Major Depressive Disorder and Impulsive Reactivity to Emotion: Toward a Dual Process View of Depression

PubMed Central

Carver, Charles S.; Johnson, Sheri L.; Joormann, Jutta

2012-01-01

Objective Dual process theories of behavior have been used to suggest that vulnerability to depression involves elevated reactivity to emotions. This study tests that idea, examining self-reported reactivity. Design Comparison between persons with at least one lifetime episode of major depressive disorder (lifetime MDD) and those without this diagnosis, controlling for symptoms of alcohol use (a potential externalizing confound) and current symptoms of depression (a potential state-dependent confound). Methods Undergraduates (N = 120) completed a clinical interview to diagnose lifetime MDD and a series of self-reports bearing on diverse aspects of self-control, including reactivity to emotion. Thirty-four were diagnosed with lifetime MDD; 86 did not meet criteria for MDD. The groups were then compared on three factors underlying the scales assessing self-control. Results The MDD group had higher scores than controls on the two factors that reflect impulsive reactivity to diverse emotions, including emotions that are positive in valence. These effects were not explained by associations with either externalizing symptoms or current depressive symptoms. Conclusions Reflexive reactivity to emotions characterizes depression, in addition to some externalizing problems, and it may deserve study as a potential transdiagnostic feature. PMID:23865405

Reporting of research quality characteristics of studies published in 6 major clinical dental specialty journals.

PubMed

Pandis, Nikolaos; Polychronopoulou, Argy; Madianos, Phoebus; Makou, Margarita; Eliades, Theodore

2011-06-01

The objective of this article was to record reporting characteristics related to study quality of research published in major specialty dental journals with the highest impact factor (Journal of Endodontics, Journal of Oral and Maxillofacial Surgery, American Journal of Orthodontics and Dentofacial Orthopedics; Pediatric Dentistry, Journal of Clinical Periodontology, and International Journal of Prosthetic Dentistry). The included articles were classified into the following 3 broad subject categories: (1) cross-sectional (snap-shot), (2) observational, and (3) interventional. Multinomial logistic regression was conducted for effect estimation using the journal as the response and randomization, sample calculation, confounding discussed, multivariate analysis, effect measurement, and confidence intervals as the explanatory variables. The results showed that cross-sectional studies were the dominant design (55%), whereas observational investigations accounted for 13%, and interventions/clinical trials for 32%. Reporting on quality characteristics was low for all variables: random allocation (15%), sample size calculation (7%), confounding issues/possible confounders (38%), effect measurements (16%), and multivariate analysis (21%). Eighty-four percent of the published articles reported a statistically significant main finding and only 13% presented confidence intervals. The Journal of Clinical Periodontology showed the highest probability of including quality characteristics in reporting results among all dental journals. Copyright © 2011 Elsevier Inc. All rights reserved.

Major depressive disorder and impulsive reactivity to emotion: toward a dual-process view of depression.

PubMed

Carver, Charles S; Johnson, Sheri L; Joormann, Jutta

2013-09-01

Dual-process theories of behaviour have been used to suggest that vulnerability to depression involves elevated reactivity to emotions. This study tests that idea, examining self-reported reactivity. Comparison between persons with at least one lifetime episode of major depressive disorder (lifetime MDD) and those without this diagnosis, controlling for symptoms of alcohol use (a potential externalizing confound) and current symptoms of depression (a potential state-dependent confound). Undergraduates (N = 120) completed a clinical interview to diagnose lifetime MDD and a series of self-reports bearing on diverse aspects of self-control, including reactivity to emotion. Thirty-four people were diagnosed with lifetime MDD; 86 did not meet criteria for MDD. The groups were then compared on three factors underlying the scales assessing self-control. The MDD group had higher scores than controls on the two factors that reflect impulsive reactivity to diverse emotions, including emotions that are positive in valence. These effects were not explained by associations with either externalizing symptoms or current depressive symptoms. Reflexive reactivity to emotions characterizes depression, in addition to some externalizing problems, and it may deserve study as a potential trans-diagnostic feature. Reflexive reactivity to emotions characterizes persons diagnosed with major depressive disorder. Findings suggest desirability of focusing treatment partly on management of reflexive reactions to emotions. Measures were self-reports, rather than behavioural responses to emotions. © 2013 The British Psychological Society.

Metabolic syndrome and shift work: a systematic review.

PubMed

Canuto, Raquel; Garcez, Anderson S; Olinto, Maria T A

2013-12-01

The aim of this systematic review was to examine the association between shift work and metabolic syndrome (MetS) as well as the potential confounders investigated. A systematic search was conducted with the aim of finding original articles on the association between shift work and MetS. The included articles were chosen based on established inclusion criteria; their methodological quality was assessed using a validated quality checklist. A total of 10 articles were included in this review. The majority of the studies were classified as having a low risk of bias. The definitions of MetS and shift work varied between studies. Among the ten studies, eight found a positive association between shift work and MetS after controlling for socio-demographic and behavioral factors. Only three studies included sleep duration as a confounder, and these studies presented discordant results. We conclude that there was insufficient evidence regarding the association between shift work and prevalent MetS when the confounders are taken into account. Copyright © 2012 Elsevier Ltd. All rights reserved.

Breast milk and cognitive development—the role of confounders: a systematic review

PubMed Central

Walfisch, Asnat; Sermer, Corey; Cressman, Alex; Koren, Gideon

2013-01-01

Objectives The association between breastfeeding and child cognitive development is conflicted by studies reporting positive and null effects. This relationship may be confounded by factors associated with breastfeeding, specifically maternal socioeconomic class and IQ. Design Systematic review of the literature. Setting and participants Any prospective or retrospective study, in any language, evaluating the association between breastfeeding and cognitive development using a validated method in healthy term infants, children or adults, was included. Primary and secondary outcome measures Extracted data included the study design, target population and sample size, breastfeeding exposure, cognitive development assessment tool used and participants’ age, summary of the results prior to, and following, adjustment for confounders, and all confounders adjusted for. Study quality was assessed as well. Results 84 studies met our inclusion criteria (34 rated as high quality, 26 moderate and 24 low quality). Critical assessment of accepted studies revealed the following associations: 21 null, 28 positive, 18 null after adjusting for confounders and 17 positive—diminished after adjusting for confounders. Directionality of effect did not correlate with study quality; however, studies showing a decreased effect after multivariate analysis were of superior quality compared with other study groupings (14/17 high quality, 82%). Further, studies that showed null or diminished effect after multivariate analysis corrected for significantly more confounders (7.7±3.4) as compared with those that found no change following adjustment (5.6±4.5, p=0.04). The majority of included studies were carried out during childhood (75%) and set in high-income countries (85.5%). Conclusions Much of the reported effect of breastfeeding on child neurodevelopment is due to confounding. It is unlikely that additional work will change the current synthesis. Future studies should attempt to rigorously control for all important confounders. Alternatively, study designs using sibling cohorts discordant for breastfeeding may yield more robust conclusions. PMID:23975102

When can the cause of a population decline be determined?

PubMed

Hefley, Trevor J; Hooten, Mevin B; Drake, John M; Russell, Robin E; Walsh, Daniel P

2016-11-01

Inferring the factors responsible for declines in abundance is a prerequisite to preventing the extinction of wild populations. Many of the policies and programmes intended to prevent extinctions operate on the assumption that the factors driving the decline of a population can be determined. Exogenous factors that cause declines in abundance can be statistically confounded with endogenous factors such as density dependence. To demonstrate the potential for confounding, we used an experiment where replicated populations were driven to extinction by gradually manipulating habitat quality. In many of the replicated populations, habitat quality and density dependence were confounded, which obscured causal inference. Our results show that confounding is likely to occur when the exogenous factors that are driving the decline change gradually over time. Our study has direct implications for wild populations, because many factors that could drive a population to extinction change gradually through time. © 2016 John Wiley & Sons Ltd/CNRS.

When can the cause of a population decline be determined?

USGS Publications Warehouse

Hefley, Trevor J.; Hooten, Mevin B.; Drake, John M.; Russell, Robin E.; Walsh, Daniel P.

2016-01-01

Inferring the factors responsible for declines in abundance is a prerequisite to preventing the extinction of wild populations. Many of the policies and programmes intended to prevent extinctions operate on the assumption that the factors driving the decline of a population can be determined. Exogenous factors that cause declines in abundance can be statistically confounded with endogenous factors such as density dependence. To demonstrate the potential for confounding, we used an experiment where replicated populations were driven to extinction by gradually manipulating habitat quality. In many of the replicated populations, habitat quality and density dependence were confounded, which obscured causal inference. Our results show that confounding is likely to occur when the exogenous factors that are driving the decline change gradually over time. Our study has direct implications for wild populations, because many factors that could drive a population to extinction change gradually through time.

Depression or anxiety in adult twins is associated with asthma diagnosis but not with offspring asthma.

PubMed

Tedner, S G; Lundholm, C; Olsson, H; Almqvist, C

2016-06-01

Asthma is common in both children and adults in the Western world, just like anxiety and depression. While some research has revealed that these diseases might share important environmental and pathophysiological aspects, the exact mechanisms still remain unclear. To study the correlation firstly between depression or anxiety and asthma diagnosis in adult twins and secondly the association between parental depression or anxiety and offspring asthma in children of twins. In total, 24 685 adult twins aged 20-47 years were interviewed or completed a Web-based questionnaire and their children were identified through the Multi-Generation Register. Asthma diagnosis was obtained from the Patient Register and the Prescribed Drug Register. Assessment of depression and anxiety was obtained from questionnaires using Center for Epidemiologic Studies Depression Scale (CES-D), major depression and generalized anxiety disorder (GAD) from DSM-IV. The association between depression or anxiety and asthma was analyzed with logistic regression adjusting for confounders in twins and offspring. To address genetic and familial environmental confounding, we performed a cotwin analysis using disease-discordant twin pairs. We found an association between asthma and CES-D, major depression and GAD, for example adjusted OR for major depression and register-based asthma 1.56 (1.36-1.79). Most of the point estimates remained in the co-twin control analysis, indicating that the association was likely not due to genetic or familial environmental factors. There was no association between parental depression and/or anxiety and asthma diagnosis in the offspring which implies lack of genetic confounding. We found an association between own asthma diagnosis and anxiety or depression, but not with offspring asthma. Our results indicate that the associations were not due to confounding from genes or environment shared by the twins. © 2016 John Wiley & Sons Ltd.

Anesthesia in Experimental Stroke Research

PubMed Central

Hoffmann, Ulrike; Sheng, Huaxin; Ayata, Cenk; Warner, David S.

2016-01-01

Anesthetics have enabled major advances in development of experimental models of human stroke. Yet their profound pharmacologic effects on neural function can confound the interpretation of experimental stroke research. Anesthetics have drug and dose-specific effects on cerebral blood flow and metabolism, neurovascular coupling, autoregulation, ischemic depolarizations, excitotoxicity, inflammation, neural networks, and numerous molecular pathways relevant for stroke outcome. Both pre- and post-conditioning properties have been described. Anesthetics also modulate systemic arterial blood pressure, lung ventilation, and thermoregulation, all of which may interact with the ischemic insult as well as the therapeutic interventions. These confounds present a dilemma. Here, we provide an overview of the anesthetic mechanisms of action and molecular and physiologic effects on factors relevant to stroke outcomes that can guide the choice and optimization of the anesthetic regimen in experimental stroke. PMID:27534542

Assessing Sensitivity to Unmeasured Confounding Using a Simulated Potential Confounder

ERIC Educational Resources Information Center

Carnegie, Nicole Bohme; Harada, Masataka; Hill, Jennifer L.

2016-01-01

A major obstacle to developing evidenced-based policy is the difficulty of implementing randomized experiments to answer all causal questions of interest. When using a nonexperimental study, it is critical to assess how much the results could be affected by unmeasured confounding. We present a set of graphical and numeric tools to explore the…

Betel nut usage is a major risk factor for coronary artery disease.

PubMed

Khan, Muhammad Shahzeb; Bawany, Faizan Imran; Ahmed, Muhammad Umer; Hussain, Mehwish; Khan, Asadullah; Lashari, Muhammad Nawaz

2013-12-27

The objective of our study was to assess betel nut usage as one of the major risk factors associated with coronary artery disease. This case control study consisted of 300 controls and 300 cases. A structured questionnaire was administered to the participants to assess consumption of betel nut and confounding variables. A respondent was considered a regular consumer of betel nut if he/she consumed one or more pieces of betel nut every day for a period of greater than 6 months. About 8 in 10 betel nut chewers developed coronary artery disease. After adjusting for diabetes and hypertension, the odds ratio analysis depicted 7.72 times greater likelihood for coronary artery disease in patients who chewed betel nut for more than 10 years. Our study concludes that betel nut chewing is a significant risk factor leading to the development of coronary artery disease.

Betel Nut Usage Is a Major Risk Factor for Coronary Artery Disease

PubMed Central

Khan, Muhammad Shahzeb; Bawany, Faizan Imran; Ahmed, Muhammad Umer; Hussain, Mehwish; Khan, Asadullah; Lashari, Muhammad Nawaz

2014-01-01

Aim: The objective of our study was to assess betel nut usage as one of the major risk factors associated with coronary artery disease. Methods: This case control study consisted of 300 controls and 300 cases. A structured questionnaire was administered to the participants to assess consumption of betel nut and confounding variables. A respondent was considered a regular consumer of betel nut if he/she consumed one or more pieces of betel nut every day for a period of greater than 6 months. Results: About 8 in 10 betel nut chewers developed coronary artery disease. After adjusting for diabetes and hypertension, the odds ratio analysis depicted 7.72 times greater likelihood for coronary artery disease in patients who chewed betel nut for more than 10 years. Conclusion: Our study concludes that betel nut chewing is a significant risk factor leading to the development of coronary artery disease. PMID:24576380

Depression and smoking: a 5-year prospective study of patients with major depressive disorder.

PubMed

Holma, Irina A K; Holma, K Mikael; Melartin, Tarja K; Ketokivi, Mikko; Isometsä, Erkki T

2013-06-01

Major depressive disorder (MDD) and smoking are major public health problems and epidemiologically strongly associated. However, the relationship between smoking and depression and whether this is influenced by common confounding factors remain unclear, in part due to limited longitudinal data on covariation. In the Vantaa Depression Study, psychiatric out- and inpatients with DSM-IV MDD and aged 20-59 years at were followed from baseline to 6 months, 18 months, and 5 years. We investigated course of depression, smoking, and comorbid alcohol-use disorders among the 214 patients (79.6% of 269) participating at least three time points; differences between smoking versus nonsmoking patients, and covariation of MDD, smoking, and alcohol-use disorders. Overall, 31.3% of the patients smoked regularly, 41.1% intermittently, and 27.6% never. Smokers were younger, had more alcohol-use disorders and Cluster B and C personality disorder symptoms, a higher frequency of lifetime suicide attempts, higher neuroticism, smaller social networks, and lower perceived social support than never smokers. Smoking and depression had limited longitudinal covariation. Depression, smoking, and alcohol-use disorders all exhibited strong autoregressive tendencies. Among adult psychiatric MDD patients, smoking is strongly associated with substance-use and personality disorders, which may confound research on the impact of smoking. Rather than depression or smoking covarying or predicting each other, depression, smoking, and alcohol-use disorders each have strong autoregressive tendencies. These findings are more consistent with common factors causing their association than either of the conditions strongly predisposing to the other. © 2013 Wiley Periodicals, Inc.

Cardiovascular and Cerebrovascular Events Are Associated With Nontraumatic Osteonecrosis of the Femoral Head.

PubMed

Sung, Pei-Hsun; Yang, Yao-Hsu; Chiang, Hsin-Ju; Chiang, John Y; Chen, Chi-Jen; Yip, Hon-Kan; Lee, Mel S

2018-04-01

Endothelial dysfunction has been identified as an etiologic factor for osteonecrosis of the femoral head (ONFH) and major adverse cardiovascular and cerebrovascular events (defined as major cardiovascular disease [CVD] and cerebrovascular accident [CVA]). However, the incidence of major adverse cardiovascular and cerebrovascular events in patients with nontraumatic ONFH and any association between the two diagnoses remain unclear. We compared a large cohort of patients with nontraumatic ONFH and a matched control group without this diagnosis and (1) examined the frequency and hazard ratio (HR) of major adverse cardiovascular and cerebrovascular events in both groups adjusted for age, sex, socioeconomic status, and associated comorbidities (which we defined as the adjusted HR), (2) determined whether any association of ONFH and major adverse cardiovascular and cerebrovascular events was stable after adjusting for confounding variables, and (3) compared the occurrence of major adverse cardiovascular and cerebrovascular events with time in both groups. A population-based cohort with a 14-year dataset period (1997-2010) from the Taiwan National Health Insurance Research Database was used for this retrospective study. The database includes a greater than 99.5% Asian population randomly selected from more than 23 million citizens and foreigners residing in Taiwan for longer than 6 months. A total of 1562 patients with nontraumatic ONFH were identified from a population of one million patients in the database after excluding initially concomitant diagnoses of major CVD and CVA. The comparison group (n = 15,620) without ONFH was analyzed in a one-to-10 ratio by matching the study cohort based on age, sex, income, and urbanization. The patients with ONFH had a higher frequency of major adverse cardiovascular and cerebrovascular events than their counterparts without ONFH (19% versus 14%; p < 0.001). The patients with ONFH had 1.34- and 1.27-fold adjusted HRs for occurrence of major CVD and CVA as compared with the normal population (95% CI, 1.11-1.61, p = 0.002, and 95% CI, 1.09-1.47, p = 0.002, respectively). Sensitivity analysis showed a consistent association between ONFH and major adverse cardiovascular and cerebrovascular events after controlling for potentially relevant confounding variables such as hypertension and diabetes. After adjusting for potential confounders including surgery and medications, ONFH remained independently associated with major CVD (adjusted HR, 1.51, 95% CI 1.09-2.03, p = 0.026) and CVA (adjusted HR, 2.44, 95% CI 1.69-3.51, p < 0.001), apart from age older than 65 years and traditional atherosclerotic risk factors. The cumulative incidence of major adverse cardiovascular and cerebrovascular events also was higher in the ONFH group than the non-ONFH group (30.3% vs 23.1% at the end of followup, p < 0.001). Patients with ONFH have a strong association with major adverse cardiovascular and cerebrovascular events as compared with the normal population, suggesting a potential common pathway involving endothelial dysfunction. In view of this association in the relatively young population with ONFH, it is important to closely monitor these patients, treat relevant comorbidities early, and investigate preventative measures for these major adverse events. Level III, prognostic study.

Quantification of confounding factors in MRI-based dose calculations as applied to prostate IMRT

NASA Astrophysics Data System (ADS)

Maspero, Matteo; Seevinck, Peter R.; Schubert, Gerald; Hoesl, Michaela A. U.; van Asselen, Bram; Viergever, Max A.; Lagendijk, Jan J. W.; Meijer, Gert J.; van den Berg, Cornelis A. T.

2017-02-01

Magnetic resonance (MR)-only radiotherapy treatment planning requires pseudo-CT (pCT) images to enable MR-based dose calculations. To verify the accuracy of MR-based dose calculations, institutions interested in introducing MR-only planning will have to compare pCT-based and computer tomography (CT)-based dose calculations. However, interpreting such comparison studies may be challenging, since potential differences arise from a range of confounding factors which are not necessarily specific to MR-only planning. Therefore, the aim of this study is to identify and quantify the contribution of factors confounding dosimetric accuracy estimation in comparison studies between CT and pCT. The following factors were distinguished: set-up and positioning differences between imaging sessions, MR-related geometric inaccuracy, pCT generation, use of specific calibration curves to convert pCT into electron density information, and registration errors. The study comprised fourteen prostate cancer patients who underwent CT/MRI-based treatment planning. To enable pCT generation, a commercial solution (MRCAT, Philips Healthcare, Vantaa, Finland) was adopted. IMRT plans were calculated on CT (gold standard) and pCTs. Dose difference maps in a high dose region (CTV) and in the body volume were evaluated, and the contribution to dose errors of possible confounding factors was individually quantified. We found that the largest confounding factor leading to dose difference was the use of different calibration curves to convert pCT and CT into electron density (0.7%). The second largest factor was the pCT generation which resulted in pCT stratified into a fixed number of tissue classes (0.16%). Inter-scan differences due to patient repositioning, MR-related geometric inaccuracy, and registration errors did not significantly contribute to dose differences (0.01%). The proposed approach successfully identified and quantified the factors confounding accurate MRI-based dose calculation in the prostate. This study will be valuable for institutions interested in introducing MR-only dose planning in their clinical practice.

The ACCE method: an approach for obtaining quantitative or qualitative estimates of residual confounding that includes unmeasured confounding

PubMed Central

Smith, Eric G.

2015-01-01

Background:  Nonrandomized studies typically cannot account for confounding from unmeasured factors.  Method:  A method is presented that exploits the recently-identified phenomenon of  “confounding amplification” to produce, in principle, a quantitative estimate of total residual confounding resulting from both measured and unmeasured factors.  Two nested propensity score models are constructed that differ only in the deliberate introduction of an additional variable(s) that substantially predicts treatment exposure.  Residual confounding is then estimated by dividing the change in treatment effect estimate between models by the degree of confounding amplification estimated to occur, adjusting for any association between the additional variable(s) and outcome. Results:  Several hypothetical examples are provided to illustrate how the method produces a quantitative estimate of residual confounding if the method’s requirements and assumptions are met.  Previously published data is used to illustrate that, whether or not the method routinely provides precise quantitative estimates of residual confounding, the method appears to produce a valuable qualitative estimate of the likely direction and general size of residual confounding. Limitations:  Uncertainties exist, including identifying the best approaches for: 1) predicting the amount of confounding amplification, 2) minimizing changes between the nested models unrelated to confounding amplification, 3) adjusting for the association of the introduced variable(s) with outcome, and 4) deriving confidence intervals for the method’s estimates (although bootstrapping is one plausible approach). Conclusions:  To this author’s knowledge, it has not been previously suggested that the phenomenon of confounding amplification, if such amplification is as predictable as suggested by a recent simulation, provides a logical basis for estimating total residual confounding. The method's basic approach is straightforward.  The method's routine usefulness, however, has not yet been established, nor has the method been fully validated. Rapid further investigation of this novel method is clearly indicated, given the potential value of its quantitative or qualitative output. PMID:25580226

Confounding by dietary pattern of the inverse association between alcohol consumption and type 2 diabetes risk

USDA-ARS?s Scientific Manuscript database

Epidemiology of dietary components and disease risk limits interpretability due to potential residual confounding by correlated dietary components. Dietary pattern analyses by factor analysis or partial least squares may overcome the limitation. To examine confounding by dietary pattern as well as ...

Confounding by dietary patterns of the inverse association between alcohol consumption and type 2 diabetes risk

USDA-ARS?s Scientific Manuscript database

Epidemiology of dietary components and disease risk limits interpretability due to potential residual confounding by correlated dietary components. Dietary pattern analyses by factor analysis or partial least squares may overcome this limitation. To examine confounding by dietary pattern as well as ...

Comparing Affiliate Stigma Between Family Caregivers of People With Different Severe Mental Illness in Taiwan.

PubMed

Chang, Chih-Cheng; Yen, Cheng-Fang; Jang, Fong-Lin; Su, Jian-An; Lin, Chung-Ying

2017-07-01

The family caregivers of people with mental illness may internalize the public stereotypes into the affiliate stigma (i.e., the self-stigma of family members). This study aimed to compare the affiliate stigma across schizophrenia, bipolar disorder, and major depressive disorder, and to investigate potential factors associated with affiliate stigma. Each caregiver of family members with schizophrenia (n = 215), bipolar disorder (n = 85), and major depressive disorder (n = 159) completed the Affiliate Stigma Scale, Rosenberg Self-Esteem Scale, Caregiver Burden Inventory, Taiwanese Depression Questionnaire, and Beck Anxiety Inventory. After controlling for potential confounders, the hierarchical regression models showed that caregivers of a family member with schizophrenia had a higher level of affiliate stigma than those of bipolar disorder (β = -0.109; p < 0.05) and major depressive disorder (β = -0.230; p < 0.001). Self-esteem, developmental burden, and emotional burden were significant factors for affiliate stigma. The affiliate stigma of caregivers is associated with their self-esteem, caregiver burden, and by the diagnosis.

Developing hazelnut tissue culture medium free of ion confounding

USDA-ARS?s Scientific Manuscript database

The general approach for tissue culture medium optimization is to use salts as factors in experimental design and analysis. However, using salts as factors leads to ion confounding, making it difficult to detect the effects of individual ions on particular growth responses. This study focused on tes...

Supervised normalization of microarrays

PubMed Central

Mecham, Brigham H.; Nelson, Peter S.; Storey, John D.

2010-01-01

Motivation: A major challenge in utilizing microarray technologies to measure nucleic acid abundances is ‘normalization’, the goal of which is to separate biologically meaningful signal from other confounding sources of signal, often due to unavoidable technical factors. It is intuitively clear that true biological signal and confounding factors need to be simultaneously considered when performing normalization. However, the most popular normalization approaches do not utilize what is known about the study, both in terms of the biological variables of interest and the known technical factors in the study, such as batch or array processing date. Results: We show here that failing to include all study-specific biological and technical variables when performing normalization leads to biased downstream analyses. We propose a general normalization framework that fits a study-specific model employing every known variable that is relevant to the expression study. The proposed method is generally applicable to the full range of existing probe designs, as well as to both single-channel and dual-channel arrays. We show through real and simulated examples that the method has favorable operating characteristics in comparison to some of the most highly used normalization methods. Availability: An R package called snm implementing the methodology will be made available from Bioconductor (http://bioconductor.org). Contact: jstorey@princeton.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:20363728

Effects of Age at First Childbirth and Other Factors on Central Obesity in Postmenopausal Women: The 2013–2015 Korean National Health and Nutrition Examination Survey

PubMed Central

Lee, Wang Jin; Lee, Joo Ha; Kwag, Byoung Gyu; Chang, Shin Hae; Choi, Yu Jin

2018-01-01

Background Waist circumference is one of the key components of metabolic syndrome. Recent studies demonstrated that the reproductive profile was associated with metabolic syndrome in postmenopausal women. This study focused on the association between central obesity and age at first childbirth. It also considered other factors associated with central obesity in postmenopausal women. Methods This study was based on the 2013–2015 Korean National Health and Nutrition Examination Survey and involved 3,143 naturally postmenopausal women. These women were divided into three groups according to their age at first childbirth: 19 years or younger (n=252), 20–29 years (n=2,695), and 30 years or older (n=196). Multivariate analysis using logistic regression was performed to evaluate the effects of various reproductive factors, including other confounding factors. Results During adjustment for confounding factors, in the early age at first childbirth group, odds ratios (95% confidence intervals) for central obesity decreased. In the final model, younger age at first childbirth was not significantly related to central obesity (waist circumference more than 85 cm) in naturally postmenopausal women after adjusting for other confounding factors. Conclusion Younger age at first childbirth was not significantly associated with central obesity after adjustment for confounding factors. PMID:29788703

Human Health and Exposure to Electromagnetic Radiation

DTIC Science & Technology

1992-07-01

electromagnetic field exposures and cancer. Studies of electrical and electronic workers are suggestive of such a link, but are subject to the confounding factor ...associations between cancer and electrical installations 108 51 Factors associated with increased risk of childhood cancer in the Denver studies 109 52...It is important in epidemiological studies to make Arenuous efforts to adjust for possible confounding factors , many - in particular the early

Epidemiologic methods in clinical trials.

PubMed

Rothman, K J

1977-04-01

Epidemiologic methods developed to control confounding in non-experimental studies are equally applicable for experiments. In experiments, most confounding is usually controlled by random allocation of subjects to treatment groups, but randomization does not preclude confounding except for extremely large studies, the degree of confounding expected being inversely related to the size of the treatment groups. In experiments, as in non-experimental studies, the extent of confounding for each risk indicator should be assessed, and if sufficiently large, controlled. Confounding is properly assessed by comparing the unconfounded effect estimate to the crude effect estimate; a common error is to assess confounding by statistical tests of significance. Assessment of confounding involves its control as a prerequisite. Control is most readily and cogently achieved by stratification of the data, though with many factors to control simultaneously, multivariate analysis or a combination of multivariate analysis and stratification might be necessary.

Conditional Random Fields for Fast, Large-Scale Genome-Wide Association Studies

PubMed Central

Huang, Jim C.; Meek, Christopher; Kadie, Carl; Heckerman, David

2011-01-01

Understanding the role of genetic variation in human diseases remains an important problem to be solved in genomics. An important component of such variation consist of variations at single sites in DNA, or single nucleotide polymorphisms (SNPs). Typically, the problem of associating particular SNPs to phenotypes has been confounded by hidden factors such as the presence of population structure, family structure or cryptic relatedness in the sample of individuals being analyzed. Such confounding factors lead to a large number of spurious associations and missed associations. Various statistical methods have been proposed to account for such confounding factors such as linear mixed-effect models (LMMs) or methods that adjust data based on a principal components analysis (PCA), but these methods either suffer from low power or cease to be tractable for larger numbers of individuals in the sample. Here we present a statistical model for conducting genome-wide association studies (GWAS) that accounts for such confounding factors. Our method scales in runtime quadratic in the number of individuals being studied with only a modest loss in statistical power as compared to LMM-based and PCA-based methods when testing on synthetic data that was generated from a generalized LMM. Applying our method to both real and synthetic human genotype/phenotype data, we demonstrate the ability of our model to correct for confounding factors while requiring significantly less runtime relative to LMMs. We have implemented methods for fitting these models, which are available at http://www.microsoft.com/science. PMID:21765897

Exercise-induced neuroprotective effects on neurodegenerative diseases: the key role of trophic factors.

PubMed

Campos, Carlos; Rocha, Nuno Barbosa F; Lattari, Eduardo; Paes, Flávia; Nardi, António E; Machado, Sérgio

2016-06-01

Age-related neurodegenerative disorders, like Alzheimer's or Parkinson's disease, are becoming a major issue to public health care. Currently, there is no effective pharmacological treatment to address cognitive impairment in these patients. Here, we aim to explore the role of exercise-induced trophic factor enhancement in the prevention or delay of cognitive decline in patients with neurodegenerative diseases. There is a significant amount of evidence from animal and human studies that links neurodegenerative related cognitive deficits with changes on brain and peripheral trophic factor levels. Several trials with elderly individuals and patients with neurodegenerative diseases report exercise induced cognitive improvements and changes on trophic factor levels including BDNF, IGF-I, among others. Further studies with healthy aging and clinical populations are needed to understand how diverse exercise interventions produce different variations in trophic factor signaling. Genetic profiles and potential confounders regarding trophic factors should also be addressed in future trials.

Confounding by dietary patterns of the inverse association between alcohol consumption and type 2 diabetes risk.

PubMed

Imamura, Fumiaki; Lichtenstein, Alice H; Dallal, Gerard E; Meigs, James B; Jacques, Paul F

2009-07-01

The ability to interpret epidemiologic observations is limited because of potential residual confounding by correlated dietary components. Dietary pattern analyses by factor analysis or partial least squares may overcome the limitation. To examine confounding by dietary pattern as well as standard risk factors and selected nutrients, the authors modeled the longitudinal association between alcohol consumption and 7-year risk of type 2 diabetes mellitus in 2,879 healthy adults enrolled in the Framingham Offspring Study (1991-2001) by Cox proportional hazard models. After adjustment for standard risk factors, consumers of > or =9.0 drinks/week had a significantly lower risk of type 2 diabetes mellitus compared with abstainers (hazard ratio = 0.47, 95% confidence interval (CI): 0.27, 0.81). Adjustment for selected nutrients had little effect on the hazard ratio, whereas adjustment for dietary pattern variables by factor analysis significantly shifted the hazard ratio away from null (hazard ratio = 0.33, 95% CI: 0.17, 0.64) by 40.0% (95% CI: 16.8, 57.0; P = 0.002). Dietary pattern variables by partial least squares showed similar results. Therefore, the observed inverse association, consistent with past studies, was confounded by dietary patterns, and this confounding was not captured by individual nutrient adjustment. The data suggest that alcohol intake, not dietary patterns associated with alcohol intake, is responsible for the observed inverse association with type 2 diabetes mellitus risk.

Poppers, Kaposi's sarcoma, and HIV infection: empirical example of a strong confounding effect?

PubMed

Morabia, A

1995-01-01

Are there empirical examples of strong confounding effects? Textbooks usually show examples of weak confounding or use hypothetical examples of strong confounding to illustrate the paradoxical consequences of not separating out the effect of the studied exposure from that of second factor acting as a confounder. HIV infection is a candidate strong confounder of the spuriously high association reported between consumption of poppers, a sexual stimulant, and risk of Kaposi's sarcoma in the early phase of the AIDS epidemic. To examine this hypothesis, assumptions must be made on the prevalence of HIV infection among cases of Kaposi's sarcoma and on the prevalence of heavy popper consumption according to HIV infection in cases and controls. Results show that HIV infection may have confounded the poppers-Kaposi's sarcoma association. However, it cannot be ruled out that HIV did not qualify as a confounder because it was either an intermediate variable or an effect modifier of the association between popper inhalation and Kaposi's sarcoma. This example provides a basis to discuss the mechanism by which confounding occurs as well as the practical importance of confounding in epidemiologic research.

Overview of potential procedural and participant-related confounds for neuroimaging of the resting state

PubMed Central

Duncan, Niall W.; Northoff, Georg

2013-01-01

Studies of intrinsic brain activity in the resting state have become increasingly common. A productive discussion of what analysis methods are appropriate, of the importance of physiologic correction and of the potential interpretations of results has been ongoing. However, less attention has been paid to factors other than physiologic noise that may confound resting-state experiments. These range from straightforward factors, such as ensuring that participants are all instructed in the same manner, to more obscure participant-related factors, such as body weight. We provide an overview of such potentially confounding factors, along with some suggested approaches for minimizing their impact. A particular theme that emerges from the overview is the range of systematic differences between types of study groups (e.g., between patients and controls) that may influence resting-state study results. PMID:22964258

Neurocognitive function in an extended Afrikaner-ancestry family with affective illness.

PubMed

Savitz, Jonathan; van der Merwe, Lize; Solms, Mark; Ramesar, Rajkumar

2007-03-01

To characterize the neuropsychological profile of an extended family with unipolar depression (UPD) and other forms of affective illness. We administered a battery of neuropsychological tasks measuring various aspects of executive function and visual and verbal memory to 49 individuals in 1 extended family. Six participants had 1 lifetime episode of major depression (MDE-S), 15 were diagnosed with recurrent major depression (MDE-R), 11 had another DSM-IV diagnosis and 17 subjects were unaffected. After controlling for multiple confounding factors, including mood and medication, the MDE-R sample made significantly more errors than unaffected relatives on the Stroop Task, a measure of cognitive control. There may be at least 1 subtype of UPD characterized by a state-independent deficit in cognitive control.

Hematologic abnormalities associated with Simian Immunodeficieny Virus (SIV) Infection mimic those in HIV infection

PubMed Central

Gill, Amy F.; Ahsan, Muhammad H.; Lackner, Andrew A.; Veazey, Ronald S.

2012-01-01

Studies of hematologic abnormalities in HIV infected patients are confounded by a multitude of factors. A retrospective data analysis of SIV infected Rhesus macaques (RM) of Indian origin was performed to determine the prevalence of hematologic abnormalities free of these confounds. Hematologic data from rhesus macaques inoculated with SIV and without antiviral therapy were examined pre-inoculation, and throughout infection and the development of AIDS. Anemia, thrombocytopenia, lymphopenia, eosinophilia, and neutropenia all increased in prevalence with SIV infection. Significant increases in prevalence for both neutropenia and neutrophilia were also detected in SIV-infected macaques. SIV-infected macaques also had lower lymphocyte counts and increased prevalence of lymphopenia compared to non-infected subjects. The prevalence of eosinophilia was significantly increased during SIV infection. Concordance of hematologic abnormalities during SIV infection of macaques with similar changes in HIV infection of humans suggest that, like in HIV infection, hematologic abnormalities are major complications of SIV infection. PMID:22620272

Hematologic abnormalities associated with simian immunodeficieny virus (SIV) infection mimic those in HIV infection.

PubMed

Gill, Amy F; Ahsan, Muhammad H; Lackner, Andrew A; Veazey, Ronald S

2012-06-01

Studies of hematologic abnormalities in HIV-infected patients are confounded by a multitude of factors. A retrospective data analysis of simian immunodeficieny virus (SIV)-infected rhesus macaques (RM) of Indian origin was performed to determine the prevalence of hematologic abnormalities free of these confounds. Hematologic data from RM inoculated with SIV and without antiviral therapy were examined pre-inoculation, and throughout infection and the development of AIDS. Anemia, thrombocytopenia, lymphopenia, eosinophilia, and neutropenia all increased in prevalence with SIV infection. Significant increases in prevalence for both neutropenia and neutrophilia were also detected in SIV-infected macaques. SIV-infected macaques also had lower lymphocyte counts and increased prevalence of lymphopenia compared with non-infected subjects. The prevalence of eosinophilia was significantly increased during SIV infection. Concordance of hematologic abnormalities during SIV infection of macaques with similar changes in HIV infection of humans suggests that, like in HIV infection, hematologic abnormalities are major complications of SIV infection. © 2012 John Wiley & Sons A/S.

Angiotensin-Converting Enzyme Inhibitors and the Risk of Congenital Malformations

PubMed Central

Bateman, Brian T; Patorno, Elisabetta; Desai, Rishi J; Seely, Ellen W; Mogun, Helen; Dejene, Sara Z; Fischer, Michael A; Friedman, Alexander M; Hernandez-Diaz, Sonia; Huybrechts, Krista F

2016-01-01

Objective To examine the association between first-trimester angiotensin-converting enzyme (ACE) inhibitor exposure and the risk for overall major congenital, cardiac, and central nervous system (CNS) malformations. Methods We used a cohort of completed pregnancies linked to liveborn infants derived from Medicaid claims from 2000 to 2010. We examined the risk of malformations associated with first-trimester exposure to an ACE inhibitor. Propensity score based methods were used to control for potential confounders including maternal demographics, medical conditions, exposure to other medications, and measures of health care utilization. Results The cohort included 1,333,624 pregnancies, of which 4,107 (0.31%) were exposed to ACE inhibitors during the first trimester. The prevalence of overall malformations in the ACE inhibitor–exposed was 5.9% versus 3.3% in the unexposed (unadjusted relative risk (RR), 1.82; 95% confidence interval (CI) 1.61 to 2.06), of cardiac malformations was 3.4% versus 1.2% (RR 2.95; 95% CI 2.50 to 3.47), and of CNS malformations was 0.27% versus 0.18% (RR 1.46; 95% CI 0.81 to 2.64). After restricting the cohort to pregnancies complicated by chronic hypertension (both exposed and unexposed) and accounting for other confounding factors, there was no significant increase in the risk for any of the outcomes assessed. Relative risks associated with first-trimester ACE inhibitor exposure were 0.89 (95% CI 0.75 to 1.06) for overall malformations, 0.95 (95% CI 0.75 to 1.21) for cardiac malformations, and 0.54 (95% CI 0.26 to 1.11) for CNS malformations. Conclusions After accounting for confounders, among women with hypertension, exposure to ACE inhibitors during the first trimester was not associated with an increased risk of major congenital malformations. PMID:27926639

Angiotensin-Converting Enzyme Inhibitors and the Risk of Congenital Malformations.

PubMed

Bateman, Brian T; Patorno, Elisabetta; Desai, Rishi J; Seely, Ellen W; Mogun, Helen; Dejene, Sara Z; Fischer, Michael A; Friedman, Alexander M; Hernandez-Diaz, Sonia; Huybrechts, Krista F

2017-01-01

To examine the association between first-trimester angiotensin-converting enzyme (ACE) inhibitor exposure and the risk of overall major congenital, cardiac, and central nervous system malformations. We used a cohort of completed pregnancies linked to liveborn neonates derived from Medicaid claims from 2000 to 2010. We examined the risk of malformations associated with first-trimester exposure to an ACE inhibitor. Propensity score-based methods were used to control for potential confounders including maternal demographics, medical conditions, exposure to other medications, and measures of health care utilization. The cohort included 1,333,624 pregnancies, of which 4,107 (0.31%) were exposed to ACE inhibitors during the first trimester. The prevalence of overall malformations in the ACE inhibitor-exposed pregnancies was 5.9% compared with 3.3% in the unexposed (unadjusted relative risk, 1.82; 95% confidence interval [CI] 1.61-2.06), of cardiac malformations was 3.4% compared with 1.2% (relative risk 2.95, 95% CI 2.50-3.47), and of central nervous system malformations was 0.27% compared with 0.18% (relative risk 1.46, 95% CI 0.81-2.64). After restricting the cohort to pregnancies complicated by chronic hypertension (both exposed and unexposed) and accounting for other confounding factors, there was no significant increase in the risk of any of the outcomes assessed. Relative risks associated with first-trimester ACE inhibitor exposure were 0.89 (95% CI 0.75-1.06) for overall malformations, 0.95 (95% CI 0.75-1.21) for cardiac malformations, and 0.54 (95% CI 0.26-1.11) for CNS malformations. After accounting for confounders, among women with hypertension, exposure to ACE inhibitors during the first trimester was not associated with an increased risk of major congenital malformations.

Syphilis may be a confounding factor, not a causative agent, in syphilitic ALS.

PubMed

Tuk, Bert

2016-01-01

Based upon a review of published clinical observations regarding syphilitic amyotrophic lateral sclerosis (ALS), I hypothesize that syphilis is actually a confounding factor, not a causative factor, in syphilitic ALS. Moreover, I propose that the successful treatment of ALS symptoms in patients with syphilitic ALS using penicillin G and hydrocortisone is an indirect consequence of the treatment regimen and is not due to the treatment of syphilis. Specifically, I propose that the observed effect is due to the various pharmacological activities of penicillin G ( e.g ., a GABA receptor antagonist) and/or the multifaceted pharmacological activity of hydrocortisone. The notion that syphilis may be a confounding factor in syphilitic ALS is highly relevant, as it suggests that treating ALS patients with penicillin G and hydrocortisone-regardless of whether they present with syphilitic ALS or non-syphilitic ALS-may be effective at treating this rapidly progressive, highly devastating disease.

Meta-analysis of lung cancer in asphalt roofing and paving workers with external adjustment for confounding by coal tar

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

Fayerweather, W.E.

2007-07-01

The study's objectives were to update Partanen's and Boffetta's 1994 meta-analysis of lung cancer among roofing and paving asphalt workers and explore the role of coal tar in explaining the statistical heterogeneity among these studies. Information retrieval strategies and eligibility criteria were defined for identifying the epidemiologic studies to be included in the analysis. The relative risk ratio (RR) for lung cancer was selected as the effect measure of interest. Coal tar bias factors were developed and used to externally adjust each eligible study's published RR for confounding by coal tar. The meta-Relative Risk (meta-RR) and its variance were estimatedmore » by general variance-based methods. Heterogeneity of the RRs was assessed by heterogeneity chi-square and I{sup 2} tests. The results from this update were similar to those in Partanen's and Boffetta's original meta-analysis. Although the meta-RRs for the roofers and the pavers were no longer statistically significantly different from one another, significant heterogeneity remained within each of the coal tar-adjusted sectors. Meta-analysis of non-experimental epidemiologic studies is subject to significant uncertainties as is externally correcting studies for confounding. Given these uncertainties, the specific quantitative estimates in this (or any similar) analysis must be viewed with caution. Nevertheless, this analysis provides support for the hypothesis proposed by several major reviewers that confounding by coal tar-related PAH exposures may explain most or all of the lung cancer risks found in the epidemiologic literature on asphalt roofing and paving workers.« less

Does aircraft noise exposure increase the risk of hypertension in the population living near airports in France?

PubMed

Evrard, Anne-Sophie; Lefèvre, Marie; Champelovier, Patricia; Lambert, Jacques; Laumon, Bernard

2017-02-01

The largest study until now around 6 major European airports, the HYENA (HYpertension and Exposure to Noise near Airports) study, reported an excess risk of hypertension related to long-term aircraft noise exposure. The DEBATS (Discussion on the health effects of aircraft noise) study investigated the relationship between this exposure and the risk of hypertension in men and in women near French airports. Blood pressure of 1244 participants older than 18 years of age was measured. Information about health, socioeconomic and lifestyle factors was collected by means of a face-to-face questionnaire performed at home by an interviewer. Aircraft noise exposure was assessed for each participant's home address using noise maps. They were calculated with the Integrated Noise Model with a 1 dB(A)-resolution. The major potential confounders being risk factors for hypertension were included in the logistic regression models: age, occupational activity, body mass index, physical activity and alcohol consumption. After adjustment for the main potential confounders, an exposure-response relationship was evidenced between the risk of hypertension and aircraft noise exposure at night for men only. A 10-dB(A) increase in L night was associated with an OR of 1.34 (95% CI 1.00 to 1.97). These findings contribute to the overall evidence suggesting that aircraft noise exposure at night-time may increase the risk of hypertension in men. Hypertension is a well-known and established risk factor for cardiovascular disease. The association reported in the present study between aircraft noise and hypertension implies that aircraft noise might be a risk factor also for cardiovascular disease. 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/.

Understanding Confounding Effects in Linguistic Coordination: An Information-Theoretic Approach

PubMed Central

Gao, Shuyang; Ver Steeg, Greg; Galstyan, Aram

2015-01-01

We suggest an information-theoretic approach for measuring stylistic coordination in dialogues. The proposed measure has a simple predictive interpretation and can account for various confounding factors through proper conditioning. We revisit some of the previous studies that reported strong signatures of stylistic accommodation, and find that a significant part of the observed coordination can be attributed to a simple confounding effect—length coordination. Specifically, longer utterances tend to be followed by longer responses, which gives rise to spurious correlations in the other stylistic features. We propose a test to distinguish correlations in length due to contextual factors (topic of conversation, user verbosity, etc.) and turn-by-turn coordination. We also suggest a test to identify whether stylistic coordination persists even after accounting for length coordination and contextual factors. PMID:26115446

Directed acyclic graphs (DAGs): an aid to assess confounding in dental research.

PubMed

Merchant, Anwar T; Pitiphat, Waranuch

2002-12-01

Confounding, a special type of bias, occurs when an extraneous factor is associated with the exposure and independently affects the outcome. In order to get an unbiased estimate of the exposure-outcome relationship, we need to identify potential confounders, collect information on them, design appropriate studies, and adjust for confounding in data analysis. However, it is not always clear which variables to collect information on and adjust for in the analyses. Inappropriate adjustment for confounding can even introduce bias where none existed. Directed acyclic graphs (DAGs) provide a method to select potential confounders and minimize bias in the design and analysis of epidemiological studies. DAGs have been used extensively in expert systems and robotics. Robins (1987) introduced the application of DAGs in epidemiology to overcome shortcomings of traditional methods to control for confounding, especially as they related to unmeasured confounding. DAGs provide a quick and visual way to assess confounding without making parametric assumptions. We introduce DAGs, starting with definitions and rules for basic manipulation, stressing more on applications than theory. We then demonstrate their application in the control of confounding through examples of observational and cross-sectional epidemiological studies.

Selective serotonin reuptake inhibitor discontinuation: side effects and other factors that influence medication adherence.

PubMed

Goethe, John W; Woolley, Stephen B; Cardoni, Alex A; Woznicki, Brenda A; Piez, Deborah A

2007-10-01

Patients with major depression discontinue taking their antidepressants for many reasons. Although side effects are often cited as the reason for discontinuation, few prospective studies have addressed this question, and none has specifically examined discontinuation in patients with severe depression. Inpatients and outpatients treated with a selective serotonin reuptake inhibitor for major depressive disorder were identified after admission. Three months later, patients were contacted and interviewed to determine antidepressant usage and the side effects experienced, including when these were experienced and their severity. Between October 2001 and April 2003, 406 English- or Spanish-speaking patients aged 18 to 75 years were followed up. One in 4 patients discontinued the index antidepressant. Among specific side effects noted, only "change in weight" and "anxiety" were significant predictors of discontinuation after controlling for confounders. Experiencing 1 or more "extremely" bothersome side effects was associated with more than a doubling of the risk of discontinuation, but the presence of side effects and side effects less severe than "extremely" bothersome were not significant predictors. There were no differences among selective serotonin reuptake inhibitor antidepressants in either the presence/absence of side effects or in the discontinuation rates. The results suggest that the contribution of side effects to antidepressant discontinuation is more complex than previously suggested. Disparate findings from earlier studies may reflect aspects of study design, such as examining populations whose severity of depression varied widely or not controlling for important confounding factors. Future research should separately examine high-risk groups (or control for severity of depression) and carefully rule out other potential contributors to discontinuation.

Moving forward: response to "Studying eyewitness investigations in the field".

PubMed

Ross, Stephen J; Malpass, Roy S

2008-02-01

Field studies of eyewitness identification are richly confounded. Determining which confounds undermine interpretation is important. The blind administration confound in the Illinois study is said to undermine it's value for understanding the relative utility of simultaneous and sequential lineups. Most criticisms of the Illinois study focus on filler identifications, and related inferences about the importance of the blind confound. We find no convincing evidence supporting this line of attack and wonder at filler identifications as the major line of criticism. More debilitating problems impede using the Illinois study to address the simultaneous versus sequential lineup controversy: inability to estimate guilt independent of identification evidence, lack of protocol compliance monitoring, and assessment of lineups quality. Moving forward requires removing these limitations.

Work-Home Interference, Perceived Total Workload, and the Risk of Future Sickness Absence Due to Stress-Related Mental Diagnoses Among Women and Men: a Prospective Twin Study.

PubMed

Svedberg, Pia; Mather, Lisa; Bergström, Gunnar; Lindfors, Petra; Blom, Victoria

2018-02-01

Work-home interference has been proposed as an important explanation for sickness absence (SA). Previous studies show mixed results, have not accounted for familial factors (genetics and shared everyday environment), or investigated diagnosis specific SA. The aim was to study whether work-home interference and perceived total workload predict SA due to stress-related mental diagnoses, or SA due to other mental diagnoses, among women and men, when adjusting for various confounders and familial factors. This study included 11,916 twins, 19-47 years (49% women). Data on work-to-home and home-to-work conflicts, perceived total workload, and relevant confounders were derived from a 2005 survey, and national register data on SA spells until 2013 were obtained. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Discordant twin pair design was applied to adjust for familial factors. Each one unit increase in work-to-home and home-to-work conflicts, and perceived total workload was associated with higher odds for SA due to stress-related mental diagnoses and to SA due to other mental diagnoses among women, when adjusting for sociodemographic factors (ORs 1.15-1.31). Including health or familial factors, no associations remained. For men, each one unit increase in work-to-home conflicts was associated with higher odds for SA due to stress-related diagnoses (ORs 1.23-1.35), independently of confounders. Work-to-home conflict was independently associated with future SA due to stress-related diagnoses among men only. Health- and work-related factors seem to be important confounders when researching work-home interference, perceived total workload, and SA. Not including such confounders involves risking drawing incorrect conclusions. Further studies are needed to confirm sex differences and whether genetic factors are important for the associations studied.

Maternal smoking during pregnancy and child outcomes: Real or spurious effect?

PubMed Central

Knopik, Valerie S.

2013-01-01

Maternal smoking during pregnancy (MSDP) is a major public health concern with clearly established consequences to both mother and newborn (e.g., low birth weight, altered cardiorespiratory responses). MSDP has also been associated with higher rates of a variety of poor cognitive and behavioral outcomes in children, including ADHD, conduct disorder, impaired learning and memory, and cognitive dysfunction. However, the evidence suggesting causal effects of MSDP for these outcomes is muddied in the existing literature due to the frequent inability to separate prenatal exposure effects from other confounding environmental and genetic factors. Carefully designed studies using genetically sensitive strategies can build upon current evidence and begin to elucidate the likely complex factors contributing to associations between MSDP and child outcomes. PMID:19142764

Commentary: How can family-based quasi-experimental designs and national registers be used to address confounding in risk factor studies of psychopathology? A reflection on Obel et al. (2016).

PubMed

Larsson, Henrik

2016-04-01

Standard observational studies have reported a robust correlation between maternal smoking during pregnancy and risk of ADHD in offspring. In the accompanying article, Obel et al. used sibling-comparisons to explore the extent to which unmeasured familial confounding explains this association. This commentary highlights three important implications of the study. At a general level, Obel et al. illustrates how (1) family-based quasi-experimental designs and (2) national registers can be used to address confounding in risk factor studies of psychopathology. At a more specific level, the study suggests that maternal smoking during pregnancy is probably not a causal risk factor for ADHD. © 2016 Association for Child and Adolescent Mental Health.

Association of fasting triglyceride concentration and postprandial triglyceride response with the carotid intima-media thickness in the middle aged: The Netherlands Epidemiology of Obesity study.

PubMed

Christen, Tim; de Mutsert, Renée; Gast, Karin B; Rensen, Patrick C N; de Koning, Eelco; Rosendaal, Frits R; Trompet, Stella; Jukema, J Wouter

People are in a postprandial state for the majority of the day, postprandial triglyceride (TG) response may be more important in the etiology of atherosclerosis than fasting TGs. The objective of the study was to investigate the associations of fasting TG concentration (TGc) and postprandial TG response after a meal challenge with subclinical atherosclerosis, measured by intima-media thickness (IMT) in a middle-aged population. A total of 5574 participants (57% women) with a mean (standard deviation [SD]) age of 56 (6) years were included in this cross-sectional analysis of baseline measurements of The Netherlands Epidemiology of Obesity study. Serum TGc was measured fasting and 30 and 150 minutes after a liquid mixed meal, and the incremental area under the curve (TGiAUC) was calculated. With linear regression analyses, we calculated the differences in IMT with 95% confidence intervals, adjusted for confounding factors, and additionally for TGc or TGiAUC. Per SD of TGc (0.82 mmol/L), IMT was 8.5 μm (2.1, 14.9) greater after adjustment for TGiAUC and confounding factors. Per SD of TGiAUC (24.0 mmol/L × min), the difference in IMT was -1.7 μm (-8.5, 5.0) after adjustment for fasting TG and confounding factors. The association between TG response after a mixed meal and IMT disappeared after adjusting for TGc. The association between fasting TG concentration and IMT persisted after adjustment for postprandial TG response. These findings imply that it is not useful to perform a meal challenge in cardiovascular risk stratification. Our results support use of fasting TGc instead of postprandial TG responses for cardiovascular risk stratification in clinical practice. Copyright © 2017 National Lipid Association. Published by Elsevier Inc. All rights reserved.

How Confounder Strength Can Affect Allocation of Resources in Electronic Health Records.

PubMed

Lynch, Kristine E; Whitcomb, Brian W; DuVall, Scott L

2018-01-01

When electronic health record (EHR) data are used, multiple approaches may be available for measuring the same variable, introducing potentially confounding factors. While additional information may be gleaned and residual confounding reduced through resource-intensive assessment methods such as natural language processing (NLP), whether the added benefits offset the added cost of the additional resources is not straightforward. We evaluated the implications of misclassification of a confounder when using EHRs. Using a combination of simulations and real data surrounding hospital readmission, we considered smoking as a potential confounder. We compared ICD-9 diagnostic code assignment, which is an easily available measure but has the possibility of substantial misclassification of smoking status, with NLP, a method of determining smoking status that more expensive and time-consuming than ICD-9 code assignment but has less potential for misclassification. Classification of smoking status with NLP consistently produced less residual confounding than the use of ICD-9 codes; however, when minimal confounding was present, differences between the approaches were small. When considerable confounding is present, investing in a superior measurement tool becomes advantageous.

The DSM-III personality disorders section: a commentary.

PubMed

Frances, A

1980-09-01

The author reviews the DSM-III section on personality disorders, discusses several of its more controversial diagnoses, and suggests some possible alternatives. He attributes the continued low reliability of personality diagnoses, compared with the other major sections of DSM-III, to two inherent obstacles: the lack of clear boundaries demarcating the personality disorders from normality and from one another, and the confounding influence of state and role factors. Nonetheless, the DSM-III multiaxial system highlights the importance of personality diagnosis and, together with the provision of clearly specified diagnostic criteria, achieves a considerably improved reliability compared with previous nomenclatures.

An assessment of the possible extent of confounding in epidemiological studies of lung cancer risk among roofers

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

Mundt, D.J.; van Wijngaarden, E.; Mundt, K.A.

2007-07-01

We evaluated the likelihood and extent to which the observed increased risk of lung cancer may be due to confounding (a mixing of effects of multiple exposures) by co-exposure to other potential carcinogens present in roofing or to lifestyle variables. We conducted a review of the epidemiological and industrial hygiene literature of asphalt-exposed workers. Peer-reviewed epidemiological studies of asphalt fumes, related occupational exposures, and confounding factors were identified from MEDLINE (1966 early 2004). Industrial hygiene studies of asphalt workers were identified through MEDLINE, publicly available government documents, and asphalt industry documents. Using well established statistical methods, we quantified the extentmore » to which lung cancer relative risk estimates among roofers reflect confounding from other exposures, using different prevalence and risk scenarios. The relative risk of lung cancer varied from 1.2 to 5.0 in 13 epidemiological studies of roofers; most studies reported a relative risk between 1.2 and 1.4. Smoking, asbestos and coal tar were the most likely confounders, but the prevalence of these factors varied over time. The results of the study indicate that much of the observed risk reported in epidemiological studies of cancer among roofers is well within the range of what may have resulted from confounding by reasonable and expected levels of smoking, asbestos or coal tar. This may be particularly true for those studies that did not adjust for these confounders and where the exposure was defined as employment in the roofing industry. In addition to poorly defined asphalt exposure, uncontrolled confounding cannot reliably be ruled out in studies of lung cancer among asphalt-exposed roofers. Therefore, it is not possible to conclude whether roofers are at increased risk of lung cancer due to asphalt exposure.« less

Neurocognitive function in an extended Afrikaner-ancestry family with affective illness

PubMed Central

Savitz, Jonathan; van der Merwe, Lize; Solms, Mark; Ramesar, Rajkumar

2007-01-01

Objective To characterize the neuropsychological profile of an extended family with unipolar depression (UPD) and other forms of affective illness. Method We administered a battery of neuropsychological tasks measuring various aspects of executive function and visual and verbal memory to 49 individuals in 1 extended family. Six participants had 1 lifetime episode of major depression (MDE-S), 15 were diagnosed with recurrent major depression (MDE-R), 11 had another DSM-IV diagnosis and 17 subjects were unaffected. Results After controlling for multiple confounding factors, including mood and medication, the MDE-R sample made significantly more errors than unaffected relatives on the Stroop Task, a measure of cognitive control. Conclusion There may be at least 1 subtype of UPD characterized by a state-independent deficit in cognitive control. PMID:17353940

Childhood trauma is not a confounder of the overlap between autistic and schizotypal traits: A study in a non-clinical adult sample.

PubMed

Gong, Jing-Bo; Wang, Ya; Lui, Simon S Y; Cheung, Eric F C; Chan, Raymond C K

2017-11-01

Childhood trauma has been shown to be a robust risk factor for mental disorders, and may exacerbate schizotypal traits or contribute to autistic trait severity. However, little is known whether childhood trauma confounds the overlap between schizotypal traits and autistic traits. This study examined whether childhood trauma acts as a confounding variable in the overlap between autistic and schizotypal traits in a large non-clinical adult sample. A total of 2469 participants completed the Autism Spectrum Quotient (AQ), the Schizotypal Personality Questionnaire (SPQ), and the Childhood Trauma Questionnaire-Short Form. Correlation analysis showed that the majority of associations between AQ variables and SPQ variables were significant (p < 0.05). In the multiple regression models predicting scores on the AQ total, scores on the three SPQ subscales were significant predictors(Ps < 0.05). Scores on the Positive schizotypy and Negative schizotypy subscales were significant predictors in the multiple regression model predicting scores on the AQ Social Skill, AQ Attention Switching, AQ Attention to Detail, AQ Communication, and AQ Imagination subscales. The association between autistic and schizotypal traits could not be explained by shared variance in terms of exposure to childhood trauma. The findings point to important overlaps in the conceptualization of ASD and SSD, independent of childhood trauma. Copyright © 2017 Elsevier B.V. All rights reserved.

Demographic factors influencing the GH system: Implications for the detection of GH doping in sport.

PubMed

Nelson, Anne E; Ho, Ken K Y

2009-08-01

Application of methods for detecting GH doping depend on being able to discriminate between abnormal levels due to doping and normal physiological levels of circulating proteins that change in response to exogenous administration. Constituents of the IGF and collagen systems have been shown to be promising markers of GH abuse. Their ultimate utility, however, depends on identification of the factors that regulate their concentrations in blood. Among these are demographic factors that are known to influence these markers in the general population. In a large cross-sectional study of the GH-responsive markers in over 1000 elite athletes from 12 countries representing 4 major ethnic groups and 10 sport types, we have shown that there is a significant negative correlation between age and all the IGF and collagen markers we studied, with a rapid decrease in early adolescence. Age was the major contribution to the variability, equivalent to >80% of the attributable variation in IGF-I and the collagen markers. The IGF axis markers were all significantly higher in women, and the collagen markers significantly higher in men, however, the contribution of gender was smaller than that of age, except for IGFBP-3 and ALS. BMI had a minor contribution to variability of the GH-responsive markers. After adjustment for the confounding influences of age, gender and BMI, the effect of ethnicity in elite athletes was trivial except for IGFBP-3 and ALS, which were both lower in Africans and higher in Caucasians. Compared to age and gender, the contribution of sport type was also modest. Our findings on the influence of age, gender, BMI and sport type have also been confirmed in a study of mostly Caucasian elite athletes in the post-competition setting. In conclusion, age and gender are the major determinants of variability for IGF-I and the collagen markers, whereas ethnicity and sport type have a minor influence. Therefore, a test based on IGF-I and the collagen markers must take age into account for men and women, and ethnicity and sport type are unlikely to be confounders for these markers.

Antidepressant response in patients with major depression exposed to NSAIDs: a pharmacovigilance study.

PubMed

Gallagher, Patience J; Castro, Victor; Fava, Maurizio; Weilburg, Jeffrey B; Murphy, Shawn N; Gainer, Vivian S; Churchill, Susanne E; Kohane, Isaac S; Iosifescu, Dan V; Smoller, Jordan W; Perlis, Roy H

2012-10-01

OBJECTIVE It has been suggested that there is a mechanism by which nonsteroidal anti-inflammatory drugs (NSAIDs) may interfere with antidepressant response, and poorer outcomes among NSAID-treated patients were reported in the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study. To attempt to confirm this association in an independent population-based treatment cohort and explore potential confounding variables, the authors examined use of NSAIDs and related medications among 1,528 outpatients in a New England health care system. METHOD Treatment outcomes were classified using a validated machine learning tool applied to electronic medical records. Logistic regression was used to examine the association between medication exposure and treatment outcomes, adjusted for potential confounding variables. To further elucidate confounding and treatment specificity of the observed effects, data from the STAR*D study were reanalyzed. RESULTS NSAID exposure was associated with a greater likelihood of depression classified as treatment resistant compared with depression classified as responsive to selective serotonin reuptake inhibitors (odds ratio=1.55, 95% CI=1.21-2.00). This association was apparent in the NSAIDs-only group but not in those using other agents with NSAID-like mechanisms (cyclooxygenase-2 inhibitors and salicylates). Inclusion of age, sex, ethnicity, and measures of comorbidity and health care utilization in regression models indicated confounding; association with outcome was no longer significant in fully adjusted models. Reanalysis of STAR*D results likewise identified an association in NSAIDs but not NSAID-like drugs, with more modest effects persisting after adjustment for potential confounding variables. CONCLUSIONS These results support an association between NSAID use and poorer antidepressant outcomes in major depressive disorder but indicate that some of the observed effect may be a result of confounding.

Does consideration of larger study areas yield more accurate estimates of air pollution health effects? An illustration of the bias-variance trade-off in air pollution epidemiology.

PubMed

Pedersen, Marie; Siroux, Valérie; Pin, Isabelle; Charles, Marie Aline; Forhan, Anne; Hulin, Agnés; Galineau, Julien; Lepeule, Johanna; Giorgis-Allemand, Lise; Sunyer, Jordi; Annesi-Maesano, Isabella; Slama, Rémy

2013-10-01

Spatially-resolved air pollution models can be developed in large areas. The resulting increased exposure contrasts and population size offer opportunities to better characterize the effect of atmospheric pollutants on respiratory health. However the heterogeneity of these areas may also enhance the potential for confounding. We aimed to discuss some analytical approaches to handle this trade-off. We modeled NO2 and PM10 concentrations at the home addresses of 1082 pregnant mothers from EDEN cohort living in and around urban areas, using ADMS dispersion model. Simulations were performed to identify the best strategy to limit confounding by unmeasured factors varying with area type. We examined the relation between modeled concentrations and respiratory health in infants using regression models with and without adjustment or interaction terms with area type. Simulations indicated that adjustment for area limited the bias due to unmeasured confounders varying with area at the costs of a slight decrease in statistical power. In our cohort, rural and urban areas differed for air pollution levels and for many factors associated with respiratory health and exposure. Area tended to modify effect measures of air pollution on respiratory health. Increasing the size of the study area also increases the potential for residual confounding. Our simulations suggest that adjusting for type of area is a good option to limit residual confounding due to area-associated factors without restricting the area size. Other statistical approaches developed in the field of spatial epidemiology are an alternative to control for poorly-measured spatially-varying confounders. © 2013 Elsevier Ltd. All rights reserved.

