers. Then, using arbitrarily assigned numbers in lieu of actual names, all participants simultaneously completed self-administered surveys regarding their sexual relationships with other participants of the same social network. These new findings indicate that cross-generational sex (anal or oral sex between men with ≥10 years age difference) was more prevalent among social networks of HIV-positive MSM, and was due to older age structure of the social network, rather than behavioral differences in sex-partner selection. Members of social networks of HIV-positive MSM were also less likely to have ever disclosed their MSM identity to non-MSM. Future studies should partner with MSM advocacy groups to explore behavioral and structural interventions as possible means of reducing the cross-generational sex and sexual identity-development issues elevating HIV risk for young Chinese MSM.

Neonatal antecedents for cerebral palsy in extremely preterm babies and interaction with maternal factors.

PubMed

Tran, Uyen; Gray, Peter H; O'Callaghan, Michael J

2005-06-01

Preterm delivery is associated with an increased risk of cerebral palsy (CP). The greatest risk is for infants born <28 weeks' gestation. To identify significant neonatal risk factors for CP and explore the interactions between antenatal and neonatal risk factors, among extremely preterm infants of 27 weeks' gestation or less. Nested case control design. Infants born between 1989 and 1996, at 24-27 weeks' gestation, were evaluated: 30 with CP at 2 years corrected age and 120 control infants matched for gestation age. Neonatal variables were compared using matched analyses with the interaction between antenatal and neonatal factors being examined using logistic regression analyses. Risk factors for CP on matched analyses included patent ductus arteriosus requiring surgical ligation, peri-intraventricular haemorrhage, moderate to severe ventricular dilatation, periventricular leukomalacia (PVL) and need for home oxygen. Independent neonatal predictors were ventricular dilatation (OR 7.3; 95% CI 1.6, 32.3), PVL (OR 29.8; 95% CI 5.6, 159.1) and home oxygen use (OR 3.4; 95% CI 1.2, 9.4). No interaction terms in the logistic models were significant between the previously identified pregnancy risk factors of absence of antenatal steroids and intrauterine growth restriction and the neonatal risk factors. PVL is the most powerful independent predictor of CP in extremely preterm infants of 27 weeks' gestation or less and appears to be uninfluenced by antenatal factors.

Outbreak of Neisseria meningitidis C in workers at a large food-processing plant in Brazil: challenges of controlling disease spread to the larger community.

PubMed

Iser, B P M; Lima, H C A V; de Moraes, C; de Almeida, R P A; Watanabe, L T; Alves, S L A; Lemos, A P S; Gorla, M C O; Gonçalves, M G; Dos Santos, D A; Sobel, J

2012-05-01

SUMMARYAn outbreak of meningococcal disease (MD) with severe morbidity and mortality was investigated in midwestern Brazil in order to identify control measures. A MD case was defined as isolation of Neisseria meningitidis, or detection of polysaccharide antigen in a sterile site, or presence of clinical purpura fulminans, or an epidemiological link with a laboratory-confirmed case-patient, between June and August 2008. In 8 out of 16 MD cases studied, serogroup C ST103 complex was identified. Five (31%) cases had neurological findings and five (31%) died. The attack rate was 12 cases/100 000 town residents and 60 cases/100 000 employees in a large local food-processing plant. We conducted a matched case-control study of eight primary laboratory-confirmed cases (1:4). Factors associated with illness in single variable analysis were work at the processing plant [matched odds ratio (mOR) 22, 95% confidence interval (CI) 2·3-207·7, P<0·01], and residing <1 year in Rio Verde (mOR 7, 95% CI 1·11-43·9, P<0·02). Mass vaccination (>10 000 plant employees) stopped propagation in the plant, but not in the larger community.

The effect of an internet-based, stage-matched message intervention on young Taiwanese women's physical activity.

PubMed

Huang, Sheu-Jen; Hung, Wen-Chi; Chang, Maiga; Chang, Janie

2009-01-01

A web-based, stage-matched message intervention was designed in order to see the effect on the physical activity of young Taiwanese women with regard to several variables. The intervention was guided by the Transtheoretical Model (TTM) and was evaluated using a pre-post-test control group design. One hundred thirty female freshmen, enrolled in a nursing class in a university in Taipei, completed the survey at three different points in time. They were assigned to three groups: an experimental group with stage-matched messages on the website, a generic group with non-stage-matched messages on the website, and a control group that was given only lectures but had no access to the website. Results indicated that the subjects in the stage-matched group improved most in terms of stage-of-exercise and amount of physical activity, followed by the generic group at immediate post-test; meanwhile, the control group had a tendency toward downward change. The effect did not persist, however, for the first two groups. A significantly higher level of exercise self-efficacy was found in the stage-matched group than in the other two groups immediately after the intervention. The results suggested that a website conveying theory-based messages can serve as a useful tool for improving young females' physical activity and exercise self-efficacy. Additionally, we need research that explores different degrees and dimensions of tailoring in order to find the optimal degree of audience segmentation.