Neuropsychological functioning in older people with type 2 diabetes: the effect of controlling for confounding factors.

PubMed

Asimakopoulou, K G; Hampson, S E; Morrish, N J

2002-04-01

Neuropsychological functioning was examined in a group of 33 older (mean age 62.40 +/- 9.62 years) people with Type 2 diabetes (Group 1) and 33 non-diabetic participants matched with Group 1 on age, sex, premorbid intelligence and presence of hypertension and cardio/cerebrovascular conditions (Group 2). Data statistically corrected for confounding factors obtained from the diabetic group were compared with the matched control group. The results suggested small cognitive deficits in diabetic people's verbal memory and mental flexibility (Logical Memory A and SS7). No differences were seen between the two samples in simple and complex visuomotor attention, sustained complex visual attention, attention efficiency, mental double tracking, implicit memory, and self-reported memory problems. These findings indicate minimal cognitive impairment in relatively uncomplicated Type 2 diabetes and demonstrate the importance of control and matching for confounding factors.

Association Between Cardiovascular Risk Factors and Carpal Tunnel Syndrome in Pooled Occupational Cohorts.

PubMed

Hegmann, Kurt T; Thiese, Matthew Steven; Kapellusch, Jay; Merryweather, Andrew S; Bao, Stephen; Silverstein, Barbara; Wood, Eric M; Kendall, Richard; Wertsch, Jacqueline; Foster, James; Garg, Arun; Drury, David L

2016-01-01

The aim of the study was to ascertain if cardiovascular (CVD) risk factors are carpal tunnel syndrome (CTS) risk factors. Analysis of pooled baseline data from two large prospective cohort studies (n = 1824) assessed the relationships between a modified Framingham Heart Study CVD risk score both CTS and abnormal nerve conduction study prevalence. Quantified job exposures, personal and psychosocial confounders were statistically controlled. Odds ratio and 95% confidence intervals were calculated for individual risk scores. There was a strong relationship between CVD risk score and both CTS and abnormal nerve conduction study after adjustment for confounders, with odds ratios as high as 4.16 and 7.35, respectively. Dose responses were also observed. In this workplace population, there is a strong association between CVD risk scores and both CTS and abnormal nerve conduction study that persisted after controlling for confounders. These data suggest a potentially modifiable disease mechanism.

If it is published in the peer-reviewed literature, it must be true?

PubMed

Wagner, Louis K

2014-10-01

Epidemiological research correlating cancer rates in a population of patients with radiation doses from medical X-rays is fraught with confounding factors that obfuscate the likelihood that any positive relationship is causal. This is a review of four studies involving some of those confounding factors. Comparisons of findings with other studies not encumbered by similar confounding factors can enhance assertions of causation between medical X-rays and cancer rates. Even so, such assertions rest significantly on opinions of researchers regarding the degree of consistency between findings among various studies. The question as to what degree any findings truly represent cause and effect will likely still meet with controversy. The importance of these findings to medicine should therefore not lie in any controversy regarding causation, but in what the findings potentially mean with regard to benefit and risk for patients and the professional practice of medicine.

Obesity and peripheral arterial disease: A Mendelian Randomization analysis.

PubMed

Huang, Ya; Xu, Min; Xie, Lan; Wang, Tiange; Huang, Xiaolin; Lv, Xiaofei; Chen, Ying; Ding, Lin; Lin, Lin; Wang, Weiqing; Bi, Yufang; Sun, Yimin; Zhang, Yifei; Ning, Guang

2016-04-01

Observational studies showed that obesity is a major risk factor for peripheral arterial disease (PAD). However, conventional epidemiology studies are vulnerable to residual bias from confounding factors. We aimed to explore the causality of obesity in development of PAD using Mendelian Randomization (MR) approach. A MR analysis was performed in 11,477 community-dwelling adults aged 40 years and above recruited from two nearby communities during 2011-2013 in Shanghai, China. We genotyped 14 body mass index (BMI) associated common variants identified and validated in East Asians. PAD was defined as ankle-to-brachial index (ABI) <0.90 or >1.40. Weighted BMI genetic risk score (GRS) was used as the Instrumental Variable (IV). After adjusted for confounding factors, we found that each standard deviation (SD, 2.76 points) increase in BMI-GRS was associated with 0.43 (95% confidence interval [CI]: 0.36-0.49) kg/m(2) increase in BMI (P < 0.0001) and an odds ratio (OR) for PAD of 1.17 (95% CI: 1.07-1.27; P = 0.0004). Compared with the lowest quartile of BMI-GRS, the second, third and highest quartile associated with 9%, 19% and 45% increment of PAD risk, respectively (P for trend = 0.002). In the MR analysis, we demonstrated a causal relationship between obesity and PAD (OR = 1.44 per BMI-unit, 95% CI: 1.18-1.75; P = 0.0003). This study suggested that obesity may be causally associated with PAD after controlling for the potential intermediate factors like hypertension, dyslipidemia and hyperglycemia. Copyright © 2016. Published by Elsevier Ireland Ltd.

An investigation into the relationship between age and physiological function in highly active older adults

PubMed Central

Pollock, Ross D; Carter, Scott; Velloso, Cristiana P; Duggal, Niharika A; Lord, Janet M; Lazarus, Norman R; Harridge, Stephen D R

2015-01-01

Despite extensive research, the relationship between age and physiological function remains poorly characterised and there are currently no reliable markers of human ageing. This is probably due to a number of confounding factors, particularly in studies of a cross-sectional nature. These include inter-subject genetic variation, as well as inter-generational differences in nutrition, healthcare and insufficient levels of physical activity as well as other environmental factors. We have studied a cohort of highly and homogeneously active older male (n = 84) and female (n = 41) cyclists aged 55–79 years who it is proposed represent a model for the study of human ageing free from the majority of confounding factors, especially inactivity. The aim of the study was to identify physiological markers of ageing by assessing the relationship between function and age across a wide range of indices. Each participant underwent a detailed physiological profiling which included measures of cardiovascular, respiratory, neuromuscular, metabolic, endocrine and cognitive functions, bone strength, and health and well-being. Significant associations between age and function were observed for many functions. The maximal rate of oxygen consumption ( showed the closest association with age (r = −0.443 to −0.664; P < 0.001), but even here the variance in age for any given level was high, precluding the clear identification of the age of any individual. The results of this cross-sectional study suggest that even when many confounding variables are removed the relationship between function and healthy ageing is complex and likely to be highly individualistic and that physical activity levels must be taken into account in ageing studies. Key Points The relationship between age and physiological function remains poorly defined and there are no physiological markers that can be used to reliably predict the age of an individual. This could be due to a variety of confounding genetic and lifestyle factors, and in particular to ill-defined and low levels of physical activity. This study assessed the relationship between age and a diverse range of physiological functions in a cohort of highly active older individuals (cyclists) aged 55–79 years in whom the effects of lifestyle factors would be ameliorated. Significant associations between age and function were observed for many functions. was most closely associated with age, but even here the variance in age for any given level was high, precluding the clear identification of the age of any individual. The data suggest that the relationship between human ageing and physiological function is highly individualistic and modified by inactivity. PMID:25565071

An investigation into the relationship between age and physiological function in highly active older adults.

PubMed

Pollock, Ross D; Carter, Scott; Velloso, Cristiana P; Duggal, Niharika A; Lord, Janet M; Lazarus, Norman R; Harridge, Stephen D R

2015-02-01

The relationship between age and physiological function remains poorly defined and there are no physiological markers that can be used to reliably predict the age of an individual. This could be due to a variety of confounding genetic and lifestyle factors, and in particular to ill-defined and low levels of physical activity. This study assessed the relationship between age and a diverse range of physiological functions in a cohort of highly active older individuals (cyclists) aged 55-79 years in whom the effects of lifestyle factors would be ameliorated. Significant associations between age and function were observed for many functions. V̇O2max was most closely associated with age, but even here the variance in age for any given level was high, precluding the clear identification of the age of any individual. The data suggest that the relationship between human ageing and physiological function is highly individualistic and modified by inactivity. Despite extensive research, the relationship between age and physiological function remains poorly characterised and there are currently no reliable markers of human ageing. This is probably due to a number of confounding factors, particularly in studies of a cross-sectional nature. These include inter-subject genetic variation, as well as inter-generational differences in nutrition, healthcare and insufficient levels of physical activity as well as other environmental factors. We have studied a cohort of highly and homogeneously active older male (n = 84) and female (n = 41) cyclists aged 55-79 years who it is proposed represent a model for the study of human ageing free from the majority of confounding factors, especially inactivity. The aim of the study was to identify physiological markers of ageing by assessing the relationship between function and age across a wide range of indices. Each participant underwent a detailed physiological profiling which included measures of cardiovascular, respiratory, neuromuscular, metabolic, endocrine and cognitive functions, bone strength, and health and well-being. Significant associations between age and function were observed for many functions. The maximal rate of oxygen consumption (V̇O2max) showed the closest association with age (r = -0.443 to -0.664; P < 0.001), but even here the variance in age for any given level was high, precluding the clear identification of the age of any individual. The results of this cross-sectional study suggest that even when many confounding variables are removed the relationship between function and healthy ageing is complex and likely to be highly individualistic and that physical activity levels must be taken into account in ageing studies. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

Serotonin-1A receptors in major depression quantified using PET: controversies, confounds, and recommendations.

PubMed

Shrestha, Saurav; Hirvonen, Jussi; Hines, Christina S; Henter, Ioline D; Svenningsson, Per; Pike, Victor W; Innis, Robert B

2012-02-15

The serotonin-1A (5-HT(1A)) receptor is of particular interest in human positron emission tomography (PET) studies of major depressive disorder (MDD). Of the eight studies investigating this issue in the brains of patients with MDD, four reported decreased 5-HT(1A) receptor density, two reported no change, and two reported increased 5-HT(1A) receptor density. While clinical heterogeneity may have contributed to these differing results, methodological factors by themselves could also explain the discrepancies. This review highlights several of these factors, including the use of the cerebellum as a reference region and the imprecision of measuring the concentration of parent radioligand in arterial plasma, the method otherwise considered to be the 'gold standard'. Other potential confounds also exist that could restrict or unexpectedly affect the interpretation of results. For example, the radioligand may be a substrate for an efflux transporter - like P-gp - at the blood-brain barrier; furthermore, the binding of the radioligand to the receptor in various stages of cellular trafficking is unknown. Efflux transport and cellular trafficking may also be differentially expressed in patients compared to healthy subjects. We believe that, taken together, the existing disparate findings do not reliably answer the question of whether 5-HT(1A) receptors are altered in MDD or in subgroups of patients with MDD. In addition, useful meta-analysis is precluded because only one of the imaging centers acquired all the data necessary to address these methodological concerns. We recommend that in the future, individual centers acquire more thorough data capable of addressing methodological concerns, and that multiple centers collaborate to meaningfully pool their data for meta-analysis. Published by Elsevier Inc.

Efficacy of acarbose in different geographical regions of the world: analysis of a real-life database.

PubMed

Weng, Jianping; Soegondo, Sidartawan; Schnell, Oliver; Sheu, Wayne H-H; Grzeszczak, Wladyslaw; Watada, Hirotaka; Yamamoto, Noriyuki; Kalra, Sanjay

2015-02-01

Alpha-glucosidase inhibitors are recommended in some international guidelines as first-line, second-line and third-line treatment options but are not used worldwide due to perceived greater effectiveness in Asians than Caucasians. Data from ten post-marketing non-interventional studies using acarbose, the most widely used alpha-glucosidase inhibitor, from 21 countries, provinces and country groups were pooled. Effects on glycated hemoglobin (HbA1c ) were analysed for four major ethnicity/region groups (European Caucasians and Asians from East, Southeast and South Asia) to identify differences in the response to acarbose. The safety and efficacy populations included 67 682 and 62 905 patients, respectively. Mean HbA1c in the total population decreased by 1.12 ± 1.31% at the 3-month visit from 8.4% at baseline (p < 0.0001). Reductions in HbA1c , fasting plasma glucose and post-prandial plasma glucose were greater in patients with higher baseline values. Acarbose was well tolerated, with few episodes of hypoglycemia (0.03%) and gastrointestinal adverse events (2.76%). Data from 30 730 Caucasians from Europe and Asians from three major regions of Asia with non-missing gender/age information and baseline/3-month HbA1c data were analysed by multivariable analyses of covariance. After adjustment for relevant baseline confounding factors, Southeast and East Asians had slightly better responses to acarbose than South Asians and European Caucasians; however, the differences were small. Acarbose was effective in both European Caucasians and Asians; however, after adjustment for baseline confounding factors, significant small differences in response favoured Southeast and East Asians. © 2014 The Authors. Diabetes/Metabolism Research and Reviews published by John Wiley & Sons, Ltd.

Tests of causal links between alcohol abuse or dependence and major depression.

PubMed

Fergusson, David M; Boden, Joseph M; Horwood, L John

2009-03-01

There has been a great deal of research on the comorbidity between alcohol abuse or dependence (AAD) and major depression (MD). However, it is unclear whether AAD increases the risk of MD or vice versa. To examine the associations between AAD and MD using fixed-effects modeling to control for confounding and using structural equation models to ascertain the direction of causality. Data were gathered during the course of the Christchurch Health and Development Study, a 25-year longitudinal study of a birth cohort of children from New Zealand (635 boys, 630 girls). General community sample. The analysis was based on a sample of 1055 participants with available data on AAD and MD at ages 17 to 18, 20 to 21, and 24 to 25 years. Symptom criteria for AAD and MD from the DSM-IV at ages 17 to 18, 20 to 21, and 24 to 25 years as well as measures of life stress, cannabis use, other illicit drug use, affiliation with deviant peers, unemployment, partner substance use, and partner criminality at ages 17 to 18, 20 to 21, and 24 to 25 years. There were significant (P < .001) pooled associations between AAD and MD. Controlling for confounding factors using conditional fixed-effects models and time-dynamic covariate factors reduced the magnitude of these associations, but they remained statistically significant. Structural equation modeling suggested that the best-fitting causal model was one in which AAD led to increased risk of MD. The findings suggest that the associations between AAD and MD were best explained by a causal model in which problems with alcohol led to increased risk of MD as opposed to a self-medication model in which MD led to increased risk of AAD.

Serotonin-1A receptors in major depression quantified using PET: controversies, confounds, and recommendations

PubMed Central

Shrestha, Saurav; Hirvonen, Jussi; Hines, Christina S.; Henter, Ioline; Svenningsson, Per; Pike, Victor W.; Innis, Robert B.

2011-01-01

The serotonin-1A (5-HT1A) receptor is of particular interest in human positron emission tomography (PET) studies of major depressive disorder (MDD). Of the eight studies investigating this issue in the brains of patients with MDD, four reported decreased 5-HT1A receptor density, two reported no change, and two reported increased 5-HT1A receptor density. While clinical heterogeneity may have contributed to these differing results, methodological factors by themselves could also explain the discrepancies. This review highlights several of these factors, including the use of the cerebellum as a reference region and the imprecision of measuring the concentration of parent radioligand in arterial plasma, the method otherwise considered to be the `gold standard'. Other potential confounds also exist that could restrict or unexpectedly affect the interpretation of results. For example, the radioligand may be a substrate for an efflux transporter—like P-gp—at the blood-brain barrier; furthermore, the binding of the radioligand to the receptor in various stages of cellular trafficking is unknown. Efflux transport and cellular trafficking may also be differentially expressed in patients compared to healthy subjects. We believe that, taken together, the existing disparate findings do not reliably answer the question of whether 5-HT1A receptors are altered in MDD or in subgroups of patients with MDD. In addition, useful meta-analysis is precluded because only one of the imaging centers acquired all the data necessary to address these methodological concerns. We recommend that in the future, individual centers acquire more thorough data capable of addressing methodological concerns, and that multiple centers collaborate to meaningfully pool their data for meta-analysis. PMID:22155042

Clinical and evoked pain, personality traits, and emotional states: can familial confounding explain the associations?

PubMed

Strachan, Eric; Poeschla, Brian; Dansie, Elizabeth; Succop, Annemarie; Chopko, Laura; Afari, Niloofar

2015-01-01

Pain is a complex phenomenon influenced by context and person-specific factors. Affective dimensions of pain involve both enduring personality traits and fleeting emotional states. We examined how personality traits and emotional states are linked with clinical and evoked pain in a twin sample. 99 female twin pairs were evaluated for clinical and evoked pain using the McGill Pain Questionnaire (MPQ) and dolorimetry, and completed the 120-item International Personality Item Pool (IPIP), the Positive and Negative Affect Scale (PANAS), and ratings of stress and mood. Using a co-twin control design we examined a) the relationship of personality traits and emotional states with clinical and evoked pain and b) whether genetics and common environment (i.e. familial factors) may account for the associations. Neuroticism was associated with the sensory component of the MPQ; this relationship was not confounded by familial factors. None of the emotional state measures was associated with the MPQ. PANAS negative affect was associated with lower evoked pressure pain threshold and tolerance; these associations were confounded by familial factors. There were no associations between IPIP traits and evoked pain. A relationship exists between neuroticism and clinical pain that is not confounded by familial factors. There is no similar relationship between negative emotional states and clinical pain. In contrast, the relationship between negative emotional states and evoked pain is strong while the relationship with enduring personality traits is weak. The relationship between negative emotional states and evoked pain appears to be non-causal and due to familial factors. Copyright © 2014 Elsevier Inc. All rights reserved.

Evaluation of uncontrolled confounding in studies of environmental exposures and neurobehavioral testing in children.

PubMed

Mink, Pamela J; Goodman, Michael; Barraj, Leila M; Imrey, Harriet; Kelsh, Michael A; Yager, Janice

2004-07-01

Neurobehavioral tests are commonly used in studies of children exposed to low-level environmental concentrations of compounds known to be neurotoxic at higher levels. However, uncontrolled or incomplete control for confounding makes interpretation of results problematic because effects of confounders are often stronger than the effects of primary interest. We examined a priori the potential impact of confounding in a hypothetical study evaluating the association of a potentially neurotoxic environmental exposure with neurobehavioral function in children. We used 2 outcome measures: the Bayley Scales of Infant Development Mental Development Index and the Stanford-Binet Intelligence Scale Composite Score. We selected 3 potential confounders: maternal intelligence, home environment, and socioeconomic status as measured by years of parental education. We conducted 3 sets of analyses measuring the effect of each of the 3 confounding factors alone, 2 confounders acting simultaneously, and all 3 confounders acting simultaneously. Relatively small differences (0.5 standard deviations) in confounding variables between "exposed" and "unexposed" groups, if unmeasured and unaccounted for in the analysis, could produce spurious differences in cognitive test scores. The magnitude of this difference (3-10 points) has been suggested to have a meaningful impact in populations. The method of measuring confounders (eg, maternal intelligence) could also substantially affect the results. It is important to carefully consider the impact of potential confounders during the planning stages of an observational study. Study-to-study differences in neurobehavioral outcomes with similar environmental exposures could be partially explained by differences in the adjustment for confounding variables. Copyright 2004 Lippincott Williams and Wilkins

Procedural Factors That Affect Psychophysical Measures of Spatial Selectivity in Cochlear Implant Users

PubMed Central

Deeks, John M.; Carlyon, Robert P.

2015-01-01

Behavioral measures of spatial selectivity in cochlear implants are important both for guiding the programing of individual users’ implants and for the evaluation of different stimulation methods. However, the methods used are subject to a number of confounding factors that can contaminate estimates of spatial selectivity. These factors include off-site listening, charge interactions between masker and probe pulses in interleaved masking paradigms, and confusion effects in forward masking. We review the effects of these confounds and discuss methods for minimizing them. We describe one such method in which the level of a 125-pps masker is adjusted so as to mask a 125-pps probe, and where the masker and probe pulses are temporally interleaved. Five experiments describe the method and evaluate the potential roles of the different potential confounding factors. No evidence was obtained for off-site listening of the type observed in acoustic hearing. The choice of the masking paradigm was shown to alter the measured spatial selectivity. For short gaps between masker and probe pulses, both facilitation and refractory mechanisms had an effect on masking; this finding should inform the choice of stimulation rate in interleaved masking experiments. No evidence for confusion effects in forward masking was revealed. It is concluded that the proposed method avoids many potential confounds but that the choice of method should depend on the research question under investigation. PMID:26420785

Enhancing the estimation of blood pressure using pulse arrival time and two confounding factors.

PubMed

Baek, Hyun Jae; Kim, Ko Keun; Kim, Jung Soo; Lee, Boreom; Park, Kwang Suk

2010-02-01

A new method of blood pressure (BP) estimation using multiple regression with pulse arrival time (PAT) and two confounding factors was evaluated in clinical and unconstrained monitoring situations. For the first analysis with clinical data, electrocardiogram (ECG), photoplethysmogram (PPG) and invasive BP signals were obtained by a conventional patient monitoring device during surgery. In the second analysis, ECG, PPG and non-invasive BP were measured using systems developed to obtain data under conditions in which the subject was not constrained. To enhance the performance of BP estimation methods, heart rate (HR) and arterial stiffness were considered as confounding factors in regression analysis. The PAT and HR were easily extracted from ECG and PPG signals. For arterial stiffness, the duration from the maximum derivative point to the maximum of the dicrotic notch in the PPG signal, a parameter called TDB, was employed. In two experiments that normally cause BP variation, the correlation between measured BP and the estimated BP was investigated. Multiple-regression analysis with the two confounding factors improved correlation coefficients for diastolic blood pressure and systolic blood pressure to acceptable confidence levels, compared to existing methods that consider PAT only. In addition, reproducibility for the proposed method was determined using constructed test sets. Our results demonstrate that non-invasive, non-intrusive BP estimation can be obtained using methods that can be applied in both clinical and daily healthcare situations.

Assessment of need of patients with schizophrenia: a study in Vellore, India.

PubMed

Ernest, Sharmila; Nagarajan, Guru; Jacob, K S

2013-12-01

and aims: There is a dearth of studies investigating the prevalence and factors associated with unmet needs in people with schizophrenia from low- and middle-income countries. We aimed to study prevalence and risk factors for unmet need. A case-control study design was employed. One hundred and one (101) consecutive patients attending a psychiatric hospital were assessed using Camberwell Assessment of Need Short version (CANSAS) and Positive and Negative Syndrome Scale (PANSS). Multivariate analysis was employed to adjust for confounders. The majority of patients had many unmet needs. These unmet needs were significantly associated with lower education, poverty and persistent psychopathology on multivariate analysis. Unmet needs are associated with poverty, lower education and persistent psychopathology. There is a need to manage unmet needs, in addition to addressing psychopathology and poverty.

Generalizability of dietary patterns of the inverse association between alcohol consumption and type 2 diabetes risk

USDA-ARS?s Scientific Manuscript database

Epidemiology of dietary components and disease risk limits interpretability due to potential residual confounding by correlated dietary components. Dietary pattern analyses by factor analysis or partial least squares may overcome this limitation. To examine confounding by dietary pattern as well as ...

Risk Factors in Adolescent Hypertension

PubMed Central

Ewald, D. Rose; Haldeman, Lauren A.

2016-01-01

Hypertension is a complex and multifaceted disease, with many contributing factors. While diet and nutrition are important influences, the confounding effects of overweight and obesity, metabolic and genetic factors, racial and ethnic predispositions, socioeconomic status, cultural influences, growth rate, and pubertal stage have even more influence and make diagnosis quite challenging. The prevalence of hypertension in adolescents far exceeds the numbers who have been diagnosed; studies have found that 75% or more go undiagnosed. This literature review summarizes the challenges of blood pressure classification in adolescents, discusses the impact of these confounding influences, and identifies actions that will improve diagnosis and treatment outcomes. PMID:27335997

Are Interactions between cis-Regulatory Variants Evidence for Biological Epistasis or Statistical Artifacts?

PubMed

Fish, Alexandra E; Capra, John A; Bush, William S

2016-10-06

The importance of epistasis-or statistical interactions between genetic variants-to the development of complex disease in humans has been controversial. Genome-wide association studies of statistical interactions influencing human traits have recently become computationally feasible and have identified many putative interactions. However, statistical models used to detect interactions can be confounded, which makes it difficult to be certain that observed statistical interactions are evidence for true molecular epistasis. In this study, we investigate whether there is evidence for epistatic interactions between genetic variants within the cis-regulatory region that influence gene expression after accounting for technical, statistical, and biological confounding factors. We identified 1,119 (FDR = 5%) interactions that appear to regulate gene expression in human lymphoblastoid cell lines, a tightly controlled, largely genetically determined phenotype. Many of these interactions replicated in an independent dataset (90 of 803 tested, Bonferroni threshold). We then performed an exhaustive analysis of both known and novel confounders, including ceiling/floor effects, missing genotype combinations, haplotype effects, single variants tagged through linkage disequilibrium, and population stratification. Every interaction could be explained by at least one of these confounders, and replication in independent datasets did not protect against some confounders. Assuming that the confounding factors provide a more parsimonious explanation for each interaction, we find it unlikely that cis-regulatory interactions contribute strongly to human gene expression, which calls into question the relevance of cis-regulatory interactions for other human phenotypes. We additionally propose several best practices for epistasis testing to protect future studies from confounding. Copyright © 2016 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Eveningness and Insomnia: Independent Risk Factors of Nonremission in Major Depressive Disorder

PubMed Central

Chan, Joey Wing Yan; Lam, Siu Ping; Li, Shirley Xin; Yu, Mandy Wai Man; Chan, Ngan Yin; Zhang, Jihui; Wing, Yun-Kwok

2014-01-01

Background: It is unclear whether there is an association between chronotype and nonremission of depression, and whether the association is related to the confounding effect of insomnia. Method: A cohort of patients with major depressive disorder were assessed for chronotype (by Morningness-Eveningness Questinnaire [MEQ]), depressive symptoms, insomnia severity and clinical outcomes in a naturalistic follow-up study. Results: Of the 253 recruited subjects (age 50.8 ± 10.2 y; female: 82.6%; response rate 90.0%), 19.4%, 56.1% and 24.5% patients were classified as eveningness, intermediate, and morningness, respectively. Evening-type subjects had higher insomnia severity, more severe depressive symptoms, and higher suicidality. Eveningness was associated with nonremission of depression with an odds ratio (OR) of 3.36 (95% confidence interval [CI] 1.35–8.34, P < 0.01), independent of insomnia severity. In addition, insomnia was an independent significant factor in contributing to nonremission of depression (OR = 1.12; 95% CI 1.05–1.19, P < 0.001). Conclusion: The independent association of eveningness with nonremission of depression suggested a significant underpinning of circadian involvement in major depressive disorder. Our findings support the need for a comprehensive assessment of sleep and circadian disturbances as well as integration of sleep and chronotherapeutic intervention in the management of depression. Citation: Chan JWY, Lam SP, Li SX, Yu MWM, Chan NY, Zhang J, Wing YK. Eveningness and insomnia: independent risk factors of nonremission in major depressive disorder. SLEEP 2014;37(5):911-917. PMID:24790269

Using ecological propensity score to adjust for missing confounders in small area studies.

PubMed

Wang, Yingbo; Pirani, Monica; Hansell, Anna L; Richardson, Sylvia; Blangiardo, Marta

2017-11-09

Small area ecological studies are commonly used in epidemiology to assess the impact of area level risk factors on health outcomes when data are only available in an aggregated form. However, the resulting estimates are often biased due to unmeasured confounders, which typically are not available from the standard administrative registries used for these studies. Extra information on confounders can be provided through external data sets such as surveys or cohorts, where the data are available at the individual level rather than at the area level; however, such data typically lack the geographical coverage of administrative registries. We develop a framework of analysis which combines ecological and individual level data from different sources to provide an adjusted estimate of area level risk factors which is less biased. Our method (i) summarizes all available individual level confounders into an area level scalar variable, which we call ecological propensity score (EPS), (ii) implements a hierarchical structured approach to impute the values of EPS whenever they are missing, and (iii) includes the estimated and imputed EPS into the ecological regression linking the risk factors to the health outcome. Through a simulation study, we show that integrating individual level data into small area analyses via EPS is a promising method to reduce the bias intrinsic in ecological studies due to unmeasured confounders; we also apply the method to a real case study to evaluate the effect of air pollution on coronary heart disease hospital admissions in Greater London. © The Author 2017. Published by Oxford University Press.

State infant mortality: an ecologic study to determine modifiable risks and adjusted infant mortality rates.

PubMed

Paul, David A; Mackley, Amy; Locke, Robert G; Stefano, John L; Kroelinger, Charlan

2009-05-01

To determine factors contributing to state infant mortality rates (IMR) and develop an adjusted IMR in the United States for 2001 and 2002. Ecologic study of factors contributing to state IMR. State IMR for 2001 and 2002 were obtained from the United States linked death and birth certificate data from the National Center for Health Statistics. Factors investigated using multivariable linear regression included state racial demographics, ethnicity, state population, median income, education, teen birth rate, proportion of obesity, smoking during pregnancy, diabetes, hypertension, cesarean delivery, prenatal care, health insurance, self-report of mental illness, and number of in-vitro fertilization procedures. Final risk adjusted IMR's were standardized and states were compared with the United States adjusted rates. Models for IMR in individual states in 2001 (r2 = 0.66, P < 0.01) and 2002 (r2 = 0.81, P < 0.01) were tested. African-American race, teen birth rate, and smoking during pregnancy remained independently associated with state infant mortality rates for 2001 and 2002. Ninety five percent confidence intervals (CI) were calculated around the regression lines to model the expected IMR. After adjustment, some states maintained a consistent IMR; for instance, Vermont and New Hampshire remained low, while Delaware and Louisiana remained high. However, other states such as Mississippi, which have traditionally high infant mortality rates, remained within the expected 95% CI for IMR after adjustment indicating confounding affected the initial unadjusted rates. Non-modifiable demographic variables, including the percentage of non-Hispanic African-American and Hispanic populations of the state are major factors contributing to individual variation in state IMR. Race and ethnicity may confound or modify the IMR in states that shifted inside or outside the 95% CI following adjustment. Other factors including smoking during pregnancy and teen birth rate, which are potentially modifiable, significantly contributed to differences in state IMR. State risk adjusted IMR indicate that other factors impact infant mortality after adjustment by race/ethnicity and other risk factors.

Inhibitory Control in Siblings Discordant for Exposure to Maternal Smoking during Pregnancy

ERIC Educational Resources Information Center

Micalizzi, Lauren; Marceau, Kristine; Brick, Leslie A.; Palmer, Rohan H.; Todorov, Alexandre A.; Heath, Andrew C.; Evans, Allison; Knopik, Valerie S.

2018-01-01

Maternal smoking during pregnancy (SDP) has been linked to poorer offspring executive function across development, but SDP does not occur independent of other familial risk factors. As such, poor and inconsistent control for potential confounds, notably shared familial (i.e., genetic and environmental) confounds, preclude concluding causal effects…

Measuring behavior in mice with chronic stress depression paradigm.

PubMed

Strekalova, Tatyana; Steinbusch, Harry W M

2010-03-17

Many studies with chronic stress, a common depression paradigm, lead to inconsistent behavioral results. We are introducing a new model of stress-induced anhedonia, which provides more reproducible induction and behavioral measuring of depressive-like phenotype in mice. First, a 4-week stress procedure induces anhedonia, defined by decreased sucrose preference, in the majority of but not all C57BL/6 mice. The remaining 30-50% non-anhedonic animals are used as an internal control for stress effects that are unrelated to anhedonia. Next, a modified sucrose test enables the detection of inter-individual differences in mice. Moreover, testing under dimmed lighting precludes behavioral artifacts caused by hyperlocomotion, a major confounding factor in stressed mice. Finally, moderation of the stress load increases the reproducibility of anhedonia induction, which otherwise is difficult to provide because of inter-batch variability in laboratory mice. We believe that our new mouse model overcomes some major difficulties in measuring behavior with chronic stress depression models. Copyright 2009 Elsevier Inc. All rights reserved.

Three Mile Island epidemiologic radiation dose assessment revisited: 25 years after the accident.

PubMed

Field, R William

2005-01-01

Over the past 25 years, public health concerns following the Three Mile Island (TMI) accident prompted several epidemiologic investigations in the vicinity of TMI. One of these studies is ongoing. This commentary suggests that the major source of radiation exposure to the population has been ignored as a potential confounding factor or effect modifying factor in previous and ongoing TMI epidemiologic studies that explore whether or not TMI accidental plant radiation releases caused an increase in lung cancer in the community around TMI. The commentary also documents the observation that the counties around TMI have the highest regional radon potential in the United States and concludes that radon progeny exposure should be included as part of the overall radiation dose assessment in future studies of radiation-induced lung cancer resulting from the TMI accident.

Prenatal depression effects and interventions: a review.

PubMed

Field, Tiffany; Diego, Miguel; Hernandez-Reif, Maria

2010-12-01

This review covers research on the negative effects of prenatal depression and cortisol on fetal growth, prematurity and low birthweight. Although prenatal depression and cortisol were typically measured at around 20 weeks gestation, other research suggests the stability of depression and cortisol levels across pregnancy. Women with Dysthymia as compared to Major Depression Disorder had higher cortisol levels, and their newborns had lower gestational age and birthweight. The cortisol effects in these studies were unfortunately confounded by low serotonin and low dopamine levels which in themselves could contribute to non-optimal pregnancy outcomes. The negative effects of depression and cortisol were also potentially confounded by comorbid anxiety, by demographic factors including younger age, less education and lower SES of the mothers and by the absence of a partner or a partner who was unhappy about the pregnancy or a partner who was depressed. Substance use (especially caffeine use) was still another risk factor. All of these problems including prenatal depression, elevated cortisol, prematurity and low birthweight and even postpartum depression have been reduced by prenatal massage therapy provided by the women's partners. Massage therapy combined with group interpersonal psychotherapy was also effective for reducing depression and cortisol levels. Several limitations of these studies were noted and suggestions for future research included exploring other predictor variables like progesterone/estriol ratios, immune factors and genetic determinants. Further research is needed both on the potential use of cortisol as a screening measure and the use of other therapies that might reduce prenatal depression and cortisol in the women and prematurity and low birthweight in their infants. Copyright © 2010 Elsevier Inc. All rights reserved.

Effect of smoking on survival of patients with hepatocellular carcinoma.

PubMed

Kolly, Philippe; Knöpfli, Marina; Dufour, Jean-François

2017-11-01

Lifestyle factors such as smoking, obesity and physical activity have gained interest in the field of hepatocellular carcinoma. These factors play a significant role in the development of hepatocellular carcinoma. Several studies revealed the impact of tobacco consumption on the development of hepatocellular carcinoma and its synergistic effects with viral etiologies (hepatitis B and C). The effects of smoking on survival in patients with a diagnosed hepatocellular carcinoma have not yet been investigated in a Western cohort where hepatitis C infection is a major risk factor. Using data from a prospective cohort of patients with hepatocellular carcinoma who were followed at the University Hospital of Bern, Switzerland, survival was compared by Kaplan-Meier analysis in smokers and nonsmokers, and multivariate Cox regression was applied to control for confounding variables. Of 238 eligible hepatocellular carcinoma patients, 64 were smokers at the time of inclusion and 174 were nonsmokers. Smokers had a significant worse overall survival than nonsmokers (hazard ratio 1.77, 95% confidence interval: 1.22-2.58, P=.003). Analysis of patients according to their underlying liver disease, revealed that smoking, and not nonsmoking, affected survival of hepatitis B virus and C virus-infected patients only. In this subgroup, smoking was an independent predictor for survival (hazard ratio 2.99, 95% confidence interval: 1.7-5.23, P<.001) and remained independently predictive when adjusted for confounding variables. This study shows that smoking is an independent predictor of survival in hepatitis B virus/hepatitis C virus-infected patients with hepatocellular carcinoma. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Prolonged mounted patrolling is a risk factor for developing knee pain in Danish military personnel deployed to the Helmand Province.

PubMed

Lundin, Christina Rydahl; Houe, T; Sevelsted, A; Nissen, L

2016-10-01

Non-battle injuries have been the leading cause of medical evacuation in the recent wars in Afghanistan and Iraq. This study investigates the hypothesis, that the occurrence of knee problems could be associated with mounted patrolling in armoured vehicles independent of other risk factors. Retrospective questionnaire-based cohort study of Danish soldiers deployed to Afghanistan during 1 February-31 July 2013. 307 soldiers included. Response rate 70%. 33% reported knee pain. Significant association between knee pain and time spent weekly on mounted patrols (OR 1.23, CI 1.07 to 1.41, p=0.003). Controlled for confounders age, body mass index and duration of military employment (OR 1.22, CI 1.06 to 1.41, p=0.006). Adjusted for confounders and all other risk factors (OR 1.25, CI 1.07 to 1.48, p=0.007). The main finding in a subset of the 33% with knee pain: Significant association between more severe knee problems with Knee injury and Osteoarthritis Outcome Score below 400 and time spent weekly on mounted patrols (OR 1.49, CI 1.17 to 1.56, p=0.002). A major concern regarding knee problems among Danish deployed military personnel is identified. The risk of suffering from knee problems and the severity of symptoms increase with the amount of time spent inside a vehicle on mounted patrols. 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/

Ultrasound Elastography and MR Elastography for Assessing Liver Fibrosis: Part 2, Diagnostic Performance, Confounders, and Future Directions

PubMed Central

Tang, An; Cloutier, Guy; Szeverenyi, Nikolaus M.; Sirlin, Claude B.

2016-01-01

OBJECTIVE The purpose of the article is to review the diagnostic performance of ultrasound and MR elastography techniques for detection and staging of liver fibrosis, the main current clinical applications of elastography in the abdomen. CONCLUSION Technical and instrument-related factors and biologic and patient-related factors may constitute potential confounders of stiffness measurements for assessment of liver fibrosis. Future developments may expand the scope of elastography for monitoring liver fibrosis and predict complications of chronic liver disease. PMID:25905762

Open defecation and childhood stunting in India: an ecological analysis of new data from 112 districts.

PubMed

Spears, Dean; Ghosh, Arabinda; Cumming, Oliver

2013-01-01

Poor sanitation remains a major public health concern linked to several important health outcomes; emerging evidence indicates a link to childhood stunting. In India over half of the population defecates in the open; the prevalence of stunting remains very high. Recently published data on levels of stunting in 112 districts of India provide an opportunity to explore the relationship between levels of open defecation and stunting within this population. We conducted an ecological regression analysis to assess the association between the prevalence of open defecation and stunting after adjustment for potential confounding factors. Data from the 2011 HUNGaMA survey was used for the outcome of interest, stunting; data from the 2011 Indian Census for the same districts was used for the exposure of interest, open defecation. After adjustment for various potential confounding factors--including socio-economic status, maternal education and calorie availability--a 10 percent increase in open defecation was associated with a 0.7 percentage point increase in both stunting and severe stunting. Differences in open defecation can statistically account for 35 to 55 percent of the average difference in stunting between districts identified as low-performing and high-performing in the HUNGaMA data. In addition, using a Monte Carlo simulation, we explored the effect on statistical power of the common practice of dichotomizing continuous height data into binary stunting indicators. Our simulation showed that dichotomization of height sacrifices statistical power, suggesting that our estimate of the association between open defecation and stunting may be a lower bound. Whilst our analysis is ecological and therefore vulnerable to residual confounding, these findings use the most recently collected large-scale data from India to add to a growing body of suggestive evidence for an effect of poor sanitation on human growth. New intervention studies, currently underway, may shed more light on this important issue.

Type A personality, hostility, time urgency and unintentional injuries among Chinese undergraduates: a matched case–control study

PubMed Central

2013-01-01

Background Associations between type A behaviour pattern (TABP) and injuries are inconsistent. These inconsistencies may be due to different effects of various components of TABP, namely time urgency/impatience, hostility and competitive drive. It is important to examine the relationship between the global TABP, its two components, and unintentional injuries, among undergraduates in China. Methods On the basis of a previous cross-sectional study, we conducted a matched case–control study. 253 cases and an equal number of age-, gender-, and major-matched controls were included. The questionnaire solicited socio-demographic information, the experience of injuries, the scale of TABP, and other potential confounding factors. Besides the correlation between the global TABP and injuries, the influences of the two components of TABP on injuries were also evaluated. Conditional logistic regression was used to determine the crude odds ratios (ORs) and adjusted ORs of injury events. Results A dose–response relationship was apparent among students who rated themselves higher on the TABP scale (P-value for trend, 0.002), with a crude OR of 2.93 (95% CI: 0.93–9.19) for injuries comparing those with TABP to those with type B behaviour pattern (TBBP). After adjustment for potential confounding factors, TABP remained statistically significant, and the adjusted OR was 5.52 (95% CI: 1.43–21.27); from a comparison of students with TABP to those with TBBP. A dose–response relationship was also apparent between the hostility component and nonfatal injuries, both in crude analysis and after adjusting for other confounders. The relationship between time-hurry and injuries was not statistically significant, based on univariate and multivariate analyses. Conclusions Both the global TABP and the hostility component were associated with a dose response increase in the risk of non-fatal unintentional injuries among Chinese undergraduates. Further studies need to be conducted to confirm or reject this correlation. PMID:24219492

Unilateral spatial neglect in the acute phase of ischemic stroke can predict long-term disability and functional capacity.

PubMed

Luvizutto, Gustavo José; Moliga, Augusta Fabiana; Rizzatti, Gabriela Rizzo Soares; Fogaroli, Marcelo Ortolani; Moura Neto, Eduardo de; Nunes, Hélio Rubens de Carvalho; Resende, Luiz Antônio de Lima; Bazan, Rodrigo

2018-05-21

The aim of this study was to assess the relationship between the degree of unilateral spatial neglect during the acute phase of stroke and long-term functional independence. This was a prospective study of right ischemic stroke patients in which the independent variable was the degree of spatial neglect and the outcome that was measured was functional independence. The potential confounding factors included sex, age, stroke severity, topography of the lesion, risk factors, glycemia and the treatment received. Unilateral spatial neglect was measured using the line cancellation test, the star cancellation test and the line bisection test within 48 hours of the onset of symptoms. Functional independence was measured using the modified Rankin and Barthel scales at 90 days after discharge. The relationship between unilateral spatial neglect and functional independence was analyzed using multiple logistic regression that was corrected for confounding factors. We studied 60 patients with a median age of 68 (34-89) years, 52% of whom were male and 74% of whom were Caucasian. The risk for moderate to severe disability increased with increasing star cancellation test scores (OR=1.14 [1.03-1.26], p=0.01) corrected for the stroke severity, which was a confounding factor that had a statistically positive association with disability (OR=1.63 [1.13-2.65], p=0.01). The best chance of functional independence decreased with increasing star cancellation test scores (OR=0.86 [0.78-0.96], p=0.006) corrected for the stroke severity, which was a confounding factor that had a statistically negative association with independence (OR=0.66 [0.48-0.92], p=0.017). The severity of unilateral spatial neglect in acute stroke worsens the degree of long-term disability and functional independence.

Supervisor Autonomy and Considerate Leadership Style are Associated with Supervisors' Likelihood to Accommodate Back Injured Workers.

PubMed

McGuire, Connor; Kristman, Vicki L; Shaw, William; Williams-Whitt, Kelly; Reguly, Paula; Soklaridis, Sophie

2015-09-01

To determine the association between supervisors' leadership style and autonomy and supervisors' likelihood of supporting job accommodations for back-injured workers. A cross-sectional study of supervisors from Canadian and US employers was conducted using a web-based, self-report questionnaire that included a case vignette of a back-injured worker. Autonomy and two dimensions of leadership style (considerate and initiating structure) were included as exposures. The outcome, supervisors' likeliness to support job accommodation, was measured with the Job Accommodation Scale (JAS). We conducted univariate analyses of all variables and bivariate analyses of the JAS score with each exposure and potential confounding factor. We used multivariable generalized linear models to control for confounding factors. A total of 796 supervisors participated. Considerate leadership style (β = .012; 95% CI .009-.016) and autonomy (β = .066; 95% CI .025-.11) were positively associated with supervisors' likelihood to accommodate after adjusting for appropriate confounding factors. An initiating structure leadership style was not significantly associated with supervisors' likelihood to accommodate (β = .0018; 95% CI -.0026 to .0061) after adjusting for appropriate confounders. Autonomy and a considerate leadership style were positively associated with supervisors' likelihood to accommodate a back-injured worker. Providing supervisors with more autonomy over decisions of accommodation and developing their considerate leadership style may aid in increasing work accommodation for back-injured workers and preventing prolonged work disability.

Is the association between posttraumatic stress disorder symptoms and poor health due to a common familial or genetic factor?

PubMed Central

Roy-Byrne, Peter P.; Noonan, Carolyn; Afari, Niloofar; Buchwald, Dedra; Goldberg, Jack

2010-01-01

Objective The objective of this study was to identify genetic, familial and environmental contributions to the association between posttraumatic stress disorder (PTSD) symptoms and poor health. Methods A community sample of 1852 twin pairs was assessed for symptoms of PTSD [with the Impact of Events Scale (IES)] and self-reported global health status using a single five-level question. An ordinal logistic regression model estimated odds ratio/s (OR) for the association between PTSD and health status. Within-pair analysis assessed confounding by familial and genetic factors and adjusted for the possible confounding influence of age, sex, race, education and self-reported physician diagnosis of depression. Results The IES was strongly and significantly associated with self-reported health [OR = 1.8; 95% confidence interval (95% CI) = 1.5–2.2; highest quartile vs. lowest quartile]. This association remained significant in within-pair analysis (OR = 1.3; 95% CI=1.0–1.7), but after further adjustment for sociodemographics and depression, it was no longer significant (Ptrend=.17). Separate analysis by zygosity did not show differential effect in monozygotic or dizygotic pairs. Conclusion These findings suggest that the association between PTSD symptoms and poor health is, in part, due to familial confounding and sociodemographic factors. Little evidence of confounding by genetic factors was found. These findings suggest that early prevention efforts would have the greatest potential for improving poor health in PTSD-prone patients, whereas later intervention efforts directed at treating PTSD may have a more limited impact on improving poor health. PMID:16950376

Eveningness and insomnia: independent risk factors of nonremission in major depressive disorder.

PubMed

Chan, Joey Wing Yan; Lam, Siu Ping; Li, Shirley Xin; Yu, Mandy Wai Man; Chan, Ngan Yin; Zhang, Jihui; Wing, Yun-Kwok

2014-05-01

It is unclear whether there is an association between chronotype and nonremission of depression, and whether the association is related to the confounding effect of insomnia. A cohort of patients with major depressive disorder were assessed for chronotype (by Morningness-Eveningness Questinnaire [MEQ]), depressive symptoms, insomnia severity and clinical outcomes in a naturalistic follow-up study. Of the 253 recruited subjects (age 50.8 ± 10.2 y; female: 82.6%; response rate 90.0%), 19.4%, 56.1% and 24.5% patients were classified as eveningness, intermediate, and morningness, respectively. Evening-type subjects had higher insomnia severity, more severe depressive symptoms, and higher suicidality. Eveningness was associated with nonremission of depression with an odds ratio (OR) of 3.36 (95% confidence interval [CI] 1.35-8.34, P < 0.01), independent of insomnia severity. In addition, insomnia was an independent significant factor in contributing to nonremission of depression (OR = 1.12; 95% CI 1.05-1.19, P < 0.001). The independent association of eveningness with nonremission of depression suggested a significant underpinning of circadian involvement in major depressive disorder. Our findings support the need for a comprehensive assessment of sleep and circadian disturbances as well as integration of sleep and chronotherapeutic intervention in the management of depression.

Effect decomposition in the presence of an exposure-induced mediator-outcome confounder

PubMed Central

VanderWeele, Tyler J.; Vansteelandt, Stijn; Robins, James M.

2014-01-01

Methods from causal mediation analysis have generalized the traditional approach to direct and indirect effects in the epidemiologic and social science literature by allowing for interaction and non-linearities. However, the methods from the causal inference literature have themselves been subject to a major limitation in that the so-called natural direct and indirect effects that are employed are not identified from data whenever there is a variable that is affected by the exposure, which also confounds the relationship between the mediator and the outcome. In this paper we describe three alternative approaches to effect decomposition that give quantities that can be interpreted as direct and indirect effects, and that can be identified from data even in the presence of an exposure-induced mediator-outcome confounder. We describe a simple weighting-based estimation method for each of these three approaches, illustrated with data from perinatal epidemiology. The methods described here can shed insight into pathways and questions of mediation even when an exposure-induced mediator-outcome confounder is present. PMID:24487213

Factors Associated with Hepatitis C Knowledge Before and After an Educational Intervention among Vietnamese Americans

PubMed Central

Lee, Sunmin; Zhai, Shumenghui; Zhang, Guo (Yolanda); Ma, Xiang S; Lu, Xiaoxiao; Tan, Yin; Siu, Philip; Seals, Brenda; Ma, Grace X

2015-01-01

BACKGROUND Hepatitis C virus (HCV) is a major cause of chronic liver disease and cancer. Vietnamese Americans are at high risk of HCV infection, with men having the highest US incidence of liver cancer. This study examines an intervention to improve HCV knowledge among Vietnamese Americans. STUDY Seven Vietnamese community-based organizations in Pennsylvania and New Jersey recruited a total of 306 Vietnamese participants from 2010 to 2011. RESULTS Average knowledge scores for pretest and posttest were 3.32 and 5.88, respectively (maximum 10). After adjusting for confounding variables, age and higher education were positively associated with higher pretest scores and having a physician who spoke English or Vietnamese was negatively associated with higher pretest scores. Additionally, after adjusting for confounding variables, household income, education, and having an HCV-infected family member significantly increased knowledge scores. CONCLUSIONS Promotion and development of HCV educational programs can increase HCV knowledge among race and ethnic groups, such as Vietnamese Americans. Giving timely information to at-risk groups provides the opportunity to correct misconceptions, decrease HCV risk behaviors, and encourage testing that might improve timely HCV diagnosis and treatment. PMID:26561280

Concentrations of Water-Soluble Vitamins in Blood and Urinary Excretion in Patients with Diabetes Mellitus.

PubMed

Iwakawa, Hiromi; Nakamura, Yasuyuki; Fukui, Tomiho; Fukuwatari, Tsutomu; Ugi, Satoshi; Maegawa, Hiroshi; Doi, Yukio; Shibata, Katsumi

2016-01-01

We examined the concentrations of water-soluble vitamins in blood and urinary excretion of 22 patients with type 2 diabetes mellitus (type 2DM) and 20 healthy control participants. Macronutrient and vitamin intakes of type 2DM subjects were measured using a weighed food record method. Control participants consumed a semipurified diet for eight days. Multiple linear regression models were used to determine whether significant differences existed in vitamin concentrations in blood independent of age, sex, and other confounding factors. Concentrations of vitamins B2, B6, C, niacin, and folate in blood were significantly lower in type 2DM subjects than in controls, independent of confounding factors. Renal clearances of vitamins B6, C, niacin, and folate were significantly higher in type 2DM subjects than in controls. In conclusion, concentrations of vitamins B2, B6, C, niacin, and folate in blood were significantly lower in type 2DM subjects than in controls, independent of confounding factors; based on the evidence of increased urinary clearance of these vitamins, the lower levels were likely due to impaired reabsorption processes.

Effect of conjugal bereavement on mortality of the bereaved spouse in participants of the Renfrew/Paisley Study

PubMed Central

Hart, Carole L; Hole, David J; Lawlor, Debbie A; Smith, George Davey; Lever, Tony F

2007-01-01

Objectives To investigate how loss of a spouse affects mortality risk in the bereaved partner. Design and setting Prospective cohort study in Renfrew and Paisley in Scotland. Participants 4395 married couples aged 45–64 years when the study was carried out between 1972 and 1976. Methods The date of bereavement for the bereaved spouse was the date of death of his or her spouse. Bereavement could occur at any time during the follow‐up period, so it was considered as a time‐dependent exposure variable and the Cox proportional hazards model for time‐dependent variables was used. The relative rate (RR) of mortality was calculated for bereaved versus non‐bereaved spouses and adjusted for confounding variables. Main outcome measures Causes of death to 31 March 2004. Results Bereaved participants were at higher risk than non‐bereaved participants of dying from any cause (RR 1.27; 95% CI 1.2 to 1.35). These risks remained but were attenuated after adjustment for confounding variables. There were raised RRs for bereaved participants dying of cardiovascular disease, coronary heart disease, stroke, all cancer, lung cancer, smoking‐related cancer, and accidents or violence. After adjustment for confounding variables, RRs remained higher for bereaved participants for all these causes except for mortality from lung cancer. There was no strong statistical evidence that the increased risks of death associated with bereavement changed with time after bereavement. Conclusions Conjugal bereavement, in addition to existing risk factors, is related to mortality risk for major causes of death. PMID:17435215

Smoking and Physical Activity in Healthy Adults: A Cross-Sectional Study in Tehran

PubMed Central

Heydari, Gholamreza; Yousefifard, Mahmoud; Asady, Hadi; Baikpour, Masoud; Barat, Atena

2015-01-01

Background: Smoking and physical inactivity are two major risk factors for non-communicable diseases (NCDs). Not only these factors have a causal effect on NCDs, but they can also affect each other. This study aimed to assess the relationship between these factors as well as their effect on NCDs. Materials and Methods: A total of 2,602 healthy adults aged 30–60 years participated in this survey in 2010. Data on demographic characteristics, medical history, smoking status, physical activity and anthropometric measures including weight and height were collected and analyzed. The effect of smoking on physical activity was evaluated by logistic regression adjusting for potential confounders. Results: Among demographic characteristics, only age (P<0.001) and educational level (P<0.001) had a significant association with smoking status. Compared with nonsmokers, smokers had an odds ratio of 4.88 (95% CI, 3.34–7.13) for having unsatisfactory physical activity. Conclusion: The present study showed that cigarette smoking negatively affects the quality of physical activity. PMID:27114725

Effect of environmental tobacco smoke on atopic dermatitis among children in Korea.

PubMed

Yi, Okhee; Kwon, Ho-Jang; Kim, Ho; Ha, Mina; Hong, Soo-Jong; Hong, Yun-Chul; Leem, Jong-Han; Sakong, Joon; Lee, Chul Gab; Kim, Su-Young; Kang, Dongmug

2012-02-01

The prevalence of atopic dermatitis is increasing in many countries. Several factors are known to be associated with childhood atopic dermatitis. Environmental tobacco smoke (ETS) is one of the most common indoor pollutants, and children are more vulnerable to ETS exposure than adults are. In this study, the possible association of ETS with atopic dermatitis was evaluated in 7030 individuals aged 6-13 years who participated in the Children's Health and Environment Research study. In addition, predictive factors, such as the allergic history of the parents, children's immunoglobulin E levels and children's history of rhinitis and its association with dermatitis, were assessed. After adjustment for possible confounding variables, atopic dermatitis was found to be highly correlated with ETS, especially among children whose mothers had smoked during pregnancy and/or in the first year after birth (OR=2.06, 95% CI: 1.01-4.22). In conclusion, our results show that childhood exposure to ETS is a major risk factor for atopic dermatitis. Copyright © 2012 Elsevier Inc. All rights reserved.

Thalassaemic osteopathy: a cross-sectional preliminary study from Sri Lanka.

PubMed

Dissanayake, Ruwangi; de Silva, Shamya; Lekamwasam, Sarath; Abeysekara, Gayan; Dissanayake, Vajira H W

2014-03-01

The objectives of this study were to demonstrate the presence of low bone mineral density (BMD) and to examine the association of known risk factors for low BMD in patients with beta thalassaemia major in Sri Lanka. Thirty-eight patients were studied. Their examination and laboratory investigation findings were recorded (haematology, biochemistry, hormonal profile, COL1A1 rs1800012G>T genotype, dual energy X-ray absorptiometry (DXA) scanning). Mean age was 10.95 years (range 5-21.4). 20 (52.6%) were male. BMD was low (z score ≤-2.0) in 12 (31.5%). Regression analysis of BMD on known risk factors (age, sex, pubertal stage, ferritin level, average pre-transfusion haemoglobin, serum calcium level and COL1A1 rs1800012G>T genotype) controlling for confounding factors on each comparison, showed that only age was significantly associated with low BMD (p=0.005). Approximately one-third of patients had a low BMD. Only age was significantly associated with a low BMD.

Environmental Exposure and Risk of Childhood Leukemia: An Overview.

PubMed

Schüz, Joachim; Erdmann, Friederike

2016-11-01

Childhood leukemia is the most common cancer diagnosed in children worldwide. However, only a few causes have been established so far, mainly some genetic syndromes and high doses of ionizing radiation. Major efforts have been undertaken to study the relationship between environmental factors and the risk of childhood leukemia, inspired by geographical variation in incidence rates. Some evidence has emerged for parental occupational exposures to pesticides, whereas there is less evidence for an association with postnatal pesticide exposure. Diagnostic radiation and radon exposure have been suggested but there remains a lack of convincing studies. Extremely low-frequency magnetic fields consistently showed a small increase in risk in numerous studies, but bias and confounding cannot be ruled out as possible explanations. From among factors other than environmental and radiation-related, the most promising candidate is abnormal patterns to common infections, but which children are most at risk and the pathways are not fully understood. In conclusion, although childhood leukemia shows some distinct incidence patterns by sex, age, and geography suggesting a role of the environment in its etiology, no major environmental risk factors including radiation have been established as major contributors to the global childhood leukemia burden. Due to the young age at diagnosis and evidence of chromosomal damage before birth in many of the affected children, parental exposures remain of high interest. Although cure rates of childhood leukemia are high in economically developed countries, because of the adverse late effects of the disease and its treatment, identification of modifiable risk factors for implementing primary prevention remains the ultimate goal. Copyright © 2016 IMSS. Published by Elsevier Inc. All rights reserved.

Impact of diurnal temperature range on human health: a systematic review.

PubMed

Cheng, Jian; Xu, Zhiwei; Zhu, Rui; Wang, Xu; Jin, Liu; Song, Jian; Su, Hong

2014-11-01

Increasing epidemiological studies have shown that a rapid temperature change within 1 day is an independent risk factor for human health. This paper aimed to systematically review the epidemiological evidence on the relationship between diurnal temperature range (DTR) and human health and to propose future research directions. A literature search was conducted in October 2013 using the databases including PubMed, ScienceDirect, and EBSCO. Empirical studies regarding the relationship between DTR and mortality and morbidity were included. Twenty-five relevant studies were identified, among which, 11 investigated the relationship between DTR and mortality and 14 examined the impact of DTR on morbidity. The majority of existing studies reported that DTR was significantly associated with mortality and morbidity, particularly for cardiovascular and respiratory diseases. Notably, compared with adults, the elderly and children were more vulnerable to DTR effects. However, there were some inconsistencies regarding the susceptible groups, lag time, and threshold of DTR. The impact of DTR on human health may be confounded or modified by season, socioeconomic, and educational status. Further research is needed to further confirm the adverse effects of DTR in different geographical locations; examine the effects of DTR on the health of children aged one or under; explore extreme DTR effects on human health; analyze the difference of DTR effects on human health in different locations and the modified effects of potential confounding factors; and develop detailed preventive measures against large DTR, particularly for susceptible groups.

Risk Factors and Birth Outcomes of Anaemia in Early Pregnancy in a Nulliparous Cohort

PubMed Central

Masukume, Gwinyai; Khashan, Ali S.; Kenny, Louise C.; Baker, Philip N.; Nelson, Gill

2015-01-01

Background Anaemia in pregnancy is a major public health and economic problem worldwide, that contributes to both maternal and fetal morbidity and mortality. Objective The aim of the study was to calculate the prevalence of anaemia in early pregnancy in a cohort of ‘low risk’ women participating in a large international multicentre prospective study (n = 5 609), to identify the modifiable risk factors for anaemia in pregnancy in this cohort, and to compare the birth outcomes between pregnancies with and without anaemia in early gestation. Methods The study is an analysis of data that were collected prospectively during the Screening for Pregnancy Endpoints study. Anaemia was defined according to the World Health Organization’s definition of anaemia in pregnancy (haemoglobin < 11g/dL). Binary logistic regression with adjustment for potential confounders (country, maternal age, having a marital partner, ethnic origin, years of schooling, and having paid work) was the main method of analysis. Results The hallmark findings were the low prevalence of anaemia (2.2%), that having no marital partner was an independent risk factor for having anaemia (OR 1.34, 95% CI 1.01-1.78), and that there was no statistically significant effect of anaemia on adverse pregnancy outcomes (small for gestational age, pre-tem birth, mode of delivery, low birth weight, APGAR score < 7 at one and five minutes). Adverse pregnancy outcomes were however more common in those with anaemia than in those without. Conclusion In this low risk healthy pregnant population we found a low anaemia rate. The absence of a marital partner was a non-modifiable factor, albeit one which may reflect a variety of confounding factors, that should be considered for addition to anaemia’s conceptual framework of determinants. Although not statistically significant, clinically, a trend towards a higher risk of adverse pregnancy outcomes was observed in women that were anaemic in early pregnancy. PMID:25875012

Risk factors and birth outcomes of anaemia in early pregnancy in a nulliparous cohort.

PubMed

Masukume, Gwinyai; Khashan, Ali S; Kenny, Louise C; Baker, Philip N; Nelson, Gill

2015-01-01

Anaemia in pregnancy is a major public health and economic problem worldwide, that contributes to both maternal and fetal morbidity and mortality. The aim of the study was to calculate the prevalence of anaemia in early pregnancy in a cohort of 'low risk' women participating in a large international multicentre prospective study (n = 5 609), to identify the modifiable risk factors for anaemia in pregnancy in this cohort, and to compare the birth outcomes between pregnancies with and without anaemia in early gestation. The study is an analysis of data that were collected prospectively during the Screening for Pregnancy Endpoints study. Anaemia was defined according to the World Health Organization's definition of anaemia in pregnancy (haemoglobin < 11g/dL). Binary logistic regression with adjustment for potential confounders (country, maternal age, having a marital partner, ethnic origin, years of schooling, and having paid work) was the main method of analysis. The hallmark findings were the low prevalence of anaemia (2.2%), that having no marital partner was an independent risk factor for having anaemia (OR 1.34, 95% CI 1.01-1.78), and that there was no statistically significant effect of anaemia on adverse pregnancy outcomes (small for gestational age, pre-tem birth, mode of delivery, low birth weight, APGAR score < 7 at one and five minutes). Adverse pregnancy outcomes were however more common in those with anaemia than in those without. In this low risk healthy pregnant population we found a low anaemia rate. The absence of a marital partner was a non-modifiable factor, albeit one which may reflect a variety of confounding factors, that should be considered for addition to anaemia's conceptual framework of determinants. Although not statistically significant, clinically, a trend towards a higher risk of adverse pregnancy outcomes was observed in women that were anaemic in early pregnancy.

Clinical characteristics and outcomes with rivaroxaban vs. warfarin in patients with non-valvular atrial fibrillation but underlying native mitral and aortic valve disease participating in the ROCKET AF trial.

PubMed

Breithardt, Günter; Baumgartner, Helmut; Berkowitz, Scott D; Hellkamp, Anne S; Piccini, Jonathan P; Stevens, Susanna R; Lokhnygina, Yuliya; Patel, Manesh R; Halperin, Jonathan L; Singer, Daniel E; Hankey, Graeme J; Hacke, Werner; Becker, Richard C; Nessel, Christopher C; Mahaffey, Kenneth W; Fox, Keith A A; Califf, Robert M

2014-12-14

We investigated clinical characteristics and outcomes of patients with significant valvular disease (SVD) in the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF) trial. ROCKET AF excluded patients with mitral stenosis or artificial valve prostheses. We used Cox regression to adjust comparisons for potential confounders. Among 14 171 patients, 2003 (14.1%) had SVD; they were older and had more comorbidities than patients without SVD. The rate of stroke or systemic embolism with rivaroxaban vs. warfarin was consistent among patients with SVD [2.01 vs. 2.43%; hazard ratio (HR) 0.83, 95% confidence interval (CI) 0.55-1.27] and without SVD (1.96 vs. 2.22%; HR 0.89, 95% CI 0.75-1.07; interaction P = 0.76). However, rates of major and non-major clinically relevant bleeding with rivaroxaban vs. warfarin were higher in patients with SVD (19.8% rivaroxaban vs. 16.8% warfarin; HR 1.25, 95% CI 1.05-1.49) vs. those without (14.2% rivaroxaban vs. 14.1% warfarin; HR 1.01, 95% CI 0.94-1.10; interaction P = 0.034), even when controlling for risk factors and potential confounders. In intracranial haemorrhage, there was no interaction between patients with and without SVD where the overall rate was lower among those randomized to rivaroxaban. Many patients with 'non-valvular atrial fibrillation' have significant valve lesions. Their risk of stroke is similar to that of patients without SVD after controlling for stroke risk factors. Efficacy of rivaroxaban vs. warfarin was similar in patients with and without SVD; however, the observed risk of bleeding was higher with rivaroxaban in patients with SVD but was the same among those without SVD. Atrial fibrillation patients with and without SVD experience the same stroke-preventive benefit of oral anticoagulants. © The Author 2014. Published by Oxford University Press on behalf of the European Society of Cardiology.

Clinical characteristics and outcomes with rivaroxaban vs. warfarin in patients with non-valvular atrial fibrillation but underlying native mitral and aortic valve disease participating in the ROCKET AF trial

PubMed Central

Breithardt, Günter; Baumgartner, Helmut; Berkowitz, Scott D.; Hellkamp, Anne S.; Piccini, Jonathan P.; Stevens, Susanna R.; Lokhnygina, Yuliya; Patel, Manesh R.; Halperin, Jonathan L.; Singer, Daniel E.; Hankey, Graeme J.; Hacke, Werner; Becker, Richard C.; Nessel, Christopher C.; Mahaffey, Kenneth W.; Fox, Keith A. A.; Califf, Robert M.

2014-01-01

Aims We investigated clinical characteristics and outcomes of patients with significant valvular disease (SVD) in the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF) trial. Methods and results ROCKET AF excluded patients with mitral stenosis or artificial valve prostheses. We used Cox regression to adjust comparisons for potential confounders. Among 14 171 patients, 2003 (14.1%) had SVD; they were older and had more comorbidities than patients without SVD. The rate of stroke or systemic embolism with rivaroxaban vs. warfarin was consistent among patients with SVD [2.01 vs. 2.43%; hazard ratio (HR) 0.83, 95% confidence interval (CI) 0.55–1.27] and without SVD (1.96 vs. 2.22%; HR 0.89, 95% CI 0.75–1.07; interaction P = 0.76). However, rates of major and non-major clinically relevant bleeding with rivaroxaban vs. warfarin were higher in patients with SVD (19.8% rivaroxaban vs. 16.8% warfarin; HR 1.25, 95% CI 1.05–1.49) vs. those without (14.2% rivaroxaban vs. 14.1% warfarin; HR 1.01, 95% CI 0.94–1.10; interaction P = 0.034), even when controlling for risk factors and potential confounders. In intracranial haemorrhage, there was no interaction between patients with and without SVD where the overall rate was lower among those randomized to rivaroxaban. Conclusions Many patients with ‘non-valvular atrial fibrillation’ have significant valve lesions. Their risk of stroke is similar to that of patients without SVD after controlling for stroke risk factors. Efficacy of rivaroxaban vs. warfarin was similar in patients with and without SVD; however, the observed risk of bleeding was higher with rivaroxaban in patients with SVD but was the same among those without SVD. Atrial fibrillation patients with and without SVD experience the same stroke-preventive benefit of oral anticoagulants. PMID:25148838

Supervisor Autonomy and Considerate Leadership Style are Associated with Supervisors’ Likelihood to Accommodate Back Injured Workers

PubMed Central

McGuire, Connor; Kristman, Vicki L; Williams-Whitt, Kelly; Reguly, Paula; Shaw, William; Soklaridis, Sophie

2015-01-01

PURPOSE To determine the association between supervisors’ leadership style and autonomy and supervisors’ likelihood of supporting job accommodations for back-injured workers. METHODS A cross-sectional study of supervisors from Canadian and US employers was conducted using a web-based, self-report questionnaire that included a case vignette of a back-injured worker. Autonomy and two dimensions of leadership style (considerate and initiating structure) were included as exposures. The outcome, supervisors’ likeliness to support job accommodation, was measured with the Job Accommodation Scale. We conducted univariate analyses of all variables and bivariate analyses of the JAS score with each exposure and potential confounding factor. We used multivariable generalized linear models to control for confounding factors. RESULTS A total of 796 supervisors participated. Considerate leadership style (β= .012; 95% CI: .009–.016) and autonomy (β= .066; 95% CI: .025–.11) were positively associated with supervisors’ likelihood to accommodate after adjusting for appropriate confounding factors. An initiating structure leadership style was not significantly associated with supervisors’ likelihood to accommodate (β = .0018; 95% CI: −.0026–.0061) after adjusting for appropriate confounders. CONCLUSIONS Autonomy and a considerate leadership style were positively associated with supervisors’ likelihood to accommodate a back-injured worker. Providing supervisors with more autonomy over decisions of accommodation and developing their considerate leadership style may aid in increasing work accommodation for back-injured workers and preventing prolonged work disability. PMID:25595332

Selection bias and patterns of confounding in cohort studies: the case of the NINFEA web-based birth cohort.

PubMed

Pizzi, Costanza; De Stavola, Bianca L; Pearce, Neil; Lazzarato, Fulvio; Ghiotti, Paola; Merletti, Franco; Richiardi, Lorenzo

2012-11-01

Several studies have examined the effects of sample selection on the exposure-outcome association estimates in cohort studies, but the reasons why this selection may induce bias have not been fully explored. To investigate how sample selection of the web-based NINFEA birth cohort may change the confounding patterns present in the source population. The characteristics of the NINFEA participants (n=1105) were compared with those of the wider source population-the Piedmont Birth Registry (PBR)-(n=36 092), and the association of two exposures (parity and educational level) with two outcomes (low birth weight and birth by caesarean section), while controlling for other risk factors, was studied. Specifically the associations among measured risk factors within each dataset were examined and the exposure-outcome estimates compared in terms of relative ORs. The associations of educational level with the other risk factors (alcohol consumption, folic acid intake, maternal age, pregnancy weight gain, previous miscarriages) partly differed between PBR and NINFEA. This was not observed for parity. Overall, the exposure-outcome estimates derived from NINFEA only differed moderately from those obtained in PBR, with relative ORs ranging between 0.74 and 1.03. Sample selection in cohort studies may alter the confounding patterns originally present in the general population. However, this does not necessarily introduce selection bias in the exposure-outcome estimates, as sample selection may reduce some of the residual confounding present in the general population.

Neonatal Pain-Related Stress Predicts Cortical Thickness at Age 7 Years in Children Born Very Preterm

PubMed Central

Ranger, Manon; Chau, Cecil M. Y.; Garg, Amanmeet; Woodward, Todd S.; Beg, Mirza Faisal; Bjornson, Bruce; Poskitt, Kenneth; Fitzpatrick, Kevin; Synnes, Anne R.; Miller, Steven P.; Grunau, Ruth E.

2013-01-01

Background Altered brain development is evident in children born very preterm (24–32 weeks gestational age), including reduction in gray and white matter volumes, and thinner cortex, from infancy to adolescence compared to term-born peers. However, many questions remain regarding the etiology. Infants born very preterm are exposed to repeated procedural pain-related stress during a period of very rapid brain development. In this vulnerable population, we have previously found that neonatal pain-related stress is associated with atypical brain development from birth to term-equivalent age. Our present aim was to evaluate whether neonatal pain-related stress (adjusted for clinical confounders of prematurity) is associated with altered cortical thickness in very preterm children at school age. Methods 42 right-handed children born very preterm (24–32 weeks gestational age) followed longitudinally from birth underwent 3-D T1 MRI neuroimaging at mean age 7.9 yrs. Children with severe brain injury and major motor/sensory/cognitive impairment were excluded. Regional cortical thickness was calculated using custom developed software utilizing FreeSurfer segmentation data. The association between neonatal pain-related stress (defined as the number of skin-breaking procedures) accounting for clinical confounders (gestational age, illness severity, infection, mechanical ventilation, surgeries, and morphine exposure), was examined in relation to cortical thickness using constrained principal component analysis followed by generalized linear modeling. Results After correcting for multiple comparisons and adjusting for neonatal clinical factors, greater neonatal pain-related stress was associated with significantly thinner cortex in 21/66 cerebral regions (p-values ranged from 0.00001 to 0.014), predominately in the frontal and parietal lobes. Conclusions In very preterm children without major sensory, motor or cognitive impairments, neonatal pain-related stress appears to be associated with thinner cortex in multiple regions at school age, independent of other neonatal risk factors. PMID:24204657

Association between angiotensin II type 1 receptor gene polymorphism and essential hypertension: the Ohasama Study.

PubMed

Sugimoto, Ken; Katsuya, Tomohiro; Ohkubo, Takayoshi; Hozawa, Atsushi; Yamamoto, Koichi; Matsuo, Akiko; Rakugi, Hiromi; Tsuji, Ichiro; Imai, Yutaka; Ogihara, Toshio

2004-08-01

Gene targeting approaches have suggested that the angiotensin II type 1 receptor (AT1R) is involved in blood pressure (BP) regulation and modulation of the effect of angiotensin II. The A1166C polymorphism of the AT1 receptor gene (AT1R/A1166C) is associated with hypertension in Caucasians, but not in Japanese. The goal of this study, the Ohasama Study, was to examine the association between AT1R/A1166C and hypertension, especially home BP, in the Japanese general population. The Ohasama Study was a cohort study based on Japanese rural residents of Ohasama Town in the northern part of Japan. Subjects who gave informed consent to the study protocol and genetic analysis were recruited. Home BP was measured twice in the morning within 1 h of waking up and in the evening just before going to bed. The TaqMan polimerase chain reaction (PCR) method clearly determined AT1R/A1166C genotypes (n =1,207). The genotype distribution of AT1R/A1166C was as follows: AA 84%; AC 15%; CC 1%. There was almost no difference in baseline characteristics among the AT1R genotypes (AA, AC, CC). In the subjects not receiving antihypertensive medication (n =817), both casual BP and home BP were not different among the AT1R genotypes after adjusting for confounding factors (age, sex, body mass index, current smoking habit and current alcohol consumption). The frequency of hypertension showed no difference among AT1R genotypes after adjusting for confounding factors, though the AC and CC genotypes were more frequent in hypertensives than in normotensives. Our data suggested that the AT1R/A1166C polymorphism is not a major genetic predisposing factor for hypertension in Japanese.

An exploratory factor analysis of nutritional biomarkers associated with major depression in pregnancy

PubMed Central

Bodnar, Lisa M.; Wisner, Katherine L.; Luther, James F.; Powers, Robert W.; Evans, Rhobert W.; Gallaher, Marcia J.; Newby, P.K.

2011-01-01

Objective Major depressive disorder (MDD) during pregnancy increases the risk of adverse maternal and infant outcomes. Maternal nutritional status may be a modifiable risk factor for antenatal depression. We evaluated the association between patterns in mid-pregnancy nutritional biomarkers and MDD. Design Prospective cohort study Setting Pittsburgh, Pennsylvania, USA Subjects Women who enrolled at ≤20 weeks gestation had a diagnosis of MDD made with the Structured Clinical Interview for DSM-IV at 20-, 30-, and 36-week study visits. A total of 135 women contributed 345 person-visits. Non-fasting blood drawn at enrollment was assayed for red cell essential fatty acids, plasma folate, homocysteine, and ascorbic acid; serum 25-hydroxyvitamin D, retinol, vitamin E, carotenoids, ferritin, and soluble transferrin receptors. Nutritional biomarkers were entered into principal components analysis. Results Three factors emerged: Factor 1, Essential Fatty Acids; Factor 2, Micronutrients; and Factor 3, Carotenoids. MDD was prevalent in 21.5% of women. In longitudinal multivariable logistic models, there was no association between the Essential Fatty Acid or Micronutrient patterns and MDD either before or after adjustment for employment, education, or prepregnancy BMI. In unadjusted analysis, women with Carotenoid factor scores in the middle and upper tertiles were 60% less likely than women in the bottom tertile to have MDD during pregnancy, but after adjustment for confounders, the associations were no longer statistically significant. Conclusions While meaningful patterns were derived using nutritional biomarkers, significant associations with MDD were not observed in multivariable adjusted analyses. Larger, more diverse samples are needed to understand nutrition-depression relationships during pregnancy. PMID:22152590

An exploratory factor analysis of nutritional biomarkers associated with major depression in pregnancy.

PubMed

Bodnar, Lisa M; Wisner, Katherine L; Luther, James F; Powers, Robert W; Evans, Rhobert W; Gallaher, Marcia J; Newby, P K

2012-06-01

Major depressive disorder (MDD) during pregnancy increases the risk of adverse maternal and infant outcomes. Maternal nutritional status may be a modifiable risk factor for antenatal depression. We evaluated the association between patterns in mid-pregnancy nutritional biomarkers and MDD. Prospective cohort study. Pittsburgh, Pennsylvania, USA. Women who enrolled at ≤20 weeks' gestation and had a diagnosis of MDD made with the Structured Clinical Interview for DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 4th edition) at 20-, 30- and 36-week study visits. A total of 135 women contributed 345 person-visits. Non-fasting blood drawn at enrolment was assayed for red cell essential fatty acids, plasma folate, homocysteine and ascorbic acid; serum 25-hydroxyvitamin D, retinol, vitamin E, carotenoids, ferritin and soluble transferrin receptors. Nutritional biomarkers were entered into principal components analysis. Three factors emerged: Factor 1, Essential Fatty Acids; Factor 2, Micronutrients; and Factor 3, Carotenoids. MDD was prevalent in 21·5 % of women. In longitudinal multivariable logistic models, there was no association between the Essential Fatty Acids or Micronutrients pattern and MDD either before or after adjustment for employment, education or pre-pregnancy BMI. In unadjusted analysis, women with factor scores for Carotenoids in the middle and upper tertiles were 60 % less likely than women in the bottom tertile to have MDD during pregnancy, but after adjustment for confounders the associations were no longer statistically significant. While meaningful patterns were derived using nutritional biomarkers, significant associations with MDD were not observed in multivariable adjusted analyses. Larger, more diverse samples are needed to understand nutrition-depression relationships during pregnancy.

The alarming problems of confounding equivalence using logistic regression models in the perspective of causal diagrams.

PubMed

Yu, Yuanyuan; Li, Hongkai; Sun, Xiaoru; Su, Ping; Wang, Tingting; Liu, Yi; Yuan, Zhongshang; Liu, Yanxun; Xue, Fuzhong

2017-12-28

Confounders can produce spurious associations between exposure and outcome in observational studies. For majority of epidemiologists, adjusting for confounders using logistic regression model is their habitual method, though it has some problems in accuracy and precision. It is, therefore, important to highlight the problems of logistic regression and search the alternative method. Four causal diagram models were defined to summarize confounding equivalence. Both theoretical proofs and simulation studies were performed to verify whether conditioning on different confounding equivalence sets had the same bias-reducing potential and then to select the optimum adjusting strategy, in which logistic regression model and inverse probability weighting based marginal structural model (IPW-based-MSM) were compared. The "do-calculus" was used to calculate the true causal effect of exposure on outcome, then the bias and standard error were used to evaluate the performances of different strategies. Adjusting for different sets of confounding equivalence, as judged by identical Markov boundaries, produced different bias-reducing potential in the logistic regression model. For the sets satisfied G-admissibility, adjusting for the set including all the confounders reduced the equivalent bias to the one containing the parent nodes of the outcome, while the bias after adjusting for the parent nodes of exposure was not equivalent to them. In addition, all causal effect estimations through logistic regression were biased, although the estimation after adjusting for the parent nodes of exposure was nearest to the true causal effect. However, conditioning on different confounding equivalence sets had the same bias-reducing potential under IPW-based-MSM. Compared with logistic regression, the IPW-based-MSM could obtain unbiased causal effect estimation when the adjusted confounders satisfied G-admissibility and the optimal strategy was to adjust for the parent nodes of outcome, which obtained the highest precision. All adjustment strategies through logistic regression were biased for causal effect estimation, while IPW-based-MSM could always obtain unbiased estimation when the adjusted set satisfied G-admissibility. Thus, IPW-based-MSM was recommended to adjust for confounders set.

A Bayesian Framework to Account for Complex Non-Genetic Factors in Gene Expression Levels Greatly Increases Power in eQTL Studies

PubMed Central

Durbin, Richard; Winn, John

2010-01-01

Gene expression measurements are influenced by a wide range of factors, such as the state of the cell, experimental conditions and variants in the sequence of regulatory regions. To understand the effect of a variable of interest, such as the genotype of a locus, it is important to account for variation that is due to confounding causes. Here, we present VBQTL, a probabilistic approach for mapping expression quantitative trait loci (eQTLs) that jointly models contributions from genotype as well as known and hidden confounding factors. VBQTL is implemented within an efficient and flexible inference framework, making it fast and tractable on large-scale problems. We compare the performance of VBQTL with alternative methods for dealing with confounding variability on eQTL mapping datasets from simulations, yeast, mouse, and human. Employing Bayesian complexity control and joint modelling is shown to result in more precise estimates of the contribution of different confounding factors resulting in additional associations to measured transcript levels compared to alternative approaches. We present a threefold larger collection of cis eQTLs than previously found in a whole-genome eQTL scan of an outbred human population. Altogether, 27% of the tested probes show a significant genetic association in cis, and we validate that the additional eQTLs are likely to be real by replicating them in different sets of individuals. Our method is the next step in the analysis of high-dimensional phenotype data, and its application has revealed insights into genetic regulation of gene expression by demonstrating more abundant cis-acting eQTLs in human than previously shown. Our software is freely available online at http://www.sanger.ac.uk/resources/software/peer/. PMID:20463871

Influence of GSTM1 and GSTT1 genotypes and confounding factors on the frequency of sister chromatid exchange and micronucleus among road construction workers.

PubMed

Kumar, Anil; Yadav, Anita; Giri, Shiv Kumar; Dev, Kapil; Gautam, Sanjeev Kumar; Gupta, Ranjan; Aggarwal, Neeraj

2011-07-01

In the present study, we have investigated the influence of polymorphism of GSTM1 and GSTT1 genes and confounding factors such as age, sex, exposure duration and consumption habits on cytogenetic biomarkers. Frequency of sister chromatid exchanges (SCEs), high frequency cell (HFC) and cytokinesis blocked micronuclei (CBMN) were evaluated in peripheral blood lymphocytes of 115 occupationally exposed road construction workers and 105 unexposed individuals. The distribution of null and positive genotypes of glutathione-S transferase gene was evaluated by multiplex PCR among control and exposed subjects. An increased frequency of CBMN (7.03±2.08); SCE (6.95±1.76) and HFC (6.28±1.69) were found in exposed subjects when compared to referent (CBMN - 3.35±1.10; SCE - 4.13±1.30 and HFC - 3.98±1.56). These results were found statistically significant at p<0.05. When the effect of confounding factors on the frequency of studied biomarkers was evaluated, a strong positive interaction was found. The individuals having GSTM1 and GSTT1 null genotypes had higher frequency of CBMN, SCE and HFC. The association between GSTM1 and GSTT1 genotypes and studied biomarkers was found statistically significant at p<0.05. Our findings suggest that individuals having null type of GST are more susceptible to cytogenetic damage by occupational exposure regardless of confounding factors. There is a significant effect of polymorphism of these genes on cytogenetic biomarkers which are considered as early effects of genotoxic carcinogens. Copyright © 2011 Elsevier Ltd. All rights reserved.

Epidemiological evidence that indoor air pollution from cooking with solid fuels accelerates skin aging in Chinese women.

PubMed

Li, Miaozhu; Vierkötter, Andrea; Schikowski, Tamara; Hüls, Anke; Ding, Anan; Matsui, Mary S; Deng, Binwei; Ma, Chuan; Ren, Aiguo; Zhang, Juan; Tan, Jingze; Yang, Yajun; Jin, Li; Krutmann, Jean; Li, Zhiwen; Wang, Sijia

2015-08-01

Recently, we showed that outdoor air pollution exposure from traffic and industry is associated with an increased risk of skin aging in Caucasian women. In China, indoor air pollution exposure caused by the use of solid fuels like coal is a major health problem and might also increase the risk of skin aging in Chinese women. As cooking with solid fuels is a major source of indoor air pollution exposure in China, we aimed to test if cooking with solid fuels is associated with more pronounced skin aging in Chinese women. We conducted two cross-sectional studies in China to assess the association between cooking with solid fuels and signs of skin aging. In Pingding (in northern China) we assessed N=405 and in Taizhou (in southern China) N=857 women between 30 and 90 years of age. Skin aging was evaluated by the SCINEXA score. Indoor air pollution exposure, sun exposure, smoking and other confounders were assessed by questionnaires. Associations were then tested by linear and logistic regression analyses adjusted for further confounders. The analysis showed that cooking with solid fuels was significantly associated with a 5-8% more severe wrinkle appearance on face and an 74% increased risk of having fine wrinkles on back of hands in both studies combined, independent of age and other influences on skin aging. The present studies thus corroborate our previous finding that air pollution is associated with skin aging and extend it by showing that indoor air pollution might be another risk factor for skin aging. Copyright © 2015. Published by Elsevier Ireland Ltd.

Use of instrumental variables in the analysis of generalized linear models in the presence of unmeasured confounding with applications to epidemiological research.

PubMed

Johnston, K M; Gustafson, P; Levy, A R; Grootendorst, P

2008-04-30

A major, often unstated, concern of researchers carrying out epidemiological studies of medical therapy is the potential impact on validity if estimates of treatment are biased due to unmeasured confounders. One technique for obtaining consistent estimates of treatment effects in the presence of unmeasured confounders is instrumental variables analysis (IVA). This technique has been well developed in the econometrics literature and is being increasingly used in epidemiological studies. However, the approach to IVA that is most commonly used in such studies is based on linear models, while many epidemiological applications make use of non-linear models, specifically generalized linear models (GLMs) such as logistic or Poisson regression. Here we present a simple method for applying IVA within the class of GLMs using the generalized method of moments approach. We explore some of the theoretical properties of the method and illustrate its use within both a simulation example and an epidemiological study where unmeasured confounding is suspected to be present. We estimate the effects of beta-blocker therapy on one-year all-cause mortality after an incident hospitalization for heart failure, in the absence of data describing disease severity, which is believed to be a confounder. 2008 John Wiley & Sons, Ltd

The relationship between type D personality and chronic heart failure is not confounded by disease severity as assessed by BNP.

PubMed

Pelle, Aline J; van den Broek, Krista C; Szabó, Balázs; Kupper, Nina

2010-11-05

Psychological factors, like Type D personality (i.e., the tendency to experience negative emotions and to inhibit emotional distress) have been linked to impaired health outcomes. Criticism on the role of psychological factors in cardiac disease has postulated that such constructs may be confounded by disease severity. Hence, we examined whether Type D personality is associated with brain natriuretic peptide (BNP), a sensitive marker of disease severity in chronic heart failure (CHF), in 202 consecutive CHF outpatients. No differences in logBNP levels were found between Type D and non-Type D patients (t(200) = -1.03, p = .30). After adjusting for demographic and clinical confounders, Type D personality remained unassociated with logBNP levels (β=.04, p = .55), whereas older age (β = .27, p<.001), being prescribed beta-blockers (β = .15, p = .02), lower left ventricular ejection fraction (β = -.38, p<.0001), and kidney dysfunction (β = .17, p = .01) were associated with higher logBNP. To conclude, Type D personality was not associated with BNP in CHF outpatients, whereas clinical variables were associated with BNP. These findings oppose the suggestion that Type D personality is confounded by indicators of disease severity. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

Peer influence as a potential magnifier of ADHD diagnosis.

PubMed

Aronson, Brian

2016-11-01

The prevalence of Attention Deficit and Hyperactivity Disorder (ADHD) is growing in America, but its cause is unclear. Scholars have identified many environmental factors that can cause or confound ADHD diagnosis, but epidemiological studies that try to control for confounding factors still find evidence that rates of ADHD diagnosis are increasing. As a preliminary explanation to ADHD's increasing prevalence, this article examines whether core ADHD diagnostic traits are subject to peer influence. If ADHD diagnosis can be confounded by peer influence, there are several mechanisms that could have caused increased rates of diagnosis. With data drawn from two schools across three waves in the National Longitudinal Survey of Adolescent Health (n = 2193), the author uses a stochastic actor oriented model to estimate the effect of peer influence on inattention, controlling for alternative network and behavioral causes. Results indicate that respondents have a strong likelihood to modify their self-reports of inattention, a core ADHD trait, to resemble that of their friends. Copyright © 2016 Elsevier Ltd. All rights reserved.

Desire thinking as a confounder in the relationship between mindfulness and craving: Evidence from a cross-cultural validation of the Desire Thinking Questionnaire.

PubMed

Chakroun-Baggioni, Nadia; Corman, Maya; Spada, Marcantonio M; Caselli, Gabriele; Gierski, Fabien

2017-10-01

Desire thinking and mindfulness have been associated with craving. The aim of the present study was to validate the French version of the Desire Thinking Questionnaire (DTQ) and to investigate the relationship between mindfulness, desire thinking and craving among a sample of university students. Four hundred and ninety six university students completed the DTQ and measures of mindfulness, craving and alcohol use. Results from confirmatory factor analyses showed that the two-factor structure proposed in the original DTQ exhibited suitable goodness-of-fit statistics. The DTQ also demonstrated good internal reliability, temporal stability and predictive validity. A set of linear regressions revealed that desire thinking had a confounding effect in the relationship between mindfulness and craving. The confounding role of desire thinking in the relationship between mindfulness and craving suggests that interrupting desire thinking may be a viable clinical option aimed at reducing craving. Copyright © 2017 Elsevier B.V. All rights reserved.

Offspring ADHD as a risk factor for parental marital problems: controls for genetic and environmental confounds.

PubMed

Schermerhorn, Alice C; D'Onofrio, Brian M; Slutske, Wendy S; Emery, Robert E; Turkheimer, Eric; Harden, K Paige; Heath, Andrew C; Martin, Nicholas G

2012-12-01

Previous studies have found that child attention-deficit/hyperactivity disorder (ADHD) is associated with more parental marital problems. However, the reasons for this association are unclear. The association might be due to genetic or environmental confounds that contribute to both marital problems and ADHD. Data were drawn from the Australian Twin Registry, including 1,296 individual twins, their spouses, and offspring. We studied adult twins who were discordant for offspring ADHD.Using a discordant twin pairs design, we examined the extent to which genetic and environmental confounds,as well as measured parental and offspring characteristics, explain the ADHD-marital problems association. Offspring ADHD predicted parental divorce and marital conflict. The associations were also robust when comparing differentially exposed identical twins to control for unmeasured genetic and environmental factors, when controlling for measured maternal and paternal psychopathology,when restricting the sample based on timing of parental divorce and ADHD onset, and when controlling for other forms of offspring psychopathology. Each of these controls rules out alternative explanations for the association. The results of the current study converge with those of prior research in suggesting that factors directly associated with offspring ADHD increase parental marital problems.

Offspring ADHD as a Risk Factor for Parental Marital Problems: Controls for Genetic and Environmental Confounds

PubMed Central

Schermerhorn, Alice C.; D’Onofrio, Brian M.; Slutske, Wendy S.; Emery, Robert E.; Turkheimer, Eric; Harden, K. Paige; Heath, Andrew C.; Martin, Nicholas G.

2013-01-01

Background Previous studies have found that child attention-deficit/hyperactivity disorder (ADHD) is associated with more parental marital problems. The reasons for this association are unclear, however. The association might be due to genetic or environmental confounds that contribute to both marital problems and ADHD. Method Data were drawn from the Australian Twin Registry, including 1296 individual twins, their spouses, and offspring. We studied adult twins who were discordant for offspring ADHD. Using a discordant twin pairs design, we examined the extent to which genetic and environmental confounds, as well as measured parental and offspring characteristics, explain the ADHD-marital problems association. Results Offspring ADHD predicted parental divorce and marital conflict. The associations were also robust when comparing differentially exposed identical twins to control for unmeasured genetic and environmental factors, when controlling for measured maternal and paternal psychopathology, when restricting the sample based on timing of parental divorce and ADHD onset, and when controlling for other forms of offspring psychopathology. Each of these controls rules out alternative explanations for the association. Conclusion The results of the current study converge with those of prior research in suggesting that factors directly associated with offspring ADHD increase parental marital problems. PMID:22958575

Biomechanical and psychosocial exposures are independent risk factors for carpal tunnel syndrome: assessment of confounding using causal diagrams.

PubMed

Harris-Adamson, Carisa; Eisen, Ellen A; Neophytou, Andreas; Kapellusch, Jay; Garg, Arun; Hegmann, Kurt T; Thiese, Matthew S; Dale, Ann Marie; Evanoff, Bradley; Bao, Stephen; Silverstein, Barbara; Gerr, Fred; Burt, Susan; Rempel, David

2016-11-01

Between 2001 and 2010, six research groups conducted coordinated prospective studies of carpal tunnel syndrome (CTS) incidence among US workers from various industries to estimate exposure-response relationships. This analysis examined the presence and magnitude of confounding between biomechanical and workplace psychosocial factors and incidence of dominant-hand CTS. 1605 participants, without CTS at enrolment, were followed for up to 3.5 years (2471 person-years). Demographic information, medical history and workplace psychosocial stress measures were collected at baseline. Individual workplace biomechanical exposures were collected for each task and combined across the workweek using time-weighted averaging (TWA). CTS case criteria were based on symptoms and results of electrophysiological testing. HRs were estimated with Cox proportional hazard models. Confounding was assessed using causal diagrams and an empirical criterion of 10% or greater change in effect estimate magnitude. There were 109 incident CTS cases (IR=4.41/100 person-years; 6.7% cumulative incidence). The relationships between CTS and forceful repetition rate, % time forceful hand exertion and the Threshold Limit Value for Hand Activity Level (TLV-HAL) were slightly confounded by decision latitude with effect estimates being attenuated towards the null (10-14% change) after adjustment. The risk of CTS among participants reporting high job strain was attenuated towards the null by 14% after adjusting for the HAL Scale or the % time forceful hand exertions. Although attenuation of the relationships between CTS and some biomechanical and work psychosocial exposures was observed after adjusting for confounding, the magnitudes were small and confirmed biomechanical and work psychosocial exposures as independent risk factors for incident CTS. 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/.

Reproductive history and post-reproductive mortality: A sibling comparison analysis using Swedish register data.

PubMed

Barclay, Kieron; Keenan, Katherine; Grundy, Emily; Kolk, Martin; Myrskylä, Mikko

2016-04-01

A growing body of evidence suggests that reproductive history influences post-reproductive mortality. A potential explanation for this association is confounding by socioeconomic status in the family of origin, as socioeconomic status is related to both fertility behaviours and to long-term health. We examine the relationship between age at first birth, completed parity, and post-reproductive mortality and address the potential confounding role of family of origin. We use Swedish population register data for men and women born 1932-1960, and examine both all-cause and cause-specific mortality. The contributions of our study are the use of a sibling comparison design that minimizes residual confounding from shared family background characteristics and assessment of cause-specific mortality that can shed light on the mechanisms linking reproductive history to mortality. Our results were entirely consistent with previous research on this topic, with teenage first time parents having higher mortality, and the relationship between parity and mortality following a U-shaped pattern where childless men and women and those with five or more children had the highest mortality. These results indicate that selection into specific fertility behaviours based upon socioeconomic status and experiences within the family of origin does not explain the relationship between reproductive history and post-reproductive mortality. Additional analyses where we adjust for other lifecourse factors such as educational attainment, attained socioeconomic status, and post-reproductive marital history do not change the results. Our results add an important new level of robustness to the findings on reproductive history and mortality by showing that the association is robust to confounding by factors shared by siblings. However it is still uncertain whether reproductive history causally influences health, or whether other confounding factors such as childhood health or risk-taking propensity could explain the association. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Nonlinear Predictive Models for Multiple Mediation Analysis: With an Application to Explore Ethnic Disparities in Anxiety and Depression Among Cancer Survivors.

PubMed

Yu, Qingzhao; Medeiros, Kaelen L; Wu, Xiaocheng; Jensen, Roxanne E

2018-04-02

Mediation analysis allows the examination of effects of a third variable (mediator/confounder) in the causal pathway between an exposure and an outcome. The general multiple mediation analysis method (MMA), proposed by Yu et al., improves traditional methods (e.g., estimation of natural and controlled direct effects) to enable consideration of multiple mediators/confounders simultaneously and the use of linear and nonlinear predictive models for estimating mediation/confounding effects. Previous studies find that compared with non-Hispanic cancer survivors, Hispanic survivors are more likely to endure anxiety and depression after cancer diagnoses. In this paper, we applied MMA on MY-Health study to identify mediators/confounders and quantify the indirect effect of each identified mediator/confounder in explaining ethnic disparities in anxiety and depression among cancer survivors who enrolled in the study. We considered a number of socio-demographic variables, tumor characteristics, and treatment factors as potential mediators/confounders and found that most of the ethnic differences in anxiety or depression between Hispanic and non-Hispanic white cancer survivors were explained by younger diagnosis age, lower education level, lower proportions of employment, less likely of being born in the USA, less insurance, and less social support among Hispanic patients.

Validation sampling can reduce bias in health care database studies: an illustration using influenza vaccination effectiveness.

PubMed

Nelson, Jennifer Clark; Marsh, Tracey; Lumley, Thomas; Larson, Eric B; Jackson, Lisa A; Jackson, Michael L

2013-08-01

Estimates of treatment effectiveness in epidemiologic studies using large observational health care databases may be biased owing to inaccurate or incomplete information on important confounders. Study methods that collect and incorporate more comprehensive confounder data on a validation cohort may reduce confounding bias. We applied two such methods, namely imputation and reweighting, to Group Health administrative data (full sample) supplemented by more detailed confounder data from the Adult Changes in Thought study (validation sample). We used influenza vaccination effectiveness (with an unexposed comparator group) as an example and evaluated each method's ability to reduce bias using the control time period before influenza circulation. Both methods reduced, but did not completely eliminate, the bias compared with traditional effectiveness estimates that do not use the validation sample confounders. Although these results support the use of validation sampling methods to improve the accuracy of comparative effectiveness findings from health care database studies, they also illustrate that the success of such methods depends on many factors, including the ability to measure important confounders in a representative and large enough validation sample, the comparability of the full sample and validation sample, and the accuracy with which the data can be imputed or reweighted using the additional validation sample information. Copyright © 2013 Elsevier Inc. All rights reserved.

Validation sampling can reduce bias in healthcare database studies: an illustration using influenza vaccination effectiveness

PubMed Central

Nelson, Jennifer C.; Marsh, Tracey; Lumley, Thomas; Larson, Eric B.; Jackson, Lisa A.; Jackson, Michael

2014-01-01

Objective Estimates of treatment effectiveness in epidemiologic studies using large observational health care databases may be biased due to inaccurate or incomplete information on important confounders. Study methods that collect and incorporate more comprehensive confounder data on a validation cohort may reduce confounding bias. Study Design and Setting We applied two such methods, imputation and reweighting, to Group Health administrative data (full sample) supplemented by more detailed confounder data from the Adult Changes in Thought study (validation sample). We used influenza vaccination effectiveness (with an unexposed comparator group) as an example and evaluated each method’s ability to reduce bias using the control time period prior to influenza circulation. Results Both methods reduced, but did not completely eliminate, the bias compared with traditional effectiveness estimates that do not utilize the validation sample confounders. Conclusion Although these results support the use of validation sampling methods to improve the accuracy of comparative effectiveness findings from healthcare database studies, they also illustrate that the success of such methods depends on many factors, including the ability to measure important confounders in a representative and large enough validation sample, the comparability of the full sample and validation sample, and the accuracy with which data can be imputed or reweighted using the additional validation sample information. PMID:23849144

Associations between workplace factors and carpal tunnel syndrome: A multi-site cross sectional study.

PubMed

Fan, Z Joyce; Harris-Adamson, Carisa; Gerr, Fred; Eisen, Ellen A; Hegmann, Kurt T; Bao, Stephen; Silverstein, Barbara; Evanoff, Bradley; Dale, Ann Marie; Thiese, Matthew S; Garg, Arun; Kapellusch, Jay; Burt, Susan; Merlino, Linda; Rempel, David

2015-05-01

Few large epidemiologic studies have used rigorous case criteria, individual-level exposure measurements, and appropriate control for confounders to examine associations between workplace psychosocial and biomechanical factors and carpal tunnel syndrome (CTS). Pooling data from five independent research studies, we assessed associations between prevalent CTS and personal, work psychosocial, and biomechanical factors while adjusting for confounders using multivariable logistic regression. Prevalent CTS was associated with personal factors of older age, obesity, female sex, medical conditions, previous distal upper extremity disorders, workplace measures of peak forceful hand activity, a composite measure of force and repetition (ACGIH Threshold Limit Value for Hand Activity Level), and hand vibration. In this cross-sectional analysis of production and service workers, CTS prevalence was associated with workplace and biomechanical factors. The findings were similar to those from a prospective analysis of the same cohort with differences that may be due to recall bias and other factors. © 2015 Wiley Periodicals, Inc.

Evaluation in medical education: A topical review of target parameters, data collection tools and confounding factors.

PubMed

Schiekirka, Sarah; Feufel, Markus A; Herrmann-Lingen, Christoph; Raupach, Tobias

2015-01-01

Evaluation is an integral part of education in German medical schools. According to the quality standards set by the German Society for Evaluation, evaluation tools must provide an accurate and fair appraisal of teaching quality. Thus, data collection tools must be highly reliable and valid. This review summarises the current literature on evaluation of medical education with regard to the possible dimensions of teaching quality, the psychometric properties of survey instruments and potential confounding factors. We searched Pubmed, PsycINFO and PSYNDEX for literature on evaluation in medical education and included studies published up until June 30, 2011 as well as articles identified in the "grey literature". RESULTS are presented as a narrative review. We identified four dimensions of teaching quality: structure, process, teacher characteristics, and outcome. Student ratings are predominantly used to address the first three dimensions, and a number of reliable tools are available for this purpose. However, potential confounders of student ratings pose a threat to the validity of these instruments. Outcome is usually operationalised in terms of student performance on examinations, but methodological problems may limit the usability of these data for evaluation purposes. In addition, not all examinations at German medical schools meet current quality standards. The choice of tools for evaluating medical education should be guided by the dimension that is targeted by the evaluation. Likewise, evaluation results can only be interpreted within the context of the construct addressed by the data collection tool that was used as well as its specific confounding factors.

The Association Between Major Depressive Disorder and Outcomes in Older Veterans Hospitalized With Pneumonia.

PubMed

DeWaters, Ami L; Chansard, Matthieu; Anzueto, Antonio; Pugh, Mary Jo; Mortensen, Eric M

2018-01-01

Major depressive disorder ("depression") has been identified as an independent risk factor for mortality for many comorbid conditions, including heart failure, cancer and stroke. Major depressive disorder has also been linked to immune suppression by generating a chronic inflammatory state. However, the association between major depression and pneumonia has not been examined. The aim of this study was to examine the association between depression and outcomes, including mortality and intensive care unit admission, in Veterans hospitalized with pneumonia. We conducted a retrospective national study using administrative data of patients hospitalized at any Veterans Administration acute care hospital. We included patients ≥65 years old hospitalized with pneumonia from 2002-2012. Depressed patients were further analyzed based on whether they were receiving medications to treat depression. We used generalized linear mixed effect models to examine the association of depression with the outcomes of interest after controlling for potential confounders. Patients with depression had a significantly higher 90-day mortality (odds ratio 1.12, 95% confidence interval 1.07-1.17) compared to patients without depression. Patients with untreated depression had a significantly higher 30-day (1.11, 1.04-1.20) and 90-day (1.20, 1.13-1.28) mortality, as well as significantly higher intensive care unit admission rates (1.12, 1.03-1.21), compared to patients with treated depression. For older veterans hospitalized with pneumonia, a concurrent diagnosis of major depressive disorder, and especially untreated depression, was associated with higher mortality. This highlights that untreated major depressive disorder is an independent risk factor for mortality for patients with pneumonia. Published by Elsevier Inc.

Estimates of 2012/13 influenza vaccine effectiveness using the case test-negative control design with different influenza negative control groups.

PubMed

Nunes, Baltazar; Machado, Ausenda; Guiomar, Raquel; Pechirra, Pedro; Conde, Patrícia; Cristovão, Paula; Falcão, Isabel

2014-07-31

In recent years several reports of influenza vaccine effectiveness (VE) have been made early for public health decision. The majority of these studies use the case test-negative control design (TND), which has been showed to provide, under certain conditions, unbiased estimates of influenza VE. Nevertheless, discussions have been taken on the best influenza negative control group to use. The present study aims to contribute to the knowledge on this field by comparing influenza VE estimates using three test-negative controls: all influenza negative, non-influenza respiratory virus and pan-negative. Incident ILI patients were prospectively selected and swabbed by a sample of general practitioners. Cases were ILI patients tested positive for influenza and controls ILI patients tested negative for influenza. The influenza negative control group was divided into non-influenza virus control group and pan-negative control group. Data were collected on vaccination status and confounding factors. Influenza VE was estimated as one minus the odds ratio of been vaccinated in cases versus controls adjusted for confounding effect by logistic regression. Confounder adjusted influenza VE against medically attended laboratory-confirmed influenza was 68.4% (95% CI: 20.7-87.4%) using all influenza negatives controls, 82.1% (95% CI: 47.6-93.9%) using non-influenza controls and 49.4% (95% CI: -44.7% to 82.3%) using pan-negative controls. Influenza VE estimates differed according to the influenza negative control group used. These results are in accordance with the expected under the hypothesis of differential viral interference between influenza vaccinated and unvaccinated individuals. Given the wide importance of TND study further studies should be conducted in order to clarify the observed differences. Copyright © 2014 Elsevier Ltd. All rights reserved.

Male fertility: psychiatric considerations.

PubMed

Hall, Elise; Burt, Vivien K

2012-02-01

To examine: 1) current knowledge on normal biologic variation of seminal parameters; 2) how stress and psychological factors affect sperm quality in fertile and infertile males; and 3) how mental illness and psychopharmacologic agents can affect male fertility. English-language Medline, Embase, and Psycinfo were searched for relevant publications (from 1970 to January 2011) for systematic review. None. None. None. Possible effects of stress, mood, and psychotropic medications on male factor fertility. Male-factor infertility is influenced by myriad factors (obesity, tobacco, etc.). Stress alone may reduce testosterone levels and spermatogenesis. Infertility assessment and treatment can lead to distress and negatively affect sperm samples. Available research has failed to control for potentially confounding variables. Although some trends have been identified, larger-scale studies that adequately control all confounding variables are needed before conclusions can be made about the relationship between stress, psychotropic agents, and male infertility. Copyright © 2012 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Racial and ethnic differences in utilization of mental health services among high-risk youths.

PubMed

Garland, Ann F; Lau, Anna S; Yeh, May; McCabe, Kristen M; Hough, Richard L; Landsverk, John A

2005-07-01

Racial and ethnic disparities in mental health service use have been identified as a major public health problem. However, the extent to which these disparities may be accounted for by other confounding sociodemographic or clinical predictors of service use (e.g., family income, functional impairment, caregiver strain) is relatively unexplored, especially for youth services. The goal of this study was to test for racial/ethnic disparities in use of a variety of outpatient, inpatient, and informal mental health services among high-risk youths, with the effects of other predictive factors controlled. Participants were 1,256 youths ages 6-18 years who received services in a large, publicly funded system of care (including the child welfare, juvenile justice, special education, alcohol and drug abuse, and mental health service sectors). Youths and caregivers were interviewed with established measures of mental health service use, psychiatric diagnoses, functional impairment, caregiver strain, and parental depression. Significant racial/ethnic group differences in likelihood of receiving any mental health service and, specifically, formal outpatient services were found after the effects of potentially confounding variables were controlled. Race/ethnicity did not exert a significant effect on the use of informal or 24-hour-care services. Racial/ethnic disparities in service use remain a public health problem.

Dietary Patterns and Insomnia Symptoms in Chinese Adults: The China Kadoorie Biobank.

PubMed

Yu, Canqing; Shi, Zumin; Lv, Jun; Guo, Yu; Bian, Zheng; Du, Huaidong; Chen, Yiping; Tao, Ran; Huang, Ying; Chen, Junshi; Chen, Zhengming; Li, Liming

2017-03-04

Limited attention has been paid to the effect of dietary patterns on sleep problems. In the present study, we analyzed the cross-sectional data of 481,242 adults aged 30-79 years from the China Kadoorie Biobank. A laptop-based questionnaire was administered to collect information on food intakes and insomnia symptoms. Logistic regression was used to estimate the odds ratios of each insomnia symptom according to quartiles of each dietary pattern, with adjustment for potential confounders. Two major dietary patterns were derived by factor analysis. The traditional northern dietary pattern was characterized by high intakes of wheat and other staple food, whereas the modern dietary pattern was characterized by high intakes of meat, poultry, fish, eggs, fresh fruit, and dairy products. Both dietary patterns were associated with a decreased prevalence of insomnia symptoms ( p for trend < 0.001); after adjustment for potential confounders, individuals who had the highest quartile score of traditional northern dietary pattern were 12%-19% less likely to have insomnia symptoms compared to those in the lowest quartile (odds ratio: 0.81-0.88), and the corresponding values for the modern dietary pattern were 0.89-1.01. Furthermore, interactions of these two dietary patterns on insomnia symptoms were observed. Further prospective studies are needed to elucidate the relationship between diet and insomnia.

Nutritional Risk is Associated with Chronic Musculoskeletal Pain in Community-dwelling Older Persons: The PAINEL Study.

PubMed

Bárbara Pereira Costa, Aline; Andrade Carneiro Machado, Luciana; Marcos Domingues Dias, João; Keller Coelho de Oliveira, Adriana; Ude Viana, Joana; da Silva, Sílvia Lanziotti Azevedo; Gonçalves Pereira Couto, Flávia; Lustosa Torres, Juliana; Mendes, Liliane P; Correa Dias, Rosangela

2016-01-01

Malnutrition is a risk factor for noncommunicable diseases related to ageing, and it can also contribute to musculoskeletal health. This study investigated whether nutritional risk is associated with chronic musculoskeletal pain in community-dwelling older persons. Nutritional risk was assessed by the DETERMINE Checklist. Chronic musculoskeletal pain was defined as the presence of pain in the past six months that did not disappear for at least 30 consecutive days. Multivariate logistic regression including confounding variables was used for the analysis. The sample was comprised of 383 participants (age 75.6 ± SD 6.1); the majority were at moderate-to-high nutritional risk (69%) and approximately one third presented chronic musculoskeletal pain (30%). The nutritional risk score was independently associated with chronic musculoskeletal pain: adding one unit in the risk score produces an 11% increment in the odds of presenting pain (OR 1.109, 95% CI 1.022-1.204). Individuals classified into moderate- or high-risk categories also had substantially higher odds (∼90%) of presenting chronic musculoskeletal pain when compared to those in the low-risk category, although our findings were only marginally significant. This is the first study to demonstrate the association between nutritional risk and chronic musculoskeletal pain above and beyond the contributed effects from relevant confounders.

Small intestinal permeability is increased in diarrhoea predominant IBS, while alterations in gastroduodenal permeability in all IBS subtypes are largely attributable to confounders.

PubMed

Mujagic, Z; Ludidi, S; Keszthelyi, D; Hesselink, M A M; Kruimel, J W; Lenaerts, K; Hanssen, N M J; Conchillo, J M; Jonkers, D M A E; Masclee, A A M

2014-08-01

Intestinal permeability has been studied in small groups of IBS patients with contrasting findings. To assess intestinal permeability at different sites of the GI tract in different subtypes of well-characterised IBS patients and healthy controls (HC), and to assess potential confounding factors. IBS patients and HC underwent a multi-sugar test to assess site-specific intestinal permeability. Sucrose excretion and lactulose/rhamnose ratio in 0-5 h urine indicated gastroduodenal and small intestinal permeability, respectively. Sucralose/erythritol ratio in 0-24 h and 5-24 h urine indicated whole gut and colonic permeability, respectively. Linear regression analysis was used to assess the association between IBS groups and intestinal permeability and to adjust for age, sex, BMI, anxiety or depression, smoking, alcohol intake and use of medication. Ninety-one IBS patients, i.e. 37% IBS-D, 23% IBS-C, 33% IBS-M and 7% IBS-U and 94 HC were enrolled. Urinary sucrose excretion was significantly increased in the total IBS group [μmol, median (Q1;Q3): 5.26 (1.82;11.03) vs. 2.44 (0.91;5.85), P < 0.05], as well as in IBS-C and IBS-D vs. HC. However, differences attenuated when adjusting for confounders. The lactulose/rhamnose ratio was increased in IBS-D vs. HC [0.023 (0.013;0.038) vs. 0.014 (0.008;0.025), P < 0.05], which remained significant after adjustment for confounders. No difference was found in 0-24 and 5-24 h sucralose/erythritol ratio between groups. Small intestinal permeability is increased in patients with IBS-D compared to healthy controls, irrespective of confounding factors. Adjustment for confounders is necessary when studying intestinal permeability, especially in a heterogeneous disorder such as IBS. © 2014 John Wiley & Sons Ltd.

Prevalence of cholera risk factors between migrant Haitians and Dominicans in the Dominican Republic.

PubMed

Lund, Andrea J; Keys, Hunter M; Leventhal, Stephanie; Foster, Jennifer W; Freeman, Matthew C

2015-03-01

To determine whether cholera risk factor prevalence in the Dominican Republic can be explained by nationality, independent of other factors, given the vulnerability of many Haitians in the country and the need for targeted prevention. A cross-sectional, observational household survey (103 Haitian and 260 Dominican) was completed in 18 communities in July 2012. The survey included modules for demographics, knowledge, socioeconomic status, and access to adequate water, sanitation, and hygiene (WASH) infrastructure. Logistic regression assessed differential access to WASH infrastructure and Poisson regression assessed differences in cholera knowledge, controlling for potential confounders. Dominican and Haitian households differed on demographic characteristics. Haitians had lower educational attainment, socioeconomic status, and less knowledge of cholera than Dominicans (adjusted odds ratio [aOR] = 0.66; 95% confidence interval [95%CI] = 0.55-0.81). Access to improved drinking water was low for both groups, but particularly low among rural Haitians (aOR = 0.21; 95%CI: 0.04-1.01). No differences were found in access to sanitation after adjusting for sociodemographic confounders (aOR = 1.00; 95%CI: 0.57-1.76). Urban/rural geography and socioeconomic status play a larger role in cholera risk factor prevalence than nationality, indicating that Haitians' perceived vulnerability to cholera is confounded by contextual factors. Understanding the social dynamics that lead to cholera risk can inform control strategies, leading to better targeting and the possibility of eliminating cholera from the island.

Human exposure to high natural background radiation: what can it teach us about radiation risks?

PubMed Central

Hendry, Jolyon H; Simon, Steven L; Wojcik, Andrzej; Sohrabi, Mehdi; Burkart, Werner; Cardis, Elisabeth; Laurier, Dominique; Tirmarche, Margot; Hayata, Isamu

2014-01-01

Natural radiation is the major source of human exposure to ionising radiation, and its largest contributing component to effective dose arises from inhalation of 222Rn and its radioactive progeny. However, despite extensive knowledge of radiation risks gained through epidemiologic investigations and mechanistic considerations, the health effects of chronic low-level radiation exposure are still poorly understood. The present paper reviews the possible contribution of studies of populations living in high natural background radiation (HNBR) areas (Guarapari, Brazil; Kerala, India; Ramsar, Iran; Yangjiang, China), including radon-prone areas, to low dose risk estimation. Much of the direct information about risk related to HNBR comes from case–control studies of radon and lung cancer, which provide convincing evidence of an association between long-term protracted radiation exposures in the general population and disease incidence. The success of these studies is mainly due to the careful organ dose reconstruction (with relatively high doses to the lung), and to the fact that large-scale collaborative studies have been conducted to maximise the statistical power and to ensure the systematic collection of information on potential confounding factors. In contrast, studies in other (non-radon) HNBR areas have provided little information, relying mainly on ecological designs and very rough effective dose categorisations. Recent steps taken in China and India to establish cohorts for follow-up and to conduct nested case–control studies may provide useful information about risks in the future, provided that careful organ dose reconstruction is possible and information is collected on potential confounding factors. PMID:19454802

Infant developmental milestones and adult intelligence: A 34-year follow-up.

PubMed

Flensborg-Madsen, Trine; Mortensen, Erik Lykke

2015-07-01

A number of studies suggest a positive association between faster infant motor development and intellectual function in childhood and adolescence. However, studies investigating the relationship between infant motor development and intelligence in adulthood are lacking. To investigate whether age at achievement of 12 motor developmental milestones was associated with adult intelligence and to evaluate the influence of sex, parental social status, parity, mother's cigarette consumption in the last trimester, gestational age, birthweight, and birth length on this association. Mothers of 9125 children of the Copenhagen Perinatal Cohort recorded 12 developmental milestones during the child's first year of life. A subsample of the cohort comprising 1155 individuals participated in a follow-up when they were aged 20-34 years and were administered the Wechsler Adult Intelligence Scale (WAIS). Associations between motor developmental milestones and IQ were analysed by multiple linear regression adjusting for potential confounding factors. Later acquisition of infant developmental milestones was associated with lower subsequent IQ, and the majority of significant associations were found for Performance IQ. Correlations were generally small (r < 0.10), but significant interactions were found between parental social status and age of attaining developmental milestones, with associations being significantly stronger in the offspring of lower social status parents. The effects remained significant after adjusting for possible confounding factors. This is the first study to find significant interactions with parental social status, thereby suggesting that associations between early motor development and intelligence are stronger in infants of low social status parents. Copyright © 2015 Elsevier B.V. All rights reserved.

Cognitive functions in children exposed to antiepileptic drugs in utero - Study in Georgia.

PubMed

Kasradze, Sofia; Gogatishvili, Nino; Lomidze, Giorgi; Ediberidze, Tamar; Lazariashvili, Marine; Khomeriki, Ketevan; Mamukadze, Shorena; Metreveli, Mariam; Gagoshidze, Tamar; Tatishvili, Nino; Tomson, Torbjörn

2017-01-01

The cognitive teratogenicity of antiepileptic drugs (AEDs) has gained increasing attention in the last decade. The objective of the current study was to assess the effects of AED fetal exposure on the cognitive development of children of mothers with epilepsy from Georgia in a controlled study taking into consideration major confounding factors. A prospective cohort group was formed from children and mothers registered in the Georgian National AED-Pregnancy Registry. The study group's age- and gender-matched control children without fetal AED exposure were selected retrospectively. The Intelligence Quotient (IQ) using the Wechsler Adult Intelligence Scale - revised (WAIS-R) was assessed in mothers. The Wechsler Preschool and Primary Scale of Intelligence (WPPSI-4) were used to assess intellectual functioning for children of both study and control groups. Linear regression analysis was performed to detect association of AED exposure on the cognitive performance of children. In total, 100 children aged 36 to 72months were evaluated. The IQ of WWE was significantly lower compared to women without epilepsy in all modalities. Exposure to valproate (VPA) (n=18) was associated with lowest cognitive performance regarding Full Scale IQ (FSIQ) (β, -12.04; p=0.006) and verbal comprehension (VCI) (β, -8.89; p=0.019). Maternal FSIQ, maternal performance IQ (PIQ), and child's age at first phrases were independent factors associated with the cognitive development of children. Multivariate analysis showed VPA to be an independent predictor for decreased cognitive performance. Maternal FSIQ, PIQ, and child developmental achievements were significant confounders for cognitive performance in children. Copyright © 2016 Elsevier Inc. All rights reserved.

Drosophila melanogaster as a model system for the evaluation of anti-aging compounds.

PubMed

Jafari, Mahtab

2010-01-01

Understanding the causes of aging is a complex problem due to the multiple factors that influence aging, which include genetics, environment, metabolism and reproduction, among others. These multiple factors create logistical difficulties in the evaluation of anti-aging agents. There is a need for good model systems to evaluate potential anti-aging compounds. The model systems used should represent the complexities of aging in humans, so that the findings may be extrapolated to human studies, but they should also present an opportunity to minimize the variables so that the experimental results can be accurately interpreted. In addition to positively affecting lifespan, the impact of the compound on the physiologic confounders of aging, including fecundity and the health span--the period of life where an organism is generally healthy and free from serious or chronic illness--of the model organism needs to be evaluated. Fecundity is considered a major confounder of aging in fruit flies. It is well established that female flies that are exposed to toxic substances typically reduce their dietary intake and their reproductive output and display an artifactual lifespan extension. As a result, drugs that achieve longevity benefits by reducing fecundity as a result of diminished food intake are probably not useful candidates for eventual treatment of aging in humans and should be eliminated during the screening process. Drosophila melanogaster provides a suitable model system for the screening of anti-aging compounds as D. melanogaster and humans have many conserved physiological and biological pathways. In this paper, I propose an algorithm to screen anti-aging compounds using Drosophila melanogaster as a model system.

Comorbidity of intellectual disability confounds ascertainment of autism: implications for genetic diagnosis.

PubMed

Polyak, Andrew; Kubina, Richard M; Girirajan, Santhosh

2015-10-01

While recent studies suggest a converging role for genetic factors towards risk for nosologically distinct disorders including autism, intellectual disability (ID), and epilepsy, current estimates of autism prevalence fail to take into account the impact of comorbidity of these disorders on autism diagnosis. We aimed to assess the effect of comorbidity on the diagnosis and prevalence of autism by analyzing 11 years (2000-2010) of special education enrollment data on approximately 6.2 million children per year. We found a 331% increase in the prevalence of autism from 2000 to 2010 within special education, potentially due to a diagnostic recategorization from frequently comorbid features such as ID. The decrease in ID prevalence equaled an average of 64.2% of the increase of autism prevalence for children aged 3-18 years. The proportion of ID cases potentially undergoing recategorization to autism was higher (P = 0.007) among older children (75%) than younger children (48%). Some US states showed significant negative correlations between the prevalence of autism compared to that of ID while others did not, suggesting state-specific health policy to be a major factor in categorizing autism. Further, a high frequency of autistic features was observed when individuals with classically defined genetic syndromes were evaluated for autism using standardized instruments. Our results suggest that current ascertainment practices are based on a single facet of autism-specific clinical features and do not consider associated comorbidities that may confound diagnosis. Longitudinal studies with detailed phenotyping and deep molecular genetic analyses are necessary to completely understand the cause of this complex disorder. © 2015 Wiley Periodicals, Inc.

Voice Outcomes of Adults Diagnosed with Pediatric Vocal Fold Nodules and Impact of Speech Therapy.

PubMed

Song, Brian H; Merchant, Maqdooda; Schloegel, Luke

2017-11-01

Objective To evaluate the voice outcomes of adults diagnosed with vocal fold nodules (VFNs) as children and to assess the impact of speech therapy on long-term voice outcomes. Study Design Prospective cohort study. Setting Large health care system. Subjects and Methods Subjects diagnosed with VFNs as children between the years 1996 and 2008 were identified within a medical record database of a large health care system. Included subjects were 3 to 12 years old at the time of diagnosis, had a documented laryngeal examination within 90 days of diagnosis, and were ≥18 years as of December 31, 2014. Qualified subjects were contacted by telephone and administered the Vocal Handicap Index-10 (VHI-10) and a 15-item questionnaire inquiring for confounding factors. Results A total of 155 subjects were included, with a mean age of 21.4 years (range, 18-29). The male:female ratio was 2.3:1. Mean VHI-10 score for the entire cohort was 5.4. Mean VHI-10 scores did not differ between those who received speech therapy (6.1) and those who did not (4.5; P = .08). Both groups were similar with respect to confounding risk factors that can contribute to dysphonia, although the no-therapy group had a disproportionately higher number of subjects who consumed >10 alcoholic drinks per week ( P = .01). Conclusion The majority of adults with VFNs as children will achieve a close-to-normal voice quality when they reach adulthood. In our cohort, speech therapy did not appear to have an impact on the long-term voice outcomes.

Malignant Tumors of the Female Reproductive System

PubMed Central

Labrèche, France

2012-01-01

This review summarizes the epidemiology of cancer of the female reproductive system and associated lifestyle factors. It also assesses the available evidence for occupational factors associated with these cancers. Cervical, endometrial, and ovarian cancers are relatively common, and cause significant cancer morbidity and mortality worldwide, whereas vulvar, vaginal, fallopian tube cancers, and choriocarcinomas are very rare. As several lifestyle factors are known to play a major role in the etiology of these cancers, very few published studies have investigated possible relationships with occupational factors. Some occupational exposures have been associated with increased risks of these cancers, but apart from the available evidence on the relationships between asbestos fibers and ovarian cancer, and tetrachloroethylene and cervical cancer, the data is rather scarce. Given the multifactorial nature of cancers of the female reproductive system, it is of the utmost importance to conduct occupational studies that will gather detailed data on potential individual confounding factors, in particular reproductive history and other factors that influence the body's hormonal environment, together with information on socio-economic status and lifestyle factors, including physical activity from multiple sources. Studies on the mechanisms of carcinogenesis in the female reproductive organs are also needed in order to elucidate the possible role of chemical exposures in the development of these cancers. PMID:23019529

Prevention of motor‐vehicle deaths by changing vehicle factors

PubMed Central

Robertson, Leon S

2007-01-01

Objective To estimate the effect of changing vehicle factors to reduce mortality in a comprehensive study. Design/methods Odds of death in the United States during 2000–2005 were analyzed, involving specific makes and models of 1999–2005 model year cars, minivans, and sport utility vehicles using logistic regression after selection of factors to be included by examination of least‐squares correlations of vehicle factors to maximize independence of predictors. Based on the regression coefficients, percentages of deaths preventable by changes in selected factors were calculated. Correlations of vehicle characteristics to environmental and behavioral risk factors were also examined to assess any potential confounding. Results Deaths in the studied vehicles would have been 42% lower had all had electronic stability control (ESC) systems. Improved crashworthiness as measured by offset frontal and side crash tests would have produced an additional 28% reduction, and static stability improvement would have reduced the deaths 11%. Although weight–power that reduces fuel economy is associated with lower risk to drivers, it increases risk of deaths to pedestrians and bicyclists but has an overall minor effect compared to the other factors. Conclusion A large majority of motor‐vehicle‐related fatalities could be avoided by universal adoption of the most effective technologies. PMID:17916886

The role of parenting in the prediction of criminal involvement: findings from a nationally representative sample of youth and a sample of adopted youth.

PubMed

Beaver, Kevin M; Schwartz, Joseph A; Connolly, Eric J; Al-Ghamdi, Mohammed Said; Kobeisy, Ahmed Nezar

2015-03-01

The role of parenting in the development of criminal behavior has been the source of a vast amount of research, with the majority of studies detecting statistically significant associations between dimensions of parenting and measures of criminal involvement. An emerging group of scholars, however, has drawn attention to the methodological limitations-mainly genetic confounding-of the parental socialization literature. The current study addressed this limitation by analyzing a sample of adoptees to assess the association between 8 parenting measures and 4 criminal justice outcome measures. The results revealed very little evidence of parental socialization effects on criminal behavior before controlling for genetic confounding and no evidence of parental socialization effects on criminal involvement after controlling for genetic confounding. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Five-factor model personality traits as predictors of incident coronary heart disease in the community: a 10.5-year cohort study based on the Baltimore epidemiologic catchment area follow-up study.

PubMed

Lee, Hochang Benjamin; Offidani, Emanuela; Ziegelstein, Roy C; Bienvenu, Oscar Joseph; Samuels, Jack; Eaton, William W; Nestadt, Gerald

2014-01-01

Certain personality and behavioral traits (e.g., type A and type D) have been reported to be associated with development and progression of coronary heart disease (CHD), but few have examined the relationship using a comprehensive assessment of personality along with a structured assessment of psychiatric disorders. Based on participants (age: 47.3 ± 12.8; female: 62.6%) of the Baltimore Epidemiologic Catchment Area follow-up study, we examined the relationship between the 5 major domains of personality traits (neuroticism, extraversion, openness, agreeableness, and conscientiousness) and incident CHD between Wave III (1993-1996) and Wave IV (2004-2005). Incident CHD developed in 65 participants during the follow-up. Those with incident CHD had lower on openness (44.06 ± 9.29 vs. 47.18 ± 8.80; p = 0.007) and extraversion (45.98 ± 9.25 vs. 49.12 ± 8.92; p = 0.007) scores than those without. Logistic regression models revealed an inverse association (OR = 0.73; 95% CI = 0.54-0.98) between openness factor z-scores and incident CHD after adjusting for putative confounding factors, including DSM III-R Major Depressive Disorder. High openness appears to be an independent protective factor for incident CHD in the community. Future studies should examine behavioral and pathophysiologic mechanisms underlying this association. Copyright © 2014 Academy of Psychosomatic Medicine. Published by Elsevier Inc. All rights reserved.

The burden of anaemia and associated factors in HIV positive Nigerian women.