Dense real-time stereo matching using memory efficient semi-global-matching variant based on FPGAs

NASA Astrophysics Data System (ADS)

Buder, Maximilian

2012-06-01

This paper presents a stereo image matching system that takes advantage of a global image matching method. The system is designed to provide depth information for mobile robotic applications. Typical tasks of the proposed system are to assist in obstacle avoidance, SLAM and path planning. Mobile robots pose strong requirements about size, energy consumption, reliability and output quality of the image matching subsystem. Current available systems either rely on active sensors or on local stereo image matching algorithms. The first are only suitable in controlled environments while the second suffer from low quality depth-maps. Top ranking quality results are only achieved by an iterative approach using global image matching and color segmentation techniques which are computationally demanding and therefore difficult to be executed in realtime. Attempts were made to still reach realtime performance with global methods by simplifying the routines. The depth maps are at the end almost comparable to local methods. An equally named semi-global algorithm was proposed earlier that shows both very good image matching results and relatively simple operations. A memory efficient variant of the Semi-Global-Matching algorithm is reviewed and adopted for an implementation based on reconfigurable hardware. The implementation is suitable for realtime execution in the field of robotics. It will be shown that the modified version of the efficient Semi-Global-Matching method is delivering equivalent result compared to the original algorithm based on the Middlebury dataset. The system has proven to be capable of processing VGA sized images with a disparity resolution of 64 pixel at 33 frames per second based on low cost to mid-range hardware. In case the focus is shifted to a higher image resolution, 1024×1024-sized stereo frames may be processed with the same hardware at 10 fps. The disparity resolution settings stay unchanged. A mobile system that covers preprocessing, matching and interfacing operations is also presented.

Liver transplant using donors after cardiac death: a single-center approach providing outcomes comparable to donation after brain death.

PubMed

Vanatta, Jason M; Dean, Amanda G; Hathaway, Donna K; Nair, Satheesh; Modanlou, Kian A; Campos, Luis; Nezakatgoo, Nosratollah; Satapathy, Sanjaya K; Eason, James D

2013-04-01

Organ donation after cardiac death remains an available resource to meet the demand for transplant. However, concern persists that outcomes associated with donation after cardiac death liver allografts are not equivalent to those obtained with organ donation after brain death. The aim of this matched case control study was to determine if outcomes of liver transplants with donation after cardiac death donors is equivalent to outcomes with donation after brain death donors by controlling for careful donor and recipient selection, surgical technique, and preservation solution. A retrospective, matched case control study of adult liver transplant recipients at the University of Tennessee/Methodist University Hospital Transplant Institute, Memphis, Tennessee was performed. Thirty-eight donation after cardiac death recipients were matched 1:2, with 76 donation after brain death recipients by recipient age, recipient laboratory Model for End Stage Liver Disease score, and donor age to form the 2 groups. A comprehensive approach that controlled for careful donor and recipient matching, surgical technique, and preservation solution was used to minimize warm ischemia time, cold ischemia time, and ischemia-reperfusion injury. Patient and graft survival rates were similar in both groups at 1 and 3 years (P = .444 and P = .295). There was no statistically significant difference in primary nonfunction, vascular complications, or biliary complications. In particular, there was no statistically significant difference in ischemic-type diffuse intrahepatic strictures (P = .107). These findings provide further evidence that excellent patient and graft survival rates expected with liver transplants using organ donation after brain death donors can be achieved with organ donation after cardiac death donors without statistically higher rates of morbidity or mortality when a comprehensive approach that controls for careful donor and recipient matching, surgical technique, and preservation solution is used.

Bone density of the radius, spine, and proximal femur in osteoporosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mazess, R.B.; Barden, H.; Ettinger, M.

1988-02-01

Bone mineral density (BMD) was measured in 140 normal young women (aged 20 to 39 years) and in 423 consecutive women over age 40 referred for evaluation of osteoporosis. Lumbar spine and proximal femur BMD was measured using dual-photon absorptiometry (/sup 153/Gd), whereas the radius shaft measurement used single-photon absorptiometry (/sup 125/I). There were 324 older women with no fractures, of which 278 aged 60 to 80 years served as age-matched controls. There were 99 women with fractures including 32 with vertebral and 22 with hip fractures. Subsequently, another 25 women with hip fractures had BMD measured in another laboratory;more » their mean BMD was within 2% of that of the original series. The mean age in both the nonfracture and fracture groups was 70 +/- 5 years. The BMD in the age-matched controls was 20% to 25% below that of normal young women for the radius, spine, and femur, but the Ward's triangle region of the femur showed even greater loss (35%). The mean BMD at all sites in the crush fracture cases was about 10% to 15% below that of age-matched controls. Spinal abnormality was best discriminated by spine and femoral measurements (Z score about 0.9). In women with hip fractures, the BMD was 10% below that of age-matched controls for the radius and the spine, and the BMD for the femoral sites was about 25% to 30% below that of age-matched control (Z score about 1.6). Femoral densities gave the best discrimination of hip fracture cases and even reflected spinal osteopenia. In contrast, neither the spine nor the radius reflected the full extent of femoral osteopenia in hip fracture.« less

Proton pump inhibitor use and recurrent Clostridium difficile-associated disease: a case-control analysis matched by propensity score.