PubMed

Ezechi, O C; Kalejaiye, O O; Gab-Okafor, C V; Oladele, D A; Oke, B; Ekama, S O; Odunukwe, N N; Ujah, I A O

2013-02-01

Anaemia is the most common complication of pregnancy and a predictor of poor maternal and foetal outcomes. HIV infection is now recognized as one of the major contributors to anaemia in pregnancy. It is therefore important to determine the burden and risk factors of anaemia in maternal HIV infection in others to plan effective prevention strategies as well as optimize management outcomes. To determine the prevalence and risk factors of anaemia in pregnant HIV positive Nigerians. The prevalence and possible risk factors of anaemia were investigated in HIV positive pregnant Nigerian women at a large HIV treatment clinic in southwestern Nigeria using a cross-sectional design between January 2006 and December 2011. Nine hundred and eighty-five (42.5 %) women of 2,318 HIV positive pregnant women seen during the period were anaemic by WHO standard defined by haemoglobin <11 g/dl. Majority were of mild to moderate severity (97.9 %). Short inter birth interval (p = 0.002), presence of opportunistic infections (OIs), (p = 0.001), use of zidovudine containing regimen (p = 0.0005) and CD4 cell count <200 cells/mm(3) (p = 0.001) were found to be independently associated with anaemia in HIV positive pregnant women after controlling for confounding variables. Anaemia was found to be high at 42.5 % among the HIV positive women studied and was found to be independently associated with short inter birth interval, presence of OIs, advanced HIV disease and use of zidovudine containing HAART regimen.

Are the changes in the peripheral brain-derived neurotrophic factor levels due to platelet activation?

PubMed Central

Serra-Millàs, Montserrat

2016-01-01

Brain-derived neurotrophic factor (BDNF) plays an important role in central nervous system development, neurogenesis and neuronal plasticity. BDNF is also expressed in several non-neuronal tissues, and it could play an important role in other processes, such as cancer, angiogenesis, etc. Platelets are the major source of peripheral BDNF. However, platelets also contain high amounts of serotonin; they express specific surface receptors during activation, and a multitude of pro-inflammatory and immunomodulatory bioactive compounds are secreted from the granules. Until recently, there was insufficient knowledge regarding the relationship between BDNF and platelets. Recent studies showed that BDNF is present in two distinct pools in platelets, in α-granules and in the cytoplasm, and only the BDNF in the granules is secreted following stimulation, representing 30% of the total BDNF in platelets. BDNF has an important role in the pathophysiology of depression. Low levels of serum BDNF have been described in patients with major depressive disorder, and BDNF levels increased with chronic antidepressant treatment. Interestingly, there is an association between depression and platelet function. This review analyzed studies that evaluated the relationship between BDNF and platelet activation and the effect of treatments on both parameters. Only a few studies consider this possible confounding factor, and it could be very important in diseases such as depression, which show changes in both parameters. PMID:27014600

Risk profiles for weight gain among postmenopausal women: A classification and regression tree analysis approach

USDA-ARS?s Scientific Manuscript database

Risk factors for obesity and weight gain are typically evaluated individually while "adjusting for" the influence of other confounding factors, and few studies, if any, have created risk profiles by clustering risk factors. We identified subgroups of postmenopausal women homogeneous in their cluster...

Severe edentulism is a major risk factor influencing stroke incidence in rural Ecuador (The Atahualpa Project).

PubMed

Del Brutto, Oscar H; Mera, Robertino M; Zambrano, Mauricio; Del Brutto, Victor J

2017-02-01

Background There is no information on stroke incidence in rural areas of Latin America, where living conditions and cardiovascular risk factors are different from urban centers. Aim Using a population-based prospective cohort study design, we aimed to assess risk factors influencing stroke incidence in community-dwelling adults living in rural Ecuador. Methods First-ever strokes occurring from 1 June 2012 to 31 May 2016, in Atahualpa residents aged ≥40 years, were identified from yearly door-to-door surveys and other overlapping sources. Poisson regression models adjusted for demographics, cardiovascular risk factors, edentulism and the length of observation time per subject were used to estimate stroke incidence rate ratio as well as factors influencing such incidence. Results Of 807 stroke-free individuals prospectively enrolled in the Atahualpa Project, follow-up was achieved in 718 (89%), contributing 2,499 years of follow-up (average 3.48 ± 0.95 years). Overall stroke incidence rate was 2.97 per 100 person-years of follow-up (95% CI: 1.73-4.2), which increased to 4.77 (95% CI: 1.61-14.1) when only persons aged ≥57 years were considered. Poisson regression models, adjusted for relevant confounders, showed that high blood pressure (IRR: 5.24; 95% CI: 2.55-7.93) and severe edentulism (IRR: 5.06; 95% CI: 2.28-7.85) were the factors independently increasing stroke incidence. Conclusions Stroke incidence in this rural setting is comparable to that reported from the developed world. Besides age and high blood pressure, severe edentulism is a major factor independently predicting incident strokes. Public awareness of the consequences of poor dental care might reduce stroke incidence in rural settings.

N-acetyltransferase single nucleotide polymorphisms: Emerging concepts serve as a paradigm for understanding complexities of personalized medicine

PubMed Central

Hein, David W.

2009-01-01

Arylamine N-acetyltransferase 1 (NAT1) and 2 (NAT2) exhibit single nucleotide polymorphisms (SNPs) in human populations that modify drug and carcinogen metabolism. This paper updates the identity, location, and functional effects of these SNPs and then follows with emerging concepts for understanding why pharmacogenetic findings may not be replicated consistently. Using this paradigm as an example, laboratory-based mechanistic analyses can reveal complexities such that genetic polymorphisms become biologically and medically relevant when confounding factors are more fully understood and considered. As medical care moves to a more personalized approach, the implications of these confounding factors will be important in understanding the complexities of personalized medicine. PMID:19379125

Does Anaemia Have Major Public Health Importance in Children Aged 6-59 Months in the Duggina Fanigo District of Wolaita Zone, Southern Ethiopia?

PubMed

Tiku, Yohannes Samuel; Mekonnen, Tefera Chane; Workie, Shimelash Bitew; Amare, Endale

2018-01-01

Globally, a large number of children aged 6-59 months are affected by anaemia. In Ethiopia, like other developing countries, more than 40% of children under 5 years are affected by anaemia. Anaemia during infancy and childhood period is associated with poor health and impaired cognitive development, leading to reduced academic achievement and earning potential in their adult life. The aim of this research was to assess whether anaemia remained a major public health problem among children aged 6-59 months or not in Duggina Fanigo District of Wolaita Zone, South Ethiopia in 2016. A community-based cross-sectional study was conducted from February to March 2016, on 404 mothers with children aged 6-59 months who were selected through the systematic sampling method. Socio-demographic and other data on associated factors was collected using a pre-tested questionnaire. Capillary blood was taken from the fingertip of each child and hemoglobin was measured using Haemo-Cue digital photometer. All the necessary safety measures were taken during blood collection. Data analysis was made using SPSS version 21. Multivariable logistic regression analysis was used to assess the association of independent variables with outcome variables and to control the possible confounding factors. The overall prevalence of anaemia was 51.4%. Anaemia was common among young children as compared to older children. After controlling the effect of confounding and adjusting for age, gender and altitude, explanatory variables like low dietary diversity (AOR = 3.24; 95% CI [1.68-6.23]), food insecurity (AOR = 3.63; 95% CI [2.18-6.04]), stunting (AOR = 2.60; 95% CI [1.56-4.35]), underweight (AOR = 2.46; 95% CI [1.29-4.67]) and fever within 2 weeks (AOR = 2.49; 95% CI [1.29-4.81]) prior to the survey were significantly associated with anaemia. In conclusion, the overall prevalence of anaemia among children aged 6-59 months has remained a major public health importance in the study area. Integrated efforts need to be prioritized to improve the health as well as the nutritional status of children aged 6-59 months through appropriate feeding practices in infants and children. © 2017 S. Karger AG, Basel.

Telomere length and telomerase in a well-characterized sample of individuals with major depressive disorder compared to controls.

PubMed

Simon, Naomi M; Walton, Zandra E; Bui, Eric; Prescott, Jennifer; Hoge, Elizabeth; Keshaviah, Aparna; Schwarz, Noah; Dryman, Taylor; Ojserkis, Rebecca A; Kovachy, Benjamin; Mischoulon, David; Worthington, John; De Vivo, Immaculata; Fava, Maurizio; Wong, Kwok-Kin

2015-08-01

Leukocyte telomere length (LTL) is a marker of cellular turnover and oxidative stress. Studies suggest major depressive disorder (MDD) is associated with oxidative stress, but examinations of MDD and LTL have yielded mixed results, likely because of differences in measurement methods and unmeasured confounding. This study examined LTL and telomerase activity in 166 individuals with MDD compared to 166 age- and gender-matched matched controls free of any psychiatric disorder, using well-validated assays and clinical assessment methods, and controlling for a range of potential confounders. Subjects aged 18 to 70 were evaluated by trained raters and provided blood for LTL and telomerase activity measurement. LTL was assayed using Southern blot and replicated with qPCR, and telomerase activity was assayed with a repeat amplification protocol using a commercial kit. There was no significant difference in telomere length for individuals with MDD [mean (SD)=9.1 (3.0)kbp] compared to controls [mean(SD)=8.9(2.5)kbp] measured by Southern blot (p=0.65) or by confirmatory qPCR (p=0.91) assays. Controlling for potential confounders did not alter the results. Telomerase activity did not differ by MDD diagnosis overall (p=0.40), but the effect of MDD was significantly modified by gender (t(299)=2.67, p=0.0079) even after controlling for potential confounders, with telomerase activity significantly greater only in males with MDD versus controls. Our well-characterized, well-powered examination of concurrently assessed telomere length and telomerase activity in individuals with clinically significant, chronic MDD and matched controls failed to provide strong evidence of an association of MDD with shorter LTL, while telomerase activity was higher in men with MDD [corrected]. Copyright © 2015 Elsevier Ltd. All rights reserved.

Self-efficacy difference among patients with cancer with different socioeconomic status: application of latent class analysis and standardization and decomposition analysis.

PubMed

Yuan, Changrong; Wei, Chunlan; Wang, Jichuan; Qian, Huijuan; Ye, Xianghong; Liu, Yingyan; Hinds, Pamela S

2014-06-01

Although the relationship between partial socioeconomic status (SES) and self-efficacy has been studied in previous studies, few research have examined self-efficacy difference among patients with cancer with different SES. A cross-sectional survey involving 764 patients with cancer was completed. Latent class analysis (LCA) was applied to identify distinct groups of patients with cancer using four SES indicators (education, income, employment status and health insurance status). Standardization and decomposition analysis (SDA) was then used to examine differences in patients' self-efficacy among SES groups and the components of the differences attributed to confounding factors, such as gender, age, anxiety, depression and social support. Participants were classified into four distinctive SES groups via using LCA method, and the observed self-efficacy level significantly varied by SES groups; as theorized, higher self-efficacy was associated with higher SES. The self-efficacy differences by SES groups were decomposed into "real" group differences and factor component effects that are attributed to group differences in confounding factor compositions. Self-efficacy significantly varies by SES. Social support significantly confounded the observed differences in self-efficacy between different SES groups among Chinese patients with cancer. Copyright © 2014 Elsevier Ltd. All rights reserved.

Persistent smoking as a predictor of disability pension due to musculoskeletal diagnoses: a 23 year prospective study of Finnish twins.

PubMed

Ropponen, Annina; Korhonen, Tellervo; Svedberg, Pia; Koskenvuo, Markku; Silventoinen, Karri; Kaprio, Jaakko

2013-12-01

To investigate whether stability or changes in smoking predict disability pension (DP) due to low back diagnoses (LBD) and musculoskeletal diagnoses (MSD) after taking familial confounding into account using a co-twin design. Longitudinal smoking patterns and multiple covariates in a population-based cohort of 17,451 Finnish twins (6959 complete pairs) born before 1958 were surveyed through questionnaires in 1975 and 1981. The outcome data were collected from the national pension registers until the end of 2004. Cox proportional hazards regression models were used for statistical analyses. Disability pension due to low back diagnoses was granted to 408 individuals and disability pension due to musculoskeletal diagnoses to 1177 individuals during the follow-up of 23 years. Being a persistent smoker (current smoker both 1975 and 1981) predicted a significantly increased risk for disability pension (hazard ratio 1.69, 95% confidence interval 1.46, 1.97) compared to those individuals who had never smoked. The association remained when several confounding factors, including familial factors, were taken into account. Persistent smoking predicts early disability pension due to musculoskeletal diagnoses and low back diagnoses independently from numerous confounding factors, including familial effects shared by the co-twins. © 2013.

The relationship between urinary tract infection during pregnancy and preeclampsia: causal, confounded or spurious?

PubMed

Karmon, Anatte; Sheiner, Eyal

2008-06-01

Preeclampsia is a major cause of maternal morbidity, although its precise etiology remains elusive. A number of studies suggest that urinary tract infection (UTI) during the course of gestation is associated with elevated risk for preeclampsia, while others have failed to prove such an association. In our medical center, pregnant women who were exposed to at least one UTI episode during pregnancy were 1.3 times more likely to have mild preeclampsia and 1.8 times more likely to have severe preeclampsia as compared to unexposed women. Our results are based on univariate analyses and are not adjusted for potential confounders. This editorial aims to discuss the relationship between urinary tract infection and preeclampsia, as well as examine the current problems regarding the interpretation of this association. Although the relationship between UTI and preeclampsia has been demonstrated in studies with various designs, carried-out in a variety of settings, the nature of this association is unclear. By taking into account timeline, dose-response effects, treatment influences, and potential confounders, as well as by neutralizing potential biases, future studies may be able to clarify the relationship between UTI and preeclampsia by determining if it is causal, confounded, or spurious.

Maternal and Paternal Height and the Risk of Preeclampsia.

PubMed

Lee, Yunsung; Magnus, Per

2018-04-01

The etiology of preeclampsia is unknown. Tall women have been found to have lower incidence of preeclampsia. This points to a possible biological causal effect but may be because of socioeconomic confounding. We used paternal height as an unexposed control to examine confounding. The MoBa (Norwegian Mother and Child Cohort Study) was used to extract data on parental heights, maternal prepregnancy weight, other background factors, and pregnancy outcomes for 99 968 singleton births. Multiple logistic regression was used to estimate odds ratios for preeclampsia according to parental height. The adjusted odds ratio for preeclampsia was 0.74 (95% CI, 0.66-0.82) for women >172 cm as compared with women <164 cm. The adjusted odds ratio for preeclampsia for men >186 cm was 1.03 (95% CI, 0.93-1.15) compared with men <178 cm. The association between maternal height and preeclampsia is unlikely to be because of confounding by familial, socioeconomic factors or by fetal genes related to height. The observed association between maternal height and preeclampsia merits further investigation. © 2018 American Heart Association, Inc.

Does the frequency of anxiety and depressive disorders differ between diagnostic subtypes of anorexia nervosa and bulimia?

PubMed

Godart, Nathalie; Berthoz, Sylvie; Rein, Zoé; Perdereau, Fabienne; Lang, François; Venisse, Jean-Luc; Halfon, Olivier; Bizouard, Pierre; Loas, Gwénolé; Corcos, Maurice; Jeammet, Philippe; Flament, Martine; Curt, Florence

2006-12-01

The objective of the present work is to determine whether the prevalence of depressive and anxiety disorders varies in subgroups of eating disorders (ED) according to age, ED duration, mode of care provision, and body mass index (BMI). Using the Mini International Neuropsychiatric Interview (MINI), the frequency of anxiety and depressive disorders was evaluated in 271 ED participants. Their prevalence was compared in subgroups of anorexics (AN-R and AN-BN) and bulimics (BN), both before and after controlling for potential confounding variables. Current or lifetime comorbidity of anxiety and depressive disorders did not differ between AN-R and AN-BN groups. Social phobia, panic disorders, and obsessive-compulsive disorder (OCD) were significantly more frequent in AN-BN and AN-R groups. Panic disorder was more frequent in the BN group. Several confounding factors, in particular those identified in the present study, may explain previous conflicting results on the frequency of anxiety and depressive disorders in ED. Nevertheless, the study confirmed that OCD is more frequent in AN, even after controlling for confounding factors. Copyright 2006 by Wiley Periodicals, Inc.

Early life adversity is associated with a smaller hippocampus in male but not female depressed in-patients: a case-control study.

PubMed

Colle, Romain; Segawa, Tomoyuki; Chupin, Marie; Tran Dong, Minh Ngoc Thien Kim; Hardy, Patrick; Falissard, Bruno; Colliot, Olivier; Ducreux, Denis; Corruble, Emmanuelle

2017-02-15

Three studies assessed the association of early life adversity (ELA) and hippocampal volumes in depressed patients, of which one was negative and the two others did not control for several potential confounding variables. Since the association of ELA and hippocampal volumes differ in male and female healthy volunteers, we investigated the association of ELA and hippocampal volumes in depressed patients, while focusing specifically on sex and controlling for several relevant socio-demographic and clinical variables. Sixty-three depressed in-patients treated in a psychiatric setting, with a current Major Depressive Episode (MDE) and a Major Depressive Disorder (MDD) were included and assessed for ELA. Hippocampal volumes were measured with brain magnetic resonance imaging (MRI) and automatic segmentation. They were compared between patients with (n = 28) or without (n = 35) ELA. After bivariate analyses, multivariate regression analyses tested the interaction of sex and ELA on hippocampal volume and were adjusted for several potential confounding variables. The subgroups of men (n = 26) and women (n = 37) were assessed separately. Patients with ELA had a smaller hippocampus than those without ELA (4.65 (±1.11) cm 3 versus 5.25 (±1.01) cm 3 ), bivariate: p = 0.03, multivariate: HR = 0.40, 95%CI [0.23;0.71], p = 0.002), independently from other factors. This association was found in men (4.43 (±1.22) versus 5.67 (±0.77) cm 3 ), bivariate: p = 0.006, multivariate HR = 0.23, 95%CI [0.06;0.82], p = 0.03) but not in women. ELA is associated with a smaller hippocampus in male but not female depressed in-patients. The reasons for this association should be investigated in further studies.

Childhood maltreatment preceding depressive disorder at age 18 years: A prospective Brazilian birth cohort study.

PubMed

Gallo, Erika Alejandra Giraldo; De Mola, Christian Loret; Wehrmeister, Fernando; Gonçalves, Helen; Kieling, Christian; Murray, Joseph

2017-08-01

Childhood maltreatment is linked with increased risk for mental illness in adolescence and adulthood. However, little evidence is available on whether different forms of maltreatment have specific effects, and no prospective studies in low- or middle-income countries have addressed this issue. Participants in a population-based, birth cohort study in Pelotas, Brazil (N=3715) self-reported exposure to maltreatment (emotional abuse, physical neglect, physical abuse, sexual abuse, domestic violence) in confidential questionnaires at age 15 years, and were assessed for major depression in interviews at age 18 years, using the MINI. Confounding variables concerning family characteristics were measured in interviews with mothers in the perinatal period and at age 11 years. Females exposed to emotional abuse (OR=2.7; 95%CI=1.9, 3.8) and domestic violence (OR=1.9; 95%CI=1.2, 2.9) were at increased risk for depression after adjustment for confounders and other types of maltreatment. Females exposed to two or more forms of maltreatment were at particularly high risk for depression (OR=4.1; 95%Cl=2.8, 6.1) compared with females not exposed to maltreatment. In adjusted analyses, maltreatment was not associated with depression for males. Detailed information about maltreatment such as timing and frequency was not available, and 1534 individuals were not included in the analyses, who had poorer and less educated mothers. Emotional abuse and domestic violence are strong risk factors for major depression for females. Early intervention to prevent maltreatment and its consequences is critical, especially for girls exposed to poly-maltreatment. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Associations between otitis media and child behavioural and learning difficulties: Results from a Danish cohort.

PubMed

Niclasen, J; Obel, C; Homøe, P; Kørvel-Hanquist, A; Dammeyer, J

2016-05-01

Findings from studies investigating early childhood episodes of otitis media (OM) and developmental outcomes are inconclusive. This may in part be because large-scale prospective studies controlling for relevant confounding factors are sparse. The present study investigates associations between OM in early childhood and later behavioural and learning difficulties controlling for relevant confounding factors. The study applied data from the Aarhus Birth Cohort's 10-12-year-old follow-up (N=7578). Associations between retrospective parent-reported OM (no OM; 1-3 episodes of OM with/without tympanostomy tubes; 4+ OM episodes without tympanostomy tubes and; 4+ OM episodes with tympanostomy tubes) one the one hand, and parent- and teacher-reported scores on the Strengths and Difficulties Questionnaire (SDQ) and parent-reported academic difficulties on the other hand, were investigated. The following variables were controlled for: parental educational level, maternal and paternal school problems, parental post-natal smoking, breastfeeding, and age at which the child started walking. All analyses were stratified by gender. Large differences in background characteristics were observed for the group of children with 4+ OM episodes with tympanostomy tubes compared to the no OM group. After controlling for relevant confounders, negative associations were consistently observed for the group of children with 4+ episodes of OM with tympanostomy tubes compared to the group of children without OM. This was particularly so for girls. The findings suggest an association between 4+ episodes of early OM with tympanostomy tubes and behavioural and learning difficulties later in childhood. The large inter-group differences, i.e. impact of residual and unmeasured confounding factors, may in part explain the observed associations and underline the need to include these in future studies. Copyright © 2016. Published by Elsevier Ireland Ltd.

Factors influencing tests of auditory processing: a perspective on current issues and relevant concerns.

PubMed

Cacace, Anthony T; McFarland, Dennis J

2013-01-01

Tests of auditory perception, such as those used in the assessment of central auditory processing disorders ([C]APDs), represent a domain in audiological assessment where measurement of this theoretical construct is often confounded by nonauditory abilities due to methodological shortcomings. These confounds include the effects of cognitive variables such as memory and attention and suboptimal testing paradigms, including the use of verbal reproduction as a form of response selection. We argue that these factors need to be controlled more carefully and/or modified so that their impact on tests of auditory and visual perception is only minimal. To advocate for a stronger theoretical framework than currently exists and to suggest better methodological strategies to improve assessment of auditory processing disorders (APDs). Emphasis is placed on adaptive forced-choice psychophysical methods and the use of matched tasks in multiple sensory modalities to achieve these goals. Together, this approach has potential to improve the construct validity of the diagnosis, enhance and develop theory, and evolve into a preferred method of testing. Examination of methods commonly used in studies of APDs. Where possible, currently used methodology is compared to contemporary psychophysical methods that emphasize computer-controlled forced-choice paradigms. In many cases, the procedures used in studies of APD introduce confounding factors that could be minimized if computer-controlled forced-choice psychophysical methods were utilized. Ambiguities of interpretation, indeterminate diagnoses, and unwanted confounds can be avoided by minimizing memory and attentional demands on the input end and precluding the use of response-selection strategies that use complex motor processes on the output end. Advocated are the use of computer-controlled forced-choice psychophysical paradigms in combination with matched tasks in multiple sensory modalities to enhance the prospect of obtaining a valid diagnosis. American Academy of Audiology.

Factors associated with higher oxytocin requirements in labor.

PubMed

Frey, Heather A; Tuuli, Methodius G; England, Sarah K; Roehl, Kimberly A; Odibo, Anthony O; Macones, George A; Cahill, Alison G

2015-09-01

To identify clinical characteristics associated with high maximum oxytocin doses in women who achieve complete cervical dilation. A retrospective nested case-control study was performed within a cohort of all term women at a single center between 2004 and 2008 who reached the second stage of labor. Cases were defined as women who had a maximum oxytocin dose during labor >20 mu/min, while women in the control group had a maximum oxytocin dose during labor of ≤20 mu/min. Exclusion criteria included no oxytocin administration during labor, multiple gestations, major fetal anomalies, nonvertex presentation, and prior cesarean delivery. Multiple maternal, fetal, and labor factors were evaluated with univariable analysis and multivariable logistic regression. Maximum oxytocin doses >20 mu/min were administered to 108 women (3.6%), while 2864 women received doses ≤20 mu/min. Factors associated with higher maximum oxytocin dose after adjusting for relevant confounders included maternal diabetes, birthweight >4000 g, intrapartum fever, administration of magnesium, and induction of labor. Few women who achieve complete cervical dilation require high doses of oxytocin. We identified maternal, fetal and labor factors that characterize this group of parturients.

Estrogen Receptor 1 ( ESR1) Gene Polymorphisms and Obesity Phenotypes in a Population of Young Adults.

PubMed

Correa-Rodríguez, María; Schmidt-RioValle, Jacqueline; González-Jiménez, Emilio; Rueda-Medina, Blanca

2017-06-01

Obesity is considered an increasingly serious health problem determined by multiple genetic and environmental factors. Estrogens have been found to play a major role in body weight and adiposity regulation through estrogen receptor 1 ( ESR1). The aim of this study was to determine whether genotype and haplotype frequencies of ESR1 polymorphisms are associated with body composition measures in a population of 572 young adults. A lack of significant association between genotypes of ESR1 gene polymorphisms and obesity phenotypes was seen after adjustment for confounding factors. Linkage disequilibrium (LD) analysis identified a single LD block for the ESR1 gene including PvuII and XbaI single-nucleotide polymorphisms (SNPs) (pairwise r 2 = .66). None of the haplotypes identified revealed statistically significant associations with any of the obesity phenotypes. Our results suggest that polymorphisms of the ESR1 gene do not contribute significantly to the genetic risk for obesity phenotypes in a population of young Caucasian adults.

Is infant feeding pattern associated with father's quality of life?

PubMed

Chen, Yi Chun; Chie, Wei-Chu; Chang, Pei-Jen; Chuang, Chao-Hua; Lin, Yu-Hsuan; Lin, Shio-Jean; Chen, Pau-Chung

2010-12-01

The aim of this study was to compare the health-related quality of life of fathers under different infant feeding type scenarios. The Medical Outcomes Study 36-item Short-Form was used to measure the health-related quality of life of 1,699 fathers, and the scores were used to look for associations with different infant feeding methods. Multivariable linear regression analysis was used to explore the contribution of the other potential related factors on fathers' quality of life. After controlling for confounding factors, fathers whose infants were ever being breast-fed reported lower scores than fathers whose infants were bottle-fed. Except for the infant feeding pattern, having a job, higher family income, and being the major caregiver were positively related to the father's quality of life. Fathers may not benefit during breast-feeding process. Because fathers' involvement plays an important role in the success of breast-feeding, the development of interventions that enable fathers to support their breast-feeding partner is very important.

Current issues relating to psychosocial job strain and cardiovascular disease research.

PubMed

Theorell, T; Karasek, R A

1996-01-01

The authors comment on recent reviews of cardiovascular job strain research by P. L. Schnall and P. A. Landsbergis (1994), and by T. S. Kristensen (1995), which conclude that job strain as defined by the demand-control model (the combination of contributions of low job decision latitudes and high psychological job demands) is confirmed as a risk factor for cardiovascular mortality in a large majority of studies. Lack of social support at work appears to further increase risk. Several still-unresolved research questions are examined in light of recent studies: (a) methodological issues related to use of occupational aggregate estimations and occupational career aggregate assessments, use of standard scales for job analysis and recall bias issues in self-reporting; (b) confounding factors and differential strengths of association by subgroups in job strain-cardiovascular disease analyses with respect to social class, gender, and working hours; and (c) review of results of monitoring job strain-blood pressure associations and associated methodological issues.

Association between total serum cholesterol and suicide attempts in subjects with major depressive disorder: Exploring the role of clinical and biochemical confounding factors.

PubMed

Bartoli, Francesco; Crocamo, Cristina; Dakanalis, Antonios; Riboldi, Ilaria; Miotto, Alessio; Brosio, Enrico; Clerici, Massimo; Carrà, Giuseppe

2017-04-01

We tested whether serum total cholesterol levels might be associated with recent suicide attempts in subjects with major depressive disorder, after controlling for relevant individual characteristics. We conducted a comparative cross-sectional study including consecutive inpatients with major depressive disorder. We differentiated subjects admitted for a recent serious (violent or non-violent) suicide attempt and those without such recent history. Total cholesterol was measured from fasting blood tests. At univariate analyses, suicide attempters had levels of total cholesterol (174.0±45.7mg/dL) lower than non-attempters (193.9±42.6mg/dL) (p=0.004). This was confirmed among both violent (174.1±46.2mg/dL) and non-violent (173.8±46.1mg/dL) suicide attempters (p=0.035 and 0.016, respectively). However, logistic regression analyses, sequentially including demographic, clinical (comorbid alcohol and personality disorders), and biochemical factors, did not show any association between serum cholesterol and recent suicide attempts (p=0.172). Similar findings were observed in multinomial logistic regression analyses, for both violent (p=0.512) and non-violent (p=0.157) suicide attempts. Our findings do not support the hypothesis that serum cholesterol and suicide attempts are associated among subjects with major depressive disorder. The identification of valid and accessible biological markers of suicidal behaviors still represents a challenge for future research. Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Risk of Breast Cancer Associated with Reproductive and Fertility Factors According to a Family History of Breast Cancer

DTIC Science & Technology

1999-10-01

also ruled out as confounders. Polycystic ovaries and endometriosis, possible indications for using OCs, were evaluated as potential confounders, but...Cn polymorphism In the MTHFR gone with breast and/or A irne genomic deletion of hMLHI in a family with Muir-Torre syndrome . J.J.P.canoer risk In...reduion I te,1Teth-A Muir-Torre syndrome (MTS) is an autosomal dominant condition characterized by se- Miylonetetrathydrofoiate reductase (MTHFR

Concepts and considerations of tooth wear: Part II--The mechanical component.

PubMed

Raigrodski, Ariel J; Dogan, Sami

2008-05-01

Identification of etiological factors is essential for successful management of tooth wear. In many cases, the diagnosis may be complicated because of the multiple etiologic factors which may confound the clinical appearance of tooth wear. Comprehensively addressing all of these factors is paramount to the long-term success of patient management.

Systematic review of the quality of prognosis studies in systemic lupus erythematosus.

PubMed

Lim, Lily S H; Lee, Senq J; Feldman, Brian M; Gladman, Dafna D; Pullenayegum, Eleanor; Uleryk, Elizabeth; Silverman, Earl D

2014-10-01

Prognosis studies examine outcomes and/or seek to identify predictors or factors associated with outcomes. Many prognostic factors have been identified in systemic lupus erythematosus (SLE), but few have been consistently found across studies. We hypothesized that this is due to a lack of rigor of study designs. This study aimed to systematically assess the methodologic quality of prognosis studies in SLE. A search of prognosis studies in SLE was performed using MEDLINE and Embase, from January 1990 to June 2011. A representative sample of 150 articles was selected using a random number generator and assessed by 2 reviewers. Each study was assessed by a risk of bias tool according to 6 domains: study participation, study attrition, measurement of prognostic factors, measurement of outcomes, measurement/adjustment for confounders, and appropriateness of statistical analysis. Information about missing data was also collected. A cohort design was used in 71% of studies. High risk of bias was found in 65% of studies for confounders, 57% for study participation, 56% for attrition, 36% for statistical analyses, 20% for prognostic factors, and 18% for outcome. Missing covariate or outcome information was present in half of the studies. Only 6 studies discussed reasons for missing data and 2 imputed missing data. Lack of rigorous study design, especially in addressing confounding, study participation and attrition, and inadequately handled missing data, has limited the quality of prognosis studies in SLE. Future prognosis studies should be designed with consideration of these factors to improve methodologic rigor. Copyright © 2014 by the American College of Rheumatology.

Success Providing Postpartum Intrauterine Devices in Private-Sector Health Care Facilities in Nigeria: Factors Associated With Uptake.

PubMed

Eluwa, George Ie; Atamewalen, Ronke; Odogwu, Kingsley; Ahonsi, Babatunde

2016-06-20

Use of modern contraceptive methods in Nigeria remained at 10% between 2008 and 2013 despite substantive investments in family planning services. Many women in their first postpartum year, in particular, have an unmet need for family planning. We evaluated use of postpartum intrauterine device (IUD) insertion and determined factors associated with its uptake in Nigeria. Data were collected between May 2014 and February 2015 from 11 private health care facilities in 6 southern Nigerian states. Women attending antenatal care in participating facilities were counseled on all available contraceptive methods including the postpartum IUD. Data were abstracted from participating facility records and evaluated using a cross-sectional analysis. Categorical variables were calculated as proportions while continuous variables were calculated as medians with the associated interquartile range (IQR). Multivariate logistic regression analysis was used to identify factors associated with uptake of the postpartum IUD while controlling for potential confounding factors, including age, educational attainment, marital status, parity, number of living children, and previous use of contraception. During the study period, 728 women delivered in the 11 facilities. The median age was 28 years, and most women were educated (73% had completed at least the secondary level). The majority (96%) of the women reported they were married, and the median number of living children was 3 (IQR, 2-4). Uptake of the postpartum IUD was 41% (n = 300), with 8% (n = 25) of the acceptors experiencing expulsion of the IUD within 6 weeks post-insertion. After controlling for potential confounding factors, several characteristics were associated with greater likelihood of choosing the postpartum IUD, including lower education, having a higher number of living children, and being single. Women who had used contraceptives previously were less likely to choose the postpartum IUD than women who had not previously used contraception (adjusted odds ratio, 0.68; 95% confidence interval, 0.55 to 0.84). A high percentage (41%) of women delivering in private health care facilities in southern Nigeria accepted immediate postpartum IUD insertion. Scale-up of postpartum IUD services is a promising approach to increasing uptake of long-acting reversible contraceptives among women in Nigeria. © Eluwa et al.

Benzodiazepine exposure in pregnancy and risk of major malformations: a critical overview.

PubMed

Bellantuono, Cesario; Tofani, Stefania; Di Sciascio, Guido; Santone, Giovanni

2013-01-01

Benzodiazepines (BDZs) safety profiles in pregnancy suggest that the risk of major malformations (MMs) cannot be considered simply as a "class effect". The aim of this paper was to review and update the available literature on the risks of MMs in women exposed to BDZs in the first trimester of pregnancy. PubMed was searched for English-language articles, from January 2001 to November 2011, introducing as keywords "teratogens", " major malformation", "foetus", "infant", "newborn", "pregnancy", in conjunction with "benzodiazepines" as a keyword or BDZ generic name as text words. Twelve studies were selected for the review. BDZ exposure during the first trimester of pregnancy seems not to be associated with an increasing risk of congenital MMs. Diazepam and chlordiazepoxide should be considered drugs of first choice. Data published in the last 10 years did not indicate an absolute contraindication in prescribing BDZs during the first gestational trimester. In any case, studies analyzed suffer from a number of methodological limitations such as lack of careful report of BDZ patterns of use in pregnancy, possible influences of recall bias, lack of controlling for confounding factors and lack of data concerning possible MMs in aborted fetuses. Copyright © 2013 Elsevier Inc. All rights reserved.

A prospective cohort study of disability pension due to mental diagnoses: the importance of health factors and behaviors

PubMed Central

2013-01-01

Background Previous studies have found associations between various health factors and behaviors and mental disorders. However, knowledge of such associations with disability pension (DP) due to mental diagnoses is scarce. Moreover, the influence of familial factors (genetics and family background) on the associations are mainly unknown. The aim of the study was to investigate associations between health factors and behaviors and future DP due to mental diagnoses in a twin cohort, accounting for familial confounding. Methods A prospective cohort study of Swedish twins (N=28 613), including survey data and national register data on DP and other background factors was conducted. Cox proportional hazards regression models were used to calculate hazard ratios (HR) with 95% confidence intervals (CI) for the whole twin cohort, and for discordant twin pairs. Results During follow-up 1998–2008 (median 10 years), 2.2% of the cohort was granted a DP with a mental diagnosis. In the fully adjusted analyses of the whole cohort, the associations of poor or moderate self-rated health (SRH), under- or overweight, former or current tobacco use, or being an abstainer from alcohol were significantly associated with risk of DP due to mental diagnoses. Analyses of discordant twin pairs confirmed all these associations, except for current tobacco use, being independent from familial confounding. Exclusion of individuals with current or previous depression or anxiety at baseline did not influence the associations found. Conclusions Poor or moderate SRH, under- or overweight, former tobacco use or being an abstainer from alcohol seem to be strong direct predictors of DP due to mental diagnoses, independently of several confounders of this study, including familial factors. PMID:23816331

Corporal punishment of adolescents by parents: a risk factor in the epidemiology of depression, suicide, alcohol abuse, child abuse, and wife beating.

PubMed

Straus, M A; Kantor, G K

1994-01-01

Over 90% of parents of toddlers spank or use other forms of corporal punishment. Although the rate declines each year from about age five, this study of a large national sample of U.S. adults found that almost half recalled having been corporally punished during their teen years. This high prevalence indicates a need to investigate the possibility that corporal punishment puts adolescents at increased risk of developing mental health and social relationship problems later in life. The analysis, which controlled for a number of possible confounding risk factors such as low socioeconomic status, found that children who experienced corporal punishment in adolescence had an increased risk later in life of depressive symptoms, suicidal thoughts, alcohol abuse, physical abuse of children, and wife beating. The consistent association of corporal punishment with major adult problem behavior, together with the fact that at least half of all adolescents are victims of corporal punishment by their parents, indicates a need to replicate the study using longitudinal data. If the findings are confirmed, it suggests that a major step in primary prevention of violence and mental health problems can be achieved by a national effort to reduce or eliminate all use of corporal punishment.

Cannabis use and the course and outcome of major depressive disorder: A population based longitudinal study.

PubMed

Feingold, Daniel; Rehm, Jürgen; Lev-Ran, Shaul

2017-05-01

Cannabis use has been reported to affect the course of various psychiatric disorders, however its effect on the course of major depressive disorder (MDD) is not yet clear. We used data from Wave 1 and Wave 2 of the National Epidemiologic survey on Alcohol and Related Conditions (NESARC). Individuals with baseline MDD (N=2,348) were included in the study. Cannabis users without a Cannabis Use Disorder (CUDs) and individuals with a CUD were compared to nonusers using linear and logistic regression analyses controlling for sociodemographics, psychiatric disorders and substance use disorders at baseline. No differences were found in rates of remission between the groups. Level of cannabis use was associated with significantly more depressive symptoms at follow-up, particularly anhedonia, changes in body weight, insomnia or hypersomnia and psychomotor problems. After adjusting for baseline confounding factors, no associations were found between cannabis use and suicidality, functionality and quality of life. We conclude that many of the associations between cannabis use and a more severe course of MDD do not seem to be attributed to cannabis use itself but to associated sociodemographic and clinical factors. Further longitudinal studies using depression severity indices are required. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Effects of environmental lead pollution on blood lead and sex hormone levels among occupationally exposed group in an E-waste dismantling area.

PubMed

Yang, Yan; Lu, Xiao Song; Li, Ding Long; Yu, Yun Jiang

2013-06-01

To study the effects of environmental multi-media lead pollution on blood lead and sex hormone levels among lead exposed males engaged in E-waste dismantling, and the correlation between confounding factors and sex hormone levels. An E-waste dismantling area in Taizhou of Zhejiang Province was selected as the research site. One hundred and fifty two samples were collected from the groundwater, soil, rice, corn, chicken, and pork in the dismantling area. The effects of the multi-media lead pollution on the male blood lead and sex hormone levels of FSH, LH, and T, as well as the correlation with confounding factors, were studied. The blood lead concentrations in the males aged under 31, from 31 to 45 and from 46 to 60 were 98.55, 100.23, and 101.45 μg/L, respectively. Of all the environmental media lead exposures, the groundwater, rice and soil were main contributing factors to the lead accumulation in humans. FSH and LH levels increased with the age while the T levels decreased with the age instead. There was a significant correlation between the FSH and LH levels and wearing masks. There was correlation between the FSH, LH, and T levels, and the mean values of lead concentrations in environmental media, and the sex hormone levels were correlated with the confounding factor of wearing masks. Copyright © 2013 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

Risk factors for recurrent gastroesophageal reflux disease after fundoplication in pediatric patients: a case-control study.

PubMed

Ngerncham, Monawat; Barnhart, Douglas C; Haricharan, Ramanath N; Roseman, Jeffrey M; Georgeson, Keith E; Harmon, Carroll M

2007-09-01

Recurrent gastroesophageal reflux disease (rGERD) is a common problem after fundoplication. Previous studies attempting to identify risk factors for rGERD have failed to control for confounding variables. The purpose of this study was to identify significant risk factors for rGERD after controlling for potential confounding variables. A retrospective, matched case-control study was conducted at a tertiary children's hospital. Cases (n = 116) met 1 of these criteria: reoperation for rGERD, symptomatic rGERD (confirmed by upper gastrointestinal series, esophagogastroduodenoscopy, or pH monitoring), or postoperative reinstitution of antireflux medication for more than 8 weeks. Controls (n = 209) were matched for surgeon, approach (laparoscopic/open), technique (partial/complete), and approximate operative date. Univariate and multivariable associations were analyzed by conditional logistic regression. Significant risk factors for rGERD were age of less than 6 years (odds ratio [OR], 3.6; 95% confidence interval [CI], 1.7-7.5), preoperative hiatal hernia (OR, 3.2; 95% CI, 1.4-7.3), postoperative retching (OR, 5.1; 95% CI, 2.6-10.0), and postoperative esophageal dilatation (OR, 10.8; 95% CI, 1.8-65.4). Interestingly, significant association was not found between neurologic impairment and rGERD after controlling for potential confounding variables. Age of less than 6 years, preoperative hiatal hernia, postoperative retching, and postoperative esophageal dilatation are independently associated with increased risk of rGERD. Neurologic impairment alone does not increase the risk of developing rGERD.

Not only body weight perception but also body mass index is relevant to suicidal ideation and self-harming behavior in Japanese adolescents.

PubMed

Kinoshita, Kuni; Kinoshita, Yoshihiro; Shimodera, Shinji; Nishida, Atsushi; Inoue, Ken; Watanabe, Norio; Oshima, Norihito; Akechi, Tatsuo; Sasaki, Tsukasa; Inoue, Shimpei; Furukawa, Toshiaki A; Okazaki, Yuji

2012-04-01

Whether a low body mass index (BMI) is directly associated with a high risk of suicidal ideation or self-harming behavior in adolescents is still inconclusive. This study has, therefore, evaluated the relevance of BMI to suicidal ideation and self-harming behavior after controlling for body weight perception (BWP) and other potential confounding factors. BMI, BWP, suicidal ideation, and self-harming behavior were all assessed using a self-report questionnaire administered to 18,104 Japanese adolescents. Potential confounding factors were also evaluated. The data were then analyzed using bivariate and multivariate logistic regression. Low BMI was associated with suicidal ideation and deliberate self-harm when controlling for sex, age, drug use, emotional distress, and BWP. Low BMI may be an independent risk factor for suicidal ideation and deliberate self-harming behavior in Japanese adolescents.

Factors Influencing Observed Tillage Impacts on Herbicide Transport

USDA-ARS?s Scientific Manuscript database

The widespread use and potential human health effects of the herbicides atrazine and glyphosate have generated interest in establishing how no-tillage impacts loading of these herbicides to runoff water in comparison to other tillage practices. In this study, potentially confounding factors such as ...

Do time-invariant confounders explain away the association between job stress and workers' mental health? Evidence from Japanese occupational panel data.

PubMed

Oshio, Takashi; Tsutsumi, Akizumi; Inoue, Akiomi

2015-02-01

It is well known that job stress is negatively related to workers' mental health, but most recent studies have not controlled for unobserved time-invariant confounders. In the current study, we attempted to validate previous observations on the association between job stress and workers' mental health, by removing the effects of unobserved time-invariant confounders. We used data from three to four waves of an occupational Japanese cohort survey, focusing on 31,382 observations of 9741 individuals who participated in at least two consecutive waves. We estimated mean-centered fixed effects models to explain psychological distress in terms of the Kessler 6 (K6) scores (range: 0-24) by eight job stress indicators related to the job demands-control, effort-reward imbalance, and organizational injustice models. Mean-centered fixed effects models reduced the magnitude of the association between jobs stress and K6 scores to 44.8-54.2% of those observed from pooled ordinary least squares. However, the association remained highly significant even after controlling for unobserved time-invariant confounders for all job stress indicators. In addition, alternatively specified models showed the robustness of the results. In all, we concluded that the validity of major job stress models, which link job stress and workers' mental health, was robust, although unobserved time-invariant confounders led to an overestimation of the association. Copyright © 2014 Elsevier Ltd. All rights reserved.

Confounding adjustment in comparative effectiveness research conducted within distributed research networks.

PubMed

Toh, Sengwee; Gagne, Joshua J; Rassen, Jeremy A; Fireman, Bruce H; Kulldorff, Martin; Brown, Jeffrey S

2013-08-01

A distributed research network (DRN) of electronic health care databases, in which data reside behind the firewall of each data partner, can support a wide range of comparative effectiveness research (CER) activities. An essential component of a fully functional DRN is the capability to perform robust statistical analyses to produce valid, actionable evidence without compromising patient privacy, data security, or proprietary interests. We describe the strengths and limitations of different confounding adjustment approaches that can be considered in observational CER studies conducted within DRNs, and the theoretical and practical issues to consider when selecting among them in various study settings. Several methods can be used to adjust for multiple confounders simultaneously, either as individual covariates or as confounder summary scores (eg, propensity scores and disease risk scores), including: (1) centralized analysis of patient-level data, (2) case-centered logistic regression of risk set data, (3) stratified or matched analysis of aggregated data, (4) distributed regression analysis, and (5) meta-analysis of site-specific effect estimates. These methods require different granularities of information be shared across sites and afford investigators different levels of analytic flexibility. DRNs are growing in use and sharing of highly detailed patient-level information is not always feasible in DRNs. Methods that incorporate confounder summary scores allow investigators to adjust for a large number of confounding factors without the need to transfer potentially identifiable information in DRNs. They have the potential to let investigators perform many analyses traditionally conducted through a centralized dataset with detailed patient-level information.

Probabilistic bias analysis in pharmacoepidemiology and comparative effectiveness research: a systematic review.

PubMed

Hunnicutt, Jacob N; Ulbricht, Christine M; Chrysanthopoulou, Stavroula A; Lapane, Kate L

2016-12-01

We systematically reviewed pharmacoepidemiologic and comparative effectiveness studies that use probabilistic bias analysis to quantify the effects of systematic error including confounding, misclassification, and selection bias on study results. We found articles published between 2010 and October 2015 through a citation search using Web of Science and Google Scholar and a keyword search using PubMed and Scopus. Eligibility of studies was assessed by one reviewer. Three reviewers independently abstracted data from eligible studies. Fifteen studies used probabilistic bias analysis and were eligible for data abstraction-nine simulated an unmeasured confounder and six simulated misclassification. The majority of studies simulating an unmeasured confounder did not specify the range of plausible estimates for the bias parameters. Studies simulating misclassification were in general clearer when reporting the plausible distribution of bias parameters. Regardless of the bias simulated, the probability distributions assigned to bias parameters, number of simulated iterations, sensitivity analyses, and diagnostics were not discussed in the majority of studies. Despite the prevalence and concern of bias in pharmacoepidemiologic and comparative effectiveness studies, probabilistic bias analysis to quantitatively model the effect of bias was not widely used. The quality of reporting and use of this technique varied and was often unclear. Further discussion and dissemination of the technique are warranted. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Using propensity scores to estimate the effects of insecticides on stream invertebrates from observational data

USGS Publications Warehouse

Lester L. Yuan,; Amina I. Pollard,; Carlisle, Daren M.

2009-01-01

Analyses of observational data can provide insights into relationships between environmental conditions and biological responses across a broader range of natural conditions than experimental studies, potentially complementing insights gained from experiments. However, observational data must be analyzed carefully to minimize the likelihood that confounding variables bias observed relationships. Propensity scores provide a robust approach for controlling for the effects of measured confounding variables when analyzing observational data. Here, we use propensity scores to estimate changes in mean invertebrate taxon richness in streams that have experienced insecticide concentrations that exceed aquatic life use benchmark concentrations. A simple comparison of richness in sites exposed to elevated insecticides with those that were not exposed suggests that exposed sites had on average 6.8 fewer taxa compared to unexposed sites. The presence of potential confounding variables makes it difficult to assert a causal relationship from this simple comparison. After controlling for confounding factors using propensity scores, the difference in richness between exposed and unexposed sites was reduced to 4.1 taxa, a difference that was still statistically significant. Because the propensity score analysis controlled for the effects of a wide variety of possible confounding variables, we infer that the change in richness observed in the propensity score analysis was likely caused by insecticide exposure.

Using propensity scores to estimate the effects of insecticides on stream invertebrates from observational data

USGS Publications Warehouse

Yuan, L.L.; Pollard, A.I.; Carlisle, D.M.

2009-01-01

Analyses of observational data can provide insights into relationships between environmental conditions and biological responses across a broader range of natural conditions than experimental studies, potentially complementing insights gained from experiments. However, observational data must be analyzed carefully to minimize the likelihood that confounding variables bias observed relationships. Propensity scores provide a robust approach for controlling for the effects of measured confounding variables when analyzing observational data. Here, we use propensity scores to estimate changes in mean invertebrate taxon richness in streams that have experienced insecticide concentrations that exceed aquatic life use benchmark concentrations. A simple comparison of richness in sites exposed to elevated insecticides with those that were not exposed suggests that exposed sites had on average 6.8 fewer taxa compared to unexposed sites. The presence of potential confounding variables makes it difficult to assert a causal relationship from this simple comparison. After controlling for confounding factors using propensity scores, the difference in richness between exposed and unexposed sites was reduced to 4.1 taxa, a difference that was still statistically significant. Because the propensity score analysis controlled for the effects of a wide variety of possible confounding variables, we infer that the change in richness observed in the propensity score analysis was likely caused by insecticide exposure. ?? 2009 SETAC.

On Estimation of the Survivor Average Causal Effect in Observational Studies when Important Confounders are Missing Due to Death

PubMed Central

Egleston, Brian L.; Scharfstein, Daniel O.; MacKenzie, Ellen

2008-01-01

We focus on estimation of the causal effect of treatment on the functional status of individuals at a fixed point in time t* after they have experienced a catastrophic event, from observational data with the following features: (1) treatment is imposed shortly after the event and is non-randomized, (2) individuals who survive to t* are scheduled to be interviewed, (3) there is interview non-response, (4) individuals who die prior to t* are missing information on pre-event confounders, (5) medical records are abstracted on all individuals to obtain information on post-event, pre-treatment confounding factors. To address the issue of survivor bias, we seek to estimate the survivor average causal effect (SACE), the effect of treatment on functional status among the cohort of individuals who would survive to t* regardless of whether or not assigned to treatment. To estimate this effect from observational data, we need to impose untestable assumptions, which depend on the collection of all confounding factors. Since pre-event information is missing on those who die prior to t*, it is unlikely that these data are missing at random (MAR). We introduce a sensitivity analysis methodology to evaluate the robustness of SACE inferences to deviations from the MAR assumption. We apply our methodology to the evaluation of the effect of trauma center care on vitality outcomes using data from the National Study on Costs and Outcomes of Trauma Care. PMID:18759833

A review of caffeine use as a risk or protective factor for women's health and pregnancy.

PubMed

Peacock, Amy; Mattick, Richard P; Bruno, Raimondo

2017-07-01

To provide a narrative synthesis of recently published studies on caffeine use as a risk or protective factor for health outcomes, with a focus on women's health and pregnancy. Based on predominantly observational studies, moderate caffeine intake has been shown to be a protective factor for liver cancer, certain bowel conditions, colorectal cancer, skin cancer, and regular menstrual cycle function. However, heavy consumption is a risk factor for osteoporosis, urinary incontinence, and poorer birth and child developmental outcomes. Residual confounding and issues surrounding retrospective self-reported intake are cited as key limitations in the majority of these studies. Moderate caffeine intake has been associated with lower risk of cardiovascular disease and metabolic syndrome; however, recent genetic epidemiology studies provide no evidence for a causal relationship. Greater inclusion of female participants in studies, and analysis of sex differences in the relationship between caffeine intake and certain health conditions, is necessary. The current literature suggests caffeine's role as a risk or protective factor differs across health conditions. Often, there are plausible biological mechanisms for this relationship. However, a continued precautionary stance is recommended until direct causal pathways are established. Review of recently published studies does not suggest that current intake guidelines for adults and for pregnant woman need to be modified.

[Risk factors of stillbirths in Fortaleza-Brazil: a case-control study].

PubMed

Rouquayrol, M Z; Correia, L L; Barbosa, L M; Xavier, L G; Oliveira, J W; Fonseca, W

1996-01-01

Stillbirths are a common event in areas where reproductive health care is poorly delivered, such as the Northeast region of Brazil. This case-control study aimed to identify risk factors associated to foetal deaths occurred in a major obstetric facility of Fortaleza, 1.7 million inhabitants, Northeastern Brazil. 125 stillborn foetus over 20 weeks of gestation (cases) were compared to 250 healthy newborns (controls), in relation to socioeconomic, reproductive, behavioral and morbidity characteristics of their mothers. Crude and adjusted Odds Ratios were then calculated. After adjustment for confounders, the following characteristics of the mother remained as risk factors for stillbirths, with OR statistically significant at the 95% level: attending <5 antenatal consultations during pregnancy (OR=3.30; CI=1.92 - 5.07 ), illiterate mother (OR=3.30; CI=1.84 - 5.92 ), mother's age above 19 (OR=2.73; CI=1.42 - 5.24 ), monthly family income of 1 minimum wage or less (OR=2.12; CI=1.03 - 4.35 ) and severe illnesses or complication during pregnancy (OR=1.75; CI=1.01 - 3.03 ). Inadequate attendance to antenatal care consultations was the risk factor most strongly associated to stillbirths. Similarly, it was the condition most amenable to change in a short term, among those identified as risk factors.

Is familial risk for depression confounded by individual and familial socioeconomic factors and neighborhood environmental factors? A 7-year follow-up study in Sweden.

PubMed

Hamano, Tsuyoshi; Li, Xinjun; Lönn, Sara Larsson; Nabika, Toru; Sundquist, Jan; Sundquist, Kristina

2018-05-16

Family history of depression is an important risk factor for depression. The aim of this study was to examine whether the effect of family history of depression is confounded by individual and familial socioeconomic factors (i.e., country of origin, educational attainment, family income and mobility) and neighborhood environmental factors (i.e., neighborhood deprivation and neighborhood social capital). The study population comprised 188,907 individuals aged 20-44 years from a nationwide sample of primary care centers in Sweden. Among these individuals, 22,014 with a first event of depression (6,486 men and 15,528 women) were identified during the 7-year follow-up period. Family history of depression was defined as depression in at least one parent. Cross-classified multilevel logistic regression models were used to calculate odds ratios with 95% credible intervals. Increased familial odds were observed after adjustment for individual and familial socioeconomic factors and neighborhood environmental factors for both men and women. Our results suggest that family history of depression is an independent risk factor for depression. Offspring of parents with depression are important targets for disease prevention, regardless of individual and familial socioeconomic factors and neighborhood environmental factors. Copyright © 2018. Published by Elsevier B.V.

Implementing the undergraduate mini-CEX: a tailored approach at Southampton University.

PubMed

Hill, Faith; Kendall, Kathleen; Galbraith, Kevin; Crossley, Jim

2009-04-01

The mini-clinical evaluation exercise (mini-CEX) is widely used in the UK to assess clinical competence, but there is little evidence regarding its implementation in the undergraduate setting. This study aimed to estimate the validity and reliability of the undergraduate mini-CEX and discuss the challenges involved in its implementation. A total of 3499 mini-CEX forms were completed. Validity was assessed by estimating associations between mini-CEX score and a number of external variables, examining the internal structure of the instrument, checking competency domain response rates and profiles against expectations, and by qualitative evaluation of stakeholder interviews. Reliability was evaluated by overall reliability coefficient (R), estimation of the standard error of measurement (SEM), and from stakeholders' perceptions. Variance component analysis examined the contribution of relevant factors to students' scores. Validity was threatened by various confounding variables, including: examiner status; case complexity; attachment specialty; patient gender, and case focus. Factor analysis suggested that competency domains reflect a single latent variable. Maximum reliability can be achieved by aggregating scores over 15 encounters (R = 0.73; 95% confidence interval [CI] +/- 0.28 based on a 6-point assessment scale). Examiner stringency contributed 29% of score variation and student attachment aptitude 13%. Stakeholder interviews revealed staff development needs but the majority perceived the mini-CEX as more reliable and valid than the previous long case. The mini-CEX has good overall utility for assessing aspects of the clinical encounter in an undergraduate setting. Strengths include fidelity, wide sampling, perceived validity, and formative observation and feedback. Reliability is limited by variable examiner stringency, and validity by confounding variables, but these should be viewed within the context of overall assessment strategies.

High dietary choline and betaine intake is associated with low insulin resistance in the Newfoundland population.

PubMed

Gao, Xiang; Wang, Yongbo; Sun, Guang

2017-01-01

Dietary betaine supplement could ameliorate insulin resistance (IR) in animals, but no data are available for choline. Reports on humans are rare. The aim of this study was to investigate the association between dietary choline and betaine intake and IR in humans. We assessed 2394 adults from the CODING (Complex Diseases in the Newfoundland population: Environment and Genetics) study. Intake of dietary choline and betaine was evaluated from the Willett Food Frequency Questionnaire. IR was estimated by homeostatic model assessment (HOMA-IR) and the quantitative insulin-sensitivity check index (QUICKI). Partial correlation analysis was used to determine the correlations of dietary choline and betaine intake with IR adjusted for major confounding factors. Dietary choline and betaine intake was inversely correlated with levels of fasting glucose and insulin, HOMA-IR, HOMA-β (r = -0.08 to -0.27 for choline and r = -0.06 to -0.16 for betaine; P < 0.05) and positively related to QUICKI (r = 0.16-0.25 for choline and r = 0.11-0.16 for betaine; P < 0.01) in both sexes after controlling for age, total calorie intake, and physical activity level. The significant associations disappeared in men after percent trunk fat was added as a confounding factor. Furthermore, individuals with the highest tertile of dietary choline and betaine intake had the lowest IR severity. Dietary choline and betaine intake, however, was the lowest in the high IR group, intermediate in the medium group, and the highest in the low IR group. This study demonstrated that higher intake of dietary choline and betaine is associated with lower IR in the general population. Copyright © 2016 Elsevier Inc. All rights reserved.

A Prospective Study of Different Types of Dietary Fiber and Risk of Cardiovascular Disease: Tehran Lipid and Glucose Study.

PubMed

Mirmiran, Parvin; Bahadoran, Zahra; Khalili Moghadam, Sajad; Zadeh Vakili, Azita; Azizi, Fereidoun

2016-11-07

This study was designed to examine the hypothesis that dietary of intake different types of fiber could modify the risk of cardiovascular disease (CVD) in a large prospective cohort among Iranian adults. In 2006-2008, we used a validated food frequency questionnaire to assess dietary fiber intake among 2295 health professionals with no previous history of heart disease. Subjects were subsequently followed until 2012 for incidence of CVD events. Multivariate Cox proportional hazard regression models, adjusted for potential confounders were used to estimate the risk of CVD across tertiles of total dietary fiber and different types of fiber. Linear regression models were also used to indicate the association of dietary fiber intakes with changes of cardiovascular risk factors during the follow-up. Mean age of participants (42.8% men) was 38.2 ± 13.4, at baseline. Mean (SD) dietary intake of total fiber was 23.4 (8.9) g/day. After adjustment for cardiovascular risk score and dietary confounders, a significant inverse association was observed between intakes of total, soluble and insoluble dietary fiber and CVD risk, in the highest compared to the lowest tertiles (HR = 0.39, 95% CI = 0.18-0.83, HR = 0.19, 95% CI = 0.09-0.41, and HR = 0.31, 95% CI = 0.14-0.69, respectively). Inverse relations were observed between risk of CVD and dietary fiber from legumes, fruits and vegetables; however, dietary fiber intake from grain and nut sources was not related to risk of CVD. Our findings confirmed that higher intakes of dietary fiber from different sources is associated with CVD events and modify its major risk-related factors.

A Prospective Study of Different Types of Dietary Fiber and Risk of Cardiovascular Disease: Tehran Lipid and Glucose Study

PubMed Central

Mirmiran, Parvin; Bahadoran, Zahra; Khalili Moghadam, Sajad; Zadeh Vakili, Azita; Azizi, Fereidoun

2016-01-01

Background and aim: This study was designed to examine the hypothesis that dietary of intake different types of fiber could modify the risk of cardiovascular disease (CVD) in a large prospective cohort among Iranian adults. Methods: In 2006–2008, we used a validated food frequency questionnaire to assess dietary fiber intake among 2295 health professionals with no previous history of heart disease. Subjects were subsequently followed until 2012 for incidence of CVD events. Multivariate Cox proportional hazard regression models, adjusted for potential confounders were used to estimate the risk of CVD across tertiles of total dietary fiber and different types of fiber. Linear regression models were also used to indicate the association of dietary fiber intakes with changes of cardiovascular risk factors during the follow-up. Results: Mean age of participants (42.8% men) was 38.2 ± 13.4, at baseline. Mean (SD) dietary intake of total fiber was 23.4 (8.9) g/day. After adjustment for cardiovascular risk score and dietary confounders, a significant inverse association was observed between intakes of total, soluble and insoluble dietary fiber and CVD risk, in the highest compared to the lowest tertiles (HR = 0.39, 95% CI = 0.18–0.83, HR = 0.19, 95% CI = 0.09–0.41, and HR = 0.31, 95% CI = 0.14–0.69, respectively). Inverse relations were observed between risk of CVD and dietary fiber from legumes, fruits and vegetables; however, dietary fiber intake from grain and nut sources was not related to risk of CVD. Conclusion: Our findings confirmed that higher intakes of dietary fiber from different sources is associated with CVD events and modify its major risk-related factors. PMID:27827978

Antidepressant medications and osteoporosis.

PubMed

Rizzoli, R; Cooper, C; Reginster, J-Y; Abrahamsen, B; Adachi, J D; Brandi, M L; Bruyère, O; Compston, J; Ducy, P; Ferrari, S; Harvey, N C; Kanis, J A; Karsenty, G; Laslop, A; Rabenda, V; Vestergaard, P

2012-09-01

Use of antidepressant medications that act on the serotonin system has been linked to detrimental impacts on bone mineral density (BMD), and to osteoporosis. This article reviews current evidence for such effects, and identifies themes for future research. Serotonin receptors are found in all major types of bone cell (osteoblasts, osteocytes, and osteoclasts), indicating an important role of the neuroendocrine system in bone. Observational studies indicate a complex relationship between depression, antidepressants, and fracture. First, the presence of depression itself increases fracture risk, in relation with decreased BMD and an increase in falls. A range of aspects of depression may operate, including behavioral factors (e.g., smoking and nutrition), biological changes, and confounders (e.g., comorbidities and concomitant medications). A substantial proportion of depressed patients receive antidepressants, mostly selective serotonin reuptake inhibitors (SSRIs). Some of these have been linked to decreased BMD (SSRIs) and increased fracture risk (SSRIs and tricyclic agents). Current use of SSRIs and tricyclics increases fracture risk by as much as twofold versus nonusers, even after adjustment for potential confounders. While there is a dose-response relationship for SSRIs, the effect does not appear to be homogeneous across the whole class of drugs and may be linked to affinity for the serotonin transporter system. The increase in risk is the greatest in the early stages of treatment, with a dramatic increase after initiation, reaching a peak within 1 month for tricyclics and 8 months for SSRIs. Treatment-associated increased risk diminishes towards baseline in the year following discontinuation. The body of evidence suggests that SSRIs should be considered in the list of medications that are risk factors for osteoporotic fractures. Copyright © 2012 Elsevier Inc. All rights reserved.

Hypertension and exposure to noise near airports: the HYENA study.

PubMed

Jarup, Lars; Babisch, Wolfgang; Houthuijs, Danny; Pershagen, Göran; Katsouyanni, Klea; Cadum, Ennio; Dudley, Marie-Louise; Savigny, Pauline; Seiffert, Ingeburg; Swart, Wim; Breugelmans, Oscar; Bluhm, Gösta; Selander, Jenny; Haralabidis, Alexandros; Dimakopoulou, Konstantina; Sourtzi, Panayota; Velonakis, Manolis; Vigna-Taglianti, Federica

2008-03-01

An increasing number of people are exposed to aircraft and road traffic noise. Hypertension is an important risk factor for cardiovascular disease, and even a small contribution in risk from environmental factors may have a major impact on public health. The HYENA (Hypertension and Exposure to Noise near Airports) study aimed to assess the relations between noise from aircraft or road traffic near airports and the risk of hypertension. We measured blood pressure and collected data on health, socioeconomic, and lifestyle factors, including diet and physical activity, via questionnaire at home visits for 4,861 persons 45-70 years of age, who had lived at least 5 years near any of six major European airports. We assessed noise exposure using detailed models with a resolution of 1 dB (5 dB for United Kingdom road traffic noise), and a spatial resolution of 250 x 250 m for aircraft and 10 x 10 m for road traffic noise. We found significant exposure-response relationships between night-time aircraft as well as average daily road traffic noise exposure and risk of hypertension after adjustment for major confounders. For night-time aircraft noise, a 10-dB increase in exposure was associated with an odds ratio (OR) of 1.14 [95% confidence interval (CI), 1.01-1.29]. The exposure-response relationships were similar for road traffic noise and stronger for men with an OR of 1.54 (95% CI, 0.99-2.40) in the highest exposure category (> 65 dB; p(trend) = 0.008). Our results indicate excess risks of hypertension related to long-term noise exposure, primarily for night-time aircraft noise and daily average road traffic noise.