PubMed

Kim, Yong Gil; Graham, David Y; Jang, Byung Ik

2012-01-01

Clostridium difficile has been increasingly diagnosed in hospitalized patients. An association between proton pump inhibitors (PPIs) use and Clostridium difficile-associated disease (CDAD) and between recurrent CDAD has been suggested. The aim of this study is to investigate whether PPI use is associated with the development of recurrent CDAD. This was a retrospective case-control study of patients with CDAD at Yeungnam University Medical Center, seen from January 2004 to December 2008. C. difficile infection was diagnosed by the presence of C. difficile toxin in the stool. Those with recurrent disease were matched with nonrecurrent controls using multivariate matched sampling methods that incorporated the propensity score. Recurrent CDAD developed in 28 (14.1%) of the 198 patients with diarrhea and positive C. difficile stool toxin assays. Multivariate analysis of the total population of recurrent versus nonrecurrent CDAD revealed that additional use of non-C. difficile antimicrobial therapy (concomitant with the treatment or after or both), poor response to therapy with metronidazole or vancomycin, and recent gastrointestinal surgery were risk factors for recurrent CDAD. We were able to match 21 recurrent CDAD subjects with 21 without recurrent CDAD. Among the matched patients only PPI use was associated with recurrent CDAD (ie, 47.6% vs. 4.8%, P=0.004 for recurrent vs. nonrecurrent CDAD, respectively). Among the matched patient groups, only PPI therapy was associated with recurrent CDAD. Prospective studies are needed to clarify whether avoidance of PPIs or specific cotherapies will reduce the incidence of recurrent C. difficile-associated diarrhea.

Risk factors for late onset gram-negative infections: a case-control study.

PubMed

Samanta, Srabani; Farrer, Kate; Breathnach, Aodhan; Heath, Paul T

2011-01-01

To determine the incidence, mortality and risk factors for neonatal late onset gram-negative sepsis and meningitis (LOGNS). Retrospective case-control study. Tertiary neonatal unit in London. Consecutive inborn infants with late onset (>48 h of life) invasive gram-negative infections diagnosed between 1999 and 2005. Controls were healthy infants matched for gestation and time of admission to the neonatal unit. Clinical and risk factor data. 73 cases of LOGNS were identified of which 48 were inborn and included in the study (incidence 1.85/1000 live births). Enterobacter spp. (28%), Escherichia coli (27%) and Klebsiella spp. (21%) were the most common pathogens. The majority of infants were of very low birthweight (VLBW; 79%), and cases and controls were well matched (median gestation 26 weeks). Overall case death was 27% in cases versus 13.5% in controls (p=0.08). There was no significant difference between cases and controls regarding maternal risk factors. Mechanical ventilation, total parenteral nutrition (TPN) and its duration, presence of a central venous line and its duration, use of specific antibiotics and the occurrence of necrotising enterocolitis at or before the first positive culture were all significantly associated with case status in univariate analysis. In multivariate logistic regression analysis, only duration of TPN at or before first positive blood culture remained independently associated with LOGNS (p<0.001). LOGNS occurs predominantly in VLBW infants. When the influence of gestational age is accounted for, the only independent risk factor found for late onset gram-negative neonatal infections is the duration of TPN.

Fibromyalgia and seizures.

PubMed

Tatum, William O; Langston, Michael E; Acton, Emily K

2016-06-01

The purpose of this case-matched study was to determine how frequently fibromyalgia is associated with different paroxysmal neurological disorders and explore the utility of fibromyalgia as a predictor for the diagnosis of psychogenic non-epileptic seizures. The billing diagnosis codes of 1,730 new, non-selected patient encounters were reviewed over a three-year period for an epileptologist in a neurology clinic to identify all patients with historical diagnoses of fibromyalgia. The frequency with which epileptic seizures, psychogenic non-epileptic seizures, and physiological non-epileptic events were comorbid with fibromyalgia was assessed. Age and gender case-matched controls were used for a between-group comparison. Wilcoxon tests were used to analyse interval data, and Chi-square was used to analyse categorical data (p<0.05). Fibromyalgia was retrospectively identified in 95/1,730 (5.5%) patients in this cohort. Females represented 95% of the fibromyalgia sample (age: 53 years; 95% CI: 57, 51). Forty-three percent of those with fibromyalgia had a non-paroxysmal, neurological primary clinical diagnosis, most commonly chronic pain. Paroxysmal events were present in 57% of fibromyalgia patients and 54% of case-matched controls. Among patients with fibromyalgia and paroxysmal disorders, 11% had epileptic seizures, 74% had psychogenic non-epileptic seizures, and 15% had physiological non-epileptic events, compared to case-matched controls with 37% epileptic seizures, 51% psychogenic non-epileptic events, and 12% physiological non-epileptic events (p = 0.009). Fibromyalgia was shown to be a predictor for the diagnosis of psychogenic non-epileptic seizures in patients with undifferentiated paroxysmal spells. However, our results suggest that the specificity and sensitivity of fibromyalgia as a marker for psychogenic non-epileptic seizures in a mixed general neurological population of patients is less than previously described.

Shivering in Febrile Children: Frequency and Usefulness in Predicting Serious Bacterial Infections - A Prospective Case-Control Study.

PubMed

Erell, Yair; Youngster, Ilan; Abu-Kishk, Ibrahim; Kozer, Eran

2017-11-01

A prospective case-control study was conducted in a pediatric emergency department to describe the proportion of febrile children experiencing shivering and its clinical significance. Shivering was reported in 186 of 645 febrile children (28.8%). The rate of serious bacterial infection was similar in 86 children with shivering and 86 matched controls. Copyright © 2017 Elsevier Inc. All rights reserved.

A novel case-control design to estimate the extent of over-diagnosis of breast cancer due to organised population-based mammography screening.