Insulin dysfunction and Tau pathology.

PubMed

El Khoury, Noura B; Gratuze, Maud; Papon, Marie-Amélie; Bretteville, Alexis; Planel, Emmanuel

2014-01-01

The neuropathological hallmarks of Alzheimer's disease (AD) include senile plaques of β-amyloid (Aβ) peptides (a cleavage product of the Amyloid Precursor Protein, or APP) and neurofibrillary tangles (NFT) of hyperphosphorylated Tau protein assembled in paired helical filaments (PHF). NFT pathology is important since it correlates with the degree of cognitive impairment in AD. Only a small proportion of AD is due to genetic variants, whereas the large majority of cases (~99%) is late onset and sporadic in origin. The cause of sporadic AD is likely to be multifactorial, with external factors interacting with biological or genetic susceptibilities to accelerate the manifestation of the disease. Insulin dysfunction, manifested by diabetes mellitus (DM) might be such factor, as there is extensive data from epidemiological studies suggesting that DM is associated with an increased relative risk for AD. Type 1 diabetes (T1DM) and type 2 diabetes (T2DM) are known to affect multiple cognitive functions in patients. In this context, understanding the effects of diabetes on Tau pathogenesis is important since Tau pathology show a strong relationship to dementia in AD, and to memory loss in normal aging and mild cognitive impairment. Here, we reviewed preclinical studies that link insulin dysfunction to Tau protein pathogenesis, one of the major pathological hallmarks of AD. We found more than 30 studies reporting Tau phosphorylation in a mouse or rat model of insulin dysfunction. We also payed attention to potential sources of artifacts, such as hypothermia and anesthesia, that were demonstrated to results in Tau hyperphosphorylation and could major confounding experimental factors. We found that very few studies reported the temperature of the animals, and only a handful did not use anesthesia. Overall, most published studies showed that insulin dysfunction can promote Tau hyperphosphorylation and pathology, both directly and indirectly, through hypothermia.

Insulin dysfunction and Tau pathology

PubMed Central

El Khoury, Noura B.; Gratuze, Maud; Papon, Marie-Amélie; Bretteville, Alexis; Planel, Emmanuel

2013-01-01

The neuropathological hallmarks of Alzheimer's disease (AD) include senile plaques of β-amyloid (Aβ) peptides (a cleavage product of the Amyloid Precursor Protein, or APP) and neurofibrillary tangles (NFT) of hyperphosphorylated Tau protein assembled in paired helical filaments (PHF). NFT pathology is important since it correlates with the degree of cognitive impairment in AD. Only a small proportion of AD is due to genetic variants, whereas the large majority of cases (~99%) is late onset and sporadic in origin. The cause of sporadic AD is likely to be multifactorial, with external factors interacting with biological or genetic susceptibilities to accelerate the manifestation of the disease. Insulin dysfunction, manifested by diabetes mellitus (DM) might be such factor, as there is extensive data from epidemiological studies suggesting that DM is associated with an increased relative risk for AD. Type 1 diabetes (T1DM) and type 2 diabetes (T2DM) are known to affect multiple cognitive functions in patients. In this context, understanding the effects of diabetes on Tau pathogenesis is important since Tau pathology show a strong relationship to dementia in AD, and to memory loss in normal aging and mild cognitive impairment. Here, we reviewed preclinical studies that link insulin dysfunction to Tau protein pathogenesis, one of the major pathological hallmarks of AD. We found more than 30 studies reporting Tau phosphorylation in a mouse or rat model of insulin dysfunction. We also payed attention to potential sources of artifacts, such as hypothermia and anesthesia, that were demonstrated to results in Tau hyperphosphorylation and could major confounding experimental factors. We found that very few studies reported the temperature of the animals, and only a handful did not use anesthesia. Overall, most published studies showed that insulin dysfunction can promote Tau hyperphosphorylation and pathology, both directly and indirectly, through hypothermia. PMID:24574966

Total and Abdominal Adiposity and Hypertension in Indigenous Women in Midwest Brazil

PubMed Central

Lima, Rosangela Costa; de Souza, Maria Cristina Corrêa

2016-01-01

Background Obesity is a major risk factor for hypertension, and abdominal fat in particular has been more strongly associated with cardiovascular diseases and its prevalence has increased in Brazilian indigenous populations. Objective The objective of this study was to estimate the prevalence of hypertension among indigenous women and its association with total and abdominal obesity after adjustment for confounding factors. Methods This cross-sectional study evaluated indigenous non-pregnant women aged 20–59 years living in two villages of the indigenous reserve of Dourados, state of Mato Grosso do Sul, Brazil. Data were collected by trained interviewers. Households were visited and were selected by simple random sampling using SPSS software version 21. The casting of lots was performed from a list of households located on a map of villages. To locate the selected households, a Global Positioning System device was used. A questionnaire was used to obtain data on socio-demographic, lifestyle and health-related variables and to obtain anthropometric data on weight, height, and waist circumference (WC). Blood pressure was measured twice during home visits. Results Data were collected between June and October 2013 with 362 women. Most of them were aged <40 years (66.3%) and had low educational level (≤4 years of schooling, 82.0%), had overweight/obesity (74.0%), WC ≥80 cm (83.7%), and family history of hypertension (60.5%). The prevalence of hypertension was 42.0% (CI 95%: 37.0–47.2). In the multivariable analysis, respondents with WC 80–87 cm and ≥88 cm showed approximately 2 times higher prevalence rates of hypertension compared with those with WC <80 cm after adjusting for confounding factors. There was no association between body mass index (BMI) and hypertension in this study. Conclusions The overall prevalence of hypertension was high and associated only with abdominal adiposity but not with BMI. PMID:27294870

Association of Major Depressive Disorder with Serum Myeloperoxidase and other Markers of Inflammation: A Twin Study

PubMed Central

Vaccarino, Viola; Brennan, Marie-Luise; Miller, Andrew H.; Bremner, J. Douglas; Ritchie, James C.; Lindau, Frauke; Veledar, Emir; Su, Shaoyong; Murrah, Nancy V.; Jones, Linda; Jawed, Farhan; Dai, Jun; Goldberg, Jack; Hazen, Stanley L.

2008-01-01

Background Major depressive disorder (MDD) has been linked to inflammation, but this association may be due to common precursors to both depression and inflammation. Myeloperoxidase (MPO) is an inflammatory enzyme produced by activated leukocytes which predicts risk of coronary heart disease. We sought to examine whether MPO and other markers of inflammation are associated with MDD, and whether the association is confounded by genetic or other shared familial factors. Methods We examined 178 monozygotic and dizygotic middle-aged male twin pairs. We assessed MDD with the Structured Clinical Interview for Psychiatry Disorders. Blood markers of inflammation included MPO, interleukin-6, white blood cell count, C-reactive protein, tumor necrosis factor (TNF)-α, the TNF-α soluble receptor II, and fibrinogen. Analyses were conducted in the overall sample and among 67 twin pairs discordant for MDD using mixed effects regression. Results Twins with a history of MDD had 32% higher levels of MPO (p<0.0001); this difference persisted after adjusting for other risk factors. Among dizygotic MDD-discordant twin pairs, twins with MDD had 77% higher MPO than their brothers without MDD after adjusting for other factors (p<0.0001). In contrast, no significant association was found in monozygotic twins (p=0.13). Similar, but weaker, associations were found between MDD and other inflammatory biomarkers. Conclusion MPO is a useful biomarker of immune activation in MDD. However, the association between inflammation and MDD is largely due to common genetic liability. Our results are consistent with the hypothesis that genes promoting inflammation are involved in the pathogenesis of MDD. PMID:18514165

Incidence and Survival in Breast Cancer Patients and Stressful Life Events.

PubMed

Fallah, Raheleh; Akbari, Mohammad Esmaeil; Azargashb, Eznollah; Khayamzadeh, E

2016-01-01

Due to increasing incidence of breast cancer, recognition of risk factors has become increasingly important. Over the past few decades, among risk factors of this disease, stressful life events have attracted particular attention, but their relationship with breast cancer incidence and survival remains a mystery. This study aimed to examine the relationship between severe stressful life events and incidence and survival of women with breast cancer. In this case-control study, using a structured telephone interview with 355 women with breast cancer and also with 516 women with benign breast diseases who were matched in demographic characteristics, necessary information about the experience of major stressful events in the years before the diagnosis were collected. Data were analyzed using statistical methods of χ2, t, and Kaplan-Meier with a significance level of <0.05. Generally, in the case and control groups, there were no significant association between experience of stressful life events and incidence of breast cancer. Regarding associations between each of the events and incidence of breast cancer only "severe interpersonal problems with spouse" was significant. In the breast cancer group, even after controlling confounding variables, there was no significant association between major stressful events and disease-free survival, or overall 5-and 10-year survival. In this study, only "severe interpersonal problems with spouse" was confirmed as a risk factor. This result can be useful in developing preventive policies. More research regarding the interactive effects of psycho-social factors in the incidence and survival of breast cancer with stressful life events is recommended.

Dynamic changes in quality of life after three first-line therapies for EGFR mutation-positive advanced non-small-cell lung cancer.

PubMed

Yang, Szu-Chun; Lin, Chien-Chung; Lai, Wu-Wei; Chang, Sheng-Mao; Hwang, Jing-Shiang; Su, Wu-Chou; Wang, Jung-Der

2018-01-01

Three different tyrosine kinase inhibitors have been approved as first-line therapies for epidermal growth factor receptor (EGFR) mutation-positive advanced non-small-cell lung cancer with similar overall survival. This study determined dynamic changes in quality of life (QoL) for patients using these therapies after controlling for potential confounders. From 2011 to 2016, we prospectively assessed the utility values and QoL scores of patients using the EuroQol five-dimension and World Health Organization Quality-of-Life - Brief questionnaires. QoL functions after initiation of treatment were estimated using a kernel-smoothing method. Dynamic changes in major determinants were repeatedly assessed for constructing mixed models. A total of 344 patients were enrolled, with 934 repeated assessments. After controlling for performance status, disease progression, EGFR mutation subtype and other confounders, the mixed models showed significantly lower QoL scores for afatinib versus gefitinib in the physical, psychological and social domains, and 10 facets. The differences seemed to appear 10 months after initiation of treatment. In contrast, there was no significant difference between erlotinib and gefitinib in the scores of all domains and facets. QoL in patients receiving afatinib seemed to be lower than in those receiving gefitinib. Since the sample sizes in this study were relatively small, more studies are warranted to corroborate these results.

No Relationship Between Hamstring Flexibility and Hamstring Injuries in Male Amateur Soccer Players: A Prospective Study.

PubMed

van Doormaal, Mitchell C M; van der Horst, Nick; Backx, Frank J G; Smits, Dirk-Wouter; Huisstede, Bionka M A

2017-01-01

In soccer, although hamstring flexibility is thought to play a major role in preventing hamstring injuries, the relationship between hamstring flexibility and hamstring injuries remains unclear. To investigate the relationship between hamstring flexibility and hamstring injuries in male amateur soccer players. Case-control study; Level of evidence, 3. This study included 450 male first-class amateur soccer players (mean age, 24.5 years). Hamstring flexibility was measured by performing the sit-and-reach test (SRT). The relationship between hamstring flexibility and the occurrence of hamstring injuries in the following year, while adjusting for the possible confounding effects of age and previous hamstring injuries, was determined with a multivariate logistic regression analysis. Of the 450 soccer players, 21.8% reported a hamstring injury in the previous year. The mean (±SD) baseline score for the SRT was 21.2 ± 9.2 cm. During the 1-year follow-up period, 23 participants (5.1%) suffered a hamstring injury. In the multivariate analysis, while adjusting for age and previous injuries, no significant relationship was found between hamstring flexibility and hamstring injuries ( P = .493). In this group of soccer players, hamstring flexibility (measured with the SRT) was not related to hamstring injuries. Age and previous hamstring injuries as possible confounders did not appear to influence this relationship. Other etiological factors need to be examined to further elucidate the mechanism of hamstring injuries.

The Schizotypal Personality Questionnaire-Brief lacks measurement invariance across three countries.

PubMed

Liu, Shujuan; Mellor, David; Ling, Mathew; Saiz, José L; Vinet, Eugenia V; Xu, Xiaoyan; Renati, Solomon; Byrne, Linda K

2017-12-01

The Schizotypal Personality Questionnaire-Brief (SPQ-B) is a commonly-used tool for measuring schizotypal personality traits and due to its wide application, its cross-cultural validity is of interest. Previous studies suggest that the SPQ-B either has a three- or four-factor structure, but the majority of studies have been conducted in Western contexts and little is known about the psychometric properties of the scale in other populations. In this study factorial invariance testing across three cultural contexts-Australia, China and Chile was conducted. In total, 729 young adults (Mean age = 23.99 years, SD = 9.87 years) participated. Invariance testing did not support the four-factor model across three countries. Confirmatory Factor Analyses revealed that neither the four- nor three-factor model had strong fit in any of the settings. However, in comparison with other competing models, the four-factor model showed the best for the Australian sample, while the three-factor model was the most reasonable for both Chinese and Chilean samples. The reliability of the SPQ-B scores, estimated with Omega, ranged from 0.86 to 0.91. These findings suggest that the SPQ-B factors are not consistent across different cultural groups. We suggest that these differences could be attributed to potential confounding cultural and translation issues. Copyright © 2017 Elsevier B.V. All rights reserved.

Sick-building symptoms in office workers in northeastern France: a pilot study.

PubMed

Teculescu, D B; Sauleau, E A; Massin, N; Bohadana, A B; Buhler, O; Benamghar, L; Mur, J M

1998-07-01

To verify that sick building symptoms are present in north-eastern France office workers; to try to identify new confounding factors. The design was that of a cross-sectional study with control group. We studied with the same methods the personnel of an air-conditioned building (n=425), and of a naturally ventilated building (n=351). Air temperature and humidity, bacterial and fungal densities were measured by the same technical staff in the two buildings. A standard questionnaire on irritative and respiratory symptoms, personal and family history, and lifestyle was completed by the participants. In univariate analysis, exposure to air-conditioning was associated with an increased prevalence of symptoms (odds ratios-OR-between 1.54 and 2.84). A significant increase in sickness absence was also found among subjects working in air-conditioned offices. As a series of factors were suspected to interfere with these associations, logistic regression was applied. This method confirmed exposure to be an independent determinant of 7 symptoms, and also identified two determinants not previously described: a family history of respiratory diseases and "do-it-yourself' activities. we found the sick building symptoms to be present in a group of French office workers exposed to air-conditioning. We confirmed the influence of a number of confounding factors and described two further confounders - do-it-yourself activities at home and a history of familial respiratory disease.

More Precise Estimation of Lower-Level Interaction Effects in Multilevel Models.

PubMed

Loeys, Tom; Josephy, Haeike; Dewitte, Marieke

2018-01-01

In hierarchical data, the effect of a lower-level predictor on a lower-level outcome may often be confounded by an (un)measured upper-level factor. When such confounding is left unaddressed, the effect of the lower-level predictor is estimated with bias. Separating this effect into a within- and between-component removes such bias in a linear random intercept model under a specific set of assumptions for the confounder. When the effect of the lower-level predictor is additionally moderated by another lower-level predictor, an interaction between both lower-level predictors is included into the model. To address unmeasured upper-level confounding, this interaction term ought to be decomposed into a within- and between-component as well. This can be achieved by first multiplying both predictors and centering that product term next, or vice versa. We show that while both approaches, on average, yield the same estimates of the interaction effect in linear models, the former decomposition is much more precise and robust against misspecification of the effects of cross-level and upper-level terms, compared to the latter.

Perinatal risk factors for pneumothorax and morbidity and mortality in very low birth weight infants.

PubMed

García-Muñoz Rodrigo, Fermín; Urquía Martí, Lourdes; Galán Henríquez, Gloria; Rivero Rodríguez, Sonia; Tejera Carreño, Patricia; Molo Amorós, Silvia; Cabrera Vega, Pedro; Rodríguez Ramón, Fernando

2017-11-01

To determine the perinatal risk factors for pneumothorax in Very-Low-Birth-Weight (VLBW) infants and the associated morbidity and mortality in this population. Retrospective analysis of data collected prospectively from a cohort of VLBW neonates assisted in our Unit (2006-2013). We included all consecutive in-born patients with ≤ 1500 g, without severe congenital anomalies. Perinatal history, demographics, interventions and clinical outcomes were collected. Associations were evaluated by logistic regression analysis. During the study period, 803 VLBW infants were assisted in our Unit, of whom 763 were inborn. Ten patients (1.2%) died in delivery room, and 18 (2.2%) with major congenital anomalies were excluded. Finally, 735 (91.5%) neonates were included in the study. Seventeen (2.3%) developed pneumothorax during the first week of life [median (IQR): 2 (1-2) days]. After correcting for GA and other confounders, prolonged rupture of membranes [aOR =1.002 (95% CI 1.000-1.003); p = 0.040] and surfactant administration [aOR = 6.281 (95% CI 1.688-23.373); p = 0.006] were the independent risk factors associated with pneumothorax. Patients with pneumothorax had lower probabilities of survival without major brain damage (MBD): aOR = 0.283 (95% CI = 0.095-0.879); p = 0.029. Pneumothorax in VLBW seems to be related to perinatal inflammation and surfactant administration, and it is significantly associated with a reduction in the probabilities of survival without MBD.

Does nailfold capillaroscopy help predict future outcomes in systemic sclerosis? A systematic literature review.

PubMed

Paxton, Dolcie; Pauling, John D

2018-02-14

Nailfold capillaroscopy (NC) is an important diagnostic tool in systemic sclerosis (SSc). Confirmation of NC as a prognostic factor could facilitate earlier intervention and slow disease progression in SSc. We undertook a systematic literature review to evaluate the prognostic value of NC in predicting SSc disease progression. Standardised searches of EMBASE and MEDLINE were undertaken to identify longitudinal studies of adult subjects with SSc reporting the prognostic value of NC for any aspect of disease progression and/or survival. Non-English, non-original research, animal studies, non-adult studies and non-full length reports were excluded from the analysis (PROSPERO 2017:CRD42017071719). Wide heterogeneity in study design, prognostic factor measurement and study outcomes necessitated a qualitative data synthesis. The "QUality In Prognosis Studies" (QUIPS) risk-of-bias tool was used to assess study quality. Study selection, data extraction and risk-of-bias assessment were each undertaken independently by 2 reviewers and consensus reached where necessary. Of 942 retrieved articles, 18 studies fulfilled the inclusion criteria. The majority of studies (17/18, 94%) reported positive associations between baseline NC appearances (using a variety of qualitative, semi-quantitative and quantitative NC endpoints) and clinical outcomes including digital ulcer (DU) occurrence/healing, survival, disease progression (using domains of Medsger disease severity scale), calcinosis, skin progression, pulmonary arterial hypertension (PAH), and/or a composite analysis of "cardiovascular events". Application of the QUIPS tool identified a moderate-high risk of potential bias in 6/18 studies for study participation, 3/18 studies for study attrition, 10/18 for prognostic factor measurement, 5/18 for outcome measurement, 13/18 for confounders and 13/18 for statistical analyses. Study quality limited the strength of the conclusions drawn from these studies. The most important source of potential bias across the studies was insufficient adjustment for potential confounders; such as existing DU disease in studies evaluating future DU occurrence. Recent work suggests NC evolution is an important predictor of disease progression in SSc. High levels of potential bias relating to study confounding and statistical analysis make it difficult to draw conclusions regarding the prognostic role of NC in SSc. There is strong evidence supporting an association between NC abnormalities (particularly capillary loss) and disease severity (particularly vascular manifestations such as DU, calcinosis and PAH). Evolution of NC appearances may represent a more important predictor of disease progression which could have important implications for the future use of NC in the routine longitudinal assessment and management of SSc. Copyright © 2018 Elsevier Inc. All rights reserved.

Testing for gene-environment interaction under exposure misspecification.

PubMed

Sun, Ryan; Carroll, Raymond J; Christiani, David C; Lin, Xihong

2017-11-09

Complex interplay between genetic and environmental factors characterizes the etiology of many diseases. Modeling gene-environment (GxE) interactions is often challenged by the unknown functional form of the environment term in the true data-generating mechanism. We study the impact of misspecification of the environmental exposure effect on inference for the GxE interaction term in linear and logistic regression models. We first examine the asymptotic bias of the GxE interaction regression coefficient, allowing for confounders as well as arbitrary misspecification of the exposure and confounder effects. For linear regression, we show that under gene-environment independence and some confounder-dependent conditions, when the environment effect is misspecified, the regression coefficient of the GxE interaction can be unbiased. However, inference on the GxE interaction is still often incorrect. In logistic regression, we show that the regression coefficient is generally biased if the genetic factor is associated with the outcome directly or indirectly. Further, we show that the standard robust sandwich variance estimator for the GxE interaction does not perform well in practical GxE studies, and we provide an alternative testing procedure that has better finite sample properties. © 2017, The International Biometric Society.

Beyond greening and browning: the need for an integrated understanding of Arctic change

NASA Astrophysics Data System (ADS)

Gamon, J. A.; Huemmrich, K. F.; Hmimina, G.; Yu, R.

2017-12-01

Satellite records and field observations povide contradictory evidence for "greening" or "browning" of Arctic tundra. Large-scale observations of apparent greening have been based on satellite vegetation indices (e.g NDVI). However, a clear interpretation of these trends are confounded by changing snow cover and surface hydrology, both of which influence NDVI and are known to be changing independently of any direct vegetation response. Field studies have demonstrated greening in some areas, but not others, and have also documented changing permafrost depth, surface hydrology and snow cover. Together, these confounding factors can explain some of the contradictory evidence based regarding greening and browning. Given the multiple influences on Arctic NDVI, simple conclusions regarding greening and browning from satellite data alone can be incorrect; when these confounding factors are taken into account, some areas that show apparent greening in the satellite record appear to be undergoing productivity declines due to surface drying. These contradictory interpretations have profound implications for our understanding of changing surface energy balance, biogeochemistry, and surface-atmosphere feedbacks. To better address Arctic ecosystem responses to a changing climate, an integrated, multi-scale, multivariate approach that considers hydrology, permafrost, snow cover and vegetation is needed.

Birth weight and mortality: causality or confounding?

PubMed

Basso, Olga; Wilcox, Allen J; Weinberg, Clarice R

2006-08-15

The association between birth weight and mortality is among the strongest seen in epidemiology. While preterm delivery causes both small babies and high mortality, it does not explain this association. Fetal growth restriction has also been proposed, although its features are unclear because it lacks a definition independent of weight. If, as some postulate, birth weight is not itself on the causal path to mortality, its relation with mortality would have to be explained by confounding factors that decrease birth weight and increase mortality. In this paper, the authors explore the characteristics such confounders would require in order to achieve the observed association between birth weight and mortality. Through a simple simulation, they found that the observed steep gradient of risk for small babies at term can be produced by a rare condition or conditions (with a total prevalence of 0.5%) having profound effects on both fetal growth (-1.7 standard deviations) and mortality (relative risk = 160). Candidate conditions might include malformations, fetal or placental aneuploidy, infections, or imprinting disorders. If such rare factors underlie the association of birth weight with mortality, it would have broad implications for the study of fetal growth restriction and birth weight, and for the prevention of infant mortality.

A Genetically Informed Study of Associations between Family Functioning and Child Psychosocial Adjustment

ERIC Educational Resources Information Center

Schermerhorn, Alice C.; D'Onofrio, Brian M.; Turkheimer, Eric; Ganiban, Jody M.; Spotts, Erica L.; Lichtenstein, Paul; Reiss, David; Neiderhiser, Jenae M.

2011-01-01

Research has documented associations between family functioning and offspring psychosocial adjustment, but questions remain regarding whether these associations are partly due to confounding genetic factors and other environmental factors. The current study used a genetically informed approach, the Children of Twins design, to explore the…

Critical assessment of opposing views on trends in childhood cancer.

PubMed

Bukowski, J A

2000-01-01

Two articles reaching opposite conclusions on the current trends in childhood cancer have recently appeared in the literature. One concluded that pediatric cancers have increased dramatically, suggesting an effect from environmental hazards; the other concluded that rates for the major pediatric cancers have remained fairly stable, except for modest increases due to improvements in diagnosis or reporting. This review discusses the reasons for this discrepancy, including differences in the populations, age groups, and time periods analyzed. The arguments in favor of an increase are examined and shown to provide no convincing evidence that environmental pollutants have increased pediatric cancer rates over the past 20 to 30 years. Any suggested increase appears to be the result of non-causal factors, such as selective analysis and reporting, residual confounding by age, random variation, and stepwise improvements in diagnosis and classification.

Emerging technologies in bioremediation: constraints and opportunities.

PubMed

Rayu, Smriti; Karpouzas, Dimitrios G; Singh, Brajesh K

2012-11-01

Intensive industrialisation, inadequate disposal, large-scale manufacturing activities and leaks of organic compounds have resulted in long-term persistent sources of contamination of soil and groundwater. This is a major environmental, policy and health issue because of adverse effects of contaminants on humans and ecosystems. Current technologies for remediation of contaminated sites include chemical and physical remediation, incineration and bioremediation. With recent advancements, bioremediation offers an environmentally friendly, economically viable and socially acceptable option to remove contaminants from the environment. Three main approaches of bioremediation include use of microbes, plants and enzymatic remediation. All three approaches have been used with some success but are limited by various confounding factors. In this paper, we provide a brief overview on the approaches, their limitations and highlights emerging technologies that have potential to revolutionise the enzymatic and plant-based bioremediation approaches.

Effects of psychosocial work factors on lifestyle changes: a cohort study.

PubMed

Allard, Karin Olofsson; Thomsen, Jane Frølund; Mikkelsen, Sigurd; Rugulies, Reiner; Mors, Ole; Kærgaard, Anette; Kolstad, Henrik A; Kaerlev, Linda; Andersen, Johan Hviid; Hansen, Ase Marie; Bonde, Jens Peter

2011-12-01

To evaluate the effect of the demand-control-support model, the effort-reward imbalance model, and emotional demands on smoking, alcohol consumption, physical activity, and body mass index. This is a 2-year prospective cohort study of 3224 public sector employees. Measures were assessed with questionnaires. Multiple regression analyses were used to predict changes in lifestyle factors. Low reward predicted smoking, low-decision latitude predicted being inactive, and high demands predicted high-alcohol consumption but only for men at follow-up even after controlling for potential confounders. There were no other significant findings in the expected direction except for some of the confounders. We found only limited and inconsistent support for the hypothesis that a poor psychosocial work environment is associated with an adverse lifestyle.

A Genetically Informed Study of the Processes Underlying the Association Between Parental Marital Instability and Offspring Adjustment

PubMed Central

D’Onofrio, Brian M.; Turkheimer, Eric; Emery, Robert E.; Heath, Andrew C.; Madden, Pamela A.; Slutske, Wendy S.; Martin, Nicholas G.

2010-01-01

Parental divorce is associated with problematic offspring adjustment, but the relation may be due to shared genetic or environmental factors. One way to test for these confounds is to study offspring of twins discordant for divorce. The current analyses used this design to separate the mechanisms responsible for the association between parental divorce, experienced either before or after the age of 16, and offspring well-being. The results were consistent with a causal role of divorce in earlier initiation of sexual intercourse and emotional difficulties, in addition to a greater probability of educational problems, depressed mood, and suicidal ideation. In contrast, the increased risk for cohabitation and earlier initiation of drug use was explained by selection factors, including genetic confounds. PMID:16756440

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

A propensity score approach to correction for bias due to population stratification using genetic and non-genetic factors.

PubMed

Zhao, Huaqing; Rebbeck, Timothy R; Mitra, Nandita

2009-12-01

Confounding due to population stratification (PS) arises when differences in both allele and disease frequencies exist in a population of mixed racial/ethnic subpopulations. Genomic control, structured association, principal components analysis (PCA), and multidimensional scaling (MDS) approaches have been proposed to address this bias using genetic markers. However, confounding due to PS can also be due to non-genetic factors. Propensity scores are widely used to address confounding in observational studies but have not been adapted to deal with PS in genetic association studies. We propose a genomic propensity score (GPS) approach to correct for bias due to PS that considers both genetic and non-genetic factors. We compare the GPS method with PCA and MDS using simulation studies. Our results show that GPS can adequately adjust and consistently correct for bias due to PS. Under no/mild, moderate, and severe PS, GPS yielded estimated with bias close to 0 (mean=-0.0044, standard error=0.0087). Under moderate or severe PS, the GPS method consistently outperforms the PCA method in terms of bias, coverage probability (CP), and type I error. Under moderate PS, the GPS method consistently outperforms the MDS method in terms of CP. PCA maintains relatively high power compared to both MDS and GPS methods under the simulated situations. GPS and MDS are comparable in terms of statistical properties such as bias, type I error, and power. The GPS method provides a novel and robust tool for obtaining less-biased estimates of genetic associations that can consider both genetic and non-genetic factors. 2009 Wiley-Liss, Inc.

Depression and Physical Inactivity as Confounding the Effect of Obesity on Atrial Fibrillation.

PubMed

Garimella, Roja S; Sears, Samuel F; Gehi, Anil K

2016-06-01

Obesity is associated with an increased likelihood for the development of atrial fibrillation (AF) and with worsened AF symptom severity. However, other factors that are correlated with obesity may confound or mediate the relation of obesity with AF symptom severity. The purpose of this study was to determine if depression and physical inactivity may confound the association of obesity and AF symptom severity. Health status and demographic data were captured by questionnaire for 332 outpatients with documented AF. Weight/height was measured and body mass index (kg/m(2)) calculated. Recent depression symptom severity was assessed using the Patient Health Questionnaire-9 questionnaire. Physical activity during the last month was assessed by questionnaire. AF symptom severity was assessed using the University of Toronto AF Severity scale. Multivariate linear regression was used to evaluate which factors were associated with AF symptom severity. Obesity in patients with AF is associated with increased depression severity. In bivariate analysis, increasing body mass index (p = 0.001), lower levels of physical activity (p <0.001), and more severe depression (p <0.001) were associated with worsened AF symptom severity. In multivariate analysis, only physical activity and depression persisted as significant predictors of AF symptom severity. In conclusion, although obesity likely contributes to the substrate predisposing to the development of AF, other factors may contribute to or mediate the worsened AF symptoms associated with obesity. Depression symptoms and physical inactivity, factors closely correlated with obesity, may exacerbate symptoms in patients with AF. Copyright © 2016 Elsevier Inc. All rights reserved.

Bayesian effect estimation accounting for adjustment uncertainty.

PubMed

Wang, Chi; Parmigiani, Giovanni; Dominici, Francesca

2012-09-01

Model-based estimation of the effect of an exposure on an outcome is generally sensitive to the choice of which confounding factors are included in the model. We propose a new approach, which we call Bayesian adjustment for confounding (BAC), to estimate the effect of an exposure of interest on the outcome, while accounting for the uncertainty in the choice of confounders. Our approach is based on specifying two models: (1) the outcome as a function of the exposure and the potential confounders (the outcome model); and (2) the exposure as a function of the potential confounders (the exposure model). We consider Bayesian variable selection on both models and link the two by introducing a dependence parameter, ω, denoting the prior odds of including a predictor in the outcome model, given that the same predictor is in the exposure model. In the absence of dependence (ω= 1), BAC reduces to traditional Bayesian model averaging (BMA). In simulation studies, we show that BAC, with ω > 1, estimates the exposure effect with smaller bias than traditional BMA, and improved coverage. We, then, compare BAC, a recent approach of Crainiceanu, Dominici, and Parmigiani (2008, Biometrika 95, 635-651), and traditional BMA in a time series data set of hospital admissions, air pollution levels, and weather variables in Nassau, NY for the period 1999-2005. Using each approach, we estimate the short-term effects of on emergency admissions for cardiovascular diseases, accounting for confounding. This application illustrates the potentially significant pitfalls of misusing variable selection methods in the context of adjustment uncertainty. © 2012, The International Biometric Society.

Residential Proximity to Major Roadways Is Associated With Increased Levels of AC133+ Circulating Angiogenic Cells.

PubMed

DeJarnett, Natasha; Yeager, Ray; Conklin, Daniel J; Lee, Jongmin; O'Toole, Timothy E; McCracken, James; Abplanalp, Wes; Srivastava, Sanjay; Riggs, Daniel W; Hamzeh, Ihab; Wagner, Stephen; Chugh, Atul; DeFilippis, Andrew; Ciszewski, Tiffany; Wyatt, Brad; Becher, Carrie; Higdon, Deirdre; Ramos, Kenneth S; Tollerud, David J; Myers, John A; Rai, Shesh N; Shah, Jasmit; Zafar, Nagma; Krishnasamy, Sathya S; Prabhu, Sumanth D; Bhatnagar, Aruni

2015-11-01

Previous studies have shown that residential proximity to a roadway is associated with increased cardiovascular disease risk. Yet, the nature of this association remains unclear, and its effect on individual cardiovascular disease risk factors has not been assessed. The objective of this study was to determine whether residential proximity to roadways influences systemic inflammation and the levels of circulating angiogenic cells. In a cross-sectional study, cardiovascular disease risk factors, blood levels of C-reactive protein, and 15 antigenically defined circulating angiogenic cell populations were measured in participants (n=316) with moderate-to-high cardiovascular disease risk. Attributes of roadways surrounding residential locations were assessed using geographic information systems. Associations between road proximity and cardiovascular indices were analyzed using generalized linear models. Close proximity (<50 m) to a major roadway was associated with lower income and higher rates of smoking but not C-reactive protein levels. After adjustment for potential confounders, the levels of circulating angiogenic cells in peripheral blood were significantly elevated in people living in close proximity to a major roadway (CD31(+)/AC133(+), AC133(+), CD34(+)/AC133(+), and CD34(+)/45(dim)/AC133(+) cells) and positively associated with road segment distance (CD31(+)/AC133(+), AC133(+), and CD34(+)/AC133(+) cells), traffic intensity (CD31(+)/AC133(+) and AC133(+) cells), and distance-weighted traffic intensity (CD31(+)/34(+)/45(+)/AC133(+) cells). Living close to a major roadway is associated with elevated levels of circulating cells positive for the early stem marker AC133(+). This may reflect an increased need for vascular repair. Levels of these cells in peripheral blood may be a sensitive index of cardiovascular injury because of residential proximity to roadways. © 2015 American Heart Association, Inc.

DIFFERENCES IN STEROID MEASUREMENTS FOLLOWING ADULT AND HATCHLING EXPOSURE TO THE PHYTOESTROGEN APIGENIN

EPA Science Inventory

Weak estrogens, such as those produced by plants, may comprise the majority of the total estrogen load in exposed populations. Because of
their potential to produce confounding estrogenic and anti-estrogenic effects in competition with endogenous estradiol, several questions

Dyslipidemia in chronic kidney disease: are statins still indicated in reduction cardiovascular risk in patients on dialysis treatment?

PubMed

Scarpioni, Roberto; Ricardi, Marco; Melfa, Luigi; Cristinelli, Luciano

2010-12-01

Chronic kidney disease (CKD) is an increasingly health disease all around the world with a high burden of mortality and cardiovascular (CV) morbidity rate. Even when renal replacement therapy is reached, more than half patients die, mainly for CV causes due either to uremia-related cardiovascular risk factors (such as anemia, hyperhomocysteinemia, mineral bone disease-CKD with hyperparathyroidism, oxidative stress, hypoalbuminemia, chronic inflammation, prothrombotic factors) or to traditional ones (age, male gender, diabetes, obesity, hypertension, smoking, insulin levels, family history, dyslipidemia). Among the latter causes dyslipidemia represents one of the major, potentially correctable risk factor. Statins have demonstrated to effectively and safely reduce cholesterol levels in CKD patients. Here we will examine the effects of statins on CV risk factors in CKD patients and particularly in patients on dialysis treatment, in the light of the unfavorable results of the large trials 4D and AURORA, recently published, underlining the role of malnutrition/inflammation as confounding factor. Probably it will be that only with a real prevention, starting statins even in the early stages of CKD, as indicated by post hoc analysis of large trials, that we will reach results in reducing the mortality rate in CKD patients. In the meanwhile, all the other remediable CV risk factors have to be at the same time corrected. © 2010 Blackwell Publishing Ltd.

Exam anxiety in the undergraduate medical students of Taibah University.

PubMed

Khoshhal, Khalid I; Khairy, Gamal A; Guraya, Salman Y; Guraya, Shaista S

2017-04-01

Assessment is perceived to create highly stressful environment among medical students. Several studies have reported exam-related anxiety symptoms but the contributing factors seem to differ across institutions. This study aimed to determine the prevalence of exam anxiety, gender differences and the variables that moderate exam anxiety among students of a Saudi medical school. A cross-section study was done on 5th year medical students by administering a 12-statement self-administered questionnaire. The degree of exam anxiety was gauged by a visual analog scale. Of 125 students, 111 responded (response rate 89%). About 65% students experienced exam anxiety due to various reasons. Studying all night before exam (28 students; 25.2%) and extensive course load (26 students; 23.4%) were the major confounding factors. Female students experienced more stress due to extensive course load as compared with male students (p = .00). The data about the identified risk factors for exam anxiety can help medical educators to deeply understand the reasons for exam anxiety. There is a need to reassess the amount of study material in undergraduate medical curricula and students need to organize their time management skills to cope with exam anxiety.

Selection bias in rheumatic disease research.

PubMed

Choi, Hyon K; Nguyen, Uyen-Sa; Niu, Jingbo; Danaei, Goodarz; Zhang, Yuqing

2014-07-01

The identification of modifiable risk factors for the development of rheumatic conditions and their sequelae is crucial for reducing the substantial worldwide burden of these diseases. However, the validity of such research can be threatened by sources of bias, including confounding, measurement and selection biases. In this Review, we discuss potentially major issues of selection bias--a type of bias frequently overshadowed by other bias and feasibility issues, despite being equally or more problematic--in key areas of rheumatic disease research. We present index event bias (a type of selection bias) as one of the potentially unifying reasons behind some unexpected findings, such as the 'risk factor paradox'--a phenomenon exemplified by the discrepant effects of certain risk factors on the development versus the progression of osteoarthritis (OA) or rheumatoid arthritis (RA). We also discuss potential selection biases owing to differential loss to follow-up in RA and OA research, as well as those due to the depletion of susceptibles (prevalent user bias) and immortal time bias. The lesson remains that selection bias can be ubiquitous and, therefore, has the potential to lead the field astray. Thus, we conclude with suggestions to help investigators avoid such issues and limit the impact on future rheumatology research.

Selection bias in rheumatic disease research

PubMed Central

Choi, Hyon K.; Nguyen, Uyen-Sa; Niu, Jingbo; Danaei, Goodarz; Zhang, Yuqing

2014-01-01

The identification of modifiable risk factors for the development of rheumatic conditions and their sequelae is crucial for reducing the substantial worldwide burden of these diseases. However, the validity of such research can be threatened by sources of bias, including confounding, measurement and selection biases. In this Review, we discuss potentially major issues of selection bias—a type of bias frequently overshadowed by other bias and feasibility issues, despite being equally or more problematic—in key areas of rheumatic disease research. We present index event bias (a type of selection bias) as one of the potentially unifying reasons behind some unexpected findings, such as the ‘risk factor paradox’—a phenomenon exemplified by the discrepant effects of certain risk factors on the development versus the progression of osteoarthritis (OA) or rheumatoid arthritis (RA). We also discuss potential selection biases owing to differential loss to follow-up in RA and OA research, as well as those due to the depletion of susceptibles (prevalent user bias) and immortal time bias. The lesson remains that selection bias can be ubiquitous and, therefore, has the potential to lead the field astray. Thus, we conclude with suggestions to help investigators avoid such issues and limit the impact on future rheumatology research. PMID:24686510

The Association Between Headaches and Temporomandibular Disorders is Confounded by Bruxism and Somatic Symptoms.

PubMed

van der Meer, Hedwig A; Speksnijder, Caroline M; Engelbert, Raoul H H; Lobbezoo, Frank; Nijhuis-van der Sanden, Maria W G; Visscher, Corine M

2017-09-01

The objective of this observational study was to establish the possible presence of confounders on the association between temporomandibular disorders (TMD) and headaches in a patient population from a TMD and Orofacial Pain Clinic. Several subtypes of headaches have been diagnosed: self-reported headache, (probable) migraine, (probable) tension-type headache, and secondary headache attributed to TMD. The presence of TMD was subdivided into 2 subtypes: painful TMD and function-related TMD. The associations between the subtypes of TMD and headaches were evaluated by single regression models. To study the influence of possible confounding factors on this association, the regression models were extended with age, sex, bruxism, stress, depression, and somatic symptoms. Of the included patients (n=203), 67.5% experienced headaches. In the subsample of patients with a painful TMD (n=58), the prevalence of self-reported headaches increased to 82.8%. The associations found between self-reported headache and (1) painful TMD and (2) function-related TMD were confounded by the presence of somatic symptoms. For probable migraine, both somatic symptoms and bruxism confounded the initial association found with painful TMD. The findings of this study imply that there is a central working mechanism overlapping TMD and headache. Health care providers should not regard these disorders separately, but rather look at the bigger picture to appreciate the complex nature of the diagnostic and therapeutic process.

Perceived fairness of pay among people with and without disabilities: a propensity score matched analysis of working Australians.

PubMed

Milner, Allison; Aitken, Zoe; Krnjacki, Lauren; Bentley, Rebecca; Blakely, Tony; LaMontagne, Anthony D; Kavanagh, Anne M

2015-09-01

Equity and fairness at work are associated with a range of organizational and health outcomes. Past research suggests that workers with disabilities experience inequity in the workplace. It is difficult to conclude whether the presence of disability is the reason for perceived unfair treatment due to the possible confounding of effect estimates by other demographic or socioeconomic factors. The data source was the Household, Income, and Labor Dynamics in Australia (HILDA) survey (2001-2012). Propensity for disability was calculated from logistic models including gender, age, education, country of birth, and father's occupational skill level as predictors. We then used nearest neighbor (on propensity score) matched analysis to match workers with disabilities to workers without disability. Results suggest that disability is independently associated with lower fairness of pay after controlling for confounding factors in the propensity score matched analysis; although results do suggest less than half a standard deviation difference, indicating small effects. Similar results were apparent in standard multivariable regression models and alternative propensity score analyses (stratification, covariate adjustment using the propensity score, and inverse probability of treatment weighting). Whilst neither multivariable regression nor propensity scores adjust for unmeasured confounding, and there remains the potential for other biases, similar results for the two methodological approaches to confounder adjustment provide some confidence of an independent association of disability with perceived unfairness of pay. Based on this, we suggest that the disparity in the perceived fairness of pay between people with and without disabilities may be explained by worse treatment of people with disabilities in the workplace.

Family structure and risk behaviors: the role of the family meal in assessing likelihood of adolescent risk behaviors.

PubMed

Goldfarb, Samantha; Tarver, Will L; Sen, Bisakha

2014-01-01

Previous literature has asserted that family meals are a key protective factor for certain adolescent risk behaviors. It is suggested that the frequency of eating with the family is associated with better psychological well-being and a lower risk of substance use and delinquency. However, it is unclear whether there is evidence of causal links between family meals and adolescent health-risk behaviors. The purpose of this article is to review the empirical literature on family meals and adolescent health behaviors and outcomes in the US. A SEARCH WAS CONDUCTED IN FOUR ACADEMIC DATABASES: Social Sciences Full Text, Sociological Abstracts, PsycINFO®, and PubMed/MEDLINE. We included studies that quantitatively estimated the relationship between family meals and health-risk behaviors. Data were extracted on study sample, study design, family meal measurement, outcomes, empirical methods, findings, and major issues. Fourteen studies met the inclusion criteria for the review that measured the relationship between frequent family meals and various risk-behavior outcomes. The outcomes considered by most studies were alcohol use (n=10), tobacco use (n=9), and marijuana use (n=6). Other outcomes included sexual activity (n=2); depression, suicidal ideation, and suicide attempts (n=4); violence and delinquency (n=4); school-related issues (n=2); and well-being (n=5). The associations between family meals and the outcomes of interest were most likely to be statistically significant in unadjusted models or models controlling for basic family characteristics. Associations were less likely to be statistically significant when other measures of family connectedness were included. Relatively few analyses used sophisticated empirical techniques available to control for confounders in secondary data. More research is required to establish whether or not the relationship between family dinners and risky adolescent behaviors is an artifact of underlying confounders. We recommend that researchers make more frequent use of sophisticated methods to reduce the problem of confounders in secondary data, and that the scope of adolescent problem behaviors also be further widened.

Appropriate and inappropriate methods for investigating the "gateway" hypothesis, with a review of the evidence linking prior snus use to later cigarette smoking.

PubMed

Lee, Peter N

2015-03-20

The "gateway hypothesis" usually refers to the possibility that the taking up of habit A, which is considered harmless (or less harmful), may lead to the subsequent taking up of another habit, B, which is considered harmful (or more harmful). Possible approaches to designing and analysing studies to test the hypothesis are discussed. Evidence relating to the use of snus (A) as a gateway for smoking (B) is then evaluated in detail. The importance of having appropriate data available on the sequence of use of A and B and on other potential confounding factors that may lead to the taking up of B is emphasised. Where randomised trials are impractical, the preferred designs include the prospective cohort study in which ever use of A and of B is recorded at regular intervals, and the cross-sectional survey in which time of starting to use A and B is recorded. Both approaches allow time-stratified analytical methods to be used, in which, in each time period, risk of initiating B among never users of B at the start of the interval is compared according to prior use of A. Adjustment in analysis for the potential confounding factors is essential. Of 11 studies of possible relevance conducted in Sweden, Finland or Norway, only one seriously addresses potential confounding by those other factors involved in the initiation of smoking. Furthermore, 5 of the 11 studies are of a design that does not allow proper testing of the gateway hypothesis for various reasons, and the analysis is unsatisfactory, sometimes seriously, in all the remaining six. While better analyses could be attempted for some of the six studies identified as having appropriate design, the issues of confounding remain, and more studies are clearly needed. To obtain a rapid answer, a properly designed cross-sectional survey is recommended.

High birth weight and perinatal mortality among siblings: A register based study in Norway, 1967-2011.

PubMed

Kristensen, Petter; Keyes, Katherine M; Susser, Ezra; Corbett, Karina; Mehlum, Ingrid Sivesind; Irgens, Lorentz M

2017-01-01

Perinatal mortality according to birth weight has an inverse J-pattern. Our aim was to estimate the influence of familial factors on this pattern, applying a cohort sibling design. We focused on excess mortality among macrosomic infants (>2 SD above the mean) and hypothesized that the birth weight-mortality association could be explained by confounding shared family factors. We also estimated how the participant's deviation from mean sibling birth weight influenced the association. We included 1 925 929 singletons, born term or post-term to mothers with more than one delivery 1967-2011 registered in the Medical Birth Registry of Norway. We examined z-score birth weight and perinatal mortality in random-effects and sibling fixed-effects logistic regression models including measured confounders (e.g. maternal diabetes) as well as unmeasured shared family confounders (through fixed effects models). Birth weight-specific mortality showed an inverse J-pattern, being lowest (2.0 per 1000) at reference weight (z-score +1 to +2) and increasing for higher weights. Mortality in the highest weight category was 15-fold higher than reference. This pattern changed little in multivariable models. Deviance from mean sibling birth weight modified the mortality pattern across the birth weight spectrum: small and medium-sized infants had increased mortality when being smaller than their siblings, and large-sized infants had an increased risk when outweighing their siblings. Maternal diabetes and birth weight acted in a synergistic fashion with mortality among macrosomic infants in diabetic pregnancies in excess of what would be expected for additive effects. The inverse J-pattern between birth weight and mortality is not explained by measured confounders or unmeasured shared family factors. Infants are at particularly high mortality risk when their birth weight deviates substantially from their siblings. Sensitivity analysis suggests that characteristics related to maternal diabetes could be important in explaining the increased mortality among macrosomic infants.

Does caregiving cause psychological distress? The case for familial and genetic vulnerabilities in female twins.

PubMed

Vitaliano, Peter P; Strachan, Eric; Dansie, Elizabeth; Goldberg, Jack; Buchwald, Dedra

2014-04-01

Informal caregiving can be deleterious to mental health, but research results are inconsistent and may reflect an interaction between caregiving and vulnerability to stress. We examined psychological distress among 1,228 female caregiving and non-caregiving twins. By examining monozygotic and dizygotic twin pairs discordant for caregiving, we assessed the extent to which distress is directly related to caregiving or confounded by common genes and environmental exposures. Caregiving was associated with distress as measured by mental health functioning, anxiety, perceived stress, and depression. The overall association between caregiving and distress was confounded by common genes and environment for mental health functioning, anxiety, and depression. Common environment also confounded the association of caregiving and perceived stress. Vulnerability to distress is a factor in predicting caregivers' psychosocial functioning. Additional research is needed to explicate the mechanisms by which common genes and environment increase the risk of distress among informal caregivers.

Indoor biofuel air pollution and respiratory health: the role of confounding factors among women in highland Guatemala.

PubMed

Bruce, N; Neufeld, L; Boy, E; West, C

1998-06-01

A number of studies have reported associations between indoor biofuel air pollution in developing countries and chronic obstructive lung disease (COLD) in adults and acute lower respiratory infection (ALRI) in children. Most of these studies have used indirect measures of exposure and generally dealt inadequately with confounding. More reliable, quantified information about this presumed effect is an important pre-requisite for prevention, not least because of the technical, economic and cultural barriers to achieving substantial exposure reductions in the world's poorest households, where ambient pollution levels are typically between ten and a hundred times higher than recommended standards. This study was carried out as part of a programme of research designed to inform the development of intervention studies capable of providing quantified estimates of health benefits. The association between respiratory symptoms and the use of open fires and chimney woodstoves ('planchas'), and the distribution of confounding factors, were examined in a cross-sectional study of 340 women aged 15-45 years, living in a poor rural area in the western highlands of Guatemala. The prevalence of reported cough and phlegm was significantly higher for three of six symptom measures among women using open fires. Although this finding is consistent with a number of other studies, none has systematically examined the extent to which strong associations with confounding variables in these settings limit the ability of observational studies to define the effect of indoor air pollution adequately. Very strong associations (P < 0.0001) were found between the type of fire and a number of household and socioeconomic factors including the arrangement of rooms, floor type, and possession of a radio and television. The spouse's economic activity type was also significantly associated (P < 0.05). Thus, while 82% of open fire users had dirt floors and only 18% cement or tile floors, the situation was reversed for plancha users, only 16% of whom had dirt floors. Confounding presents a substantial problem for observational studies of indoor air pollution and health, although there is a reasonable case for believing that the observed association is causal. Intervention studies are required for stronger evidence of this association, and more importantly, to determine the size of health benefit achievable through feasible exposure reductions.

Anxiety in Asperger's Syndrome: Assessment in Real Time

ERIC Educational Resources Information Center

Hare, Dougal J.; Wood, Christopher; Wastell, Sarah; Skirrow, Paul

2015-01-01

Anxiety is a major problem for many people with Asperger's syndrome who may have qualitatively different fears from a non-Asperger's syndrome population. Research has relied on measures developed for non-Asperger's syndrome populations that require reporting past experiences of anxiety, which may confound assessment in people with Asperger's…

Assisted Reproductive Technology and Risk for Autism Spectrum Disorder

ERIC Educational Resources Information Center

Zachor, Ditza A.; Itzchak, E. Ben

2011-01-01

Epidemiologic studies on maternal and pregnancy risk factors for autism spectrum disorder (ASD), including use of assisted reproductive technology (ART), found conflicting results. This study included the following aims: to assess frequencies of ART in a large ASD group; to examine confounding birth and familial risk factors in the ASD with ART…

Maternal Age at Childbirth and Offspring Disruptive Behaviors: Testing the Causal Hypothesis

ERIC Educational Resources Information Center

D'Onofrio, Brian M.; Goodnight, Jackson A.; Van Hulle, Carol A.; Rodgers, Joseph Lee; Rathouz, Paul J.; Waldman, Irwin D.; Lahey, Benjamin B.

2009-01-01

Background: Recent studies suggest that the association between maternal age at childbearing (MAC) and children's disruptive behaviors is the result of family factors that are confounded with both variables, rather than a casual effect of environmental factors specifically related to MAC. These studies, however, relied on restricted samples and…

Child Migration and Academic Performance: The Case of Basic Education in Ghana

ERIC Educational Resources Information Center

Tamanja, Emmanuel Makabu J.

2016-01-01

The nexus between migration and academic performance is complex and difficult to extricate. Not only are there several factors affecting academic performance, but also many of these factors are confounding, making it difficult to identify and isolate in order to address. Furthermore, the discourse appears silent on the nexus between child…

Assay dilution factors confound measures of total antioxidant capacity in polyphenol-rich juices

USDA-ARS?s Scientific Manuscript database

The extent to which sample dilution factor (DF) affects Total Antioxidant Capacity (TAC) values is poorly understood. Thus, we examined the impact of DF on the ORAC, FRAP, DPPH, and Total Phenols (TP) assays using pomegranate juice (PJ), grape juice (GJ), selected flavonoids, ascorbic acid, and ella...

Factors associated with employment status before and during pregnancy: Implications for studies of pregnancy outcomes.

PubMed

Rocheleau, Carissa M; Bertke, Stephen J; Lawson, Christina C; Romitti, Paul A; Desrosiers, Tania A; Agopian, Aaron J; Bell, Erin; Gilboa, Suzanne M

2017-04-01

Potential confounding or effect modification by employment status is frequently overlooked in pregnancy outcome studies. To characterize how employed and non-employed women differ, we compared demographics, behaviors, and reproductive histories by maternal employment status for 8,343 mothers of control (non-malformed) infants in the National Birth Defects Prevention Study (1997-2007) and developed a multivariable model for employment status anytime during pregnancy and the 3 months before conception. Sixteen factors were independently associated with employment before or during pregnancy, including: maternal age, pre-pregnancy body mass index, pregnancy intention, periconceptional/first trimester smoking and alcohol consumption, and household income. Employment status was significantly associated with many common risk factors for adverse pregnancy outcomes. Pregnancy outcome studies should consider adjustment or stratification by employment status. In studies of occupational exposures, these differences may cause uncontrollable confounding if non-employed women are treated as unexposed instead of excluded from analysis. Am. J. Ind. Med. 60:329-341, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

The link between early onset drinking and early onset alcohol-impaired driving in young males.

PubMed

Zhang, Lening; Wieczorek, William F; Welte, John W

2014-05-01

Young drivers represent a disproportionate number of the individuals involved in alcohol-impaired driving. Although there is a known association between drinking and alcohol-impaired driving in young drivers, the link between early onset drinking and early onset alcohol-impaired driving has not been explored. The present study aimed to assess this link along with potentially confounding factors. The assessment used a proportional hazards model with data collected from the Buffalo Longitudinal Study of Young Men, a population-based sample of 625 males at aged 16-19. Controlling for the effects of potentially relevant confounds, the early onset of drinking was the most influential factor in predicting the early onset of alcohol-impaired driving. Race and the early onset of other forms of delinquency also played a significant role in the early onset of alcohol-impaired driving. Preventing an early start of drinking among adolescents may be the most critical factor to address in preventing an early start of alcohol-impaired driving.

Outcomes after helicopter versus ground emergency medical services for major trauma--propensity score and instrumental variable analyses: a retrospective nationwide cohort study.

PubMed

Tsuchiya, Asuka; Tsutsumi, Yusuke; Yasunaga, Hideo

2016-11-29

Because of a lack of randomized controlled trials and the methodological weakness of currently available observational studies, the benefits of helicopter emergency medical services (HEMS) over ground emergency medical services (GEMS) for major trauma patients remain uncertain. The aim of this retrospective nationwide cohort study was to compare the mortality of adults with serious traumatic injuries who were transported by HEMS and GEMS, and to analyze the effects of HEMS in various subpopulations. Using the Japan Trauma Data Bank, we evaluated all adult patients who had an injury severity score ≥ 16 transported by HEMS or GEMS during the daytime between 2004 and 2014. We compared in-hospital mortality between patients transported by HEMS and GEMS using propensity score matching, inverse probability of treatment weighting and instrumental variable analyses to adjust for measured and unmeasured confounding factors. Eligible patients (n = 21,286) from 192 hospitals included 4128 transported by HEMS and 17,158 transported by GEMS. In the propensity score-matched model, there was a significant difference in the in-hospital mortality between HEMS and GEMS groups (22.2 vs. 24.5%, risk difference -2.3% [95% confidence interval, -4.2 to -0.5]; number needed to treat, 43 [95% confidence interval, 24 to 220]). The inverse probability of treatment weighting (20.8% vs. 23.9%; risk difference, -3.9% [95% confidence interval, -5.7 to -2.1]; number needed to treat, 26 [95% confidence interval, 17 to 48]) and instrumental variable analyses showed similar results (risk difference, -6.5% [95% confidence interval, -9.2 to -3.8]; number needed to treat, 15 [95% confidence interval, 11 to 27]). HEMS transport was significantly associated with lower in-hospital mortality after falls, compression injuries, severe chest injuries, extremity (including pelvic) injuries, and traumatic arrest on arrival to the emergency department. HEMS was associated with a significantly lower mortality than GEMS in adult patients with major traumatic injuries after adjusting for measured and unmeasured confounders.

Determining Surgical Complications in the Overweight (DISCOVER): a multicentre observational cohort study to evaluate the role of obesity as a risk factor for postoperative complications in general surgery.

PubMed

Nepogodiev, Dmitri; Chapman, Stephen J; Glasbey, James; Kelly, Michael; Khatri, Chetan; Drake, Thomas M; Kong, Chia Yew; Mitchell, Harriet; Harrison, Ewen M; Fitzgerald, J Edward; Bhangu, Aneel

2015-07-20

Obesity is increasingly prevalent among patients undergoing surgery. Conflicting evidence exists regarding the impact of obesity on postoperative complications. This multicentre study aims to determine whether obesity is associated with increased postoperative complications following general surgery. This prospective, multicentre cohort study will be performed utilising a collaborative methodology. Consecutive adults undergoing open or laparoscopic, elective or emergency, gastrointestinal, bariatric or hepatobiliary surgery will be included. Day case patients will be excluded. The primary end point will be the overall 30-day major complication rate (Clavien-Dindo grade III-V complications). Data will be collected to risk-adjust outcomes for potential confounding factors, such as preoperative cardiac risk. This study will be disseminated through structured medical student networks using established collaborative methodology. The study will be powered to detect a two-percentage point increase in the major postoperative complication rate in obese versus non-obese patients. Following appropriate assessment, an exemption from full ethics committee review has been received, and the study will be registered as a clinical audit or service evaluation at each participating hospital. Dissemination will take place through national and local research collaborative networks. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Genetic and environmental determinants of the susceptibility of Amerindian derived populations for having hypertriglyceridemia

PubMed Central

Aguilar-Salinas, Carlos A.; Tusie-Luna, Teresa; Pajukanta, Päivi

2014-01-01

Here, we discuss potential explanations for the higher prevalence of hypertriglyceridemia in populations with an Amerindian background. Although environmental factors are the triggers, the search for the ethnic related factors that explains the increased susceptibility of the Amerindians is a promising area for research. The study of the genetics of hypertriglyceridemia in Hispanic populations faces several challenges. Ethnicity could be a major confounding variable to prove genetic associations. Despite that, the study of hypertriglyceridemia in Hispanics has resulted in significant contributions. Two GWAS reports have exclusively included Mexican mestizos. Fifty percent of the associations reported in Caucasians could be generalized to the Mexicans, but in many cases the Mexican lead SNP was different than that reported in Europeans. Both reports included new associations with apo B or triglycerides concentrations. The frequency of susceptibility alleles in Mexicans is higher than that found in Europeans for several of the genes with the greatest effect on triglycerides levels. An example is the SNP rs964184 in APOA5. The same trend was observed for ANGPTL3 and TIMD4 variants. In summary, we postulate that the study of the genetic determinants of hypertriglyceridemia in Amerindian populations which have major changes in their lifestyle, may prove to be a great resource to identify new genes and pathways associated with hypertriglyceridemia. PMID:24768220

Hospital ownership and financial performance: what explains the different findings in the empirical literature?

PubMed

Shen, Yu-Chu; Eggleston, Karen; Lau, Joseph; Schmid, Christopher H

2007-01-01

This study applies meta-analytic methods to conduct a quantitative review of the empirical literature on hospital ownership since 1990. We examine four financial outcomes across 40 studies: cost, revenue, profit margin, and efficiency. We find that variation in the magnitudes of ownership effects can be explained by a study's research focus and methodology. Studies using empirical methods that control for few confounding factors tend to find larger differences between for-profit and not-for-profit hospitals than studies that control for a wider range of confounding factors. Functional form and sample size also matter. Failure to apply log transformation to highly skewed expenditure data yields misleadingly large estimated differences between for-profits and not-for-profits. Studies with fewer than 200 observations also produce larger point estimates and wide confidence intervals.

Neurochemistry of major depression: a study using magnetic resonance spectroscopy.

PubMed

Godlewska, Beata R; Near, Jamie; Cowen, Philip J

2015-02-01

Magnetic resonance spectroscopy (MRS) is an acceptable non-invasive means of studying brain neurochemistry in depression. Previous studies in depressed patients have focused on measurement of the amino acid neurotransmitters, γ-aminobutyric acid (GABA) and glutamate. The aim of this study is to use MRS in conjunction with the ultrashort echo time 'SPECIAL' technique to measure cortical levels of GABA, glutamate and glutathione (GSH) levels in unmedicated patients with major depression. We also examined the effect of 6-week treatment with the selective serotonin re-uptake inhibitor, escitalopram. We studied patients with DSM-IV major depression and healthy age-matched controls using proton MRS. GABA, glutamate and GSH were measured relative to creatine in a voxel placed in occipital cortex. There was no difference in GABA or glutamate levels between depressed participants and controls; however, depressed patients had lower GSH levels. Six-week escitalopram treatment, which resulted in significant clinical responses in some patients, did not alter concentrations of GABA, glutamate or GSH. The sources of variability of GABA and glutamate measures in different studies of depressed patients require further study. Our results suggest that concomitant treatment with selective serotonin re-uptake inhibitors (SSRIs) is unlikely to be an important confounding factor. If lowered GSH levels can be confirmed, they may represent the presence of oxidative stress in some depressed patients.

Mothers' spanking of 3-year-old children and subsequent risk of children's aggressive behavior.

PubMed

Taylor, Catherine A; Manganello, Jennifer A; Lee, Shawna J; Rice, Janet C

2010-05-01

The goal was to examine the association between the use of corporal punishment (CP) against 3-year-old children and subsequent aggressive behavior among those children. Respondents (N = 2461) participated in the Fragile Families and Child Well-being Study (1998-2005), a population-based, birth cohort study of children born in 20 large US cities. Maternal reports of CP, children's aggressive behaviors at 3 and 5 years of age, and a host of key demographic features and potential confounding factors, including maternal child physical maltreatment, psychological maltreatment, and neglect, intimate partner aggression victimization, stress, depression, substance use, and consideration of abortion, were assessed. Frequent use of CP (ie, mother's use of spanking more than twice in the previous month) when the child was 3 years of age was associated with increased risk for higher levels of child aggression when the child was 5 years of age (adjusted odds ratio: 1.49 [95% confidence interval: 1.2-1.8]; P < .0001), even with controlling for the child's level of aggression at age 3 and the aforementioned potential confounding factors and key demographic features. Despite American Academy of Pediatrics recommendations to the contrary, most parents in the United States approve of and have used CP as a form of child discipline. The current findings suggest that even minor forms of CP, such as spanking, increase risk for increased child aggressive behavior. Importantly, these findings cannot be attributed to possible confounding effects of a host of other maternal parenting risk factors.

Parental mental health, childhood psychiatric disorders, and asthma attacks in island Puerto Rican youth.

PubMed

Ortega, Alexander N; Goodwin, Renee D; McQuaid, Elizabeth L; Canino, Glorisa

2004-01-01

Previous research documents an association of poor parental mental health with asthma in children. This study aims to determine whether the associations between parental mental health problems and childhood asthma attacks persist after controlling for childhood anxiety and depression and other confounding factors. A community household sample of youth ages 4 to 17 years and their primary caregivers from the US Commonwealth of Puerto Rico was studied to determine the associations between parental mental health and childhood asthma attacks. Regression models that predicted asthma attacks in youth controlled for parental mental health problems, childhood anxiety and depression, zone of residence, and parents' age, education, and perception of poverty. After adjusting for children's depressive and anxiety disorders as well as other important confounders, associations between parental depression, suicide attempts, ataque de nervios, and history of mental health treatment and asthma attacks in offspring, by parental report, persisted. Additionally, the frequency of parental mental health problems was associated with children's asthma attacks. Parents with mental health problems were more likely to report histories of asthma attacks in their children compared with parents without mental health problems in Puerto Rico. These associations were not attributable to internalizing disorders in youth but persisted independent of childhood psychopathology and other confounding factors. Clinicians and researchers should recognize the relations between poor parental mental health and childhood asthma and explore the potential role of family psychosocial and behavioral factors related to the manifestation of the disease.

The effects of sleep duration on the incidence of cardiovascular events among middle-aged male workers in Japan.

PubMed

Hamazaki, Yuko; Morikawa, Yuko; Nakamura, Koshi; Sakurai, Masaru; Miura, Katsuyuki; Ishizaki, Masao; Kido, Teruhiko; Naruse, Yuchi; Suwazono, Yasushi; Nakagawa, Hideaki

2011-09-01

Although previous epidemiological studies have investigated the relationship between sleep duration and various cardiovascular events, the results have been inconsistent. Accordingly, we conducted a follow-up survey to investigate the relationship between sleep duration and cardiovascular events among male workers, accounting for occupational factors that might confound the true relationship. A total of 2282 male employees aged 35-54 years based in a factory in Japan were followed for 14 years. The risk of cardiovascular events was compared among 4 groups stratified based on sleep duration at baseline (<6, 6-6.9, 7-7.9, and ≥8 hours). Cardiovascular events included stroke, coronary events and sudden cardiac death. The hazard ratios for events were calculated using a Cox proportional hazards model, with the 7-7.9-hour group serving as a reference. The model was adjusted for potential confounders including traditional cardiovascular risk factors and working characteristics. During 14 years of follow-up, 64 cardiovascular events were recorded including 30 strokes, 27 coronary events and 7 sudden cardiac deaths. After adjustment for possible confounders, the hazard ratios for cardiovascular and coronary events in the <6-hour group were 3.49 [95% confidence interval (95% CI) 1.30-9.40] and 4.95 (95% CI 1.31-18.73), respectively. There was no significant increment in the risk of stroke for any sleep duration groups. Short sleep duration (<6 hours) was a significant risk factor for coronary events in a Japanese male working population.

A comparison of estimators from self-controlled case series, case-crossover design, and sequence symmetry analysis for pharmacoepidemiological studies.

PubMed

Takeuchi, Yoshinori; Shinozaki, Tomohiro; Matsuyama, Yutaka

2018-01-08

Despite the frequent use of self-controlled methods in pharmacoepidemiological studies, the factors that may bias the estimates from these methods have not been adequately compared in real-world settings. Here, we comparatively examined the impact of a time-varying confounder and its interactions with time-invariant confounders, time trends in exposures and events, restrictions, and misspecification of risk period durations on the estimators from three self-controlled methods. This study analyzed self-controlled case series (SCCS), case-crossover (CCO) design, and sequence symmetry analysis (SSA) using simulated and actual electronic medical records datasets. We evaluated the performance of the three self-controlled methods in simulated cohorts for the following scenarios: 1) time-invariant confounding with interactions between the confounders, 2) time-invariant and time-varying confounding without interactions, 3) time-invariant and time-varying confounding with interactions among the confounders, 4) time trends in exposures and events, 5) restricted follow-up time based on event occurrence, and 6) patient restriction based on event history. The sensitivity of the estimators to misspecified risk period durations was also evaluated. As a case study, we applied these methods to evaluate the risk of macrolides on liver injury using electronic medical records. In the simulation analysis, time-varying confounding produced bias in the SCCS and CCO design estimates, which aggravated in the presence of interactions between the time-invariant and time-varying confounders. The SCCS estimates were biased by time trends in both exposures and events. Erroneously short risk periods introduced bias to the CCO design estimate, whereas erroneously long risk periods introduced bias to the estimates of all three methods. Restricting the follow-up time led to severe bias in the SSA estimates. The SCCS estimates were sensitive to patient restriction. The case study showed that although macrolide use was significantly associated with increased liver injury occurrence in all methods, the value of the estimates varied. The estimations of the three self-controlled methods depended on various underlying assumptions, and the violation of these assumptions may cause non-negligible bias in the resulting estimates. Pharmacoepidemiologists should select the appropriate self-controlled method based on how well the relevant key assumptions are satisfied with respect to the available data.

Hospitalizations for Accidents and Induries in the U.S. Navy. IV. A Comparison of Nuclear and Conventionally Powered Surface Ships.

DTIC Science & Technology

1986-04-01

SURFACE SHIPS C. M. BONE J . C. HELMKAMP DTIC REPORT NO. 86-8 IWELECTE "’AUG 2 71986 ~. DistributLlU hti~ NAVAL HEALTH RESEARCH CENTER Q... P.O. BOX 85122...carrier and cruiser personnel comparisons. This risk was 1.5 and 2. J times the risk of hospitalization, respectively, for the same aged personnel...in these two groups, some confounding bias may have occurred. 10 Pr,, ’e ’, j .*-~~’V**, *~*~**** ,’*. ’~ Another confounding factor may stem from duty

The development of a modified spectral ripple test.

PubMed

Aronoff, Justin M; Landsberger, David M

2013-08-01

Poor spectral resolution can be a limiting factor for hearing impaired listeners, particularly for complex listening tasks such as speech understanding in noise. Spectral ripple tests are commonly used to measure spectral resolution, but these tests contain a number of potential confounds that can make interpretation of the results difficult. To measure spectral resolution while avoiding those confounds, a modified spectral ripple test with dynamically changing ripples was created, referred to as the spectral-temporally modulated ripple test (SMRT). This paper describes the SMRT and provides evidence that it is sensitive to changes in spectral resolution.

Prestigious Science Journals Struggle to Reach Even Average Reliability

PubMed Central

Brembs, Björn

2018-01-01

In which journal a scientist publishes is considered one of the most crucial factors determining their career. The underlying common assumption is that only the best scientists manage to publish in a highly selective tier of the most prestigious journals. However, data from several lines of evidence suggest that the methodological quality of scientific experiments does not increase with increasing rank of the journal. On the contrary, an accumulating body of evidence suggests the inverse: methodological quality and, consequently, reliability of published research works in several fields may be decreasing with increasing journal rank. The data supporting these conclusions circumvent confounding factors such as increased readership and scrutiny for these journals, focusing instead on quantifiable indicators of methodological soundness in the published literature, relying on, in part, semi-automated data extraction from often thousands of publications at a time. With the accumulating evidence over the last decade grew the realization that the very existence of scholarly journals, due to their inherent hierarchy, constitutes one of the major threats to publicly funded science: hiring, promoting and funding scientists who publish unreliable science eventually erodes public trust in science. PMID:29515380

Neuromotor outcomes in infants with bronchopulmonary dysplasia.

PubMed

Karagianni, Paraskevi; Tsakalidis, Christos; Kyriakidou, Maria; Mitsiakos, Georgios; Chatziioanidis, Helias; Porpodi, Maria; Evangeliou, Athanasios; Nikolaides, Nikolaos

2011-01-01

We examine the neuromotor outcomes of preterm infants with bronchopulmonary dysplasia. Two hundred and nineteen infants (gestational age, ≤ 32 weeks; birth weight, ≤ 1500 g) were studied. Neuromotor development was assessed using the Hammersmith Infant Neurological Examination. All potential risk factors associated with neuromotor scores (P < 0.015) were included in the generalized linear model (multiple linear regression) to determine if bronchopulmonary dysplasia had an independent relationship with neuromotor scores. Infants with severe bronchopulmonary dysplasia had lower global scores at ages 6 and 12 months. After adjustment for confounding factors, scores of infants with severe bronchopulmonary dysplasia were reduced by 13.2 units, whereas scores for those with periventricular leukomalacia were reduced by 11.1 units, at age 6 months. At age 12 months, scores for those with periventricular leukomalacia were reduced by 11.9 units. Duration of hospital stay reduced scores by 0.1 for each additional day increase in hospital. Bronchopulmonary dysplasia constitutes a major cause of poor neuromotor outcomes at age 6 months, but improvements in motor outcomes occur over time. Copyright © 2011 Elsevier Inc. All rights reserved.

The natural history of substance use disorders.

PubMed

Sarvet, Aaron L; Hasin, Deborah

2016-07-01

Illicit drugs, alcohol, and tobacco use disorders contribute substantially to the global burden of disease. Knowledge about the major elements of the natural history of substance use disorders (incidence, remission, persistence, and relapse) is crucial to a broader understanding of the course and outcomes of substance use disorders. Prospective cohort studies in nonclinical samples indicate that externalizing psychopathology in earlier life, including early disordered substance use, delinquency, and personality disorders, are related to substance use disorders later in life and chronic course. Externalizing psychopathology may be initiated by early adverse experiences, for example, childhood maltreatment and stressful life events. After controlling for confounders, 'age at first use' as a causal factor for alcohol use disorder later in life and the 'drug substitution' hypothesis are not supported in general population data. Future research should focus on elaborating the causal framework that leads to the development and persistence of severe substance use disorders, with an emphasis on identifying modifiable factors for intervention by policy makers or health professionals. More research is needed on the natural history of substance use disorders in low-income and middle-income countries.

Prediction versus aetiology: common pitfalls and how to avoid them.

PubMed

van Diepen, Merel; Ramspek, Chava L; Jager, Kitty J; Zoccali, Carmine; Dekker, Friedo W

2017-04-01

Prediction research is a distinct field of epidemiologic research, which should be clearly separated from aetiological research. Both prediction and aetiology make use of multivariable modelling, but the underlying research aim and interpretation of results are very different. Aetiology aims at uncovering the causal effect of a specific risk factor on an outcome, adjusting for confounding factors that are selected based on pre-existing knowledge of causal relations. In contrast, prediction aims at accurately predicting the risk of an outcome using multiple predictors collectively, where the final prediction model is usually based on statistically significant, but not necessarily causal, associations in the data at hand.In both scientific and clinical practice, however, the two are often confused, resulting in poor-quality publications with limited interpretability and applicability. A major problem is the frequently encountered aetiological interpretation of prediction results, where individual variables in a prediction model are attributed causal meaning. This article stresses the differences in use and interpretation of aetiological and prediction studies, and gives examples of common pitfalls. © The Author 2017. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Tutorial in Biostatistics: Instrumental Variable Methods for Causal Inference*

PubMed Central

Baiocchi, Michael; Cheng, Jing; Small, Dylan S.

2014-01-01

A goal of many health studies is to determine the causal effect of a treatment or intervention on health outcomes. Often, it is not ethically or practically possible to conduct a perfectly randomized experiment and instead an observational study must be used. A major challenge to the validity of observational studies is the possibility of unmeasured confounding (i.e., unmeasured ways in which the treatment and control groups differ before treatment administration which also affect the outcome). Instrumental variables analysis is a method for controlling for unmeasured confounding. This type of analysis requires the measurement of a valid instrumental variable, which is a variable that (i) is independent of the unmeasured confounding; (ii) affects the treatment; and (iii) affects the outcome only indirectly through its effect on the treatment. This tutorial discusses the types of causal effects that can be estimated by instrumental variables analysis; the assumptions needed for instrumental variables analysis to provide valid estimates of causal effects and sensitivity analysis for those assumptions; methods of estimation of causal effects using instrumental variables; and sources of instrumental variables in health studies. PMID:24599889

Determinants of self-rated health: could health status explain the association between self-rated health and mortality?

PubMed

Murata, Chiyoe; Kondo, Takaaki; Tamakoshi, Koji; Yatsuya, Hiroshi; Toyoshima, Hideaki

2006-01-01

The purpose of this study was to investigate factors related to self-rated health and to mortality among 2490 community-living elderly. Respondents were followed for 7.3 years for all-cause mortality. To compare the relative impact of each variable, we employed logistic regression analysis for self-rated health and Cox hazard analysis for mortality. Cox analysis stratified by gender, follow-up periods, age group, and functional status was also employed. Series of analysis found that factors associated with self-rated health and with mortality were not identical. Psychological factors such as perceived isolation at home or 'ikigai (one aspect of psychological well-being)' were associated with self-rated health only. Age, functional status, and social relations were associated both with self-rated health and mortality after controlling for possible confounders. Illnesses and functional status accounted for 35-40% of variances in the fair/poor self-rated health. Differences by gender and functional status were observed in the factors related to self-rated health. Overall, self-rated health effect on mortality was stronger for people with no functional impairment, for shorter follow-up period, and for young-old age group. Although, illnesses and functional status were major determinants of self-rated health, economical, psychological, and social factors were also related to self-rated health.

The INHANCE consortium: toward a better understanding of the causes and mechanisms of head and neck cancer.

PubMed

Winn, D M; Lee, Y-C A; Hashibe, M; Boffetta, P

2015-09-01

The International Head and Neck Cancer Epidemiology (INHANCE) consortium is a collaboration of research groups leading large epidemiology studies to improve the understanding of the causes and mechanisms of head and neck cancer. The consortium includes investigators of 35 studies who have pooled their data on 25 500 patients with head and neck cancer (i.e., cancers of the oral cavity, oropharynx, hypopharynx, and larynx) and 37 100 controls. The INHANCE analyses have confirmed that tobacco use and alcohol intake are key risk factors of these diseases and have provided precise estimates of risk and dose response, the benefit of quitting, and the hazard of smoking even a few cigarettes per day. Other risk factors include short height, lean body mass, low education and income, and a family history of head and neck cancer. Risk factors are generally similar for oral cavity, pharynx, and larynx, although the magnitude of risk may vary. Some major strengths of pooling data across studies include more precise estimates of risk and the ability to control for potentially confounding factors and to examine factors that may interact with each other. The INHANCE consortium provides evidence of the scientific productivity and discoveries that can be obtained from data pooling projects. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Solar radiation increases suicide rate after adjusting for other climate factors in South Korea.

PubMed

Jee, Hee-Jung; Cho, Chul-Hyun; Lee, Yu Jin; Choi, Nari; An, Hyonggin; Lee, Heon-Jeong

2017-03-01

Previous studies have indicated that suicide rates have significant seasonal variations. There is seasonal discordance between temperature and solar radiation due to the monsoon season in South Korea. We investigated the seasonality of suicide and assessed its association with climate variables in South Korea. Suicide rates were obtained from the National Statistical Office of South Korea, and climatic data were obtained from the Korea Meteorological Administration for the period of 1992-2010. We conducted analyses using a generalized additive model (GAM). First, we explored the seasonality of suicide and climate variables such as mean temperature, daily temperature range, solar radiation, and relative humidity. Next, we identified confounding climate variables associated with suicide rate. To estimate the adjusted effect of solar radiation on the suicide rate, we investigated the confounding variables using a multivariable GAM. Suicide rate showed seasonality with a pattern similar to that of solar radiation. We found that the suicide rate increased 1.008 times when solar radiation increased by 1 MJ/m 2 after adjusting for other confounding climate factors (P < 0.001). Solar radiation has a significant linear relationship with suicide after adjusting for region, other climate variables, and time trends. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Maternal smoking during pregnancy and children's cognitive and physical development: a causal risk factor?

PubMed

Gilman, Stephen E; Gardener, Hannah; Buka, Stephen L

2008-09-01

There remains considerable debate regarding the effects of maternal smoking during pregnancy on children's growth and development. Evidence that exposure to maternal smoking during pregnancy is associated with numerous adverse outcomes is contradicted by research suggesting that these associations are spurious. The authors investigated the relation between maternal smoking during pregnancy and 14 developmental outcomes of children from birth through age 7 years, using data from the Collaborative Perinatal Project (1959-1974; n = 52,919). In addition to adjusting for potential confounders measured contemporaneously with maternal smoking, the authors fitted conditional fixed-effects models among siblings that controlled for unmeasured confounders. Results from the conditional analyses indicated a birth weight difference of -85.63 g associated with smoking of >or=20 cigarettes daily during pregnancy (95% confidence interval: -131.91, -39.34) and 2.73 times' higher odds of being overweight at age 7 years (95% confidence interval: 1.30, 5.71). However, the associations between maternal smoking and 12 other outcomes studied (including Apgar score, intelligence, academic achievement, conduct problems, and asthma) were entirely eliminated after adjustment for measured and unmeasured confounders. The authors conclude that the hypothesized effects of maternal smoking during pregnancy on these outcomes either are not present or are not distinguishable from a broader range of familial factors associated with maternal smoking.

Educational inequality in cardiovascular diseases: a sibling approach.

PubMed

Søndergaard, Grethe; Dalton, Susanne Oksbjerg; Mortensen, Laust Hvas; Osler, Merete

2018-02-01

Educational inequality in diseases in the circulatory system (here termed cardiovascular disease) is well documented but may be confounded by early life factors. The aim of this observational study was to examine whether the associations between education and all cardiovascular diseases, ischaemic heart disease and stroke, respectively, were explained by family factors shared by siblings. The study population included all individuals born in Denmark between 1950 and 1979 who had at least one full sibling born in the same period. Using Cox regression, data were analysed in conventional cohort and within-sibship analyses in which the association was examined within siblings discordant on education. Assuming that attenuation of associations in the within-sibship as compared with the cohort analyses would indicate confounding from factors shared within families. A lower educational status was associated with a higher risk of cardiovascular disease, ischaemic heart disease and stroke. All associations attenuated in the within-sibship analyses, in particular in the analyses on ischaemic heart disease before age 45 years. For instance, in the cohort analyses, the hazard rate of ischaemic heart disease among women less than 45 years who had a primary school education was 94% (hazard ratio 1.94 (1.78-2.12) higher than among those with a vocational education, while it attenuated to 51% (hazard ratio 1.51 (1.34-1.71)) in the within-sibship analysis. Confounding from factors shared by siblings explained the associations between education and the cardiovascular disease outcomes but to varying degrees. This should be taken into account when planning interventions aimed at reducing educational inequalities in the development of cardiovascular disease, ischaemic heart disease and stroke.

Relationships among fitness, obesity, screen time and academic achievement in Japanese adolescents.

PubMed

Morita, Noriteru; Nakajima, Toshihiro; Okita, Koichi; Ishihara, Toru; Sagawa, Masato; Yamatsu, Koji

2016-09-01

Students who study intensively in one of Japan's 'cram schools' and/or spend excess time on electronic devices such as video games are in a sedentary state much of the time, and this may affect their physical fitness. We investigated whether there are relationships among obesity, physical fitness and academic achievement in Japanese students after controlling for socioeconomic and behavioral confounding factors. The data of 315 students (152 females [48%], 163 males [52%]; 12-13yrs old) were analyzed. Academic achievement was assessed by the total grade points on eight school subjects (GP8). Students with a body mass index at or above the 85th percentile of each gender were classified as the overweight/obese group. Physical fitness was evaluated by the total score on eight fitness tests. Socioeconomic and behavioral confounders including the mother's educational background, household income, cram school utilization and time spent on video games/mobile phones were used as covariates. The GP8 of the overweight/obese students was significantly lower than that of the normal weight students (27.2 vs. 29.0 points, respectively). After adjusting for the confounders, the physical fitness score was found to be a significant factor for determinants of GP8 in boys (β=0.324), but not in girls. The obesity status was a factor for GP8 in the girls (β=-0.160) but not in the boys. These results suggest that physical fitness in boys and obesity status in girls could be important factors not only for health status but also for academic achievement, independent of socioeconomic and behavioral backgrounds. Copyright © 2016 Elsevier Inc. All rights reserved.

The roles of stimulus and response uncertainty in forced-choice performance: an amendment to Hick/Hyman Law.

PubMed

Wifall, Tim; Hazeltine, Eliot; Toby Mordkoff, J

2016-07-01

Hick/Hyman Law describes one of the core phenomena in the study of human information processing: mean response time is a linear function of average uncertainty. In the original work of Hick, (1952) and Hyman, (1953), along with many follow-up studies, uncertainty regarding the stimulus and uncertainty regarding the response were confounded such that the relative importance of these two factors remains mostly unknown. The present work first replicates Hick/Hyman Law with a new set of stimuli and then goes on to separately estimate the roles of stimulus and response uncertainty. The results demonstrate that, for a popular type of task-visual stimuli mapped to vocal responses-response uncertainty accounts for a majority of the effect. The results justify a revised expression of Hick/Hyman Law and place strong constraints on theoretical accounts of the law, as well as models of response selection in general.

Cannabis use in young people: the risk for schizophrenia.

PubMed

Casadio, Paola; Fernandes, Cathy; Murray, Robin M; Di Forti, Marta

2011-08-01

Cannabis is one of the most commonly used illicit drugs, and despite the widely held belief that it is a safe drug, its long-term use has potentially harmful consequences. To date, the research on the impact of its use has largely been epidemiological in nature and has consistently found that cannabis use is associated with schizophrenia outcomes later in life, even after controlling for several confounding factors. While the majority of users can continue their use without adverse effects, it is clear from studies of psychosis that some individuals are more vulnerable to its effects than others. In addiction, evidence from both epidemiological and animal studies indicates that cannabis use during adolescence carries particular risk. Further studies are warranted given the increase in the concentration of the main active ingredient (Δ(9)-tetrahydrocannabinol) in street preparations of cannabis and a decreasing age of first-time exposure to cannabis. Copyright © 2011 Elsevier Ltd. All rights reserved.

Structure, form, and meaning in the mental lexicon: evidence from Arabic

PubMed Central

Boudelaa, Sami; Marslen-Wilson, William D.

2015-01-01

Does the organization of the mental lexicon reflect the combination of abstract underlying morphemic units or the concatenation of word-level phonological units? We address these fundamental issues in Arabic, a Semitic language where every surface form is potentially analyzable into abstract morphemic units – the word pattern and the root – and where this view contrasts with stem-based approaches, chiefly driven by linguistic considerations, in which neither roots nor word patterns play independent roles in word formation and lexical representation. Five cross-modal priming experiments examine the processing of morphologically complex forms in the three major subdivisions of the Arabic lexicon – deverbal nouns, verbs, and primitive nouns. The results demonstrate that root and word pattern morphemes function as abstract cognitive entities, operating independently of semantic factors and dissociable from possible phonological confounds, while stem-based approaches consistently fail to accommodate the basic psycholinguistic properties of the Arabic mental lexicon. PMID:26682237

The common use of improper control diets in diet-induced metabolic disease research confounds data interpretation: the fiber factor.

PubMed

Pellizzon, Michael A; Ricci, Matthew R

2018-01-01

Diets used to induce metabolic disease are generally high in fat and refined carbohydrates and importantly, are usually made with refined, purified ingredients. However, researchers will often use a low fat grain-based (GB) diet containing unrefined ingredients as the control diet. Such a comparison between two completely different diet types makes it impossible to draw conclusions regarding the phenotypic differences driven by diet. While many compositional differences can account for this, one major difference that could have the greatest impact between GB and purified diets is the fiber content, both in terms of the level and composition. We will review recent data showing how fiber differences between GB diets and purified diets can significantly influence gut health and microbiota, which itself can affect metabolic disease development. Researchers need to consider the control diet carefully in order to make the best use of precious experimental resources.

Childhood adversity, mental disorder comorbidity, and suicidal behavior in schizotypal personality disorder.

PubMed

Lentz, Vanessa; Robinson, Jennifer; Bolton, James M

2010-11-01

Schizotypal personality disorder (SPD) is a serious and relatively common psychiatric disorder, yet remains understudied among the personality disorders. The current study examines the psychiatric correlates of SPD in a representative epidemiologic sample, utilizing data from the National Epidemiological Survey on Alcohol and Related Conditions (N = 34,653). Multiple logistic regression compared people with SPD to the general population across a broad range of childhood adversities, comorbid psychiatric disorders, and suicidal behavior. SPD was strongly associated with many adverse childhood experiences. After adjusting for confounding factors, SPD was independently associated with major depression and several anxiety disorders, including post-traumatic stress disorder. Interestingly, SPD was more strongly associated with borderline and narcissistic personality disorders than cluster A personality disorders. Individuals with SPD were also more likely to attempt suicide. As a whole, these results suggest that individuals with SPD experience significant morbidity and may be at increased risk of mortality.

Success Providing Postpartum Intrauterine Devices in Private-Sector Health Care Facilities in Nigeria: Factors Associated With Uptake

PubMed Central

Eluwa, George IE; Atamewalen, Ronke; Odogwu, Kingsley; Ahonsi, Babatunde

2016-01-01

ABSTRACT Background: Use of modern contraceptive methods in Nigeria remained at 10% between 2008 and 2013 despite substantive investments in family planning services. Many women in their first postpartum year, in particular, have an unmet need for family planning. We evaluated use of postpartum intrauterine device (IUD) insertion and determined factors associated with its uptake in Nigeria. Methods: Data were collected between May 2014 and February 2015 from 11 private health care facilities in 6 southern Nigerian states. Women attending antenatal care in participating facilities were counseled on all available contraceptive methods including the postpartum IUD. Data were abstracted from participating facility records and evaluated using a cross-sectional analysis. Categorical variables were calculated as proportions while continuous variables were calculated as medians with the associated interquartile range (IQR). Multivariate logistic regression analysis was used to identify factors associated with uptake of the postpartum IUD while controlling for potential confounding factors, including age, educational attainment, marital status, parity, number of living children, and previous use of contraception. Results: During the study period, 728 women delivered in the 11 facilities. The median age was 28 years, and most women were educated (73% had completed at least the secondary level). The majority (96%) of the women reported they were married, and the median number of living children was 3 (IQR, 2–4). Uptake of the postpartum IUD was 41% (n = 300), with 8% (n = 25) of the acceptors experiencing expulsion of the IUD within 6 weeks post-insertion. After controlling for potential confounding factors, several characteristics were associated with greater likelihood of choosing the postpartum IUD, including lower education, having a higher number of living children, and being single. Women who had used contraceptives previously were less likely to choose the postpartum IUD than women who had not previously used contraception (adjusted odds ratio, 0.68; 95% confidence interval, 0.55 to 0.84). Conclusion: A high percentage (41%) of women delivering in private health care facilities in southern Nigeria accepted immediate postpartum IUD insertion. Scale-up of postpartum IUD services is a promising approach to increasing uptake of long-acting reversible contraceptives among women in Nigeria. PMID:27353620

Identifying cis-mediators for trans-eQTLs across many human tissues using genomic mediation analysis

PubMed Central

Yang, Fan; Wang, Jiebiao; Pierce, Brandon L.; Chen, Lin S.

2017-01-01

The impact of inherited genetic variation on gene expression in humans is well-established. The majority of known expression quantitative trait loci (eQTLs) impact expression of local genes (cis-eQTLs). More research is needed to identify effects of genetic variation on distant genes (trans-eQTLs) and understand their biological mechanisms. One common trans-eQTLs mechanism is “mediation” by a local (cis) transcript. Thus, mediation analysis can be applied to genome-wide SNP and expression data in order to identify transcripts that are “cis-mediators” of trans-eQTLs, including those “cis-hubs” involved in regulation of many trans-genes. Identifying such mediators helps us understand regulatory networks and suggests biological mechanisms underlying trans-eQTLs, both of which are relevant for understanding susceptibility to complex diseases. The multitissue expression data from the Genotype-Tissue Expression (GTEx) program provides a unique opportunity to study cis-mediation across human tissue types. However, the presence of complex hidden confounding effects in biological systems can make mediation analyses challenging and prone to confounding bias, particularly when conducted among diverse samples. To address this problem, we propose a new method: Genomic Mediation analysis with Adaptive Confounding adjustment (GMAC). It enables the search of a very large pool of variables, and adaptively selects potential confounding variables for each mediation test. Analyses of simulated data and GTEx data demonstrate that the adaptive selection of confounders by GMAC improves the power and precision of mediation analysis. Application of GMAC to GTEx data provides new insights into the observed patterns of cis-hubs and trans-eQTL regulation across tissue types. PMID:29021290

Identifying cis-mediators for trans-eQTLs across many human tissues using genomic mediation analysis.

PubMed

Yang, Fan; Wang, Jiebiao; Pierce, Brandon L; Chen, Lin S

2017-11-01

The impact of inherited genetic variation on gene expression in humans is well-established. The majority of known expression quantitative trait loci (eQTLs) impact expression of local genes ( cis -eQTLs). More research is needed to identify effects of genetic variation on distant genes ( trans -eQTLs) and understand their biological mechanisms. One common trans -eQTLs mechanism is "mediation" by a local ( cis ) transcript. Thus, mediation analysis can be applied to genome-wide SNP and expression data in order to identify transcripts that are " cis -mediators" of trans -eQTLs, including those " cis -hubs" involved in regulation of many trans -genes. Identifying such mediators helps us understand regulatory networks and suggests biological mechanisms underlying trans -eQTLs, both of which are relevant for understanding susceptibility to complex diseases. The multitissue expression data from the Genotype-Tissue Expression (GTEx) program provides a unique opportunity to study cis -mediation across human tissue types. However, the presence of complex hidden confounding effects in biological systems can make mediation analyses challenging and prone to confounding bias, particularly when conducted among diverse samples. To address this problem, we propose a new method: Genomic Mediation analysis with Adaptive Confounding adjustment (GMAC). It enables the search of a very large pool of variables, and adaptively selects potential confounding variables for each mediation test. Analyses of simulated data and GTEx data demonstrate that the adaptive selection of confounders by GMAC improves the power and precision of mediation analysis. Application of GMAC to GTEx data provides new insights into the observed patterns of cis -hubs and trans -eQTL regulation across tissue types. © 2017 Yang et al.; Published by Cold Spring Harbor Laboratory Press.

Advanced Maternal Age and the Risk of Low Birth Weight and Preterm Delivery: a Within-Family Analysis Using Finnish Population Registers

PubMed Central

Goisis, Alice; Remes, Hanna; Barclay, Kieron; Martikainen, Pekka; Myrskylä, Mikko

2017-01-01

Abstract Advanced maternal age at birth is considered a major risk factor for birth outcomes. It is unclear to what extent this association is confounded by maternal characteristics. To test whether advanced maternal age at birth independently increases the risk of low birth weight (<2,500 g) and preterm birth (<37 weeks’ gestation), we compared between-family models (children born to different mothers at different ages) with within-family models (children born to the same mother at different ages). The latter procedure reduces confounding by unobserved parental characteristics that are shared by siblings. We used Finnish population registers, including 124,098 children born during 1987–2000. When compared with maternal ages 25–29 years in between-family models, maternal ages of 35–39 years and ≥40 years were associated with percentage increases of 1.1 points (95% confidence intervals: 0.8, 1.4) and 2.2 points (95% confidence intervals: 1.4, 2.9), respectively, in the probability of low birth weight. The associations are similar for the risk of preterm delivery. In within-family models, the relationship between advanced maternal age and low birth weight or preterm birth is statistically and substantively negligible. In Finland, advanced maternal age is not independently associated with the risk of low birth weight or preterm delivery among mothers who have had at least 2 live births. PMID:29206985

HOMA-IR Values are Associated With Glycemic Control in Japanese Subjects Without Diabetes or Obesity: The KOBE Study.

PubMed

Hirata, Takumi; Higashiyama, Aya; Kubota, Yoshimi; Nishimura, Kunihiro; Sugiyama, Daisuke; Kadota, Aya; Nishida, Yoko; Imano, Hironori; Nishikawa, Tomofumi; Miyamatsu, Naomi; Miyamoto, Yoshihiro; Okamura, Tomonori

2015-01-01

Several studies have reported that insulin resistance was a major risk factor for the onset of type 2 diabetes mellitus in individuals without diabetes or obesity. We aimed to clarify the association between insulin resistance and glycemic control in Japanese subjects without diabetes or obesity. We conducted a community-based cross-sectional study including 1083 healthy subjects (323 men and 760 women) in an urban area. We performed multivariate regression analyses to estimate the association between the homeostasis model assessment of insulin resistance (HOMA-IR) values and markers of glycemic control, including glycated haemoglobin (HbA1c), 1,5-anhydroglucitol (1,5-AG), and fasting plasma glucose (FPG) levels, after adjustment for potential confounders. Compared with the lowest tertile of HOMA-IR values, the highest tertile was significantly associated with HbA1c and FPG levels after adjustment for potential confounders, both in men (HbA1c: β = 1.83, P = 0.001; FPG: β = 0.49, P < 0.001) and women (HbA1c: β = 0.82, P = 0.008; FPG: β = 0.39, P < 0.001). The highest tertile of HOMA-IR values was inversely associated with 1,5-AG levels compared with the lowest tertile (β = -18.42, P = 0.009) only in men. HOMA-IR values were associated with markers of glycemic control in Japanese subjects without diabetes or obesity. Insulin resistance may influence glycemic control even in a lean, non-diabetic Asian population.

Selection and Socialization Effects in Early Adolescent Alcohol Use: A Propensity Score Analysis

PubMed Central

Scalco, Matthew D.; Trucco, Elisa M.; Coffman, Donna L.; Colder, Craig R.

2015-01-01

The robust correlation between peer and adolescent alcohol use (AU) has been taken as evidence for both socialization and selection processes in the etiology of adolescent AU. Accumulating evidence from studies using a diverse range of methodological and statistical approaches suggests that both processes are involved. A major challenge in testing whether peer AU predicts an adolescent's drinking (socialization) or whether an adolescent's drinking predicts peer AU (selection) is the myriad of potentially confounding factors that might lead to an overestimation of socialization and selection effects. After creating AU transition groups based on peer and adolescent AU across two waves (N = 765; age = 10-15; 53% female), we test whether transitions into AU by adolescents and peers predict later peer and adolescent AU respectively, using (1) propensity score analysis to balance transition groups on 26 potential confounds, (2) a longitudinal design with three waves to establish temporal precedence, and (3) both adolescent (target) and peer self-report of peer AU to disentangle effects attributable to shared reporter bias. Both selection and socialization were supported using both peer self-report of AU and adolescent-report of peer AU. Although cross-sectional analyses suggested peer self-reported models were associated with smaller effects than perceived peer AU, longitudinal analyses suggest a similar sized effect across reporter of peer AU for both selection and socialization. The implications of these findings for the etiology and treatment of adolescent AU are discussed. PMID:25601099

Exercise and the Prevention of Depression: Results of the HUNT Cohort Study.

PubMed

Harvey, Samuel B; Øverland, Simon; Hatch, Stephani L; Wessely, Simon; Mykletun, Arnstein; Hotopf, Matthew

2018-01-01

The purpose of the present study was to address 1) whether exercise provides protection against new-onset depression and anxiety and 2) if so, the intensity and amount of exercise required to gain protection and, lastly, 3) the mechanisms that underlie any association. A "healthy" cohort of 33,908 adults, selected on the basis of having no symptoms of common mental disorder or limiting physical health conditions, was prospectively followed for 11 years. Validated measures of exercise, depression, anxiety, and a range of potential confounding and mediating factors were collected. Undertaking regular leisure-time exercise was associated with reduced incidence of future depression but not anxiety. The majority of this protective effect occurred at low levels of exercise and was observed regardless of intensity. After adjustment for confounders, the population attributable fraction suggests that, assuming the relationship is causal, 12% of future cases of depression could have been prevented if all participants had engaged in at least 1 hour of physical activity each week. The social and physical health benefits of exercise explained a small proportion of the protective effect. Previously proposed biological mechanisms, such as alterations in parasympathetic vagal tone, did not appear to have a role in explaining the protection against depression. Regular leisure-time exercise of any intensity provides protection against future depression but not anxiety. Relatively modest changes in population levels of exercise may have important public mental health benefits and prevent a substantial number of new cases of depression.

Impact of preterm birth on infant mortality for newborns with congenital heart defects: The EPICARD population-based cohort study.

PubMed

Laas, Enora; Lelong, Nathalie; Ancel, Pierre-Yves; Bonnet, Damien; Houyel, Lucile; Magny, Jean-François; Andrieu, Thibaut; Goffinet, François; Khoshnood, Babak

2017-05-15

Congenital heart defects (CHD) and preterm birth (PTB) are major causes of infant mortality. However, limited data exist on risk of mortality associated with PTB for newborns with CHD. Our objective was to assess impact of PTB on risk of infant mortality for newborns with CHD, while taking into account the role of associated anomalies and other potentially confounding factors. We used data on 2172 live births from a prospective population-based cohort study of CHD (the EPICARD Study) and compared neonatal, post-neonatal and overall infant mortality for infants born at <32, 32-34 and 35-36 weeks vs. those born at term (37-41 weeks). Preterm newborns had a 3.8-fold higher risk of infant death (17.9%) than term newborns (4.7%), RR 3.8, 95%CI 2.7-5.2; the risk associated with PTB was more than four-fold higher for neonatal (RR 4.3, 95% CI 2.9-6.6) and three-fold higher for post-neonatal deaths (RR 3.0, 95% CI 1.7-5.2). Survival analysis showed that newborns <35 weeks had a higher risk of mortality, which decreased but persisted after exclusion of associated anomalies and adjustment for potential confounders. Preterm birth is associated with an approximately four-fold higher risk of infant mortality for newborns with CHD. This excess risk appears to be mostly limited to newborns <35 weeks of gestation and is disproportionately due to early deaths.

Is cannabis a risk factor for suicide attempts in men and women with psychotic illness?

PubMed

Waterreus, A; Di Prinzio, P; Badcock, J C; Martin-Iverson, M; Jablensky, A; Morgan, V A

2018-05-16

To investigate whether recent cannabis use by men and women with psychotic disorders was associated with increased risk of suicide attempt, and to determine associated factors, stratified by sex. Data from 1065 men and 725 women interviewed in the Australian national survey of psychosis were analysed to model separately, for each sex, the impact of daily, casual or no past-year cannabis use and other risk factors including age, on a past-year suicide attempt. In the past year, 168 (9.4%) participants attempted suicide. Unadjusted analyses showed daily cannabis users of both sexes had significantly increased odds of attempting suicide compared to non-users. After adjusting for confounding factors, this relationship was no longer significant. Depression had the strongest association with attempting suicide for both sexes. Sex differences in other risk factors were observed. In post hoc analysis, daily cannabis use was associated with higher odds of attempting suicide in older men compared to non-users; this was not found in younger men or women. Associations between past-year cannabis use and suicide attempts were confounded by other factors (depression, loneliness, homelessness and hallucinations). The possibility of greater risk of suicidal behaviour with regular cannabis use for older men should be considered.

Coronary Artery Calcification in Japanese Men in Japan and Hawaii

PubMed Central

Abbott, Robert D.; Ueshima, Hirotsugu; Rodriguez, Beatriz L.; Kadowaki, Takashi; Masaki, Kamal H.; Willcox, Bradley J.; Sekikawa, Akira; Kuller, Lewis H.; Edmundowicz, Daniel; Shin, Chol; Kashiwagi, Atsunori; Nakamura, Yasuyuki; El-Saed, Aiman; Okamura, Tomonori; White, Roger; Curb, J. David

2013-01-01

Explanations for the low prevalence of atherosclerosis in Japan versus United States are often confounded with genetic variation. To help remove such confounding, coronary artery calcification (CAC), a marker of subclinical atherosclerosis, was compared between Japanese men in Japan and Japanese men in Hawaii. Findings are based on risk factor and CAC measurements that were made from 2001 to 2005 in 311 men in Japan and 300 men in Hawaii. Men were aged 40 to 50 years and without cardiovascular disease. After age-adjustment, there was a 3-fold excess in the odds of prevalent CAC scores ≥10 in Hawaii versus Japan (relative odds [RO] = 3.2; 95% confidence interval [CI] = 2.1,4.9). While men in Hawaii had a generally poorer risk factor profile, men in Japan were 4-times more likely to smoke cigarettes (49.5 vs. 12.7%, p<0.001). In spite of marked risk factor differences between the samples, none of the risk factors provided an explanation for the low amounts of CAC in Japan. After risk factor adjustment, the RO of CAC scores ≥10 in Hawaii versus Japan was 4.0 (95% CI = 2.2,7.4). Further studies are needed to identify factors that offer protection against atherosclerosis in Japanese men in Japan. PMID:17728270

Association between borderline dysnatremia and mortality insight into a new data mining approach.

PubMed

Girardeau, Yannick; Jannot, Anne-Sophie; Chatellier, Gilles; Saint-Jean, Olivier

2017-11-22

Even small variations of serum sodium concentration may be associated with mortality. Our objective was to confirm the impact of borderline dysnatremia for patients admitted to hospital on in-hospital mortality using real life care data from our electronic health record (EHR) and a phenome-wide association analysis (PheWAS). Retrospective observational study based on patient data admitted to Hôpital Européen George Pompidou, between 01/01/2008 and 31/06/2014; including 45,834 patients with serum sodium determinations on admission. We analyzed the association between dysnatremia and in-hospital mortality, using a multivariate logistic regression model to adjust for classical potential confounders. We performed a PheWAS to identify new potential confounders. Hyponatremia and hypernatremia were recorded for 12.0% and 1.0% of hospital stays, respectively. Adjusted odds ratios (ORa) for severe, moderate and borderline hyponatremia were 3.44 (95% CI, 2.41-4.86), 2.48 (95% CI, 1.96-3.13) and 1.98 (95% CI, 1.73-2.28), respectively. ORa for severe, moderate and borderline hypernatremia were 4.07 (95% CI, 2.92-5.62), 4.42 (95% CI, 2.04-9.20) and 3.72 (95% CI, 1.53-8.45), respectively. Borderline hyponatremia (ORa = 1.57 95% CI, 1.35-1.81) and borderline hypernatremia (ORa = 3.47 95% CI, 2.43-4.90) were still associated with in-hospital mortality after adjustment for classical and new confounding factors identified through the PheWAS analysis. Borderline dysnatremia on admission are independently associated with a higher risk of in-hospital mortality. By using medical data automatically collected in EHR and a new data mining approach, we identified new potential confounding factors that were highly associated with both mortality and dysnatremia.

Confounding the origin and function of mirror neurons.

PubMed

Rizzolatti, Giacomo

2014-04-01

Cook et al. argue that mirror neurons originate in sensorimotor associative learning and that their function is determined by their origin. Both these claims are hard to accept. It is here suggested that a major role in the origin of the mirror mechanism is played by top-down connections rather than by associative learning.

Chemical weathering indices applied to weathering profiles developed on heterogeneous felsic metamorphic parent rocks

Treesearch

Jason R. Price; Michael A. Velbel

2003-01-01

Chemical weathering indices are commonly used for characterizing weathering profiles by incorporating bulk major element oxide chemistry into a single metric for each sample. Generally, on homogeneous parent rocks, weathering indices change systematically with depth. However, the weathering of heterogeneous metamorphic rocks confounds the relationship between...

Personality and risk for postpartum depressive symptoms.

PubMed

Iliadis, S I; Koulouris, P; Gingnell, M; Sylvén, S M; Sundström-Poromaa, I; Ekselius, L; Papadopoulos, F C; Skalkidou, A

2015-06-01

Postpartum depression (PPD) is a common childbirth complication, affecting 10-15 % of newly delivered mothers. This study aims to assess the association between personality factors and PPD. All pregnant women during the period September 2009 to September 2010, undergoing a routine ultrasound at Uppsala University Hospital, were invited to participate in the BASIC study, a prospective study designed to investigate maternal well-being. Depressive symptoms were assessed with the Edinburgh Postnatal Depression Scale (EPDS) while the Depression Self-Rating Scale (DSRS) was used as a diagnostic tool for major depression. Personality traits were evaluated using the Swedish Universities Scale of Personality (SSP). One thousand thirty-seven non-depressed pregnant women were included in the study. Non-depressed women reporting high levels of neuroticism in late pregnancy were at high risk of developing postpartum depressive symptoms (PPDSs) at 6 weeks and 6 months after delivery, even after adjustment for confounders (adjusted odds ratio (aOR) = 3.4, 95 % confidence interval (CI) 1.8-6.5 and adjusted odds ratio (aOR) = 3.9, 95 % CI 1.9-7.9). The same was true for a DSRS-based diagnosis of major depression at 6 months postpartum. Somatic trait anxiety and psychic trait anxiety were associated with increased risk for PPDS at 6 weeks (aOR = 2.1, 95 % CI 1.2-3.5 and aOR = 1.9, 95 % CI 1.1-3.1), while high scores of mistrust were associated with a twofold increased risk for PPDS at 6 months postpartum (aOR 1.9, 95 % CI 1.1-3.4). Non-depressed pregnant women with high neuroticism scores have an almost fourfold increased risk to develop depressive symptoms postpartum, and the association remains robust even after controlling for most known confounders. Clinically, this could be of importance for health care professionals working with pregnant and newly delivered women.

The use of aquatic bioconcentration factors in ecological risk assessments: Confounding issues, laboratory v/s modeled results

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

Brandt, C.; Blanton, M.L.; Dirkes, R.

1995-12-31

Bioconcentration in aquatic systems is generally taken to refer to contaminant uptake through non-ingestion pathways (i.e., dermal and respiration uptake). Ecological risk assessments performed on aquatic systems often rely on published data on bioconcentration factors to calibrate models of exposure. However, many published BCFs, especially those from in situ studies, are confounded by uptake from ingestion of prey. As part of exposure assessment and risk analysis of the Columbia River`s Hanford Reach, the authors tested a methodology to estimate radionuclide BCFs for several aquatic species in the Hanford Reach of the Columbia River. The iterative methodology solves for BCFs frommore » known body burdens and environmental media concentrations. This paper provides BCF methodology description comparisons of BCF from literature and modeled values and how they were used in the exposure assessment and risk analysis of the Columbia River`s Hanford Reach.« less

A Vision for an International Multi-Sensor Snow Observing Mission

NASA Technical Reports Server (NTRS)

Kim, Edward

2015-01-01

Discussions within the international snow remote sensing community over the past two years have led to encouraging consensus regarding the broad outlines of a dedicated snow observing mission. The primary consensus - that since no single sensor type is satisfactory across all snow types and across all confounding factors, a multi-sensor approach is required - naturally leads to questions about the exact mix of sensors, required accuracies, and so on. In short, the natural next step is to collect such multi-sensor snow observations (with detailed ground truth) to enable trade studies of various possible mission concepts. Such trade studies must assess the strengths and limitations of heritage as well as newer measurement techniques with an eye toward natural sensitivity to desired parameters such as snow depth and/or snow water equivalent (SWE) in spite of confounding factors like clouds, lack of solar illumination, forest cover, and topography, measurement accuracy, temporal and spatial coverage, technological maturity, and cost.

Why Assembling Plant Genome Sequences Is So Challenging

PubMed Central

Claros, Manuel Gonzalo; Bautista, Rocío; Guerrero-Fernández, Darío; Benzerki, Hicham; Seoane, Pedro; Fernández-Pozo, Noé

2012-01-01

In spite of the biological and economic importance of plants, relatively few plant species have been sequenced. Only the genome sequence of plants with relatively small genomes, most of them angiosperms, in particular eudicots, has been determined. The arrival of next-generation sequencing technologies has allowed the rapid and efficient development of new genomic resources for non-model or orphan plant species. But the sequencing pace of plants is far from that of animals and microorganisms. This review focuses on the typical challenges of plant genomes that can explain why plant genomics is less developed than animal genomics. Explanations about the impact of some confounding factors emerging from the nature of plant genomes are given. As a result of these challenges and confounding factors, the correct assembly and annotation of plant genomes is hindered, genome drafts are produced, and advances in plant genomics are delayed. PMID:24832233

The death(s) of close friends and family moderate genetic influences on symptoms of major depressive disorder in adolescents.

PubMed

Gheyara, S; Klump, K L; McGue, M; Iacono, W G; Burt, S A

2011-04-01

Prior work has suggested that genetic influences on major depressive disorder (MDD) may be activated by the experience of negative life events. However, it is unclear whether these results persist when controlling for the possibility of confounding active gene-environment correlations (rGE). We examined a sample of 1230 adopted and biological siblings between the ages of 10 and 20 years from the Sibling Interaction and Behavior Study. MDD was measured via a lifetime DSM-IV symptom count. Number of deaths experienced served as our environmental risk experience. Because this variable is largely independent of the individual's choices/behaviors, we were able to examine gene-environment interactions while circumventing possible rGE confounds. Biometric analyses revealed pronounced linear increases in the magnitude of genetic influences on symptoms of MDD with the number of deaths experienced, such that genetic influences were estimated to be near-zero for those who had experienced no deaths but were quite large in those who had experienced two or more deaths (i.e. accounting for roughly two-thirds of the phenotypic variance). By contrast, shared and non-shared environmental influences on symptoms of MDD were not meaningfully moderated by the number of deaths experienced. Such results constructively replicate prior findings of genetic moderation of depressive symptoms by negative life events, thereby suggesting that this effect is not a function of active rGE confounds. Our findings are thus consistent with the notion that exposure to specific negative life events may serve to activate genetic risk for depression during adolescence.

Insulin-Like Growth Factor 1 (IGF-1) in Parkinson's Disease: Potential as Trait-, Progression- and Prediction Marker and Confounding Factors.

PubMed

Bernhard, Felix P; Heinzel, Sebastian; Binder, Gerhard; Weber, Karin; Apel, Anja; Roeben, Benjamin; Deuschle, Christian; Maechtel, Mirjam; Heger, Tanja; Nussbaum, Susanne; Gasser, Thomas; Maetzler, Walter; Berg, Daniela

2016-01-01

Biomarkers indicating trait, progression and prediction of pathology and symptoms in Parkinson's disease (PD) often lack specificity or reliability. Investigating biomarker variance between individuals and over time and the effect of confounding factors is essential for the evaluation of biomarkers in PD, such as insulin-like growth factor 1 (IGF-1). IGF-1 serum levels were investigated in up to 8 biannual visits in 37 PD patients and 22 healthy controls (HC) in the longitudinal MODEP study. IGF-1 baseline levels and annual changes in IGF-1 were compared between PD patients and HC while accounting for baseline disease duration (19 early stage: ≤3.5 years; 18 moderate stage: >4 years), age, sex, body mass index (BMI) and common medical factors putatively modulating IGF-1. In addition, associations of baseline IGF-1 with annual changes of motor, cognitive and depressive symptoms and medication dose were investigated. PD patients in moderate (130±26 ng/mL; p = .004), but not early stages (115±19, p>.1), showed significantly increased baseline IGF-1 levels compared with HC (106±24 ng/mL; p = .017). Age had a significant negative correlation with IGF-1 levels in HC (r = -.47, p = .028) and no correlation in PD patients (r = -.06, p>.1). BMI was negatively correlated in the overall group (r = -.28, p = .034). The annual changes in IGF-1 did not differ significantly between groups and were not correlated with disease duration. Baseline IGF-1 levels were not associated with annual changes of clinical parameters. Elevated IGF-1 in serum might differentiate between patients in moderate PD stages and HC. However, the value of serum IGF-1 as a trait-, progression- and prediction marker in PD is limited as IGF-1 showed large inter- and intraindividual variability and may be modulated by several confounders.

Insulin-Like Growth Factor 1 (IGF-1) in Parkinson's Disease: Potential as Trait-, Progression- and Prediction Marker and Confounding Factors

PubMed Central

Binder, Gerhard; Weber, Karin; Apel, Anja; Roeben, Benjamin; Deuschle, Christian; Maechtel, Mirjam; Heger, Tanja; Nussbaum, Susanne; Gasser, Thomas; Maetzler, Walter; Berg, Daniela

2016-01-01

Introduction Biomarkers indicating trait, progression and prediction of pathology and symptoms in Parkinson's disease (PD) often lack specificity or reliability. Investigating biomarker variance between individuals and over time and the effect of confounding factors is essential for the evaluation of biomarkers in PD, such as insulin-like growth factor 1 (IGF-1). Materials and Methods IGF-1 serum levels were investigated in up to 8 biannual visits in 37 PD patients and 22 healthy controls (HC) in the longitudinal MODEP study. IGF-1 baseline levels and annual changes in IGF-1 were compared between PD patients and HC while accounting for baseline disease duration (19 early stage: ≤3.5 years; 18 moderate stage: >4 years), age, sex, body mass index (BMI) and common medical factors putatively modulating IGF-1. In addition, associations of baseline IGF-1 with annual changes of motor, cognitive and depressive symptoms and medication dose were investigated. Results PD patients in moderate (130±26 ng/mL; p = .004), but not early stages (115±19, p>.1), showed significantly increased baseline IGF-1 levels compared with HC (106±24 ng/mL; p = .017). Age had a significant negative correlation with IGF-1 levels in HC (r = -.47, p = .028) and no correlation in PD patients (r = -.06, p>.1). BMI was negatively correlated in the overall group (r = -.28, p = .034). The annual changes in IGF-1 did not differ significantly between groups and were not correlated with disease duration. Baseline IGF-1 levels were not associated with annual changes of clinical parameters. Discussion Elevated IGF-1 in serum might differentiate between patients in moderate PD stages and HC. However, the value of serum IGF-1 as a trait-, progression- and prediction marker in PD is limited as IGF-1 showed large inter- and intraindividual variability and may be modulated by several confounders. PMID:26967642

Association between obesity and glomerular hyperfiltration: the confounding effect of smoking and sodium and protein intakes.

PubMed

Ogna, Adam; Forni Ogna, Valentina; Bochud, Murielle; Guessous, Idris; Paccaud, Fred; Burnier, Michel; Wuerzner, Gregoire

2016-04-01

Glomerular hyperfiltration has been suggested as a possible mechanism linking obesity and chronic kidney disease (CKD), independently of classical risk factors. We explored the association of overweight and obesity with glomerular hyperfiltration in a large sample of the Swiss adult population, accounting for several confounders including dietary factors. Data from a 2010 to 2012 cross-sectional population-based survey in Switzerland were used. Creatinine clearance (CrCl) was determined from 24-h urine collection; CrCl > 140 ml/min was used to define glomerular hyperfiltration. Participants were categorized into lean (<25 kg/m(2)), overweight (25-29.9 kg/m(2)) and obese (≥30 kg/m(2)) according to body mass index (BMI). A total of 1339 participants were included in the analysis [median (IQR) age 49.4 (34.3-63.5) years, 48.9 % men]. The prevalences of overweight and obesity were 32.2 and 14.2 %, respectively. Median CrCl was 102[84-121] ml/min in lean, 110 [87-136] ml/min in overweight and 124 [97-150] ml/min in obese participants (p < 0.001). The prevalence of glomerular hyperfiltration increased across BMI categories (10.4, 20.8 and 34.7 %, respectively; p < 0.001). This positive association remained significant after adjusting for age, sex, hypertension, diabetes, smoking and dietary factors (sodium and protein intakes): odds ratio [95 %CI] 2.39 [1.52-3.76] (p < 0.001) for overweight versus lean and 4.10[2.31-7.27] (p < 0.001) for obesity versus lean. BMI categories and glomerular hyperfiltration are positively associated, independently of other known CKD risk factors and dietary confounders, suggesting that glomerular hyperfiltration may represent an early renal phenotype in obesity. Our observations confirm the significant association of glomerular hyperfiltration with sodium and protein intakes and identify sodium intake as an important modifying factor of the association between hyperfiltration and obesity.

Psychosocial working conditions, occupational groups, and risk of disability pension due to mental diagnoses: a cohort study of 43,000 Swedish twins.

PubMed

Samuelsson, Åsa; Ropponen, Annina; Alexanderson, Kristina; Svedberg, Pia

2013-07-01

The aim of this study was to investigate associations between psychosocial working conditions, occupational groups defined by sector, and disability pension (DP) with mental diagnoses while accounting for familial confounding. A prospective population-based cohort study was conducted, including all Swedish twins who, in January 1993, were living and working in Sweden and not on old-age pension or DP (N=42 715). The twins were followed from 1993-2008 regarding DP. Data on DP, exposures, and covariates were obtained from national registries. Cox proportional hazards regression models with hazard ratios (HR) and 95% confidence intervals (95% CI) were constructed for the whole cohort, and for discordant twin pairs. The associations for the whole cohort between DP with mental diagnoses and (i) job demands (HR 1.23, 95% CI 1.06-1.43), (ii) job control (HR 0.91, 95% CI 0.83-0.99), (iii) healthcare and social work (HR 1.41, 95% CI 1.04-1.92), and (iv) service and military work (HR 2.07, 95% CI 1.37-3.14) remained after accounting for possible confounders, including familial factors, while the associations between DP and (i) social support, (ii) type of jobs, and (iii) some of the occupational groups were attenuated, becoming non-significant. In the discordant twin pair analyses, commercial work was significantly associated with lower risk of DP (HR 0.55, 95% CI 0.32-0.95). One unit increase in job demands and working in the occupational groups healthcare and social work or service and military work seem to be risk factors of DP with mental diagnoses, independent from various background factors including familial ones. However, one unit increase in job control or working in commercial work seem to be protective factors of such DP, accounting for confounding factors of this study.

Examining confounding by diet in the association between perfluoroalkyl acids and serum cholesterol in pregnancy

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

Skuladottir, Margret; Ramel, Alfons; Unit for Nutrition Research, Landspitali National University Hospital, Reykjavik

Background: Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have consistently been associated with higher cholesterol levels in cross sectional studies. Concerns have, however, been raised about potential confounding by diet and clinical relevance. Objective: To examine the association between concentrations of PFOS and PFOA and total cholesterol in serum during pregnancy taking into considerations confounding by diet. Methods: 854 Danish women who gave birth in 1988–89 and provided a blood sample and reported their diet in week 30 of gestation. Results: Mean serum PFOS, PFOA and total cholesterol concentrations were 22.3 ng/mL, 4.1 ng/mL and 7.3 mmol/L, respectively. Maternal dietmore » was a significant predictor of serum PFOS and PFOA concentrations. In particular intake of meat and meat products was positively associated while intake of vegetables was inversely associated (P for trend <0.01) with relative difference between the highest and lowest quartile in PFOS and PFOA concentrations ranging between 6% and 25% of mean values. After adjustment for dietary factors both PFOA and PFOS were positively and similarly associated with serum cholesterol (P for trend ≤0.01). For example, the mean increase in serum cholesterol was 0.39 mmol/L (95%CI: 0.09, 0.68) when comparing women in the highest to lowest quintile of PFOA concentrations. In comparison the mean increase in serum cholesterol was 0.61 mmol/L (95%CI: 0.17, 1.05) when comparing women in the highest to lowest quintile of saturated fat intake. Conclusion: In this study associations between PFOS and PFOA with serum cholesterol appeared unrelated to dietary intake and were similar in magnitude as the associations between saturated fat intake and serum cholesterol. - Highlights: • PFOS and PFOA have consistently been linked with raised serum cholesterol • Clinical relevance remains uncertain and confounding by diet has been suggested • The aim of this study was to address these issues in a cohort of 854 pregnant women • With detailed dietary information we found no indication of such confounding • As predictors cholesterol PFOSA and PFOA were similar to other known risk factors.« less

Brief Communication: Latent toxoplasmosis and salivary testosterone concentration--important confounding factors in second to fourth digit ratio studies.

PubMed

Flegr, Jaroslav; Lindová, Jitka; Pivoñková, Vera; Havlícek, Jan

2008-12-01

A sexually dimorphic characteristic, the second to fourth digit ratio (2D:4D ratio), has been shown to reflect the prenatal concentration of sex steroid hormones and to correlate with many personality, physiological, and life history traits. The correlations are usually stronger for the right than the left hand. Most studies have shown that the 2D:4D ratio does not vary with age or postnatal concentration of sex steroid hormones. Recently, a strong association between left hand 2D:4D ratio and infection with a common human parasite Toxoplasma has been reported. We hypothesized that the confounding effect of Toxoplasma infection on left hand 2D:4D ratio could be responsible for the stronger association between different traits and right hand rather than left hand 2D:4D ratio. This confounding effect of toxoplasmosis could also be responsible for the difficulty in finding an association between 2D:4D ratio and age or postnatal steroid hormone concentration. To test this hypothesis, we analyzed the association between sex and age and 2D:4D ratio in a population of 194 female and 106 male students with and without controlling for the confounding variables of Toxoplasma infection and testosterone concentration. Our results showed that the relationship between age and sex and 2D:4D ratio increased sharply when Toxoplasma infection and testosterone concentration were controlled. These results suggest that left hand 2D:4D ratio is more susceptible to postnatal influences and that the confounding factors of Toxoplasma infection, testosterone concentration and possibly also age, should be controlled in future 2D:4D ratio studies. Because of a stronger 2D:4D dimorphism in Toxoplasma-infected than Toxoplasma-free subjects, we predict that 2D:4D ratio dimorphism as well as right hand/left hand 2D:4D ratio dimorphism will be higher in countries with a high prevalence of Toxoplasma infection than in those with a low prevalence. (c) 2008 Wiley-Liss, Inc.

Statin adherence and risk of acute cardiovascular events among women: a cohort study accounting for time-dependent confounding affected by previous adherence.

PubMed

Lavikainen, Piia; Helin-Salmivaara, Arja; Eerola, Mervi; Fang, Gang; Hartikainen, Juha; Huupponen, Risto; Korhonen, Maarit Jaana

2016-06-03

Previous studies on the effect of statin adherence on cardiovascular events in the primary prevention of cardiovascular disease have adjusted for time-dependent confounding, but potentially introduced bias into their estimates as adherence and confounders were measured simultaneously. We aimed to evaluate the effect when accounting for time-dependent confounding affected by previous adherence as well as time sequence between factors. Retrospective cohort study. Finnish healthcare registers. Women aged 45-64 years initiating statin use for primary prevention of cardiovascular disease in 2001-2004 (n=42 807). Acute cardiovascular event defined as a composite of acute coronary syndrome and acute ischaemic stroke was our primary outcome. Low-energy fractures were used as a negative control outcome to evaluate the healthy-adherer effect. During the 3-year follow-up, 474 women experienced the primary outcome event and 557 suffered a low-energy fracture. The causal HR estimated with marginal structural model for acute cardiovascular events for all the women who remained adherent (proportion of days covered ≥80%) to statin therapy during the previous adherence assessment year was 0.78 (95% CI: 0.65 to 0.94) when compared with everybody remaining non-adherent (proportion of days covered <80%). The result was robust against alternative model specifications. Statin adherers had a potentially reduced risk of experiencing low-energy fractures compared with non-adherers (HR 0.90, 95% CI 0.76 to 1.07). Our study, which took into account the time dependence of adherence and confounders, as well as temporal order between these factors, is support for the concept that adherence to statins in women in primary prevention decreases the risk of acute cardiovascular events by about one-fifth in comparison to non-adherence. However, part of the observed effect of statin adherence on acute cardiovascular events may be due to the healthy-adherer effect. 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/

Occupational exposure and ovarian cancer risk.

PubMed

Le, Nhu D; Leung, Andy; Brooks-Wilson, Angela; Gallagher, Richard P; Swenerton, Kenneth D; Demers, Paul A; Cook, Linda S

2014-07-01

Relatively little work has been done concerning occupational risk factors in ovarian cancer. Although studies conducted in occupational settings have reported positive associations, their usefulness is generally limited by the lack of information on important confounders. In a population-based case-control study, we assessed risk for developing epithelial ovarian cancer (EOC) associated with occupational exposure while accounting for important confounders. Participants were identified through provincial population-based registries. Lifetime occupational history and information on potential confounding factors were obtained through a self-administered questionnaire. Unconditional logistic regression and the likelihood ratio test were used to assess EOC risk with each occupation (or industry), relative to all other occupations (or industries), adjusting for potential confounders including body mass index, oral contraceptive use, menopausal hormone therapy, parity, age at first childbirth, age at menarche, age at menopause, family history of breast and ovarian cancer in mother and sister(s), tubal ligation, partial oophorectomy, and hysterectomy. Occupations and industries were coded according to the Canadian Standard Occupational Classification (SOC) and Standard Industrial Classification (SIC). Significant excess risk was observed for several groups of teaching occupations, including SOC 27, teaching and related (adjusted OR 1.77, 95% CI 1.15-2.81) and SOC 279, other teaching and related (adjusted OR 3.11, 95% CI 1.35-8.49). Significant excess was also seen for a four-digit occupational group SOC 4131, bookkeepers and accounting clerks (adjusted OR 2.80, 95% CI 1.30-6.80). Industrial sub-groups showing significant excess risk included SIC 65, other retail stores (adjusted OR 2.19, 95 % CI 1.16-4.38); SIC 85, educational service (adjusted OR 1.45, 95% CI 1.00-2.13); and SIC 863, non-institutional health services (adjusted OR 2.54, 95% CI 1.13-6.52). Our study found an elevated EOC risk for teaching occupations and is the first study to observe such an increased risk after adjustment for potential confounders. Further studies with more detailed assessment of the work environment and unique lifestyle characteristics may be fruitful in elucidating this etiology.

Childhood Medical and Behavioral Consequences of Maternal Cocaine Use1

PubMed Central

Singer, Lynn; Farkas, Kathleen; Kliegman, Robert

2014-01-01

Reviewed available studies of the impact of fetal cocaine exposure on child medical and developmental outcome, as well as the current status of clinical psychological interventions and research strategies. Current studies are inconclusive but suggest that prenatal exposure to crack-cocaine can have significant effects on the growth and neurological development of the infant, with the potential of later learning and behavioral disabilities. Social-environmental correlates of maternal cocaine use are confounding factors with known negative effects on child outcome. Large, population-based studies using multivariate analyses are needed to determine the independent effects of cocaine on child outcome relative to other confounding variables. PMID:1382125

Pre-study feasibility and identifying sensitivity analyses for protocol pre-specification in comparative effectiveness research.