PubMed

Beckmann, Kerri R; Lynch, John W; Hiller, Janet E; Farshid, Gelareh; Houssami, Nehmat; Duffy, Stephen W; Roder, David M

2015-03-15

Debate about the extent of breast cancer over-diagnosis due to mammography screening has continued for over a decade, without consensus. Estimates range from 0 to 54%, but many studies have been criticized for having flawed methodology. In this study we used a novel study design to estimate over-diagnosis due to organised mammography screening in South Australia (SA). To estimate breast cancer incidence at and following screening we used a population-based, age-matched case-control design involving 4,931 breast cancer cases and 22,914 controls to obtain OR for yearly time intervals since women's last screening mammogram. The level of over-diagnosis was estimated by comparing the cumulative breast cancer incidence with and without screening. The former was derived by applying ORs for each time window to incidence rates in the absence of screening, and the latter, by projecting pre-screening incidence rates. Sensitivity analyses were undertaken to assess potential biases. Over-diagnosis was estimated to be 8% (95%CI 2-14%) and 14% (95%CI 8-19%) among SA women aged 45 to 85 years from 2006-2010, for invasive breast cancer and all breast cancer respectively. These estimates were robust when applying various sensitivity analyses, except for adjustment for potential confounding assuming higher risk among screened than non-screened women, which reduced levels of over-diagnosis to 1% (95%CI 5-7%) and 8% (95%CI 2-14%) respectively when incidence rates for screening participants were adjusted by 10%. Our results indicate that the level of over-diagnosis due to mammography screening is modest and considerably lower than many previous estimates, including others for Australia. © 2014 UICC.

Dietary inflammatory index and prostate cancer risk in a case-control study in Mexico.

PubMed

Vázquez-Salas, Ruth A; Shivappa, Nitin; Galván-Portillo, Marcia; López-Carrillo, Lizbeth; Hébert, James R; Torres-Sánchez, Luisa

2016-12-01

Recent evidence suggests that a pro-inflammatory diet could be associated with prostate cancer (PC) risk. To evaluate the association between dietary inflammatory index (DII) and PC risk as well as aggressiveness, we conducted a case-control study in Mexico City. Cases were 394 individuals with incident, histologically confirmed PC, who were matched by age (±5 years) with 794 population controls. Dietary information was obtained through a semi-quantitative FFQ with a 3-year frame of reference before diagnosis, for cases, or interview, for controls. On the basis of twenty-eight food parameters, we estimated the energy-adjusted DII (E-DII). According to the Gleason score at diagnosis, PC cases were categorised as high (≥8), moderate (=7) and low (≤6) PC risk. Independent, unconditional logistic regression models adjusted for potential confounders were used to estimate PC risk and PC aggressiveness. There were no significant associations between overall PC risk and E-DII (OR3rd v. 1st tertile 1·18; 95 % CI 0·85, 1·63; P=0·33) or among men with high-risk PC (Gleason≥8) (OR 1·46; 95 % CI 0·88, 2·42; P=0·14). These results do not support the hypothesis that a pro-inflammatory diet is related to PC risk and PC aggressiveness. However, further studies with larger sample sizes, with sufficient statistical power and of varying designs should be conducted to address this hypothesis.

Field-based random sampling without a sampling frame: control selection for a case-control study in rural Africa.

PubMed

Crampin, A C; Mwinuka, V; Malema, S S; Glynn, J R; Fine, P E

2001-01-01

Selection bias, particularly of controls, is common in case-control studies and may materially affect the results. Methods of control selection should be tailored both for the risk factors and disease under investigation and for the population being studied. We present here a control selection method devised for a case-control study of tuberculosis in rural Africa (Karonga, northern Malawi) that selects an age/sex frequency-matched random sample of the population, with a geographical distribution in proportion to the population density. We also present an audit of the selection process, and discuss the potential of this method in other settings.

Anxiety and depression predicted by medically unexplained symptoms in Pakistani children: a case-control study.

PubMed

Imran, Nazish; Ani, Cornelius; Mahmood, Zahid; Hassan, Khawaja Amjad; Bhatti, Muhammad Riaz

2014-02-01

To explore association between medically unexplained symptoms in children in Pakistan with emotional difficulties and functional impairments. We conducted a matched three-group case-control study of 186 children aged 8-16 years in Lahore, Pakistan. Cases were 62 children with chronic somatic symptoms for which no organic cause was identified after investigations. Two control groups of 62 children with chronic medical paediatric conditions, and 62 healthy children were identified. Cases and controls were matched for gender, age, and school class. Somatisation was measured with the Children's Somatisation Inventory (CSI-24) while anxiety and depression were measured with the Spencer Children's Anxiety Scale and the Short Mood and Feelings Questionnaire respectively. All questionnaires were translated into Urdu. Mean age was 11.7 years (SD=2.1). Cases scored significantly higher on somatisation (CSI-24), anxiety and depression than both control groups. Paediatric controls scored significantly higher than healthy controls on all three measures. Two hierarchical linear regression models were used to explore if somatisation predicted depression and anxiety while controlling for several confounders. Somatisation (higher CSI-24 scores) independently and significantly predicted higher anxiety (β=.37, p=.0001) and depression (β=.41, p=.0001) scores. This is the first study to show an association between medically unexplained symptoms and anxiety and depression in Pakistani children. This highlights the importance of screening for emotional difficulties in children presenting with unexplained somatic symptoms in this region. Copyright © 2013 Elsevier Inc. All rights reserved.

A cholera outbreak in Alborz Province, Iran: a matched case-control study.

PubMed

Moradi, Ghobad; Rasouli, Mohammad Aziz; Mohammadi, Parvin; Elahi, Elham; Barati, Hojatollah

2016-01-01

A total of 229 confirmed cholera cases were reported in Alborz Province during an outbreak that lasted from June 2011 to August 2011. This study aimed to identify potential sources of transmission in order to determine suitable interventions in similar outbreaks. In other words, the lessons learned from this retrospective study can be utilized to manage future similar outbreaks. An age-matched and sex-matched case-control study was conducted during the outbreak. For each case, two control subjects were selected from the neighborhood. A case of cholera was defined as a bacteriologically confirmed case with signs and symptoms of cholera. This study was conducted from June 14, 2011 through August 23, 2011. The data were analyzed by calculating odds ratios (ORs) using the logistic regression method. In this outbreak, 229 confirmed cholera cases were diagnosed. The following risk factors were found to be associated with cholera: consumption of unrefrigerated leftover food (OR, 3.05; 95% confidence interval [CI], 1.72 to 5.41), consumption of vegetables and fruits in the previous three days (OR, 2.75; 95% CI, 1.95 to 3.89), and a history of traveling in the previous five days (OR, 5.31; 95% CI, 2.21 to 9.72). Consumption of vegetables and fruits has remained an unresolved risk factor in cholera outbreaks in Iran in recent years. In order to reduce the risk of cholera, sanitary standards for fruits and vegetables should be observed at all points from production to consumption, the population should be educated regarding hygienic food storage during outbreaks, and sanitary standards should be maintained when traveling during cholera outbreaks.

Genetic association between ghrelin polymorphisms and Alzheimer's disease in a Japanese population.

PubMed

Shibata, Nobuto; Ohnuma, Tohru; Kuerban, Bolati; Komatsu, Miwa; Arai, Heii

2011-01-01

Ghrelin has been reported to enter the hippocampus and to bind to the neurons of the hippocampal formation. This peptide also affects neuronal glucose uptake and decreases tau hyperphosphorylation. There is increasing evidence suggesting an association between ghrelin and Alzheimer's disease (AD) pathology. The aim of this study was to investigate whether single nucleotide polymorphisms (SNPs) of the ghrelin gene are associated with AD. The SNPs were genotyped using TaqMan technology and were analyzed using a case-control study design. Our case-control dataset consisted of 182 AD patients and 143 age-matched controls. Hardy-Weinberg equilibrium and linkage disequilibrium analyses suggest that the region in and around the gene is highly polymorphic. One SNP, rs4684677 (Leu90Gln), showed a marginal association with age of AD onset. We did not detect any association between the other SNPs of the ghrelin gene and AD. There have been few genetic studies on the relationship between circulating ghrelin and functional SNPs. Further multifactorial studies are needed to clarify the relationship between ghrelin and AD. Copyright © 2011 S. Karger AG, Basel.

Demographic and Clinical Profile of Patients With Dementia Receiving Electroconvulsive Therapy: A Case-Control Study.

PubMed

Zhang, Qing-E; Sha, Sha; Ungvari, Gabor S; Chiu, Helen F K; Ng, Chee H; He, Hong-Bo; Forester, Brent P; Xiang, Yu-Tao

2016-09-01

Little is known about the clinical characteristics of patients with dementia receiving electroconvulsive therapy (ECT) for the treatment of behavioral symptoms. This study examined the demographic and clinical profile of patients with dementia receiving ECT in China. This was a retrospective, case-control study. The sample was composed of 23 patients with dementia treated with ECT and 71 sex- and age-matched controls treated for a period of 8 years (2007-2014) at the National Clinical Research Centre of Mental Disorders, China. Sociodemographic and clinical data were collected from the electronic chart management system. Multiple logistic regression analysis revealed that ECT was independently associated with high risk for suicide at admission. The recorded indications for ECT included both high risk for suicide and aggressive behavior. Most patients responded to ECT satisfactorily (56.5%) or partially (34.8%) with only mild-moderate transient memory impairment (30.4%). Although this is a preliminary study limited by the retrospective design and small sample size, findings suggest that ECT is an effective and safe therapeutic intervention to reduce the risk for suicide and aggressive behavior in dementia.

Seismic, structural, and individual factors associated with earthquake related injury

PubMed Central

Peek-Asa, C; Ramirez, M; Seligson, H; Shoaf, K

2003-01-01

Background: Earthquakes cause thousands of deaths worldwide every year, and systematic study of the causes of these deaths can lead to their prevention. Few studies have examined how multiple types of risk factors are related to physical injury during an earthquake. Methods: A population based case-control study was conducted to examine how individual characteristics, building characteristics, and seismic features of the 1994 Northridge, California, earthquake contributed to physical injury. Cases included fatal and hospital-admitted injuries caused by the earthquake. Controls were drawn from a population based phone survey of county residents. Cases were individually matched to two sets of controls: one matched by age and gender and one matched by location at the time of the earthquake. Results: Individuals over age 65 had 2.9 times the risk of injury as younger people (95% confidence interval (CI) 1.2 to 7.4) and women had a 2.4 times greater risk than men (95% CI 1.2 to 5.1). Location in multiple unit residential and commercial structures each led to increased injury risk compared with single unit residential structures, but the exact estimate varied depending on the control group used. With every increase in ground motion of 10%g, injury risk increased 2.2 times (95% CI 1.6 to 3.3). Conclusions: Controlling for other factors, it was found that individual, building, and seismic characteristics were independently predictive of increased injury risk. Prevention and preparedness efforts should focus on each of these as potential points of intervention. PMID:12642562