PubMed

Girman, Cynthia J; Faries, Douglas; Ryan, Patrick; Rotelli, Matt; Belger, Mark; Binkowitz, Bruce; O'Neill, Robert

2014-05-01

The use of healthcare databases for comparative effectiveness research (CER) is increasing exponentially despite its challenges. Researchers must understand their data source and whether outcomes, exposures and confounding factors are captured sufficiently to address the research question. They must also assess whether bias and confounding can be adequately minimized. Many study design characteristics may impact on the results; however, minimal if any sensitivity analyses are typically conducted, and those performed are post hoc. We propose pre-study steps for CER feasibility assessment and to identify sensitivity analyses that might be most important to pre-specify to help ensure that CER produces valid interpretable results.

Effectiveness of electronic stability control on single-vehicle accidents.

PubMed

Lyckegaard, Allan; Hels, Tove; Bernhoft, Inger Marie

2015-01-01

This study aims at evaluating the effectiveness of electronic stability control (ESC) on single-vehicle injury accidents while controlling for a number of confounders influencing the accident risk. Using police-registered injury accidents from 2004 to 2011 in Denmark with cars manufactured in the period 1998 to 2011 and the principle of induced exposure, 2 measures of the effectiveness of ESC were calculated: The crude odds ratio and the adjusted odds ratio, the latter by means of logistic regression. The logistic regression controlled for a number of confounding factors, of which the following were significant. For the driver: Age, gender, driving experience, valid driving license, and seat belt use. For the vehicle: Year of registration, weight, and ESC. For the accident surroundings: Visibility, light, and location. Finally, for the road: Speed limit, surface, and section characteristics. The present study calculated the crude odds ratio for ESC-equipped cars of getting in a single-vehicle injury accident as 0.40 (95% confidence interval [CI], 0.34-0.47) and the adjusted odds ratio as 0.69 (95% CI, 0.54-0.88). No difference was found in the effectiveness of ESC across the injury severity categories (slight, severe, and fatal). In line with previous results, this study concludes that ESC reduces the risk for single-vehicle injury accidents by 31% when controlling for various confounding factors related to the driver, the car, and the accident surroundings. Furthermore, it is concluded that it is important to control for human factors (at a minimum age and gender) in analyses where evaluations of this type are performed.

Prenatal Maternal Stress Associated with ADHD and Autistic Traits in early Childhood

PubMed Central

Ronald, Angelica; Pennell, Craig E.; Whitehouse, Andrew J. O.

2010-01-01

Research suggests that offspring of mothers who experience high levels of stress during pregnancy are more likely to have problems in neurobehavioral development. There is preliminary evidence that prenatal maternal stress (PNMS) is a risk factor for both autism and attention deficit hyperactivity disorder (ADHD), however most studies do not control for confounding factors and no study has investigated PNMS as a risk factor for behaviors characteristic of these disorders in early childhood. A population cohort of 2900 pregnant women were recruited before their 18th week of pregnancy and investigated prospectively. Maternal experience of stressful life events was assessed during pregnancy. When offspring were age 2 years, mothers completed the child behavior checklist. Multiple regression showed that maternal stressful events during pregnancy significantly predicted ADHD behaviors in offspring, after controlling for autistic traits and other confounding variables, in both males (p = 0.03) and females (p = 0.01). Similarly, stressful events during pregnancy significantly predicted autistic traits in the offspring after controlling for ADHD behaviors and confounding variables, in males only (p = 0.04). In conclusion, this study suggests that PNMS, in the form of typical stressful life events such as divorce or a residential move, show a small but significant association with both autistic traits and ADHD behaviors independently, in offspring at age 2 years, after controlling for multiple antenatal, obstetric, postnatal, and sociodemographic covariates. This finding supports future research using epigenetic, cross-fostering, and gene–environment interaction designs to identify the causal processes underlying this association. PMID:21833278

Approaches for Strengthening Causal Inference Regarding Prenatal Risk Factors for Childhood Behavioural and Psychiatric Disorders

ERIC Educational Resources Information Center

Lewis, Sarah J.; Relton, Caroline; Zammit, Stanley; Smith, George Davey

2013-01-01

Background: The risk of childhood behavioural and psychiatric diseases could be substantially reduced if modifiable risk factors for these disorders were identified. The critical period for many of these exposures is likely to be in utero as this is the time when brain development is most rapid. However, due to confounding and other limitations of…

Unraveling the Effect of Genes and Environment in the Transmission of Parental Antisocial Behavior to Children's Conduct Disturbance, Depression and Hyperactivity

ERIC Educational Resources Information Center

Silberg, Judy L.; Maes, Hermine; Eaves, Lindon J.

2012-01-01

Background: A critical issue in devising effective interventions for the treatment of children's behavioral and emotional problems identifying genuine family environmental factors that place children at risk. In most twin and family studies, environmental factors are confounded with both direct genetic risk from parents and the indirect effect of…

Arnica montana experimental studies: confounders and biases?

PubMed

Bellavite, Paolo; Marzotto, Marta; Bonafini, Clara

2018-03-01

Arnica montana is a popular traditional remedy widely used in complementary and alternative medicine, in part for its wound-healing properties. The authors recently showed that this plant extract and several of its homeopathic dilutions are able to modify the expression of a series of genes involved in inflammation and connective tissue regeneration. Their studies opened a debate, including criticisms to the "errors" in the methods used and the "confounders and biases". Here the authors show that the criticisms raised on methodology and statistics are not consistent and cannot be considered pertinent. The present comment also updates and reviews information concerning the action of A. montana dilutions in human macrophage cells while summarizing the major experimental advances reported on this interesting medicinal plant. Copyright © 2018. Published by Elsevier B.V.

Educational differences in cardiovascular mortality: The role of shared family factors and cardiovascular risk factors.

PubMed

Kjøllesdal, M K R; Ariansen, I; Mortensen, L H; Davey Smith, G; Næss, Ø

2016-12-01

To explore the confounding effects of early family factors shared by siblings and cardiovascular risk factors in midlife on the educational differences in mortality from cardiovascular disease (CVD). Data from national and regional health surveys in Norway (1974-2003) were linked with data from the Norwegian Family Based Life Course Study, the National Educational Registry and the Cause of Death Registry. The study population consisted of participants with at least one full sibling among the health survey participants ( n=271,310). Data were available on CVD risk factors, including weight, height, blood pressure, total cholesterol and smoking. The hazards ratio (HR) of CVD mortality was 3.44 (95% confidence interval (CI) 2.98-3.96) in the lowest educational group relative to the highest. The HRs were little altered in the within-sibship analyses. Adjusted for risk factors, the HR for CVD mortality in the cohort analyses was 2.05 (CI 1.77-2.37) in the lowest educational group relative to the highest. The respective HR in the within-sibship analyses was 2.46 (CI 1.48-2.24). Using a sibling design, we did not find that the association between education and CVD mortality was confounded by early life factors shared by siblings, but it was explained to a large extent by CVD risk factors. These results suggest that reducing levels of CVD risk factors could have the greatest effect on mortality in less well-educated people.

WHAT TO DO IF THERE IS NO REFERENCE SYSTEM

EPA Science Inventory

Efficient management and regulation of anthropogenic point source inputs requires a demonstrated and measurable ecological effect. In all ecosystems, the evaluation of anthropogenic effects is confounded by the effects of naturally existing environmental factors and river nonpoin...

Use of a pacifier and behavioural features in 2-4-month-old infants.

PubMed

Kelmanson, I A

1999-11-01

This study aimed to analyse a possible association between the use of a pacifier and particular behavioural features in 2-4-month-old infants as estimated by the means of the Early Infancy Temperament Questionnaire (EITQ). It comprised 192 randomly selected clinically healthy infants born in St Petersburg in 1997-1998. The mothers were asked to complete the questionnaires addressing infant, maternal and major demographic characteristics, and childcare practices, with particular emphasis on the use of a pacifier, as well as to fill in the EITQ. The EITQ scores nine different aspects of infant temperament: activity, rhythmicity, approach, adaptability, intensity, mood, persistence, distractibility and threshold. A total of 117 of 192 infants (60.9%) used pacifiers, and they appeared to have more rhythmic behaviour than non-users. This effect remained after adjustment was made for major potential confounding and/or modifying factors, including gender, parity, details from perinatal history and familial social background, feeding pattern, bed sharing and room sharing. With the exception of rhythmicity, no significant association was found between the use of a pacifier and any other particular feature of infant temperament. Use of a pacifier may be associated with higher rhythmicity in 2-4-month-old infants.

Effectiveness and confounding factors of penetrating astigmatic keratotomy in clinical practice

PubMed Central

Yen, Chu-Yu; Tseng, Gow-Lieng

2018-01-01

Abstract Rationale: Penetrating astigmatic keratotomy (penetrating AK) is a well-known method to correct corneal astigmatism but rarely be performed nowadays. This article reevaluated the clinical effectiveness and confounding factors of penetrating AK. Patient concerns: Penetrating AK has been introduced to serve as one alternative operation for astigmatism correction, and is thought to have the potential advantage of being more affordable and easy to perform. The purpose of our study is to evaluate the effectiveness and confounding factors of penetrating AK. Diagnoses: The chart of 95 patients with corneal astigmatism (range: 0.75–3.25 diopters [D]) who received penetrating AK from January 2014 to December 2016 was collected. The corneal astigmatism were measured by an autokeratometer (Topcon KR8100PA topographer-autorefractor), and repeated with manual keratometer in low reproducibility cases. Interventions: All patients received penetrating AK by an experienced ophthalmologist (Dr. Gow-Lieng Tseng, MD, PHD) in the operation room. Among which, 66 patients received penetrating AK with phacoemulsification simultaneously (group A), whereas 29 patients received penetrating AK at least 3 months after phacoemulsification (group B). After excluding the patients combined with other procedures or lost followed up, 79 patients are remaining for analysis. The outcome was evaluated by net correction, the difference between preoperative corneal astigmatism (PCA) and residual corneal astigmatism (RCA). Two sample t tests and Pearson test were used for effectiveness evaluation. For confounding factors, multivariate linear regression was used for statistical analysis. Outcomes: The mean preoperative and postoperative refractive cylinders were 1.97 ± 0.77 and 1.08 ± 0.64 D, respectively, in group A and 2.62 ± 1.05 and 1.51 ± 0.89 D in group B. There were no statistically significant differences in net correction between these two groups (0.9 ± 0.66 vs. 1.1 ± 0.69, P = .214). Higher PCA were associated with higher net correction in both group A (P = .002) and group B (P = .019). Compound myopic astigmatism caused less net correction than others only in group A (P = 0.031). Lessons: Penetrating AK is an accessible, affordable, and effective way to correct corneal astigmatism. The results of this procedure are comparable to modern methods in patients with low to moderate corneal astigmatism. PMID:29369200

'Mechanical restraint-confounders, risk, alliance score': testing the clinical validity of a new risk assessment instrument.

PubMed

Deichmann Nielsen, Lea; Bech, Per; Hounsgaard, Lise; Alkier Gildberg, Frederik

2017-08-01

Unstructured risk assessment, as well as confounders (underlying reasons for the patient's risk behaviour and alliance), risk behaviour, and parameters of alliance, have been identified as factors that prolong the duration of mechanical restraint among forensic mental health inpatients. To clinically validate a new, structured short-term risk assessment instrument called the Mechanical Restraint-Confounders, Risk, Alliance Score (MR-CRAS), with the intended purpose of supporting the clinicians' observation and assessment of the patient's readiness to be released from mechanical restraint. The content and layout of MR-CRAS and its user manual were evaluated using face validation by forensic mental health clinicians, content validation by an expert panel, and pilot testing within two, closed forensic mental health inpatient units. The three sub-scales (Confounders, Risk, and a parameter of Alliance) showed excellent content validity. The clinical validations also showed that MR-CRAS was perceived and experienced as a comprehensible, relevant, comprehensive, and useable risk assessment instrument. MR-CRAS contains 18 clinically valid items, and the instrument can be used to support the clinical decision-making regarding the possibility of releasing the patient from mechanical restraint. The present three studies have clinically validated a short MR-CRAS scale that is currently being psychometrically tested in a larger study.

Is the Association of Subjective SES and Self-Rated Health Confounded by Negative Mood? An Experimental Approach

PubMed Central

Kraus, Michael W.; Adler, Nancy; David Chen, Teh-Way

2012-01-01

Objective Lower subjective socioeconomic status (SSS) consistently shows associations with poorer health with the strongest relationships emerging with global self-rated health. Though often interpreted as reflecting the impact of low SSS on health, the association could also arise from confounding SSS with negative affect. In this research we sought to determine if negative affect confounds, or alternatively, is on the causal pathway linking SSS to self-rated health. Methods 300 adult participants—recruited from throughout the United States—were randomized to experience sadness, shame, or a neutral mood induction wherein they wrote about and visualized a particularly emotionally evocative event. Participants subsequently completed measures of SSS, self-rated health, depression, and negative mood. Results Consistent with predictions, neither SSS scores nor the association of SSS with self-rated health, depression, and chronic negative affect differed by mood induction condition, controlling for demographic factors that covary with SSS (e.g., age, gender, education, income). Moreover, chronic negative affect partially explained the relationship between SSS and self-rated health, independent of manipulated mood. Conclusions These findings support the utility of the measurement of SSS, and provide evidence suggesting that chronic negative affect is a likely mediator of the SSS association with global health rather than a confounder. PMID:22329426

Accounting for context in studies of health inequalities: a review and comparison of analytic approaches.

PubMed

Schempf, Ashley H; Kaufman, Jay S

2012-10-01

A common epidemiologic objective is to evaluate the contribution of residential context to individual-level disparities by race or socioeconomic position. We reviewed analytic strategies to account for the total (observed and unobserved factors) contribution of environmental context to health inequalities, including conventional fixed effects (FE) and hybrid FE implemented within a random effects (RE) or a marginal model. To illustrate results and limitations of the various analytic approaches of accounting for the total contextual component of health disparities, we used data on births nested within neighborhoods as an applied example of evaluating neighborhood confounding of racial disparities in gestational age at birth, including both a continuous and a binary outcome. Ordinary and RE models provided disparity estimates that can be substantially biased in the presence of neighborhood confounding. Both FE and hybrid FE models can account for cluster level confounding and provide disparity estimates unconfounded by neighborhood, with the latter having greater flexibility in allowing estimation of neighborhood-level effects and intercept/slope variability when implemented in a RE specification. Given the range of models that can be implemented in a hybrid approach and the frequent goal of accounting for contextual confounding, this approach should be used more often. Published by Elsevier Inc.

Experimental and clinical evidence for loss of effect (tolerance) during prolonged treatment with antiepileptic drugs.

PubMed

Löscher, Wolfgang; Schmidt, Dieter

2006-08-01

Development of tolerance (i.e., the reduction in response to a drug after repeated administration) is an adaptive response of the body to prolonged exposure to the drug, and tolerance to antiepileptic drugs (AEDs) is no exception. Tolerance develops to some drug effects much more rapidly than to others. The extent of tolerance depends on the drug and individual (genetic?) factors. Tolerance may lead to attenuation of side effects but also to loss of efficacy of AEDs and is reversible after discontinuation of drug treatment. Different experimental approaches are used to study tolerance in laboratory animals. Development of tolerance depends on the experimental model, drug, drug dosage, and duration of treatment, so that a battery of experimental protocols is needed to evaluate fully whether tolerance to effect occurs. Two major types of tolerance are known. Pharmacokinetic (metabolic) tolerance, due to induction of AED-metabolizing enzymes has been shown for most first-generation AEDs, and is easy to overcome by increasing dosage. Pharmacodynamic (functional) tolerance is due to "adaptation" of AED targets (e.g., by loss of receptor sensitivity) and has been shown experimentally for all AEDs that lose activity during prolonged treatment. Functional tolerance may lead to complete loss of AED activity and cross-tolerance to other AEDs. Convincing experimental evidence indicates that almost all first-, second-, and third-generation AEDs lose their antiepileptic activity during prolonged treatment, although to a different extent. Because of diverse confounding factors, detecting tolerance in patients with epilepsy is more difficult but can be done with careful assessment of decline during long-term individual patient response. After excluding confounding factors, tolerance to antiepileptic effect for most modern and old AEDs can be shown in small subgroups of responders by assessing individual or group response. Development of tolerance to the antiepileptic activity of an AED may be an important reason for failure of drug treatment. Knowledge of tolerance to AED effects as a mechanism of drug resistance in previous responders is important for patients, physicians, and scientists.

The Mythical Retention Chart and the Corruption of Dale's Cone of Experience

ERIC Educational Resources Information Center

Subramony, Deepak Prem; Molenda, Michael; Betrus, Anthony K.; Thalheimer, Will

2014-01-01

In response to the wide-scale proliferation of "the cone of learning"--a fanciful retention chart confounded with Dale's Cone of Experience--the authors make four major claims debunking this fantasy and provide documentary evidence to support these claims. The first claim is that the data in the mythical retention chart do not make…

Behavioral lifestyle and mental health status of Japanese factory workers.

PubMed

Ezoe, S; Morimoto, K

1994-01-01

Lifestyle factors, sometimes associated with physical health and mortality, have also been known to be associated with mental health status. This study seeks to correlate behavioral lifestyles with major components of mental health among Japanese factory workers. We administered the 28-item version of the General Health Questionnaire (GHQ-28) and a questionnaire concerning eight personal health practices to 2,132 male and 668 female factory workers at a camera-manufacturing company in Japan. There were strong negative relationships of a higher total number of favorable lifestyles as indicated by the Health Practice Index (HPI) to psychological distress and its components: somatic symptoms, anxiety-insomnia, and social dysfunction. After controlling for the effects of confounding factors that included age, marital status, and somatic condition, multiple logistic regression analysis indicated that five of the eight health factors among male workers--mental stress, nutritional balance, eating breakfast regularly, physical exercise, and working hours--were significantly related to the grade of psychological distress or its three components. Among female workers, five health practices, i.e., mental stress, physical exercise, sleeping hours, working hours, and cigarette smoking, were significantly associated with the grade of psychological distress or its three components. Good health practices might be individually and as a whole associated with better mental health status in factory workers.

THE LINK BETWEEN EARLY ONSET DRINKING AND EARLY ONSET ALCOHOL-IMPAIRED DRIVING IN YOUNG MALES

PubMed Central

Zhang, Lening; Wieczorek, William F.; Welte, John W.

2014-01-01

Background Young drivers represent a disproportionate number of the individuals involved in alcohol-impaired driving. Although there is a known association between drinking and alcohol-impaired driving in young drivers, the link between early onset drinking and early onset alcohol-impaired driving has not been explored. Objectives The present study aimed to assess this link along with potentially confounding factors. Methods The assessment used a proportional hazards model with data collected from the Buffalo Longitudinal Study of Young Men, a population based sample of 625 males at ages of 16–19 years old. Results Controlling for the effects of potentially relevant confounds, the early onset of drinking was the most influential factor in predicting the early onset of alcohol-impaired driving. Race and the early onset of other forms of delinquency also played a significant role in the early onset of alcohol-impaired driving. Conclusion Preventing an early start of drinking among adolescents may be the most critical factor to address in preventing an early start of alcohol-impaired driving. PMID:24766089

Older men with higher self-rated socioeconomic status have shorter telomeres

PubMed Central

Woo, Jean; Suen, Eddie W. C.; Leung, Jason C. S.; Tang, Nelson L. S.; Ebrahim, Shah

2009-01-01

Background: previous studies examining the relationship between socioeconomic status and telomere length showed conflicting results, one study finding shorter telomere length in subjects with lower socioeconomic status and one showing no relationship. Design: cross-sectional study. Setting: community-living elderly Chinese in Hong Kong. Objective: this study examines the relationship between self-rated social economic status and telomere length in Hong Kong Chinese men and women aged 65 years and over living in the community. Subjects and method: information was collected from 958 men and 978 women regarding possible confounding factors such as the presence of chronic diseases, smoking, physical activity level, dietary intake and body mass index. Telomere length was measured by quantitative PCR. Result: in men only, after adjustment for age and other confounding factors, a higher ranking in community standing was associated with shorter telomere length. Conclusion: men with higher self-rated socioeconomic status have shorter telomeres, possibly mediated through psychosocial rather than lifestyle factors or the presence of chronic disease. There may be cultural ethnic and age-related differences in social determinants of health. PMID:19556325

Learning Effective Connectivity Network Structure from fMRI Data Based on Artificial Immune Algorithm

PubMed Central

Ji, Junzhong; Liu, Jinduo; Liang, Peipeng; Zhang, Aidong

2016-01-01

Many approaches have been designed to extract brain effective connectivity from functional magnetic resonance imaging (fMRI) data. However, few of them can effectively identify the connectivity network structure due to different defects. In this paper, a new algorithm is developed to infer the effective connectivity between different brain regions by combining artificial immune algorithm (AIA) with the Bayes net method, named as AIAEC. In the proposed algorithm, a brain effective connectivity network is mapped onto an antibody, and four immune operators are employed to perform the optimization process of antibodies, including clonal selection operator, crossover operator, mutation operator and suppression operator, and finally gets an antibody with the highest K2 score as the solution. AIAEC is then tested on Smith’s simulated datasets, and the effect of the different factors on AIAEC is evaluated, including the node number, session length, as well as the other potential confounding factors of the blood oxygen level dependent (BOLD) signal. It was revealed that, as contrast to other existing methods, AIAEC got the best performance on the majority of the datasets. It was also found that AIAEC could attain a relative better solution under the influence of many factors, although AIAEC was differently affected by the aforementioned factors. AIAEC is thus demonstrated to be an effective method for detecting the brain effective connectivity. PMID:27045295

Racial difference in lung function in African-American and White children: effect of anthropometric, socioeconomic, nutritional, and environmental factors.

PubMed

Harik-Khan, Raida I; Muller, Denis C; Wise, Robert A

2004-11-01

African-American children have lower lung volumes than White children. However, the contributions of anthropometric, socioeconomic, nutritional, and environmental factors to this difference are unknown. From participants in the Third National Health and Nutrition Examination Survey (1988-1994), the authors selected 1,462 healthy nonsmoking children (623 White and 839 African-American) aged 8-17 years. The African-American children were taller and heavier but had lower lung function. African Americans were poorer and had lower levels of the antioxidant vitamins A and C and alpha-carotene. The authors performed regression analyses using data on anthropometric, socioeconomic, and nutritional factors and smoke exposure. Adjustment for sitting height explained 42-53% of the racial difference. Socioeconomic factors and antioxidant vitamin levels accounted for an additional 7-10%. Overall, the authors could account for only 50-63% of the racial difference. Exposure to tobacco in the home was weakly associated with forced expiratory volume in 1 second in girls, accounting for 1% of the difference. In children aged 8-12 years (n = 752), birth weight explained 3-5% of the racial difference, whereas in-utero exposure to maternal smoking had no significant effect. The authors conclude that in healthy children, the major explanatory variable for the racial difference in lung function is body habitus; socioeconomic, nutritional, and environmental confounders play a smaller role.

Birth weight and exposure to kitchen wood smoke during pregnancy in rural Guatemala.

PubMed

Boy, Erick; Bruce, Nigel; Delgado, Hernán

2002-01-01

In this study, we aimed to establish whether domestic use of wood fuel is associated with reduced birth weight, independent of key maternal, social, and economic confounding factors. We studied 1,717 women and newborn children in rural and urban communities in rural Guatemala. We identified subjects through home births reported by traditional birth attendants in six rural districts (n = 572) and all public hospital births in Quetzaltenango city during the study period (n = 1,145). All were seen within 72 hr of delivery, and data were collected on the type of household fuel used, fire type, and socioeconomic and other confounding factors. Smoking among women in the study community was negligible. Children born to mothers habitually cooking on open fires (n = 861) had the lowest mean birth weight of 2,819 g [95% confidence interval (CI), 2,790-2,848]; those using a chimney stove (n = 490) had an intermediate mean of 2,863 g (95% CI, 2,824-2,902); and those using the cleanest fuels (electricity or gas, n = 365) had the highest mean of 2,948 g (95% CI, 2,898-2,998) (p< 0.0001). The percentage of low birth weights (< 500 g) in these three groups was 19.9% (open fire), 16.8% (chimney stove), and 16.0% (electricity/gas), (trend (p = 0.08). Confounding factors were strongly associated with fuel type, but after adjustment wood users still had a birth weight 63 g lower (p = 0.05; 95% CI, 0.4-126). This is the first report of an association between biofuel use and reduced birth weight in a human population. Although there is potential for residual confounding despite adjustment, the better-documented evidence on passive smoking and a feasible mechanism through carbon monoxide exposure suggest this association may be real. Because two-thirds of households in developing countries still rely on biofuels and women of childbearing age perform most cooking tasks, the attributable risk arising from this association, if confirmed, could be substantial.

Birth weight and exposure to kitchen wood smoke during pregnancy in rural Guatemala.

PubMed Central

Boy, Erick; Bruce, Nigel; Delgado, Hernán

2002-01-01

In this study, we aimed to establish whether domestic use of wood fuel is associated with reduced birth weight, independent of key maternal, social, and economic confounding factors. We studied 1,717 women and newborn children in rural and urban communities in rural Guatemala. We identified subjects through home births reported by traditional birth attendants in six rural districts (n = 572) and all public hospital births in Quetzaltenango city during the study period (n = 1,145). All were seen within 72 hr of delivery, and data were collected on the type of household fuel used, fire type, and socioeconomic and other confounding factors. Smoking among women in the study community was negligible. Children born to mothers habitually cooking on open fires (n = 861) had the lowest mean birth weight of 2,819 g [95% confidence interval (CI), 2,790-2,848]; those using a chimney stove (n = 490) had an intermediate mean of 2,863 g (95% CI, 2,824-2,902); and those using the cleanest fuels (electricity or gas, n = 365) had the highest mean of 2,948 g (95% CI, 2,898-2,998) (p< 0.0001). The percentage of low birth weights (< 500 g) in these three groups was 19.9% (open fire), 16.8% (chimney stove), and 16.0% (electricity/gas), (trend (p = 0.08). Confounding factors were strongly associated with fuel type, but after adjustment wood users still had a birth weight 63 g lower (p = 0.05; 95% CI, 0.4-126). This is the first report of an association between biofuel use and reduced birth weight in a human population. Although there is potential for residual confounding despite adjustment, the better-documented evidence on passive smoking and a feasible mechanism through carbon monoxide exposure suggest this association may be real. Because two-thirds of households in developing countries still rely on biofuels and women of childbearing age perform most cooking tasks, the attributable risk arising from this association, if confirmed, could be substantial. PMID:11781172

Modifiable risk factors for chronic back pain: insights using the co-twin control design.

PubMed

Suri, Pradeep; Boyko, Edward J; Smith, Nicholas L; Jarvik, Jeffrey G; Williams, Frances M K; Jarvik, Gail P; Goldberg, Jack

2017-01-01

Inconsistent associations between modifiable risk factors and chronic back pain (CBP) may be due to the inability of traditional epidemiologic study designs to properly account for an array of potential genetic and environmental confounding factors. The co-twin control research design, comparing modifiable risk factors in twins discordant for CBP, offers a unique way to remove numerous confounding factors. The study aimed to examine the association of modifiable lifestyle and psychological factors with lifetime CBP. This is a cross-sectional co-twin control study in a nationwide sample of male twin members of the Vietnam Era Twin Registry. The sample is composed of 7,108 participants, including 1,308 monozygotic (MZ) pairs and 793 dizygotic pairs. The outcome measure is the self-reported lifetime history of CBP. Lifestyle factors included body mass index (BMI), smoking history, alcohol consumption, habitual physical activity, and typical sleep duration. Psychological factors included depression (Patient Health Questionnaire-9) and posttraumatic stress disorder (PTSD) symptoms (PTSD Checklist). Covariates included age, race, education, and income. Odds ratios (ORs) and 95% confidence intervals (CI) were estimated for the association of risk factors with lifetime CBP when considering twins as individuals, and a within-pair co-twin control analysis that accounted for familial and genetic factors. Funding was through VA Grant 5IK2RX001515; there were no study-specific conflicts of interest. The mean age of respondents was 62 years and the prevalence of lifetime CBP was 28%. All lifestyle factors were associated with CBP in the individual level analysis. However, none of these persisted in the within-pair analyses, except for severe obesity (BMI ≥35.0), which was associated with lifetime CBP in both individual-level (OR=1.6, 95% CI: 1.3-1.9) and within-pair analyses (MZ analysis: OR=3.7, 95% CI: 1.2-11.4). Symptoms of PTSD and depression were strongly associated with lifetime CBP in both the individual-level (moderate or severe depression: OR=4.2, 95% CI: 3.6-4.9, and severe PTSD: OR=4.8, 95% CI: 4.0-5.7) and within-pair (MZ) analyses (moderate or severe depression: OR=4.6, 95% CI: 2.4-8.7, and severe PTSD: OR=3.2, 95% CI: 1.6-6.5). Many associations between modifiable lifestyle risk factors and CBP are due to confounding by familial and genetic factors. Severe obesity, depression, and PTSD should be considered in the development of intervention strategies to reduce the prevalence of CBP. Published by Elsevier Inc.

Correction of confounding bias in non-randomized studies by appropriate weighting.

PubMed

Schmoor, Claudia; Gall, Christine; Stampf, Susanne; Graf, Erika

2011-03-01

In non-randomized studies, the assessment of a causal effect of treatment or exposure on outcome is hampered by possible confounding. Applying multiple regression models including the effects of treatment and covariates on outcome is the well-known classical approach to adjust for confounding. In recent years other approaches have been promoted. One of them is based on the propensity score and considers the effect of possible confounders on treatment as a relevant criterion for adjustment. Another proposal is based on using an instrumental variable. Here inference relies on a factor, the instrument, which affects treatment but is thought to be otherwise unrelated to outcome, so that it mimics randomization. Each of these approaches can basically be interpreted as a simple reweighting scheme, designed to address confounding. The procedures will be compared with respect to their fundamental properties, namely, which bias they aim to eliminate, which effect they aim to estimate, and which parameter is modelled. We will expand our overview of methods for analysis of non-randomized studies to methods for analysis of randomized controlled trials and show that analyses of both study types may target different effects and different parameters. The considerations will be illustrated using a breast cancer study with a so-called Comprehensive Cohort Study design, including a randomized controlled trial and a non-randomized study in the same patient population as sub-cohorts. This design offers ideal opportunities to discuss and illustrate the properties of the different approaches. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

"A Bayesian sensitivity analysis to evaluate the impact of unmeasured confounding with external data: a real world comparative effectiveness study in osteoporosis".

PubMed

Zhang, Xiang; Faries, Douglas E; Boytsov, Natalie; Stamey, James D; Seaman, John W

2016-09-01

Observational studies are frequently used to assess the effectiveness of medical interventions in routine clinical practice. However, the use of observational data for comparative effectiveness is challenged by selection bias and the potential of unmeasured confounding. This is especially problematic for analyses using a health care administrative database, in which key clinical measures are often not available. This paper provides an approach to conducting a sensitivity analyses to investigate the impact of unmeasured confounding in observational studies. In a real world osteoporosis comparative effectiveness study, the bone mineral density (BMD) score, an important predictor of fracture risk and a factor in the selection of osteoporosis treatments, is unavailable in the data base and lack of baseline BMD could potentially lead to significant selection bias. We implemented Bayesian twin-regression models, which simultaneously model both the observed outcome and the unobserved unmeasured confounder, using information from external sources. A sensitivity analysis was also conducted to assess the robustness of our conclusions to changes in such external data. The use of Bayesian modeling in this study suggests that the lack of baseline BMD did have a strong impact on the analysis, reversing the direction of the estimated effect (odds ratio of fracture incidence at 24 months: 0.40 vs. 1.36, with/without adjusting for unmeasured baseline BMD). The Bayesian twin-regression models provide a flexible sensitivity analysis tool to quantitatively assess the impact of unmeasured confounding in observational studies. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Comparative analyses of studies of childhood leukemia and magnetic fields, radon and gamma radiation.

PubMed

Kheifets, Leeka; Swanson, John; Yuan, Yingzhe; Kusters, Cynthia; Vergara, Ximena

2017-06-26

In this paper we compare the findings of epidemiologic studies of childhood leukemia that examined at least two of ELF magnetic fields and/or distance to power lines, and exposure to radon and gamma radiation or distance to nuclear plants. Many of the methodologic aspects are common to studies of non-ionising (i.e. ELF-MF) and ionising radiation. A systematic search and review of studies with more than one exposure under study identified 33 key and 35 supplementary papers from ten countries that have been included in this review. Examining studies that have looked at several radiation exposures, and comparing similarities and differences for the different types of radiation, through the use of directed acyclic graphs, we evaluate to what extent bias, confounding and other methodological issues might be operating in these studies. We found some indication of bias, although results are not clear cut. There is little evidence that confounding has had a substantial influence on results. Influence of the residential mobility on the study conduct and interpretation is complex and can manifest as a selection bias, confounding, increased measurement error or could also be a potential risk factor. Other factors associated with distance to power lines and to nuclear power plants should be investigated. A more complete and consistent reporting of results in the future studies will allow for a more informative comparison across studies and integration of results.

Why does early sexual intercourse predict subsequent maladjustment? Exploring potential familial confounds.

PubMed

Donahue, Kelly L; Lichtenstein, Paul; Långström, Niklas; D'Onofrio, Brian M

2013-02-01

Previous studies have found an association between early age at first sexual intercourse and subsequent psychosocial maladjustment. Using a quasi-experimental approach, we examined the extent to which this observed association may be due to familial confounds not explored in prior research. Using a population-based cohort of Swedish adult twins (ages 19-47; N = 12,126), we examined the nature of the association between early sexual intercourse (i.e., first intercourse occurring before age 16) and various outcomes reflecting psychosocial health, including substance use, depression, criminal convictions, and adolescent childbearing. We used two methods--discordant-twin analyses and bivariate twin modeling--to estimate the extent to which genetic and environmental confounds explained observed associations. Individuals who engaged in early intercourse were at greater risk for most of the adverse psychosocial health outcomes measured in this study. However, twin pairs discordant for engaging in early intercourse did not differ significantly in their risk for psychosocial maladjustment. Our results indicated that early age at first sexual intercourse and subsequent psychosocial maladjustment may be associated because of familial factors shared by twins. Early intercourse may be associated with poor psychosocial health largely due to shared familial influences rather than through a direct causal connection. Therefore, effective and efficient interventions should address other risk factors common to early intercourse and poor psychosocial health.

Maternal Smoking during Pregnancy and Children's Cognitive and Physical Development: A Causal Risk Factor?

PubMed Central

Gardener, Hannah; Buka, Stephen L.

2008-01-01

There remains considerable debate regarding the effects of maternal smoking during pregnancy on children's growth and development. Evidence that exposure to maternal smoking during pregnancy is associated with numerous adverse outcomes is contradicted by research suggesting that these associations are spurious. The authors investigated the relation between maternal smoking during pregnancy and 14 developmental outcomes of children from birth through age 7 years, using data from the Collaborative Perinatal Project (1959–1974; n = 52,919). In addition to adjusting for potential confounders measured contemporaneously with maternal smoking, the authors fitted conditional fixed-effects models among siblings that controlled for unmeasured confounders. Results from the conditional analyses indicated a birth weight difference of −85.63 g associated with smoking of ≥20 cigarettes daily during pregnancy (95% confidence interval: −131.91, −39.34) and 2.73 times' higher odds of being overweight at age 7 years (95% confidence interval: 1.30, 5.71). However, the associations between maternal smoking and 12 other outcomes studied (including Apgar score, intelligence, academic achievement, conduct problems, and asthma) were entirely eliminated after adjustment for measured and unmeasured confounders. The authors conclude that the hypothesized effects of maternal smoking during pregnancy on these outcomes either are not present or are not distinguishable from a broader range of familial factors associated with maternal smoking. PMID:18653646

Insulin-Like Growth Factor-1 Bioactivity Plays a Prosurvival Role in Older Participants

PubMed Central

2013-01-01

The aim of this study was to address the intriguing issue of the role of the insulin-like growth factor (IGF)-1 system in longevity looking at the role of different components of IGF system. Vital status was ascertained in 1,197 men and women aged greater than or equal to 65 years from the InCHIANTI study. Hormonal levels were categorized into quartiles, and ratio of IGF-1 to IGF-binding protein (IGFBP)-1 was calculated. The relationship between hormones and mortality was tested by Cox proportional hazard models adjusted for age, sex, and confounders. During the 8-year follow-up period, 240 died and 957 survived. Lowest quartiles of IGF-1 and IGFBP-1 were considered as reference. Compared with the lowest quartiles, IGF-1 in upper quartiles was a negative predictor of mortality independent of age and sex (p = .01) but not independent of IGFBP-1 and other confounders. IGFBP-1 in second–third quartiles was negatively associated and that in the fourth quartiles was positively associated with risk of death. IGF-1/IGFBP-1 ratio in the lowest quartiles was a strong positive predictor of mortality, in age- and sex-adjusted model (p = .005), and independent of additional confounders (p = .037). High IGFBP-1 and low IGF-1/IGFBP-1 ratio are associated with all-cause mortality in older population. PMID:23671288

Insulin-like growth factor-1 bioactivity plays a prosurvival role in older participants.

PubMed

Maggio, Marcello; Cattabiani, Chiara; Lauretani, Fulvio; Bandinelli, Stefania; De Vita, Francesca; Dall'Aglio, Elisabetta; Corsonello, Andrea; Lattanzio, Fabrizia; Paolisso, Giuseppe; Ferrucci, Luigi; Ceda, Gian Paolo

2013-11-01

The aim of this study was to address the intriguing issue of the role of the insulin-like growth factor (IGF)-1 system in longevity looking at the role of different components of IGF system. Vital status was ascertained in 1,197 men and women aged greater than or equal to 65 years from the InCHIANTI study. Hormonal levels were categorized into quartiles, and ratio of IGF-1 to IGF-binding protein (IGFBP)-1 was calculated. The relationship between hormones and mortality was tested by Cox proportional hazard models adjusted for age, sex, and confounders. During the 8-year follow-up period, 240 died and 957 survived. Lowest quartiles of IGF-1 and IGFBP-1 were considered as reference. Compared with the lowest quartiles, IGF-1 in upper quartiles was a negative predictor of mortality independent of age and sex (p = .01) but not independent of IGFBP-1 and other confounders. IGFBP-1 in second-third quartiles was negatively associated and that in the fourth quartiles was positively associated with risk of death. IGF-1/IGFBP-1 ratio in the lowest quartiles was a strong positive predictor of mortality, in age- and sex-adjusted model (p = .005), and independent of additional confounders (p = .037). High IGFBP-1 and low IGF-1/IGFBP-1 ratio are associated with all-cause mortality in older population.

The art of matching brain tissue from patients and controls for postmortem research.

PubMed

Bao, Ai-Min; Swaab, Dick F

2018-01-01

The quality of postmortem research depends strongly on a thorough clinical investigation and documentation of the patient's disorder and therapies. In addition, a systematic and professional neuropathologic investigation of both cases and controls is absolutely crucial. In the experience of the Netherlands Brain Bank (NBB), about 20% of clinical neurologic diagnoses, despite being made in first-rate clinics, have to be revised or require an extra diagnosis after a complete and thorough review by the NBB. The neuropathology examination may reveal for instance that the "controls" already have preclinical neurodegenerative alterations. In postmortem studies the patient and control groups must be matched for as many of the known confounding factors as possible. This is necessary to make the groups as similar as possible, except for the topic being investigated. Confounding factors are present before, during, and after death. They are respectively: (1) genetic background, systemic diseases, duration and gravity of illness, medicines and addictive compounds used, age, sex, gender identity, sexual orientation, circadian and seasonal fluctuations, lateralization; (2) agonal state, stress of dying; and (3) postmortem delay, freezing procedures, fixation and storage time. Consequently, a brain bank should have a large number of controls at its disposal for appropriate matching. If matching fails for some confounders, then their influence may be determined by statistical methods such as analysis of variance or regression models. Copyright © 2018 Elsevier B.V. All rights reserved.

Changes in transcriptional orientation are associated with increases in evolutionary rates of enterobacterial genes.

PubMed

Lin, Chieh-Hua; Lian, Chun-Yi; Hsiung, Chao Agnes; Chen, Feng-Chi

2011-10-05

Changes in transcriptional orientation ("CTOs") occur frequently in prokaryotic genomes. Such changes usually result from genomic inversions, which may cause a conflict between the directions of replication and transcription and an increase in mutation rate. However, CTOs do not always lead to the replication-transcription confrontation. Furthermore, CTOs may cause deleterious disruptions of operon structure and/or gene regulations. The currently existing CTOs may indicate relaxation of selection pressure. Therefore, it is of interest to investigate whether CTOs have an independent effect on the evolutionary rates of the affected genes, and whether these genes are subject to any type of selection pressure in prokaryotes. Three closely related enterbacteria, Escherichia coli, Klebsiella pneumoniae and Salmonella enterica serovar Typhimurium, were selected for comparisons of synonymous (dS) and nonsynonymous (dN) substitution rate between the genes that have experienced changes in transcriptional orientation (changed-orientation genes, "COGs") and those that do not (same-orientation genes, "SOGs"). The dN/dS ratio was also derived to evaluate the selection pressure on the analyzed genes. Confounding factors in the estimation of evolutionary rates, such as gene essentiality, gene expression level, replication-transcription confrontation, and decreased dS at gene terminals were controlled in the COG-SOG comparisons. We demonstrate that COGs have significantly higher dN and dS than SOGs when a series of confounding factors are controlled. However, the dN/dS ratios are similar between the two gene groups, suggesting that the increase in dS can sufficiently explain the increase in dN in COGs. Therefore, the increases in evolutionary rates in COGs may be mainly mutation-driven. Here we show that CTOs can increase the evolutionary rates of the affected genes. This effect is independent of the replication-transcription confrontation, which is suggested to be the major cause of inversion-associated evolutionary rate increases. The real cause of such evolutionary rate increases remains unclear but is worth further explorations.

Be(ing) prepared: Guide and Scout participation, childhood social position and mental health at age 50-a prospective birth cohort study.

PubMed

Dibben, Chris; Playford, Chris; Mitchell, Richard

2017-03-01

Mental health is a major concern in many countries. We explore whether youth participation in the Scouts and Guides could protect mental health in later life and in particular whether it might reduce inequalities in mental health associated with early life socioeconomic position. Using the 1958 birth cohort National Child Development Study, we tested whether Scouts-Guide attendance was associated with mental health (SF-36, Mental Health Index (MHI-5)) controlling for childhood risk factors and interacted with social class. Of the 9603 cohort members, 28% had participated in the Scouts-Guides. The average MHI-5 score was 74.8 (SD 18.2) at age 50. After adjustment, for potential childhood confounders, participation in Scouts-Guides was associated with a better MHI-5 score of 2.22 (CI 1.32 to 3.08). Among those who had not been a Scout-Guide, there was a gradient in mental health at age 50 by childhood social position, adjusting for other childhood risk factors. This gradient was absent among those who had been a Scout-Guide. Scout-Guides had an 18% lower odds of an MHI-5 score indicative of mood or anxiety disorder. The findings appeared robust to various tests for residual confounding. Participation in Guides or Scouts was associated with better mental health and narrower mental health inequalities, at age 50. This suggests that youth programmes that support resilience and social mobility through developing the potential for continued progressive self-education, 'soft' non-cognitive skills, self-reliance, collaboration and activities in natural environments may be protective of mental health in adulthood. 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/.

Association between air pollution and suicide: a time series analysis in four Colombian cities.

PubMed

Fernández-Niño, Julián Alfredo; Astudillo-García, Claudia Iveth; Rodríguez-Villamizar, Laura Andrea; Florez-Garcia, Víctor Alfonso

2018-05-12

Recent epidemiological studies have suggested that air pollution could be associated with suicide. However, other studies have criticized these results for being analytically weak and not taking into account potential confounding factors. As such, further studies examining the relationship under diverse contexts are necessary to help clarify this issue. This study explored the association between specific air pollutants (NO 2 , SO 2 , PM 10 , PM 2.5 , CO and O 3 ) and suicide incidence in four Colombian cities after adjusting for climatic variables and holidays. A time series of daily suicides among men and women living in Bogota, Medellin, Cali and Bucaramanga was generated using information from the National Administrative Department of Statistics (DANE) for the years 2011-2014. At the same time, the average daily concentration of each air pollutant for each city was obtained from monitoring stations belonging to the National Air Quality Surveillance System. Using this information together, we generated conditional Poisson models (stratified by day, month and year) for the suicide rate in men and women, with air pollutants as the principal explanatory variable. These models were adjusted for temperature, relative humidity, precipitation and holidays. No association was found between any of the examined pollutants and suicide: NO 2 (IRR:0.99, 95% CI: 0.95-1.04), SO 2 (IRR:0.99, 95% CI: 0.98-1.01), PM 10 (IRR:0.99, 95% CI:0.95-1.03), PM 2.5 (IRR:1.01, 95% CI: 0.98-1.05), CO (IRR:1.00, 95% CI:1.00-1.00) and O 3 (IRR: 1.00, 95% CI: 0.96-1.04). In the same way, no association was found in stratified models by sex and age group neither in lagged and cumulative effects models. After adjusting for major confounding factors, we found no statistically significant association between air pollution and suicide in Colombia. These "negative" results provide further insight into the current discussion regarding the existence of such a relationship.

The relationship between labor unions and safety in US airlines: Is there a "union effect?"

NASA Astrophysics Data System (ADS)

Zapf, Renee Catherine

Every airline union claims to work for safety and presents anecdotes where greater airline safety has been achieved through union efforts. The effect unionization has on safety outcomes in U.S. commercial airlines, however, wasn't found to be previously tested. Studies have shown that in industries such as coal mining, retail, and construction, unionization does lead to an increase in safety. This study evaluated the safety rates of 15 major US commercial airlines to compare the difference between unionized and non-unionized airlines. These safety rates were compared based on if and how long each airline's pilots and flight attendants have been unionized, to determine if unionization had an effect on safety outcomes. The 15 airlines included in the study identified as operating most of the years between 1990 and 2013, with annual departures averaging over 130,000, available through the Bureau of Transportation Statistics. Accident and Incident information was acquired through the National Transportation Safety Board database. The number of accident and incidents divided by the total departures at each airline was used as the safety rate. Union websites provided information on unionization at the airlines. Due to the complex nature of the aviation industry, a number of confounding factors could have affected the tests, including mergers, route structures, and legislation. To help control for these confounding factors, this study was limited to airlines with a stable presence in the industry over time, which limited the number of airlines included. No significant difference was found between unionized and non-unionized airlines in this study, though the mean safety rate of unionized airlines was found be better than non-unionized airlines. This study did not take into account safety improvements that were union-backed and eventually required at all airlines, regardless of unionization. Due to the large sample size of the small population the difference in safety rate means could be indicative of greater safety in unionized airlines.

The connections among suicidal behavior, lipid profile and low-grade inflammation in patients with major depressive disorder: a specific relationship with the neutrophil-to-lymphocyte ratio.

PubMed

Ekinci, Okan; Ekinci, Asli

2017-11-01

The role of inflammation and lipid metabolism in the pathophysiology of suicidal behavior has received particular attention in recent years. The neutrophil-to-lymphocyte ratio (NLR) has been suggested as a new and more reliable indicator of low-grade inflammation. NLR has been found to be altered in major depressive disorder (MDD) and has been related to various factors, including chronic stress and impulsivity that were previously reported to be related to suicidal behavior. We aimed to explore the roles of NLR, C-reactive protein (CRP) and serum lipid levels on suicidal behavior in patients with MDD. The study group consisted of 139 inpatients diagnosed with MDD [37 suicide attempters (SA); 102 suicide non-attempters (NSA)], 50 healthy controls and matched according to age, gender and education. NLR, PLR, CRP and lipid values were obtained from digital inpatient records. CRP levels and NLR were substantially higher in patients with SA than in subjects with NSA and healthy comparison subjects after adjusting the confounding factors. The logistic regression included two predictive variables for suicide status in patients with depressive disorder (A) previous suicidal history; (B) NLR. This is the first study suggesting that NLR may be a trait marker for suicidal vulnerability via a relationship between NLR and a recent suicide attempt in depressed inpatients. Future prospective studies are needed to determine the exact roles of NLR, and other inflammatory markers on suicidality in MDD.

Effect of Heart Rate on Arterial Stiffness as Assessed by Pulse Wave Velocity.

PubMed

Tan, Isabella; Butlin, Mark; Spronck, Bart; Xiao, Huanguang; Avolio, Alberto

2017-07-24

Vascular assessment is becoming increasingly important in the diagnosis of cardiovascular diseases. In particular, clinical assessment of arterial stiffness, as measured by pulse wave velocity (PWV), is gaining increased interest due to the recognition of PWV as an influential factor on the prognosis of hypertension as well as being an independent predictor of cardiovascular and all-cause mortality. Whilst age and blood pressure are established as the two major determinants of PWV, the influence of heart rate on PWV measurements remains controversial with conflicting results being observed in both acute and epidemiological studies. In a majority of studies investigating the acute effects of heart rate on PWV, results were confounded by concomitant changes in blood pressure. Observations from epidemiological studies have also failed to converge, with approximately just half of such studies reporting a significant blood-pressure-independent association between heart rate and PWV. Further to the lack of consensus on the effects of heart rate on PWV, the possible mechanisms contributing to observed PWV changes with heart rate have yet to be fully elucidated, although many investigators have attributed heart-rate related changes in arterial stiffness to the viscoelasticity of the arterial wall. With elevated heart rate being an independent prognostic factor of cardiovascular disease and its association with hypertension, the interaction between heart rate and PWV continues to be relevant in assessing cardiovascular risk. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Low socioeconomic status is a risk factor for preeclampsia: the Generation R Study.

PubMed

Silva, Lindsay M; Coolman, Marianne; Steegers, Eric Ap; Jaddoe, Vincent Wv; Moll, Henriëtte A; Hofman, Albert; Mackenbach, Johan P; Raat, Hein

2008-06-01

To examine whether maternal socioeconomic status, as indicated by maternal educational level, is associated with preeclampsia, and if so, to what extent known risk factors for preeclampsia mediate the effect of educational level. In the Generation R Study, a population-based cohort study, we examined data of 3547 pregnant women. Odds ratios of preeclampsia for low, mid-low and mid-high educational level compared with high educational level were calculated after adjustment for confounders and additional adjustment for a selection of potential mediators (family history, material factors, psychosocial factors, substance use, working conditions, preexisting medical conditions, maternal anthropometrics and blood pressure at enrollment) that individually caused more than 10% change in the odds ratio for low education. Adjusted for the confounding effects of age, gravidity and multiple pregnancy, women with low educational level were more likely to develop preeclampsia (odds ratio 5.12; 95% confidence interval: 2.20, 11.93) than women with high educational level. After additional adjustment for financial difficulties, smoking in pregnancy, working conditions, body mass index and blood pressure at enrollment, the odds ratio was 4.91 (95% confidence interval: 1.93, 12.52). Low maternal socioeconomic status is a strong risk factor for preeclampsia. Only a small part of this association can be explained by the mediating effects of established risk factors for preeclampsia. Further research is needed to disentangle the pathway from low socioeconomic status to preeclampsia.

Changes in Landscape Greenness and Climatic Factors over ...

EPA Pesticide Factsheets

Monitoring and quantifying changes in vegetation cover over large areas using remote sensing can be achieved using the Normalized Difference Vegetation Index (NDVI), an indicator of greenness. However, distinguishing gradual shifts in NDVI (e.g. climate change) versus direct and rapid changes (e.g., fire, land development) is challenging as changes can be confounded by time-dependent patterns, and variation associated with climatic factors. In the present study we leveraged a method, that we previously developed for a pilot study, to address these confounding factors by evaluating NDVI change using autoregression techniques that compare results from univariate (NDVI vs. time) and multivariate analyses (NDVI vs. time and climatic factors) for ~7,660,636 1-km2 pixels comprising the 48 contiguous states of the USA, over a 25-year period (1989−2013). NDVI changed significantly for 48% of the nation over the 25-year in the univariate analyses where most significant trends (85%) indicated an increase in greenness over time. By including climatic factors in the multivariate analyses of NDVI over time, the detection of significant NDVI trends increased to 53% (an increase of 5%). Comparisons of univariate and multivariate analyses for each pixel showed that less than 4% of the pixels had a significant NDVI trend attributable to gradual climatic changes while the remainder of pixels with a significant NDVI trend indicated that changes were due to direct factors. Whi

Disparities in breast cancer outcomes between Caucasian and African American women: a model for describing the relationship of biological and nonbiological factors

PubMed Central

2013-01-01

Breast cancer is the most common malignancy in women in the United States but significant disparities exist for African American women compared to Caucasian women. African American women present with breast cancer at a younger age and with a greater incidence under the age of 50 years, develop histologically more aggressive tumors that are at a more advanced stage at presentation, and have a worse disease-free and overall survival than Caucasian women. The biological characteristics of the primary tumor play an important role in determining the outcome of the disparity, and significant differences have been identified between African American and Caucasian breast cancer in steroid receptor and growth factor receptor content, mutations in cell cycle components, chromosomal abnormalities, and tumor suppressor and other cancer genes. The consequences of the biological factors are influenced by a variety of nonbiological factors, including socioeconomic, health care access, reproductive, and confounding factors. The nonbiological factors may act directly to enhance (or inhibit) the consequences of the biological changes, indirectly to facilitate outcome of the disparity, or as a cofounding factor, driving the association between the biological factors and the disparity. The prevention and management of the disparities will require an understanding of the relationship of biological and nonbiological factors. The present review was undertaken to promote this understanding by describing the biological basis of the four major disparities - early age of onset, more advanced stage of disease, more aggressive histologic changes, and worse survival - and the important relationship to the nonbiological factors. A model is proposed to provide a comprehensive view of this relationship, with the goal of facilitating an understanding of each disparity and the issues that need to be addressed to eliminate the disparity. PMID:23826992

Prognostic factors in canine appendicular osteosarcoma – a meta-analysis

PubMed Central

2012-01-01

Background Appendicular osteosarcoma is the most common malignant primary canine bone tumor. When treated by amputation or tumor removal alone, median survival times (MST) do not exceed 5 months, with the majority of dogs suffering from metastatic disease. This period can be extended with adequate local intervention and adjuvant chemotherapy, which has become common practice. Several prognostic factors have been reported in many different studies, e.g. age, breed, weight, sex, neuter status, location of tumor, serum alkaline phosphatase (SALP), bone alkaline phosphatase (BALP), infection, percentage of bone length affected, histological grade or histological subtype of tumor. Most of these factors are, however, only reported as confounding factors in larger studies. Insight in truly significant prognostic factors at time of diagnosis may contribute to tailoring adjuvant therapy for individual dogs suffering from osteosarcoma. The objective of this study was to systematically review the prognostic factors that are described for canine appendicular osteosarcoma and validate their scientific importance. Results A literature review was performed on selected studies and eligible data were extracted. Meta-analyses were done for two of the three selected possible prognostic factors (SALP and location), looking at both survival time (ST) and disease free interval (DFI). The third factor (age) was studied in a qualitative manner. Both elevated SALP level and the (proximal) humerus as location of the primary tumor are significant negative prognostic factors for both ST and DFI in dogs with appendicular osteosarcoma. Increasing age was associated with shorter ST and DFI, however, was not statistically significant because information of this factor was available in only a limited number of papers. Conclusions Elevated SALP and proximal humeral location are significant negative prognosticators for canine osteosarcoma. PMID:22587466

Prognostic factors in canine appendicular osteosarcoma - a meta-analysis.

PubMed

Boerman, Ilse; Selvarajah, Gayathri T; Nielen, Mirjam; Kirpensteijn, Jolle

2012-05-15

Appendicular osteosarcoma is the most common malignant primary canine bone tumor. When treated by amputation or tumor removal alone, median survival times (MST) do not exceed 5 months, with the majority of dogs suffering from metastatic disease. This period can be extended with adequate local intervention and adjuvant chemotherapy, which has become common practice. Several prognostic factors have been reported in many different studies, e.g. age, breed, weight, sex, neuter status, location of tumor, serum alkaline phosphatase (SALP), bone alkaline phosphatase (BALP), infection, percentage of bone length affected, histological grade or histological subtype of tumor. Most of these factors are, however, only reported as confounding factors in larger studies. Insight in truly significant prognostic factors at time of diagnosis may contribute to tailoring adjuvant therapy for individual dogs suffering from osteosarcoma. The objective of this study was to systematically review the prognostic factors that are described for canine appendicular osteosarcoma and validate their scientific importance. A literature review was performed on selected studies and eligible data were extracted. Meta-analyses were done for two of the three selected possible prognostic factors (SALP and location), looking at both survival time (ST) and disease free interval (DFI). The third factor (age) was studied in a qualitative manner. Both elevated SALP level and the (proximal) humerus as location of the primary tumor are significant negative prognostic factors for both ST and DFI in dogs with appendicular osteosarcoma. Increasing age was associated with shorter ST and DFI, however, was not statistically significant because information of this factor was available in only a limited number of papers. Elevated SALP and proximal humeral location are significant negative prognosticators for canine osteosarcoma.

Feelings of loneliness, but not social isolation, predict dementia onset: results from the Amsterdam Study of the Elderly (AMSTEL).

PubMed

Holwerda, Tjalling Jan; Deeg, Dorly J H; Beekman, Aartjan T F; van Tilburg, Theo G; Stek, Max L; Jonker, Cees; Schoevers, Robert A

2014-02-01

Known risk factors for Alzheimer's disease and other dementias include medical conditions, genetic vulnerability, depression, demographic factors and mild cognitive impairment. The role of feelings of loneliness and social isolation in dementia is less well understood, and prospective studies including these risk factors are scarce. We tested the association between social isolation (living alone, unmarried, without social support), feelings of loneliness and incident dementia in a cohort study among 2173 non-demented community-living older persons. Participants were followed for 3 years when a diagnosis of dementia was assessed (Geriatric Mental State (GMS) Automated Geriatric Examination for Computer Assisted Taxonomy (AGECAT)). Logistic regression analysis was used to examine the association between social isolation and feelings of loneliness and the risk of dementia, controlling for sociodemographic factors, medical conditions, depression, cognitive functioning and functional status. After adjustment for other risk factors, older persons with feelings of loneliness were more likely to develop dementia (OR 1.64, 95% CI 1.05 to 2.56) than people without such feelings. Social isolation was not associated with a higher dementia risk in multivariate analysis. Feeling lonely rather than being alone is associated with an increased risk of clinical dementia in later life and can be considered a major risk factor that, independently of vascular disease, depression and other confounding factors, deserves clinical attention. Feelings of loneliness may signal a prodromal stage of dementia. A better understanding of the background of feeling lonely may help us to identify vulnerable persons and develop interventions to improve outcome in older persons at risk of dementia.

Non-genetic risk factors in haemophilia A inhibitor management - the danger theory and the use of animal models.

PubMed

Lövgren, K M; Søndergaard, H; Skov, S; Wiinberg, B

2016-09-01

In haemophilia A (HA) management, antidrug antibodies, or inhibitors, are a serious complication that renders factor VIII (FVIII) replacement therapy ineffective, increases morbidity and reduces quality of life for affected patients. Inhibitor development aetiology is multifactorial and covers both genetic and therapy related risk factors. Many therapy-related risk factors have proven difficult to confirm due to several confounding factors and the small study populations available. However, clinical studies indicate that e.g. on-demand treatment and surgery affect inhibitor development, and explanations for this association are being investigated. A potential explanation is the danger signal effect, where the immune response is activated by endogenous or exogenous danger or damage signals present at the time and site of FVIII administration. The danger theory explains how alarm signals from stressed, injured or dying cells can activate an immune reaction, without the involvement of foreign antigens. Bleeds, trauma, surgery or concomitant infection could be events initiating danger signalling in HA patients, resulting in an immune reaction towards administered FVIII that otherwise would pass unnoticed. This role of danger in HA inhibitor formation has previously been suggested, but a thorough discussion of this subject is lacking. The present review will discuss the potential role of danger signals in haemophilia and inhibitor development, with focus on treatment related risk factors with a suspected danger signal aetiology; on-demand treatment, treatment during major bleeds or surgery, and treatment during infection or vaccination. Clinical studies as well as animal experiments addressing these factors will be reviewed. © 2016 John Wiley & Sons Ltd.

Longitudinal associations of nutritional factors with glycated hemoglobin in youth with type 1 diabetes: the SEARCH Nutrition Ancillary Study123

PubMed Central

Crandell, Jamie L; Jaacks, Lindsay M; Couch, Sarah C; Lawrence, Jean M; Mayer-Davis, Elizabeth J

2015-01-01

Background: Improved glycated hemoglobin (Hb A1c) delays the progression of microvascular and macrovascular complications in individuals with type 1 diabetes (T1D). We previously showed that higher baseline intakes of n–3 (ω-3) fatty acids and leucine are associated with preserved β cell function 2 y later in youth with T1D. Objective: In the current study, we extend this work to explore the longitudinal associations of nutritional factors with Hb A1c in youth with T1D. Design: We included 908 T1D youth with baseline and follow-up Hb A1c measurements. Nutritional factors assessed at baseline were as follows: breastfeeding status and timing of complimentary food introduction; intakes of leucine, carbohydrates, protein, fat, and fiber estimated from a food-frequency questionnaire (FFQ); and plasma biomarkers for vitamins D and E, eicosapentaenoic acid (EPA), and docosahexaenoic acid. We fit linear regression models adjusted for baseline Hb A1c, sociodemographic variables, diabetes-related variables, time between baseline and follow-up visits, saturated fat, physical activity, and for FFQ-derived nutrients, total calories. The vitamin D model was further adjusted for season and body mass index z score. Results: The mean ± SD age and diabetes duration at baseline was 10.8 ± 3.9 y and 10.1 ± 5.8 mo, respectively. A total of 9.3% of participants had poor Hb A1c (value ≥9.5%) at baseline, which increased to 18.3% during follow-up (P < 0.0001). Intakes of EPA (β = −0.045, P = 0.046), leucine (β = −0.031, P = 0.0004), and protein (β = −0.003, P = 0.0002) were significantly negatively associated with follow-up Hb A1c after adjustment for confounders. Intake of carbohydrates was significantly positively (β = 0.001, P = 0.003) associated with follow-up Hb A1c after adjustment for confounders. Conclusions: Several nutritional factors may be associated with Hb A1c during early stages of disease progression in youth recently diagnosed with T1D. In addition to the overall role of major macronutrients such as carbohydrates and protein, leucine and n–3 fatty acid intakes, such as of EPA, may be important for long-term glycemic control. PMID:25948670

Longitudinal associations of nutritional factors with glycated hemoglobin in youth with type 1 diabetes: the SEARCH Nutrition Ancillary Study.

PubMed

Lamichhane, Archana P; Crandell, Jamie L; Jaacks, Lindsay M; Couch, Sarah C; Lawrence, Jean M; Mayer-Davis, Elizabeth J

2015-06-01

Improved glycated hemoglobin (Hb A1c) delays the progression of microvascular and macrovascular complications in individuals with type 1 diabetes (T1D). We previously showed that higher baseline intakes of n-3 (ω-3) fatty acids and leucine are associated with preserved β cell function 2 y later in youth with T1D. In the current study, we extend this work to explore the longitudinal associations of nutritional factors with Hb A1c in youth with T1D. We included 908 T1D youth with baseline and follow-up Hb A1c measurements. Nutritional factors assessed at baseline were as follows: breastfeeding status and timing of complimentary food introduction; intakes of leucine, carbohydrates, protein, fat, and fiber estimated from a food-frequency questionnaire (FFQ); and plasma biomarkers for vitamins D and E, eicosapentaenoic acid (EPA), and docosahexaenoic acid. We fit linear regression models adjusted for baseline Hb A1c, sociodemographic variables, diabetes-related variables, time between baseline and follow-up visits, saturated fat, physical activity, and for FFQ-derived nutrients, total calories. The vitamin D model was further adjusted for season and body mass index z score. The mean ± SD age and diabetes duration at baseline was 10.8 ± 3.9 y and 10.1 ± 5.8 mo, respectively. A total of 9.3% of participants had poor Hb A1c (value ≥9.5%) at baseline, which increased to 18.3% during follow-up (P < 0.0001). Intakes of EPA (β = -0.045, P = 0.046), leucine (β = -0.031, P = 0.0004), and protein (β = -0.003, P = 0.0002) were significantly negatively associated with follow-up Hb A1c after adjustment for confounders. Intake of carbohydrates was significantly positively (β = 0.001, P = 0.003) associated with follow-up Hb A1c after adjustment for confounders. Several nutritional factors may be associated with Hb A1c during early stages of disease progression in youth recently diagnosed with T1D. In addition to the overall role of major macronutrients such as carbohydrates and protein, leucine and n-3 fatty acid intakes, such as of EPA, may be important for long-term glycemic control. © 2015 American Society for Nutrition.