Association between cardiovascular events and sodium-containing effervescent, dispersible, and soluble drugs: nested case-control study

PubMed Central

George, Jacob; Majeed, Waseem; Mackenzie, Isla S; Wei, Li

2013-01-01

Objective To determine whether patients taking formulations of drugs that contain sodium have a higher incidence of cardiovascular events compared with patients on non-sodium formulations of the same drugs. Design Nested case-control study. Setting UK Primary Care Patients registered on the Clinical Practice Research Datalink (CPRD). Participants All patients aged 18 or over who were prescribed at least two prescriptions of sodium-containing formulations or matched standard formulations of the same drug between January 1987 and December 2010. Main outcome measures Composite primary outcome of incident non-fatal myocardial infarction, incident non-fatal stroke, or vascular death. We performed 1:1 incidence density sampling matched controls using the UK Clinical Practice Research Datalink (CPRD). For the secondary analyses, cases were patients with the individual components of the primary study composite endpoint of hypertension, incident heart failure, and all cause mortality. Results 1 292 337 patients were included in the study cohort. Mean follow-up time was 7.23 years. A total of 61 072 patients with an incident cardiovascular event were matched with controls. For the primary endpoint of incident non-fatal myocardial infarction, incident non-fatal stroke, or vascular death the adjusted odds ratio for exposure to sodium-containing drugs was 1.16 (95% confidence interval 1.12 to 1.21). The adjusted odds ratios for the secondary endpoints were 1.22 (1.16 to 1.29) for incident non-fatal stroke, 1.28 (1.23 to 1.33) for all cause mortality, 7.18 (6.74 to 7.65) for hypertension, 0.98 (0.93 to 1.04) for heart failure, 0.94 (0.88 to 1.00) for incident non-fatal myocardial infarction, and 0.70 (0.31 to 1.59) for vascular death. The median time from date of first prescription (that is, date of entry into cohort) to first event was 3.92 years. Conclusions Exposure to sodium-containing formulations of effervescent, dispersible, and soluble medicines was associated with significantly increased odds of adverse cardiovascular events compared with standard formulations of those same drugs. Sodium-containing formulations should be prescribed with caution only if the perceived benefits outweigh these risks. PMID:24284017

Risk factors of direct heat-related hospital admissions during the 2009 heatwave in Adelaide, Australia: a matched case-control study.

PubMed

Zhang, Ying; Nitschke, Monika; Krackowizer, Antoinette; Dear, Keith; Pisaniello, Dino; Weinstein, Philip; Tucker, Graeme; Shakib, Sepehr; Bi, Peng

2016-06-02

The extreme heatwave of 2009 in South Australia dramatically increased morbidity, with a 14-fold increase in direct heat-related hospitalisation in metropolitan Adelaide. Our study aimed to identify risk factors for the excess morbidity. A matched case-control study of risk factors was conducted. Patients and matched community controls were interviewed to gather data on demographics, living environment, social support, health status and behaviour changes during the heatwave. Cases were all hospital admissions with heat-related diagnoses during the 5-day heatwave in 2009. Controls were randomly selected from communities. Descriptive analyses, simple and multiple conditional logistic regressions were performed. Adjusted ORs (AORs) were estimated. In total, 143 hospital patients and 143 matched community controls were interviewed, with a mean age of 73 years (SD 21), 96% European ethnicity, 63% retired, 36% with high school or higher education, and 8% institutional living. The regression model indicated that compared with the controls, cases were more likely to have heart disease (AOR=13.56, 95% CI 1.27 to 144.86) and dementia (AOR=26.43, 95% CI 1.99 to 350.73). The protective factors included higher education level (AOR=0.48, 95% CI 0.23 to 0.99), having air-conditioner in the bedroom (AOR=0.12, 95% CI 0.02 to 0.74), having an emergency button (AOR=0.09, 95% CI 0.01 to 0.96), using refreshment (AOR=0.10, 95% CI 0.01 to 0.84), and having more social activities (AOR=0.11, 95% CI 0.02 to 0.57). Pre-existing heart disease and dementia significantly increase the risk of direct heat-related hospitalisations during heatwaves. The presence of an air-conditioner in the bedroom, more social activities, a higher education level, use of emergency buttons and refreshments reduce the risk during heatwaves. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Aphrodisiac Use Associated with HIV Infection in Elderly Male Clients of Low-Cost Commercial Sex Venues in Guangxi, China: A Matched Case-Control Study

PubMed Central

Li, Guojian; Shen, Zhiyong; Zhang, Hongman; Lan, Guanghua; Feng, Xue; Lin, Rui; Abdullah, Abu S.; Wu, Zunyou; Shi, Cynthia X.

2014-01-01

Background Rising HIV infection rates have been observed among elderly people in Guangxi, China. Inexpensive aphrodisiacs are available for purchase in suburban and rural areas. This study aims to investigate the association between aphrodisiac use and increased HIV risk for middle-aged and elderly men in Guangxi. Methods A matched case-control study of aphrodisiac use-associated HIV infection was performed among male subjects over 50 years old who were clients of low-cost commercial sex venues in Guangxi. The cases were defined as clients who were HIV-positive and two controls were selected for each case. The cases and the controls were matched on the visited sex venue, age (±3 years), number of years of purchasing sex (±3 years), and educational attainment. Subjects were interviewed and tested for HIV. Paired t-test or McNemar Chi-squared test were used to compare the characteristics between the cases and controls. A stepwise conditional logistic regression was used to identify risk factors associated with HIV infection. Findings This study enrolled 103 cases and 206 controls. Aphrodisiac use (P = 0.02, odds ratio (OR) = 1.81, 95% CI = 1.08–3.04), never using condom during commercial sex encounter (P = 0.03, odds ratio (OR) = 1.82, 95% CI = 1.08–3.07), and lacking a stable partner (P = 0.03, odds ratio (OR) = 1.76, 95% CI = 1.05–2.98) were found to be risk factors for HIV infection among the study groups. For subjects reporting aphrodisiac use, the frequency of purchasing sex was positively correlated with the frequency of aphrodisiac use (r = 0.3; p = 0.02). Conclusions Aphrodisiac use was significantly associated with increased HIV infection risk in men over 50 years old who purchased commercial sex in the suburban and rural areas of Guangxi. Further research and interventions should address the links between aphrodisiac use, commercial sex work, condom use, and increased HIV transmission. PMID:25286369

Aphrodisiac use associated with HIV infection in elderly male clients of low-cost commercial sex venues in Guangxi, China: a matched case-control study.

PubMed

Tang, Zhenzhu; Wu, Xinghua; Li, Guojian; Shen, Zhiyong; Zhang, Hongman; Lan, Guanghua; Feng, Xue; Lin, Rui; Abdullah, Abu S; Wu, Zunyou; Shi, Cynthia X

2014-01-01

Rising HIV infection rates have been observed among elderly people in Guangxi, China. Inexpensive aphrodisiacs are available for purchase in suburban and rural areas. This study aims to investigate the association between aphrodisiac use and increased HIV risk for middle-aged and elderly men in Guangxi. A matched case-control study of aphrodisiac use-associated HIV infection was performed among male subjects over 50 years old who were clients of low-cost commercial sex venues in Guangxi. The cases were defined as clients who were HIV-positive and two controls were selected for each case. The cases and the controls were matched on the visited sex venue, age (±3 years), number of years of purchasing sex (±3 years), and educational attainment. Subjects were interviewed and tested for HIV. Paired t-test or McNemar Chi-squared test were used to compare the characteristics between the cases and controls. A stepwise conditional logistic regression was used to identify risk factors associated with HIV infection. This study enrolled 103 cases and 206 controls. Aphrodisiac use (P = 0.02, odds ratio (OR) = 1.81, 95% CI = 1.08-3.04), never using condom during commercial sex encounter (P = 0.03, odds ratio (OR) = 1.82, 95% CI = 1.08-3.07), and lacking a stable partner (P = 0.03, odds ratio (OR) = 1.76, 95% CI = 1.05-2.98) were found to be risk factors for HIV infection among the study groups. For subjects reporting aphrodisiac use, the frequency of purchasing sex was positively correlated with the frequency of aphrodisiac use (r = 0.3; p = 0.02). Aphrodisiac use was significantly associated with increased HIV infection risk in men over 50 years old who purchased commercial sex in the suburban and rural areas of Guangxi. Further research and interventions should address the links between aphrodisiac use, commercial sex work, condom use, and increased HIV transmission.

Statin use and risk of first-time psoriasis diagnosis.

PubMed

Brauchli, Yolanda B; Jick, Susan S; Meier, Christoph R

2011-07-01

Statins have been suggested as a potential treatment for psoriasis because of their anti-inflammatory properties. However, evidence on the benefits of statins is scarce. We sought to study the association between use of statins or other lipid-lowering agents and the risk of developing psoriasis. We conducted a case-control analysis using the United Kingdom-based General Practice Research Database. We identified patients with an incident psoriasis diagnosis between 1994 and 2005 and matched one control subject to each patient on age, sex, general practice, calendar time, and years of history in the database. We estimated odds ratios (ORs) with 95% confidence intervals (CIs), stratified exposure by timing and duration, and adjusted the ORs for potential confounders. We identified 36,702 incident psoriasis cases and the same number of matched controls. Adjusted ORs for current use (last prescription <30 days before index date) of 1 to 4, 5 to 19, or greater than or equal to 20 prescriptions for statins, as compared with nonuse, were 0.60 (95% CI 0.45-0.80), 1.00 (95% CI 0.84-1.18), and 1.08 (95% CI 0.92-1.28), respectively. The ORs for recent and past use (last prescription 30-89 days and ≥90 days ago, respectively) were around 1, except for past use of 1 to 4 prescriptions (OR 1.39; 95% CI 1.09-1.78). Potential of residual confounding as a result of retrospective study design is a limitation. This large case-control study does not provide evidence for an altered risk of developing psoriasis in association with long-term use of statins. The reduced psoriasis risk for current short-term statin users is interesting, but whether the association is indeed causal needs further investigation. Copyright © 2010 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

Prostate-specific antigen screening and mortality from prostate cancer.

PubMed

Marcella, Stephen W; Rhoads, George G; Carson, Jeffrey L; Merlino, Frances; Wilcox, Homer

2008-03-01

There is no available evidence from randomized trials that early detection of prostate cancer improves health outcomes, but the prostate-specific antigen (PSA) test is commonly used to screen men for prostate cancer. The objective of the study is to see if screening with PSA decreases mortality from prostate cancer. This is a case-control study using one-to-one matching on race, age, and time of availability of exposure to PSA screening. Decedents, 380, from New Jersey Vital Statistics 1997 to 2000 inclusive, 55-79 years of age at diagnosis were matched to living controls without metastatic prostate cancer. Medical records were obtained from all providers, and we abstracted information about PSA tests from 1989 to the time of diagnosis in each index case. Measurements consist of a comparison of screening (yes, no) between cases and controls. Measure of association was the odds ratio. Eligible cases were diagnosed each year from 1989 to 1999 with the median year being 1993. PSA screening was evident in 23.2-29.2% of cases and 21.8-26.1% of controls depending on the screening criteria. The unadjusted, matched odds ratio for dying of prostate cancer if ever screened was 1.09 (95% CI 0.76 to 1.60) for the most restrictive criteria and 1.19 (95% CI, 0.85 to 1.66) for the least restrictive. Adjustment for comorbidity and education level made no significant differences in these values. There were no significant interactions by age or race. PSA screening using an ever/never tabulation for tests from 1989 until 2000 did not protect New Jersey men from prostate cancer mortality.

Medical and drug risk factors associated with neuroblastoma: a case-control study.

PubMed

Kramer, S; Ward, E; Meadows, A T; Malone, K E

1987-05-01

A matched case-control study of prenatal risk factors for neuroblastoma was conducted, including 104 cases diagnosed over the period 1970-79 in the Greater Delaware Valley. Significantly elevated odds ratios (ORs) were associated with maternal use of a neurally active drug during pregnancy (OR = 2.83), sex hormone exposure 3 months prior to or during pregnancy (OR = 2.25), frequent alcohol consumption during pregnancy (OR = 9.0), and maternal use of diuretic drugs during pregnancy (OR = 5.75). Significantly more case mothers than control mothers reported use of hair coloring products during pregnancy (OR = 3.0). No association was found between cigarette smoking, coffee consumption, or medical irradiation and case-control status.

Continuous Positive Airway Pressure Adherence In Patients with Obstructive Sleep Apnea & Symptomatic BPH.

PubMed

Metta, Ramesh V V S; Zaka, Awais; Lee, Vincent C; Mador, M Jeffery

2017-04-01

Purpose To determine the short-term and long-term adherence rates with continuous positive airway pressure (CPAP) therapy in sleep apnea patients with benign prostatic hyperplasia (BPH) compared to matched controls. Methods A case-control retrospective analysis was performed in a veterans affairs hospital. All symptomatic patients with BPH (n = 107) ever started on CPAP therapy between 2006 and 2012 were compared with controls matched for severity of sleep apnea (AHI). Adherence measures were obtained at the third and twelfth month visits. The cases included symptomatic BPH patients on active medical therapy. Diuretic use among cases and controls, and severity of nocturia among the cases were also analyzed. Results The mean AHI among cases and controls was 35.6 ± 27.3 and 35.5 ± 31 (p = 0.96). The population was male and predominantly Caucasian. There was no statistically significant difference in percent days CPAP device use ≥4 h. between symptomatic BPH patients and controls at 3-month (51.6 ± 38 vs. 47.2 ± 36; p = 0.43) and 1-year (64 ± 40.5 vs. 64.7 ± 31.3; p = 0.90) visits. The use of diuretics in the cases and controls, and the severity of nocturia in the cases did not influence adherence with CPAP therapy. Conclusions BPH or diuretic use did not affect adherence with CPAP therapy in obstructive sleep apnea. Severity of nocturia did not have any influence on adherence among the cases. BPH, regardless of the severity of nocturia, and diuretic use does not influence CPAP adherence in patients with OSA.

Frequency of and risk factors associated with catastrophic musculoskeletal injuries in Quarter Horses at two Midwestern racetracks: 67 cases (2000-2011).

PubMed

Beisser, Andrea; McClure, Scott; Rezabek, Grant; Soring, Keith H; Wang, Chong

2014-11-15

To determine the incidence and anatomic location of and potential risk factors for catastrophic musculoskeletal injuries (CMIs) in racing Quarter Horses. Retrospective matched case-control study. 67 racing Quarter Horse racehorses euthanized because of CMIs and 134 matched controls. Data for Quarter Horses that sustained CMIs and the total number of race starts for each year were obtained from 2 Midwestern racing jurisdictions from 2000 through 2011. Information for each horse with a CMI and for 2 randomly selected control horses that ran in the same race but did not incur a CMI were obtained from race records, past performance reports, and video analysis. There were 61,797 race starts and 82 CMIs from 2000 through 2011 at the 2 racetracks studied, for an overall CMI incidence of 1.33 CMIs/1,000 starts. Sixty-seven horses with CMIs for which complete data were available and 134 matched control horses were included in the study. There was no difference in the incidence of CMIs between the 2 racetracks or over the years studied. The right forelimb was injured in 38 of the 67 (56.7%) horses. Injures to the carpus (24/67 [35.8%]) and metacarpophalangeal joint (fetlock joint; 23/67 [34.3%]) occurred most frequently. Case-control data indicated that the horses with a CMI had fewer starts, were more likely to have stumbled at the break, had a more erratic stride, were fatigued, and trailed in the race, compared with matched controls from the same races. Irrespective of race distance, most of the horses (47/67 [70.1%]) were injured after or within 10 yards before the finish line. The results of the present study may aid in the identification of racing Quarter Horses at risk for CMIs. The cluster of injuries near the finish line provides a specific focus for future research into methods of injury prevention in this population of racehorses.