Maternal Risk Factors and Periodontal Disease: A Cross-sectional Study among Postpartum Mothers in Tamil Nadu.

PubMed

Govindasamy, Rohini; Dhanasekaran, Manikandan; Varghese, Sheeja S; Balaji, V R; Karthikeyan, B; Christopher, Ananthi

2017-11-01

It is inconclusive that periodontitis is an independent risk factor for adverse pregnancy outcomes. This study aims to investigate the association between maternal periodontitis and preterm and/or low birth weight babies. This was a prospective cross-sectional study. After prior informed consent, 3500 postpartum mothers were selected from various hospitals in Tamil Nadu and categorized into the following groups: group-1 - Normal term normal birth weight ( n = 1100); Group-2 - Preterm normal birth weight ( n = 400); Group-3 - preterm low birth weight (PTLBW) ( n = 1000); and Group-4 - Normal term low birth weight ( n = 1000). Periodontal examination was done, and risk factors were ascertained by means of questionnaire and medical records. Comparison between case groups and control groups were done, odds ratio (OR) was calculated, and statistical significance were assessed by Chi-square tests. To control for the possible confounders, all variables with P < 0.05 were selected and entered into multivariate regression model, and OR and 95% confidence limits were again estimated. SPSS-15 software was used. Periodontitis was diagnosed in 54.8%, 52.3%, 53.8%, 59.4%, respectively. On comparison between the groups, none of periodontal parameters showed significant association except for the crude association observed in Group-4 for mild periodontitis (OR - 1.561; P = 0.000) and PTLBW. Periodontitis is not a significant independent risk factor, and obstetric factors contribute a major risk for preterm and/or low birth weight babies.

Coping with confounds in multivoxel pattern analysis: what should we do about reaction time differences? A comment on Todd, Nystrom & Cohen 2013.

PubMed

Woolgar, Alexandra; Golland, Polina; Bode, Stefan

2014-09-01

Multivoxel pattern analysis (MVPA) is a sensitive and increasingly popular method for examining differences between neural activation patterns that cannot be detected using classical mass-univariate analysis. Recently, Todd et al. ("Confounds in multivariate pattern analysis: Theory and rule representation case study", 2013, NeuroImage 77: 157-165) highlighted a potential problem for these methods: high sensitivity to confounds at the level of individual participants due to the use of directionless summary statistics. Unlike traditional mass-univariate analyses where confounding activation differences in opposite directions tend to approximately average out at group level, group level MVPA results may be driven by any activation differences that can be discriminated in individual participants. In Todd et al.'s empirical data, factoring out differences in reaction time (RT) reduced a classifier's ability to distinguish patterns of activation pertaining to two task rules. This raises two significant questions for the field: to what extent have previous multivoxel discriminations in the literature been driven by RT differences, and by what methods should future studies take RT and other confounds into account? We build on the work of Todd et al. and compare two different approaches to remove the effect of RT in MVPA. We show that in our empirical data, in contrast to that of Todd et al., the effect of RT on rule decoding is negligible, and results were not affected by the specific details of RT modelling. We discuss the meaning of and sensitivity for confounds in traditional and multivoxel approaches to fMRI analysis. We observe that the increased sensitivity of MVPA comes at a price of reduced specificity, meaning that these methods in particular call for careful consideration of what differs between our conditions of interest. We conclude that the additional complexity of the experimental design, analysis and interpretation needed for MVPA is still not a reason to favour a less sensitive approach. Copyright © 2014 Elsevier Inc. All rights reserved.

Factors that influence length of stay for in-patient gynaecology surgery: is the Case Mix Group (CMG) or type of procedure more important?

PubMed

Carey, Mark S; Victory, Rahi; Stitt, Larry; Tsang, Nicole

2006-02-01

To compare the association between the Case Mix Group (CMG) code and length of stay (LOS) with the association between the type of procedure and LOS in patients admitted for gynaecology surgery. We examined the records of women admitted for surgery in CMG 579 (major uterine/adnexal procedure, no malignancy) or 577 (major surgery ovary/adnexa with malignancy) between April 1997 and March 1999. Factors thought to influence LOS included age, weight, American Society of Anesthesiologists (ASA) score, physician, day of the week on which surgery was performed, and procedure type. Procedures were divided into six categories, four for CMG 579 and two for CMG 577. Data were abstracted from the hospital information costing system (T2 system) and by retrospective chart review. Multivariable analysis was performed using linear regression with backwards elimination. There were 606 patients in CMG 579 and 101 patients in CMG 577, and the corresponding median LOS was four days (range 1-19) for CMG 579 and nine days (range 3-30) for CMG 577. Combined analysis of both CMGs 577 and 579 revealed the following factors as highly significant determinants of LOS: procedure, age, physician, and ASA score. Although confounded by procedure type, the CMG did not significantly account for differences in LOS in the model if procedure was considered. Pairwise comparisons of procedure categories were all found to be statistically significant, even when controlled for other important variables. The type of procedure better accounts for differences in LOS by describing six statistically distinct procedure groups rather than the traditional two CMGs. It is reasonable therefore to consider changing the current CMG codes for gynaecology to a classification based on the type of procedure.

Efficient and accurate causal inference with hidden confounders from genome-transcriptome variation data

PubMed Central

2017-01-01

Mapping gene expression as a quantitative trait using whole genome-sequencing and transcriptome analysis allows to discover the functional consequences of genetic variation. We developed a novel method and ultra-fast software Findr for higly accurate causal inference between gene expression traits using cis-regulatory DNA variations as causal anchors, which improves current methods by taking into consideration hidden confounders and weak regulations. Findr outperformed existing methods on the DREAM5 Systems Genetics challenge and on the prediction of microRNA and transcription factor targets in human lymphoblastoid cells, while being nearly a million times faster. Findr is publicly available at https://github.com/lingfeiwang/findr. PMID:28821014

Hysteroscopic sterilization success in outpatient vs office setting is not affected by patient or procedural characteristics.

PubMed

Anderson, Ted L; Yunker, Amanda C; Scheib, Stacey A; Callahan, Tamara L

2013-01-01

To determine factors associated with hysteroscopic sterilization success and whether it differs between the operating room and office settings. Retrospective cohort analysis (Canadian Task Force classification II-2). Major university medical center. Six hundred thirty-eight women who underwent hysteroscopic sterilization between July 1, 2005, and June 30, 2011. Data collected included age, body mass index, previous office procedures, previous cesarean section, and presence of myomas or retroverted uterus. Place of surgery, experience of surgeon, insurance type, bilateral device placement, compliance with hysterosalpingography, and confirmation of occlusion were also recorded. Bivariate analysis of patient characteristics between groups was performed using χ(2) and independent t tests, and identified confounders and associated variables. Multivariate analysis was performed using logistic regression to assess for association and to adjust for confounders. Procedures were performed in the operating room (57%) or in the office (43%). There was no association between success in bilateral device placement or occlusion and any patient characteristic, regardless of surgery setting. Private insurance, patient age, and performance of procedures in the office setting were positively associated with likelihood of compliance with hysterosalpingography. Successful device placement and tubal occlusion are independent of patient age, body mass index, or setting of the procedure. Association between insurance type and completing hysterosalpingography illustrates an important public health problem. Patients who fail to undergo hysterosalpingography to confirm tubal occlusion may unknowingly be at risk of pregnancy and increased risk of ectopic pregnancy. Copyright © 2013 AAGL. Published by Elsevier Inc. All rights reserved.

Comorbidities of COPD Have a Major Impact on Clinical Outcomes, Particularly in African Americans

PubMed Central

Putcha, Nirupama; Han, Meilan K.; Martinez, Carlos H.; Foreman, Marilyn G.; Anzueto, Antonio R.; Casaburi, Richard; Cho, Michael H.; Hanania, Nicola A.; Hersh, Craig P.; Kinney, Gregory L.; Make, Barry J.; Steiner, Robert M.; Lutz, Sharon M.; Thomashow, Byron M.; Williams, Andre A.; Bhatt, Surya P.; Beaty, Terri H.; Bowler, Russell P.; Ramsdell, Joe W.; Curtis, Jeffrey L.; Everett, Douglas; Hokanson, John E.; Lynch, David A.; Sutherland, E. Rand; Silverman, Edwin K.; Crapo, James D.; Wise, Robert A.; Regan, Elizabeth A.; Hansel, Nadia N.

2014-01-01

Background: COPD patients have a great burden of comorbidity. However, it is not well established whether this is due to shared risk factors such as smoking, if the comorbidities impact patients’ exercise capacity and quality of life, or whether there are racial disparities in their impact on COPD. Methods: We analyzed data from 10,192 current and ex-smokers with (cases) and without COPD (controls) from the Genetic Epidemiology of COPD (COPDGene®) study cohort to establish risk for COPD comorbidities adjusted for pertinent covariates. In adjusted models, we examined comorbidity prevalence and impact in African-Americans (AA) and non-Hispanic whites (NHW). Results: Comorbidities are more common in individuals with COPD compared to those with normal spirometry (controls), and the risk persists after adjustments for covariates including pack-years smoked. After adjustment for confounders, 8 conditions were independently associated with worse exercise capacity, quality of life and dyspnea. There were racial disparities in the impact of comorbidities on exercise capacity, dyspnea and quality of life, with the presence of osteoarthritis and gastroesophageal reflux disease having a greater negative impact on all three outcomes in AAs than NHWs (p<0.05 for all interaction terms). Conclusions: Individuals with COPD have a higher risk for comorbidities than controls, an important finding shown for the first time comprehensively after accounting for confounders. Individual comorbidities are associated with worse exercise capacity, quality of life, and dyspnea, in AAs compared with NHWs. Note: The abstract of a previous version of this work was presented at the American Thoracic Society Conference in Philadelphia, PA on May 21, 2013. PMID:25695106

HOMA-IR Values are Associated With Glycemic Control in Japanese Subjects Without Diabetes or Obesity: The KOBE Study

PubMed Central

Hirata, Takumi; Higashiyama, Aya; Kubota, Yoshimi; Nishimura, Kunihiro; Sugiyama, Daisuke; Kadota, Aya; Nishida, Yoko; Imano, Hironori; Nishikawa, Tomofumi; Miyamatsu, Naomi; Miyamoto, Yoshihiro; Okamura, Tomonori

2015-01-01

Background Several studies have reported that insulin resistance was a major risk factor for the onset of type 2 diabetes mellitus in individuals without diabetes or obesity. We aimed to clarify the association between insulin resistance and glycemic control in Japanese subjects without diabetes or obesity. Methods We conducted a community-based cross-sectional study including 1083 healthy subjects (323 men and 760 women) in an urban area. We performed multivariate regression analyses to estimate the association between the homeostasis model assessment of insulin resistance (HOMA-IR) values and markers of glycemic control, including glycated haemoglobin (HbA1c), 1,5-anhydroglucitol (1,5-AG), and fasting plasma glucose (FPG) levels, after adjustment for potential confounders. Results Compared with the lowest tertile of HOMA-IR values, the highest tertile was significantly associated with HbA1c and FPG levels after adjustment for potential confounders, both in men (HbA1c: β = 1.83, P = 0.001; FPG: β = 0.49, P < 0.001) and women (HbA1c: β = 0.82, P = 0.008; FPG: β = 0.39, P < 0.001). The highest tertile of HOMA-IR values was inversely associated with 1,5-AG levels compared with the lowest tertile (β = −18.42, P = 0.009) only in men. Conclusions HOMA-IR values were associated with markers of glycemic control in Japanese subjects without diabetes or obesity. Insulin resistance may influence glycemic control even in a lean, non-diabetic Asian population. PMID:26005064

Advanced Maternal Age and the Risk of Low Birth Weight and Preterm Delivery: a Within-Family Analysis Using Finnish Population Registers.

PubMed

Goisis, Alice; Remes, Hanna; Barclay, Kieron; Martikainen, Pekka; Myrskylä, Mikko

2017-12-01

Advanced maternal age at birth is considered a major risk factor for birth outcomes. It is unclear to what extent this association is confounded by maternal characteristics. To test whether advanced maternal age at birth independently increases the risk of low birth weight (<2,500 g) and preterm birth (<37 weeks' gestation), we compared between-family models (children born to different mothers at different ages) with within-family models (children born to the same mother at different ages). The latter procedure reduces confounding by unobserved parental characteristics that are shared by siblings. We used Finnish population registers, including 124,098 children born during 1987-2000. When compared with maternal ages 25-29 years in between-family models, maternal ages of 35-39 years and ≥40 years were associated with percentage increases of 1.1 points (95% confidence intervals: 0.8, 1.4) and 2.2 points (95% confidence intervals: 1.4, 2.9), respectively, in the probability of low birth weight. The associations are similar for the risk of preterm delivery. In within-family models, the relationship between advanced maternal age and low birth weight or preterm birth is statistically and substantively negligible. In Finland, advanced maternal age is not independently associated with the risk of low birth weight or preterm delivery among mothers who have had at least 2 live births. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health.

Genetic and environmental sources of covariation between early drinking and adult functioning.

PubMed

Waldron, Jordan Sparks; Malone, Stephen M; McGue, Matt; Iacono, William G

2017-08-01

The vast majority of individuals initiate alcohol consumption for the first time in adolescence. Given the widespread nature of its use and evidence that adolescents may be especially vulnerable to its effects, there is concern about the long-term detrimental impact of adolescent drinking on adult functioning. While some researchers have suggested that genetic processes may confound the relationship, the mechanisms linking drinking and later adjustment remain unclear. The current study utilized a genetically informed sample and biometric modeling to examine the nature of the familial influences on this association and identify the potential for genetic confounding. The sample was drawn from the Minnesota Twin Family Study (MTFS), a longitudinal study consisting of 2,764 twins assessed in 2 cohorts at regular follow-ups from age 17 to age 29 (older cohort) or age 11 to age 29 (younger cohort). A broad range of adult measures was included assessing substance use, antisocial behavior, personality, socioeconomic status, and social functioning. A bivariate Cholesky decomposition was used to examine the common genetic and environmental influences on adolescent drinking and each of the measures of adult adjustment. The results revealed that genetic factors and nonshared environmental influences were generally most important in explaining the relationship between adolescent drinking and later functioning. While the presence of nonshared environmental influences on the association are not inconsistent with a causal impact of adolescent drinking, the findings suggest that many of the adjustment issues associated with adolescent alcohol consumption are best understood as genetically influenced vulnerabilities. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Racial discrimination, post-traumatic stress and prescription drug problems among Aboriginal Canadians.

PubMed

Currie, Cheryl; Wild, T Cameron; Schopflocher, Donald; Laing, Lory

2015-06-24

1) To examine associations between racial discrimination and drug problems among urban-based Aboriginal adults; and 2) to determine whether these associations are best explained by symptoms of psychological stress, distress or post-traumatic stress disorder (PTSD). Data were collected through in-person surveys with a community-based sample of Aboriginal adults (N = 372) living in a mid-sized city in western Canada in 2010. Associations were examined using bootstrapped linear regression models adjusted for confounders, with continuous prescription and illicit drug problem scores as outcomes. Mediation was examined using the cross-products of coefficients method. More than 80% of Aboriginal adults had experienced racial discrimination in the past year, with the majority reporting high levels in that period. Past-year discrimination was a risk factor for PTSD symptoms and prescription drug problems in models adjusted for confounders and other forms of psychological trauma. In mediation models, PTSD symptoms explained the association between discrimination and prescription drug problems; psychological stress and distress did not. PTSD symptoms also explained this association when the covariance between mediators was controlled. The results also indicate that participation in Aboriginal cultural traditions was associated with increased discrimination. Most efforts to address Aboriginal health inequities in Canada have focused on the role Aboriginal people play in these disparities. The current findings combine with others to call for an expanded focus. Non-Aboriginal Canadians may also play a role in the health inequities observed. The findings of this study suggest efforts to reduce discrimination experienced by Aboriginal adults in cities may reduce PTSD symptomology and prescription drug problems in these populations.

Family structure and risk behaviors: the role of the family meal in assessing likelihood of adolescent risk behaviors

PubMed Central

Goldfarb, Samantha; Tarver, Will L; Sen, Bisakha

2014-01-01

Background Previous literature has asserted that family meals are a key protective factor for certain adolescent risk behaviors. It is suggested that the frequency of eating with the family is associated with better psychological well-being and a lower risk of substance use and delinquency. However, it is unclear whether there is evidence of causal links between family meals and adolescent health-risk behaviors. Purpose The purpose of this article is to review the empirical literature on family meals and adolescent health behaviors and outcomes in the US. Data sources A search was conducted in four academic databases: Social Sciences Full Text, Sociological Abstracts, PsycINFO®, and PubMed/MEDLINE. Study selection We included studies that quantitatively estimated the relationship between family meals and health-risk behaviors. Data extraction Data were extracted on study sample, study design, family meal measurement, outcomes, empirical methods, findings, and major issues. Data synthesis Fourteen studies met the inclusion criteria for the review that measured the relationship between frequent family meals and various risk-behavior outcomes. The outcomes considered by most studies were alcohol use (n=10), tobacco use (n=9), and marijuana use (n=6). Other outcomes included sexual activity (n=2); depression, suicidal ideation, and suicide attempts (n=4); violence and delinquency (n=4); school-related issues (n=2); and well-being (n=5). The associations between family meals and the outcomes of interest were most likely to be statistically significant in unadjusted models or models controlling for basic family characteristics. Associations were less likely to be statistically significant when other measures of family connectedness were included. Relatively few analyses used sophisticated empirical techniques available to control for confounders in secondary data. Conclusion More research is required to establish whether or not the relationship between family dinners and risky adolescent behaviors is an artifact of underlying confounders. We recommend that researchers make more frequent use of sophisticated methods to reduce the problem of confounders in secondary data, and that the scope of adolescent problem behaviors also be further widened. PMID:24627645

Cholangiocarcinoma—controversies and challenges

PubMed Central

Patel, Tushar

2013-01-01

Cholangiocarcinomas are a diverse group of tumors that are presumed to originate from the biliary tract epithelium either within the liver or the biliary tract. These cancers are often difficult to diagnose, their pathogenesis is poorly understood, and their dismal prognosis has resulted in a nihilistic approach to their management. The two major clinical phenotypes are intrahepatic, mass-forming tumors and large ductal tumors. Among the ductal cancers, lesions at the liver hilum are most prevalent. The risk factors, clinical presentation, natural history and management of these two types of cholangiocarcinoma are distinct. Efforts to improve outcomes for patients with these diseases are affected by several challenges to effective management. For example, designations based on anatomical characteristics have been inconsistently applied, which has confounded analysis of epidemiological trends and assessment of risk factors. The evaluation of therapeutic options, particularly systemic therapies, has been limited by a lack of appreciation of the different phenotypes. Controversies exist regarding the appropriate workup and choice of management approach. However, new and emerging tools for improved diagnosis, expanded indications for surgical approaches, an emerging role for locoregional and intrabiliary therapies and improved systemic therapies provide optimism and hope for improved outcomes in the future. PMID:21460876

An economic analysis of trial of labor after cesarean delivery.

PubMed

Friedman, Alexander M; Ananth, Cande V; Chen, Ling; D'Alton, Mary E; Wright, Jason D

2016-01-01

Given that cesarean delivery is one of the most commonly performed surgical procedures in the United States and an important contributor to obstetric care costs, this analysis sought to examine maternal hospital costs associated with trial of labor after cesarean delivery (TOLAC) versus repeat cesarean delivery (RCD). A national sample was used to identify women with singleton pregnancy who underwent either TOLAC or RCD from 2006 to 2012. Women with diagnoses that could confound cost via extended hospital length of stay prior to delivery were excluded. Other medical and obstetric covariates that could influence cost were included in an adjusted model. A total of 485,247 women were identified, including 365,596 (75.3%) cesarean deliveries without labor, 41,988 (8.6%) successful and 77,663 (16.0%) unsuccessful TOLAC deliveries. The inflation-adjusted median costs in this cohort were $5512 for cesarean without labor, $4175 for successful TOLAC, $5166 for all TOLAC attempts, and $5759 for failed TOLAC. In a multivariable model, hospital region was a major predictor of median cost as were demographic variables and medical comorbidities. TOLAC is associated with modest reductions of cost for maternal hospitalizations. However, other medical, demographic and hospital factors appear to be more important factors.

Detecting macroecological patterns in bacterial communities across independent studies of global soils.

PubMed

Ramirez, Kelly S; Knight, Christopher G; de Hollander, Mattias; Brearley, Francis Q; Constantinides, Bede; Cotton, Anne; Creer, Si; Crowther, Thomas W; Davison, John; Delgado-Baquerizo, Manuel; Dorrepaal, Ellen; Elliott, David R; Fox, Graeme; Griffiths, Robert I; Hale, Chris; Hartman, Kyle; Houlden, Ashley; Jones, David L; Krab, Eveline J; Maestre, Fernando T; McGuire, Krista L; Monteux, Sylvain; Orr, Caroline H; van der Putten, Wim H; Roberts, Ian S; Robinson, David A; Rocca, Jennifer D; Rowntree, Jennifer; Schlaeppi, Klaus; Shepherd, Matthew; Singh, Brajesh K; Straathof, Angela L; Bhatnagar, Jennifer M; Thion, Cécile; van der Heijden, Marcel G A; de Vries, Franciska T

2018-02-01

The emergence of high-throughput DNA sequencing methods provides unprecedented opportunities to further unravel bacterial biodiversity and its worldwide role from human health to ecosystem functioning. However, despite the abundance of sequencing studies, combining data from multiple individual studies to address macroecological questions of bacterial diversity remains methodically challenging and plagued with biases. Here, using a machine-learning approach that accounts for differences among studies and complex interactions among taxa, we merge 30 independent bacterial data sets comprising 1,998 soil samples from 21 countries. Whereas previous meta-analysis efforts have focused on bacterial diversity measures or abundances of major taxa, we show that disparate amplicon sequence data can be combined at the taxonomy-based level to assess bacterial community structure. We find that rarer taxa are more important for structuring soil communities than abundant taxa, and that these rarer taxa are better predictors of community structure than environmental factors, which are often confounded across studies. We conclude that combining data from independent studies can be used to explore bacterial community dynamics, identify potential 'indicator' taxa with an important role in structuring communities, and propose hypotheses on the factors that shape bacterial biogeography that have been overlooked in the past.

Portion Size: What We Know and What We Need to Know

PubMed Central

Benton, David

2015-01-01

There is increasing evidence that the portion sizes of many foods have increased and in a laboratory at least this increases the amount eaten. The conclusions are, however, limited by the complexity of the phenomenon. There is a need to consider meals freely chosen over a prolonged period when a range of foods of different energy densities are available. A range of factors will influence the size of the portion size chosen: amongst others packaging, labeling, advertising, and the unit size rather than portion size of the food item. The way portion size interacts with the multitude of factors that determine food intake needs to be established. In particular, the role of portion size on energy intake should be examined as many confounding variables exist and we must be clear that it is portion size that is the major problem. If the approach is to make a practical contribution, then methods of changing portion sizes will need to be developed. This may prove to be a problem in a free market, as it is to be expected that customers will resist the introduction of smaller portion sizes, given that value for money is an important motivator. PMID:24915353

Perceived gender inequality in the couple relationship and musculoskeletal pain in middle-aged women and men.

PubMed

Bohlin, Anna; Ahlgren, Christina; Hammarstrom, Anne; Gustafsson, Per E

2013-12-01

Musculoskeletal pain is a major health problem, especially in women, and is partially determined by psychosocial factors. The aim of the present study was to investigate whether gender inequality in the couple relationship was related to musculoskeletal pain. Participants (n=721; 364 women and 357 men) were all individuals living in a couple relationship in the Northern Swedish Cohort, a 26-year Swedish cohort study. Self-administered questionnaire data at age 42 years comprised perceived gender inequality in the couple relationship and musculoskeletal pain (in three locations, summarised into one score and median-split), concurrent demographic factors, psychological distress, and previous musculoskeletal pain at age 30 years. Associations were examined using logistic regression. Gender inequality was positively associated with symptoms of musculoskeletal pain in the total sample, remaining significant after addition of possible confounders and of previous musculoskeletal pain. Separate adjustment for concurrent psychological distress attenuated the association but not below significance. The association was present and of comparable strength in both women and men. Gender inequality in the couple relationship might contribute to the experience of musculoskeletal pain in both women and men. The results highlight the potential adverse bodily consequences of living in unequal relationships.

Toward a Phenomenology of Dwelling and Building: Hassan Fathy's "Architecture for the Poor" as an Indication.

ERIC Educational Resources Information Center

Seamon, David

The philosophy of Martin Heidegger has major bearing on work in humanistic geography and related environmental fields. Dwelling, according to Heidegger, is the process through which people make their place of existence a home. For all the seeming rightness of Heidegger's view, there is much about dwelling that confounds and alienates many present…

MAOA promoter methylation and susceptibility to carotid atherosclerosis: role of familial factors in a monozygotic twin sample

PubMed Central

2012-01-01

Background Atherosclerosis is a complex process involving both genetic and epigenetic factors. The monoamine oxidase A (MAOA) gene regulates the metabolism of key neurotransmitters and has been associated with cardiovascular risk factors. This study investigates whether MAOA promoter methylation is associated with atherosclerosis, and whether this association is confounded by familial factors in a monozygotic (MZ) twin sample. Methods We studied 84 monozygotic (MZ) twin pairs drawn from the Vietnam Era Twin Registry. Carotid intima-media thickness (IMT) was measured by ultrasound. DNA methylation in the MAOA promoter region was quantified by bisulfite pyrosequencing using genomic DNA isolated from peripheral blood leukocytes. The association between DNA methylation and IMT was first examined by generalized estimating equation, followed by matched pair analyses to determine whether the association was confounded by familial factors. Results When twins were analyzed as individuals, increased methylation level was associated with decreased IMT at four of the seven studied CpG sites. However, this association substantially reduced in the matched pair analyses. Further adjustment for MAOA genotype also considerably attenuated this association. Conclusions The association between MAOA promoter methylation and carotid IMT is largely explained by familial factors shared by the twins. Because twins reared together share early life experience, which may leave a long-lasting epigenetic mark, aberrant MAOA methylation may represent an early biomarker for unhealthy familial environment. Clarification of familial factors associated with DNA methylation and early atherosclerosis will provide important information to uncover clinical correlates of disease. PMID:23116433

Development of a minimization instrument for allocation of a hospital-level performance improvement intervention to reduce waiting times in Ontario emergency departments.

PubMed

Leaver, Chad Andrew; Guttmann, Astrid; Zwarenstein, Merrick; Rowe, Brian H; Anderson, Geoff; Stukel, Therese; Golden, Brian; Bell, Robert; Morra, Dante; Abrams, Howard; Schull, Michael J

2009-06-08

Rigorous evaluation of an intervention requires that its allocation be unbiased with respect to confounders; this is especially difficult in complex, system-wide healthcare interventions. We developed a short survey instrument to identify factors for a minimization algorithm for the allocation of a hospital-level intervention to reduce emergency department (ED) waiting times in Ontario, Canada. Potential confounders influencing the intervention's success were identified by literature review, and grouped by healthcare setting specific change stages. An international multi-disciplinary (clinical, administrative, decision maker, management) panel evaluated these factors in a two-stage modified-delphi and nominal group process based on four domains: change readiness, evidence base, face validity, and clarity of definition. An original set of 33 factors were identified from the literature. The panel reduced the list to 12 in the first round survey. In the second survey, experts scored each factor according to the four domains; summary scores and consensus discussion resulted in the final selection and measurement of four hospital-level factors to be used in the minimization algorithm: improved patient flow as a hospital's leadership priority; physicians' receptiveness to organizational change; efficiency of bed management; and physician incentives supporting the change goal. We developed a simple tool designed to gather data from senior hospital administrators on factors likely to affect the success of a hospital patient flow improvement intervention. A minimization algorithm will ensure balanced allocation of the intervention with respect to these factors in study hospitals.

MAOA promoter methylation and susceptibility to carotid atherosclerosis: role of familial factors in a monozygotic twin sample.

PubMed

Zhao, Jinying; Forsberg, Christopher W; Goldberg, Jack; Smith, Nicholas L; Vaccarino, Viola

2012-11-02

Atherosclerosis is a complex process involving both genetic and epigenetic factors. The monoamine oxidase A (MAOA) gene regulates the metabolism of key neurotransmitters and has been associated with cardiovascular risk factors. This study investigates whether MAOA promoter methylation is associated with atherosclerosis, and whether this association is confounded by familial factors in a monozygotic (MZ) twin sample. We studied 84 monozygotic (MZ) twin pairs drawn from the Vietnam Era Twin Registry. Carotid intima-media thickness (IMT) was measured by ultrasound. DNA methylation in the MAOA promoter region was quantified by bisulfite pyrosequencing using genomic DNA isolated from peripheral blood leukocytes. The association between DNA methylation and IMT was first examined by generalized estimating equation, followed by matched pair analyses to determine whether the association was confounded by familial factors. When twins were analyzed as individuals, increased methylation level was associated with decreased IMT at four of the seven studied CpG sites. However, this association substantially reduced in the matched pair analyses. Further adjustment for MAOA genotype also considerably attenuated this association. The association between MAOA promoter methylation and carotid IMT is largely explained by familial factors shared by the twins. Because twins reared together share early life experience, which may leave a long-lasting epigenetic mark, aberrant MAOA methylation may represent an early biomarker for unhealthy familial environment. Clarification of familial factors associated with DNA methylation and early atherosclerosis will provide important information to uncover clinical correlates of disease.

A community study on emotional distress among Arab and Jewish Israelis over the age of 60.

PubMed

Shemesh, Annarosa Anat; Kohn, Robert; Blumstein, Tzvia; Geraisy, Nabil; Novikov, Ilya; Levav, Itzhak

2006-01-01

The elderly constitute a vulnerable group for psychopathology, yet research on their mental health among both Arab and Jews in Israel remains limited. The same is the case in Arab countries. This paper reports on the contrasting distribution of the mean emotional distress (ED) scores and rates of suspected clinical cases, and their related risk factors, among community residents over the age of 60. Several national agencies conducted a survey on 5,055 elderly individuals to investigate their health status, including ED. The interview included socio-demographic and behavioral health items, as well as a modified 12 item-GHQ as a measure of ED. Total ED scores and prevalence rates for suspected psychopathology were calculated. Their respective risk factors were examined using univariate and multivariate methods. The ED scores were highest among Muslim Arabs (4.9), followed by Christian Arabs (4.2), Jews (3.1) and Druzes (2.8). Their estimated prevalence rates were 43.4%, 37.0%, 21.4%, and 17.0%, respectively. The gradient of these results remained unchanged in the multivariate analysis for ED scores adjusting for confounding variables. In contrast, logistic regression analysis controlling for confounding variables did not find a differential risk for suspected psychopathology between Arabs and Jews. Conceivably, the higher demoralization scores among elderly Arabs are associated with their minority status affiliation, as well as with the rapid social changes that have taken place in their midst. A cultural response style may be entertained as a possible explanation. However, these factors do not impact the risk for suspected psychopathology where no differential risk was noted after adjustments for confounders. Copyright 2005 John Wiley & Sons, Ltd.

The “Insight Paradox” in Schizophrenia: Magnitude, Moderators and Mediators of the Association Between Insight and Depression

PubMed Central

Belvederi Murri, Martino; Amore, Mario; Calcagno, Pietro; Respino, Matteo; Marozzi, Valentina; Masotti, Mattia; Bugliani, Michele; Innamorati, Marco; Pompili, Maurizio; Galderisi, Silvana; Maj, Mario

2016-01-01

The so-called “insight paradox” posits that among patients with schizophrenia higher levels of insight are associated with increased levels of depression. Although different studies examined this issue, only few took in account potential confounders or factors that could influence this association. In a sample of clinically stable patients with schizophrenia, insight and depression were evaluated using the Scale to assess Unawareness of Mental Disorder and the Calgary Depression Scale for Schizophrenia. Other rating scales were used to assess the severity of psychotic symptoms, extrapyramidal symptoms, hopelessness, internalized stigma, self-esteem, and service engagement. Regression models were used to estimate the magnitude of the association between insight and depression while accounting for the role of confounders. Putative psychological and sociodemographic factors that could act as mediators and moderators were examined using the PROCESS macro. By accounting for the role of confounding factors, the strength of the association between insight into symptoms and depression increased from 13% to 25% explained covariance. Patients with lower socioeconomic status (F = 8.5, P = .04), more severe illness (F = 4.8, P = .03) and lower levels of service engagement (F = 4.7, P = .03) displayed the strongest association between insight and depression. Lastly, hopelessness, internalized stigma and perceived discrimination acted as significant mediators. The relationship between insight and depression should be considered a well established phenomenon among patients with schizophrenia: it seems stronger than previously reported especially among patients with lower socioeconomic status, severe illness and poor engagement with services. These findings may have relevant implications for the promotion of insight among patients with schizophrenia. PMID:27069064

Serum 25-hydroxyvitamin D level is associated with myopia in the Korea national health and nutrition examination survey.

PubMed

Kwon, Jin-Woo; Choi, Jin A; La, Tae Yoon

2016-11-01

The aim of this article was to assess the associations of serum 25-hydroxyvitamin D [25(OH)D] and daily sun exposure time with myopia in Korean adults.This study is based on the Korea National Health and Nutrition Examination Survey (KNHANES) of Korean adults in 2010-2012; multiple logistic regression analyses were performed to examine the associations of serum 25(OH)D levels and daily sun exposure time with myopia, defined as spherical equivalent ≤-0.5D, after adjustment for age, sex, household income, body mass index (BMI), exercise, intraocular pressure (IOP), and education level. Also, multiple linear regression analyses were performed to examine the relationship between serum 25(OH)D levels with spherical equivalent after adjustment for daily sun exposure time in addition to the confounding factors above.Between the nonmyopic and myopic groups, spherical equivalent, age, IOP, BMI, waist circumference, education level, household income, and area of residence differed significantly (all P < 0.05). Compared with subjects with daily sun exposure time <2 hour, subjects with sun exposure time ≥2 to <5 hour, and those with sun exposure time ≥5 hour had significantly less myopia (P < 0.001). In addition, compared with subjects were categorized into quartiles of serum 25(OH)D, the higher quartiles had gradually lower prevalences of myopia after adjustment for confounding factors (P < 0.001). In multiple linear regression analyses, spherical equivalent was significantly associated with serum 25(OH)D concentration after adjustment for confounding factors (P = 0.002).Low serum 25(OH)D levels and shorter daily sun exposure time may be independently associated with a high prevalence of myopia in Korean adults. These data suggest a direct role for vitamin D in the development of myopia.

The "Insight Paradox" in Schizophrenia: Magnitude, Moderators and Mediators of the Association Between Insight and Depression.

PubMed

Belvederi Murri, Martino; Amore, Mario; Calcagno, Pietro; Respino, Matteo; Marozzi, Valentina; Masotti, Mattia; Bugliani, Michele; Innamorati, Marco; Pompili, Maurizio; Galderisi, Silvana; Maj, Mario

2016-09-01

The so-called "insight paradox" posits that among patients with schizophrenia higher levels of insight are associated with increased levels of depression. Although different studies examined this issue, only few took in account potential confounders or factors that could influence this association. In a sample of clinically stable patients with schizophrenia, insight and depression were evaluated using the Scale to assess Unawareness of Mental Disorder and the Calgary Depression Scale for Schizophrenia. Other rating scales were used to assess the severity of psychotic symptoms, extrapyramidal symptoms, hopelessness, internalized stigma, self-esteem, and service engagement. Regression models were used to estimate the magnitude of the association between insight and depression while accounting for the role of confounders. Putative psychological and sociodemographic factors that could act as mediators and moderators were examined using the PROCESS macro. By accounting for the role of confounding factors, the strength of the association between insight into symptoms and depression increased from 13% to 25% explained covariance. Patients with lower socioeconomic status (F = 8.5, P = .04), more severe illness (F = 4.8, P = .03) and lower levels of service engagement (F = 4.7, P = .03) displayed the strongest association between insight and depression. Lastly, hopelessness, internalized stigma and perceived discrimination acted as significant mediators. The relationship between insight and depression should be considered a well established phenomenon among patients with schizophrenia: it seems stronger than previously reported especially among patients with lower socioeconomic status, severe illness and poor engagement with services. These findings may have relevant implications for the promotion of insight among patients with schizophrenia. © The Author 2016. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Intelligence and all-cause mortality in the 6-Day Sample of the Scottish Mental Survey 1947 and their siblings: testing the contribution of family background.

PubMed

Iveson, Matthew H; Cukic, Iva; Der, Geoff; Batty, G David; Deary, Ian J

2018-02-01

Higher early-life intelligence is associated with a reduced risk of mortality in adulthood, though this association is apparently hardly attenuated when accounting for early-life socio-economic status (SES). However, the use of proxy measures of SES means that residual confounding may underestimate this attenuation. In the present study, the potential confounding effect of early-life SES was instead accounted for by examining the intelligence-mortality association within families. The association between early-life intelligence and mortality in adulthood was assessed in 727 members of the 6-Day Sample of the Scottish Mental Survey 1947 and, for the first time, 1580 of their younger siblings. These individuals were born between 1936 and 1958, and were followed up into later life, with deaths recorded up to 2015. Cox regression was used to estimate the relative risk of mortality associated with higher IQ scores after adjusting for shared family factors. A standard-deviation advantage in IQ score was associated with a significantly reduced mortality risk [hazard ratio = 0.76, p < 0.001, 95% confidence interval (CI) (0.68-0.84)]. This reduction in hazard was only slightly attenuated by adjusting for sex and shared family factors [hazard ratio = 0.79, p = 0.002, 95% CI (0.68-0.92)]. Although somewhat conservative, adjusting for all variance shared by a family avoids any potential residual confounding of the intelligence-mortality association arising from the use of proxy measures of early-life SES. The present study demonstrates that the longevity associated with higher early-life intelligence cannot be explained by early-life SES or within-family factors. © The Author 2017; Published by Oxford University Press on behalf of the International Epidemiological Association

Periodontal disease is associated with higher levels of C-reactive protein in non-diabetic, non-smoking acute myocardial infarction patients.

PubMed

Kodovazenitis, George; Pitsavos, Christos; Papadimitriou, Lambros; Deliargyris, Efthymios N; Vrotsos, Ioannis; Stefanadis, Christodoulos; Madianos, Phoebus N

2011-12-01

A link between periodontal disease (PD) and cardiovascular events has been proposed, but confounding by shared risk factors such as smoking and diabetes remains a concern. We examined the prevalence of PD and its contribution to C-reactive protein (CRP) levels in acute myocardial infarction (AMI) patients and in subjects without AMI and with angiographically nonobstructive coronary disease in the absence of these confounding risk factors. Periodontal status and admission CRP levels were evaluated in 87 non-diabetic and non-smoking subjects undergoing cardiac catheterization. The study group comprised of 47 patients with documented AMI, and 40 subjects without AMI and with angiographically nonobstructive coronary disease (ANCD group). Both the prevalence of PD and CRP levels were significantly higher in AMI patients compared with ANCD subjects (38.3% vs. 17.5%, p=0.03 and 44.3 vs. 8.5 mg/L, p<0.001 respectively). PD was associated with higher CRP levels in AMI patients (52.5 vs. 36.1 mg/L, p=0.04) as well as in ANCD subjects, however, in this group this was not significant (12.6 vs. 7.6 mg/L, p=0.5). Multivariable regression analysis confirmed two separate measures of PD as strong and independent contributors to elevated CRP levels in AMI patients (R2 = 0.28, R2 = 0.30, p=0.001). PD contributes to elevated CRP levels in non-diabetic, non-smoking AMI patients, independently of other confounding factors. These findings imply that periodontitis may emerge as a novel target for reducing future risk in AMI survivors. Copyright © 2011 Elsevier Ltd. All rights reserved.

Contribution of host, bacterial factors and antibiotic treatment to mortality in adult patients with bacteraemic pneumococcal pneumonia.

PubMed

Naucler, Pontus; Darenberg, Jessica; Morfeldt, Eva; Ortqvist, Ake; Henriques Normark, Birgitta

2013-06-01

Host and bacterial factors as well as different treatment regimens are likely to influence the outcome in patients with bacteraemic pneumococcal pneumonia. To estimate the relative contribution of host factors as well as bacterial factors and antibiotic treatment to mortality in bacteraemic pneumococcal pneumonia. A cohort study of 1580 adult patients with community-acquired bacteraemic pneumococcal pneumonia was conducted between 2007 and 2009 in Sweden. Data on host factors and initial antibiotic treatment were collected from patient records. Antibiotic resistance and serotype were determined for bacterial isolates. Logistic regression analyses were performed to assess risk factors for 30-day mortality. Smoking, alcohol abuse, solid tumour, liver disease and renal disease attributed to 14.9%, 13.1%, 13.1%, 8.0% and 7.4% of the mortality, respectively. Age was the strongest predictor, and mortality increased exponentially from 1.3% in patients <45 years of age to 26.1% in patients aged ≥85 years. There was considerable confounding by host factors on the association between serotype and mortality. Increasing age, liver disease and serotype were associated with mortality in patients admitted to the ICU. Combined treatment with β-lactam antibiotics and macrolide/quinolone was associated with reduced mortality in patients in the ICU, although confounding could not be ruled out. Host factors appear to be more important than the specific serotype as determinants of mortality in patients with bacteraemic pneumococcal pneumonia. Several host factors were identified that contribute to mortality, which is important for prognosis and to guide targeted prevention strategies.

First measurements of the scope for growth (SFG) in mussels from a large scale survey in the North-Atlantic Spanish coast.

PubMed

Albentosa, Marina; Viñas, Lucía; Besada, Victoria; Franco, Angeles; González-Quijano, Amelia

2012-10-01

SFG and physiological rates were measured in wild mussels from the Spanish Marine Pollution monitoring program (SMP) in order to determine seawater quality. It consists of 41 stations, covering almost 2500 km of coast, making the SMP the widest-ranging monitoring network in the Iberian Peninsula's Atlantic region. Results of the 2007 and 2008 surveys when 39 sites were sampled: (20 in 2007 and 19 in 2008, being 8 sites sampled both years) were presented. Chemical analyses were carried out to determine the relationships between physiological rates and the accumulation of toxic compounds. Data presented are the first to become available on the use of SFG as a biomarker of the marine environment on a large spatial scale (>1000 km) along Spain's Atlantic seaboard. SFG values enable significant differences to be established between the areas sampled and between the two years surveyed. The integration of biological and chemical data suggests that certain organochlorine compounds, namely chlordanes and DDTs, may have a negative effect on SFG, although such an effect is of a lesser magnitude than that associated with certain biological parameters such as condition index and mussel age. These variables act as confounding factors when attempting to determine the effect of chemical compounds present in the marine environment on mussel SFG. Further research is therefore needed on the relation between these confounding factors and SFG in order to apply the relevant corrective strategies to enable this index to be used in monitoring programs. The effect of these confounding factors is more clearly revealed in studies that cover a wide-ranging spatial and time scale, such as those carried out within the SMP. These results do not invalidate the use of biological data in monitoring programs, but rather point to the need to analyze all the factors affecting each biological process. Copyright © 2012 Elsevier B.V. All rights reserved.

Isolated and synergistic effects of PM10 and average temperature on cardiovascular and respiratory mortality.

PubMed

Pinheiro, Samya de Lara Lins de Araujo; Saldiva, Paulo Hilário Nascimento; Schwartz, Joel; Zanobetti, Antonella

2014-12-01

OBJECTIVE To analyze the effect of air pollution and temperature on mortality due to cardiovascular and respiratory diseases. METHODS We evaluated the isolated and synergistic effects of temperature and particulate matter with aerodynamic diameter < 10 µm (PM10) on the mortality of individuals > 40 years old due to cardiovascular disease and that of individuals > 60 years old due to respiratory diseases in Sao Paulo, SP, Southeastern Brazil, between 1998 and 2008. Three methodologies were used to evaluate the isolated association: time-series analysis using Poisson regression model, bidirectional case-crossover analysis matched by period, and case-crossover analysis matched by the confounding factor, i.e., average temperature or pollutant concentration. The graphical representation of the response surface, generated by the interaction term between these factors added to the Poisson regression model, was interpreted to evaluate the synergistic effect of the risk factors. RESULTS No differences were observed between the results of the case-crossover and time-series analyses. The percentage change in the relative risk of cardiovascular and respiratory mortality was 0.85% (0.45;1.25) and 1.60% (0.74;2.46), respectively, due to an increase of 10 μg/m3 in the PM10 concentration. The pattern of correlation of the temperature with cardiovascular mortality was U-shaped and that with respiratory mortality was J-shaped, indicating an increased relative risk at high temperatures. The values for the interaction term indicated a higher relative risk for cardiovascular and respiratory mortalities at low temperatures and high temperatures, respectively, when the pollution levels reached approximately 60 μg/m3. CONCLUSIONS The positive association standardized in the Poisson regression model for pollutant concentration is not confounded by temperature, and the effect of temperature is not confounded by the pollutant levels in the time-series analysis. The simultaneous exposure to different levels of environmental factors can create synergistic effects that are as disturbing as those caused by extreme concentrations.

Photosynthetic responses to temperature across leaf-canopy-ecosystem scales: a 15-year study in a Californian oak-grass savanna.

PubMed

Ma, Siyan; Osuna, Jessica L; Verfaillie, Joseph; Baldocchi, Dennis D

2017-06-01

Ecosystem CO 2 fluxes measured with eddy-covariance techniques provide a new opportunity to retest functional responses of photosynthesis to abiotic factors at the ecosystem level, but examining the effects of one factor (e.g., temperature) on photosynthesis remains a challenge as other factors may confound under circumstances of natural experiments. In this study, we developed a data mining framework to analyze a set of ecosystem CO 2 fluxes measured from three eddy-covariance towers, plus a suite of abiotic variables (e.g., temperature, solar radiation, air, and soil moisture) measured simultaneously, in a Californian oak-grass savanna from 2000 to 2015. Natural covariations of temperature and other factors caused remarkable confounding effects in two particular conditions: lower light intensity at lower temperatures and drier air and soil at higher temperatures. But such confounding effects may cancel out. At the ecosystem level, photosynthetic responses to temperature did follow a quadratic function on average. The optimum value of photosynthesis occurred within a narrow temperature range (i.e., optimum temperature, T opt ): 20.6 ± 0.6, 18.5 ± 0.7, 19.2 ± 0.5, and 19.0 ± 0.6 °C for the oak canopy, understory grassland, entire savanna, and open grassland, respectively. This paradigm confirms that photosynthesis response to ambient temperature changes is a functional relationship consistent across leaf-canopy-ecosystem scales. Nevertheless, T opt can shift with variations in light intensity, air dryness, or soil moisture. These findings will pave the way to a direct determination of thermal optima and limits of ecosystem photosynthesis, which can in turn provide a rich resource for baseline thresholds and dynamic response functions required for predicting global carbon balance and geographic shifts of vegetative communities in response to climate change.

Factors that contribute to biomarker responses in humans including a study in individuals taking Vitamin C supplementation.

PubMed

Anderson, D

2001-09-01

It is possible in many situations to identify humans exposed to potentially toxic materials in the workplace and in the environment. As in most human studies, there tends to be a high degree of interindividual variability in response to chemical insults. Some non-exposed control individuals exhibit as high a level of damage as some exposed individuals and some of these have levels of damage as low as many of the controls. Thus, it is only the mean values of the groups that can substantiate an exposure-related problem; the data on an individual basis are still of limited use. While human lymphocytes remain the most popular cell type for monitoring purposes, sperm, buccal, nasal, epithelial and placental cells are also used. However, for interpretation of responses, the issue of confounding factors must be addressed. There are endogenous confounding factors, such as age, gender, and genetic make-up and exogenous ones, including lifestyle habits (smoking, drinking, etc.) There are biomarkers of exposure, effect/response and susceptibility and the last may be influenced by the genotype and polymorphism genes existing in a population. From our own studies, confounding effects on cytogenetic damage and ras oncoproteins will be considered in relation to workers exposed to vinyl chloride and petroleum emissions and to volunteers taking Vitamin C supplementation. Smoking history, exposure and duration of employment affected the worker studies. For petroleum emissions, so did gender and season of exposure. For the non-smoking volunteer Vitamin C supplementation study, cholesterol levels, plasma Vitamin C levels, lipid peroxidation products and DNA damage in the Comet assay were also measured. Gender affected differences in Vitamin C levels, antioxidant capacity and the number of chromosome aberrations induced by bleomycin challenge in vitro. The results were the same for both high and low cholesterol subjects. The relationship between biomarkers and the various factors which affect them is complex. Sometimes the variables are not completely independent of each other.

Neuroticism explains unwanted variance in Implicit Association Tests of personality: possible evidence for an affective valence confound.

PubMed

Fleischhauer, Monika; Enge, Sören; Miller, Robert; Strobel, Alexander; Strobel, Anja

2013-01-01

Meta-analytic data highlight the value of the Implicit Association Test (IAT) as an indirect measure of personality. Based on evidence suggesting that confounding factors such as cognitive abilities contribute to the IAT effect, this study provides a first investigation of whether basic personality traits explain unwanted variance in the IAT. In a gender-balanced sample of 204 volunteers, the Big-Five dimensions were assessed via self-report, peer-report, and IAT. By means of structural equation modeling (SEM), latent Big-Five personality factors (based on self- and peer-report) were estimated and their predictive value for unwanted variance in the IAT was examined. In a first analysis, unwanted variance was defined in the sense of method-specific variance which may result from differences in task demands between the two IAT block conditions and which can be mirrored by the absolute size of the IAT effects. In a second analysis, unwanted variance was examined in a broader sense defined as those systematic variance components in the raw IAT scores that are not explained by the latent implicit personality factors. In contrast to the absolute IAT scores, this also considers biases associated with the direction of IAT effects (i.e., whether they are positive or negative in sign), biases that might result, for example, from the IAT's stimulus or category features. None of the explicit Big-Five factors was predictive for method-specific variance in the IATs (first analysis). However, when considering unwanted variance that goes beyond pure method-specific variance (second analysis), a substantial effect of neuroticism occurred that may have been driven by the affective valence of IAT attribute categories and the facilitated processing of negative stimuli, typically associated with neuroticism. The findings thus point to the necessity of using attribute category labels and stimuli of similar affective valence in personality IATs to avoid confounding due to recoding.

Major depressive disorder and depressive symptoms in intermittent explosive disorder.

PubMed

Medeiros, Gustavo C; Seger, Liliana; Grant, Jon E; Tavares, Hermano

2018-04-01

It is estimated that between 1.7 and 2.6 million people have had intermittent explosive disorder (IED) during their life in the United States alone. Co-occurring psychiatric disorders are very common in IED, being major depressive disorder arguably the most common. The objective of this study was to examine the clinical correlates of IED and depressive manifestations in 74 treatment-seeking subjects. After controlling for confounders, there were associations between major depressive disorder and severity of depressive symptoms, and (a) higher assault scores, (b) more severe hostile behavior and (c) worse social adjustment. Management of depressive symptoms may be an important for IED treatment. Copyright © 2018 Elsevier B.V. All rights reserved.

Comparing a marginal structural model with a Cox proportional hazard model to estimate the effect of time-dependent drug use in observational studies: statin use for primary prevention of cardiovascular disease as an example from the Rotterdam Study.

PubMed

de Keyser, Catherine E; Leening, Maarten J G; Romio, Silvana A; Jukema, J Wouter; Hofman, Albert; Ikram, M Arfan; Franco, Oscar H; Stijnen, Theo; Stricker, Bruno H

2014-11-01

When studying the causal effect of drug use in observational data, marginal structural modeling (MSM) can be used to adjust for time-dependent confounders that are affected by previous treatment. The objective of this study was to compare traditional Cox proportional hazard models (with and without time-dependent covariates) with MSM to study causal effects of time-dependent drug use. The example of primary prevention of cardiovascular disease (CVD) with statins was examined using up to 17.7 years of follow-up from 4,654 participants of the observational prospective population-based Rotterdam Study. In the MSM model, the weight was based on measurements of established cardiovascular risk factors and co-morbidity. In general, we could not demonstrate important differences in results from the Cox models and MSM. Results from analysis on duration of statin use suggested that substantial residual confounding by indication was not accounted for during the period shortly after statin initiation. In conclusion, although on theoretical grounds MSM is an elegant technique, lack of data on the precise time-dependent confounders, such as indication of treatment or other considerations of the prescribing physician jeopardizes the calculation of valid weights. Confounding remains a hurdle in observational effectiveness research on preventive drugs with a multitude of prescription determinants.

Permethrin Exposure Dosimetry: Biomarkers and Modifiable Factors

DTIC Science & Technology

2017-08-01

metabolite; (F = 16.16, p < 0.0001). This association holds after controlling for known confounders including sex , age, time that uniform was worn...and metabolite concentrations were examined via linear mixed modeling. All models were adjusted for creatinine, age, sex , days in BCT, number of

Testing the Developmental Origins of Health and Disease Hypothesis for Psychopathology Using Family-Based Quasi-Experimental Designs

PubMed Central

D’Onofrio, Brian M.; Class, Quetzal A.; Lahey, Benjamin B.; Larsson, Henrik

2014-01-01

The Developmental Origin of Health and Disease (DOHaD) hypothesis is a broad theoretical framework that emphasizes how early risk factors have a causal influence on psychopathology. Researchers have raised concerns about the causal interpretation of statistical associations between early risk factors and later psychopathology because most existing studies have been unable to rule out the possibility of environmental and genetic confounding. In this paper we illustrate how family-based quasi-experimental designs can test the DOHaD hypothesis by ruling out alternative hypotheses. We review the logic underlying sibling-comparison, co-twin control, offspring of siblings/twins, adoption, and in vitro fertilization designs. We then present results from studies using these designs focused on broad indices of fetal development (low birth weight and gestational age) and a particular teratogen, smoking during pregnancy. The results provide mixed support for the DOHaD hypothesis for psychopathology, illustrating the critical need to use design features that rule out unmeasured confounding. PMID:25364377

Inflammasomes make the case for littermate-controlled experimental design in studying host-microbiota interactions.

PubMed

Mamantopoulos, Michail; Ronchi, Francesca; McCoy, Kathy D; Wullaert, Andy

2018-04-19

Several human diseases are thought to evolve due to a combination of host genetic mutations and environmental factors that include alterations in intestinal microbiota composition termed dysbiosis. Although in some cases, host genetics may shape the gut microbiota and enable it to provoke disease, experimentally disentangling cause and consequence in such host-microbe interactions requires strict control over non-genetic confounding factors. Mouse genetic studies previously proposed Nlrp6/ASC inflammasomes as innate immunity regulators of the intestinal ecosystem. In contrast, using littermate-controlled experimental setups, we recently showed that Nlrp6/ASC inflammasomes do not alter the gut microbiota composition. Our analyses indicated that maternal inheritance and long-term separate housing are non-genetic confounders that preclude the use of non-littermate mice when analyzing host genetic effects on intestinal ecology. Here, we summarize and discuss our gut microbiota analyses in inflammasome-deficient mice for illustrating the importance of littermate experimental design in studying host-microbiota interactions.

Fetal growth and psychiatric and socioeconomic problems: population-based sibling comparison

PubMed Central

Class, Quetzal A.; Rickert, Martin E.; Larsson, Henrik; Lichtenstein, Paul; D’Onofrio, Brian M.

2014-01-01

Background It is unclear whether associations between fetal growth and psychiatric and socioeconomic problems are consistent with causal mechanisms. Aims To estimate the extent to which associations are a result of unmeasured confounding factors using a sibling-comparison approach. Method We predicted outcomes from continuously measured birth weight in a Swedish population cohort (n = 3 291 773), while controlling for measured and unmeasured confounding. Results In the population, lower birth weight (⩽2500 g) increased the risk of all outcomes. Sibling-comparison models indicated that lower birth weight independently predicted increased risk for autism spectrum disorder (hazard ratio for low birth weight = 2.44, 95% CI 1.99-2.97) and attention-deficit hyperactivity disorder. Although attenuated, associations remained for psychotic or bipolar disorder and educational problems. Associations with suicide attempt, substance use problems and social welfare receipt, however, were fully attenuated in sibling comparisons. Conclusions Results suggest that fetal growth, and factors that influence it, contribute to psychiatric and socioeconomic problems. PMID:25257067

Fetal growth and psychiatric and socioeconomic problems: population-based sibling comparison.

PubMed

Class, Quetzal A; Rickert, Martin E; Larsson, Henrik; Lichtenstein, Paul; D'Onofrio, Brian M

2014-11-01

It is unclear whether associations between fetal growth and psychiatric and socioeconomic problems are consistent with causal mechanisms. To estimate the extent to which associations are a result of unmeasured confounding factors using a sibling-comparison approach. We predicted outcomes from continuously measured birth weight in a Swedish population cohort (n = 3 291 773), while controlling for measured and unmeasured confounding. In the population, lower birth weight (⩽ 2500 g) increased the risk of all outcomes. Sibling-comparison models indicated that lower birth weight independently predicted increased risk for autism spectrum disorder (hazard ratio for low birth weight = 2.44, 95% CI 1.99-2.97) and attention-deficit hyperactivity disorder. Although attenuated, associations remained for psychotic or bipolar disorder and educational problems. Associations with suicide attempt, substance use problems and social welfare receipt, however, were fully attenuated in sibling comparisons. Results suggest that fetal growth, and factors that influence it, contribute to psychiatric and socioeconomic problems. Royal College of Psychiatrists.

Eco-HAB as a fully automated and ecologically relevant assessment of social impairments in mouse models of autism.

PubMed

Puścian, Alicja; Łęski, Szymon; Kasprowicz, Grzegorz; Winiarski, Maciej; Borowska, Joanna; Nikolaev, Tomasz; Boguszewski, Paweł M; Lipp, Hans-Peter; Knapska, Ewelina

2016-10-12

Eco-HAB is an open source, RFID-based system for automated measurement and analysis of social preference and in-cohort sociability in mice. The system closely follows murine ethology. It requires no contact between a human experimenter and tested animals, overcoming the confounding factors that lead to irreproducible assessment of murine social behavior between laboratories. In Eco-HAB, group-housed animals live in a spacious, four-compartment apparatus with shadowed areas and narrow tunnels, resembling natural burrows. Eco-HAB allows for assessment of the tendency of mice to voluntarily spend time together in ethologically relevant mouse group sizes. Custom-made software for automated tracking, data extraction, and analysis enables quick evaluation of social impairments. The developed protocols and standardized behavioral measures demonstrate high replicability. Unlike classic three-chambered sociability tests, Eco-HAB provides measurements of spontaneous, ecologically relevant social behaviors in group-housed animals. Results are obtained faster, with less manpower, and without confounding factors.

Weight Loss and Coronary Heart Disease: Sensitivity Analysis for Unmeasured Confounding by Undiagnosed Disease.

PubMed

Danaei, Goodarz; Robins, James M; Young, Jessica G; Hu, Frank B; Manson, JoAnn E; Hernán, Miguel A

2016-03-01

Evidence for the effect of weight loss on coronary heart disease (CHD) or mortality has been mixed. The effect estimates can be confounded due to undiagnosed diseases that may affect weight loss. We used data from the Nurses' Health Study to estimate the 26-year risk of CHD under several hypothetical weight loss strategies. We applied the parametric g-formula and implemented a novel sensitivity analysis for unmeasured confounding due to undiagnosed disease by imposing a lag time for the effect of weight loss on chronic disease. Several sensitivity analyses were conducted. The estimated 26-year risk of CHD did not change under weight loss strategies using lag times from 0 to 18 years. For a 6-year lag time, the risk ratios of CHD for weight loss compared with no weight loss ranged from 1.00 (0.99, 1.02) to 1.02 (0.99, 1.05) for different degrees of weight loss with and without restricting the weight loss strategy to participants with no major chronic disease. Similarly, no protective effect of weight loss was estimated for mortality risk. In contrast, we estimated a protective effect of weight loss on risk of type 2 diabetes. We estimated that maintaining or losing weight after becoming overweight or obese does not reduce the risk of CHD or death in this cohort of middle-age US women. Unmeasured confounding, measurement error, and model misspecification are possible explanations but these did not prevent us from estimating a beneficial effect of weight loss on diabetes.

Maternal age at first birth and offspring criminality: Using the children-of-twins design to test causal hypotheses

PubMed Central

Coyne, Claire A; Långström, Niklas; Rickert, Martin E; Lichtenstein, Paul; D’Onofrio, Brian M

2013-01-01

Teenage childbirth is a risk factor for poor offspring outcomes, particularly offspring antisocial behaviour. It is not clear if maternal age at first birth (MAFB) is causally associated with offspring antisocial behavior or if this association is due to selection factors that influence both the likelihood that a young woman gives birth early and that her offspring engage in antisocial behavior. The current study addresses the limitations of previous research by using longitudinal data from Swedish national registries and children-of-siblings and children-of-twins comparisons to identify the extent to which the association between MAFB and offspring criminal convictions is consistent with a causal influence and confounded by genetic or environmental factors that make cousins similar. We found offspring born to mothers who began childbearing earlier were more likely to be convicted of a crime than offspring born to mothers who delayed childbearing. The results from comparisons of differentially exposed cousins, especially born to discordant MZ twin sisters, provide support for a causal association between MAFB and offspring criminal convictions. The analyses also found little evidence for genetic confounding due to passive gene-environment correlation. Future studies are needed to replicate these findings and to identify environmental risk factors that mediate this causal association. PMID:23398750

Rumination, anxiety, depressive symptoms and subsequent depression in adolescents at risk for psychopathology: a longitudinal cohort study.

PubMed

Wilkinson, Paul O; Croudace, Tim J; Goodyer, Ian M

2013-10-08

A ruminative style of responding to low mood is associated with subsequent high depressive symptoms and depressive disorder in children, adolescents and adults. Scores on self-report rumination scales correlate strongly with scores on anxiety and depression symptom scales. This may confound any associations between rumination and subsequent depression. Our sample comprised 658 healthy adolescents at elevated risk for psychopathology. This study applied ordinal item (non-linear) factor analysis to pooled items from three self-report questionnaires to explore whether there were separate, but correlated, constructs of rumination, depression and anxiety. It then tested whether rumination independently predicted depressive disorder and depressive symptoms over the subsequent 12 months, after adjusting for confounding variables. We identified a single rumination factor, which was correlated with factors representing cognitive symptoms of depression, somatic symptoms of depression and anxiety symptoms; and one factor representing adaptive responses to low mood. Elevated rumination scores predicted onset of depressive disorders over the subsequent year (p = 0.035), and levels of depressive symptoms 12 months later (p < 0.0005), after adjustment for prior levels of depressive and anxiety symptoms. High rumination predicts onset of depressive disorder in healthy adolescents. Therapy that reduces rumination and increases distraction/problem-solving may reduce onset and relapse rates of depression.

Carrying the pain of abuse: gender-specific findings on the relationship between childhood physical abuse and obesity in adulthood.

PubMed

Fuller-Thomson, Esme; Sinclair, Deborah A; Brennenstuhl, Sarah

2013-01-01

Childhood abuse has been associated with negative adult health outcomes, including obesity. This study sought to investigate the association between childhood physical abuse and adult obesity, while controlling for five clusters of potentially confounding factors: childhood stressors, socioeconomic indicators, marital status, health behaviors, and mental health. Representative data from the 2005 Canadian Community Health Survey were selected. The response rate was approximately 84%. Gender-specific logistic regression analyses determined the association between abuse and obesity, while controlling for age and race and five clusters of potentially confounding factors. Of the 12,590 respondents with complete data, 2,787 were obese and 976 reported physical abuse as a child or adolescent by someone close to them. Among women with childhood physical abuse compared to no abuse, the odds of obesity were 35% higher, even when controlling for age, race, and the five clusters of factors (odds ratio (OR) = 1.35; 95% confidence interval (CI) = 1.09, 1.67). Childhood physical abuse was not associated with adult obesity among men (OR = 1.12; 95% CI = 0.82, 1.53). This study provides one of the first population-based, gender-specific analyses of the association between childhood physical abuse and obesity controlling for a wide range of factors. The gender-specific findings require further exploration.

Maternal age at first birth and offspring criminality: using the children of twins design to test causal hypotheses.

PubMed

Coyne, Claire A; Långström, Niklas; Rickert, Martin E; Lichtenstein, Paul; D'Onofrio, Brian M

2013-02-01

Teenage childbirth is a risk factor for poor offspring outcomes, particularly offspring antisocial behavior. It is not clear, however, if maternal age at first birth (MAFB) is causally associated with offspring antisocial behavior or if this association is due to selection factors that influence both the likelihood that a young woman gives birth early and that her offspring engage in antisocial behavior. The current study addresses the limitations of previous research by using longitudinal data from Swedish national registries and children of siblings and children of twins comparisons to identify the extent to which the association between MAFB and offspring criminal convictions is consistent with a causal influence and confounded by genetic or environmental factors that make cousins similar. We found offspring born to mothers who began childbearing earlier were more likely to be convicted of a crime than offspring born to mothers who delayed childbearing. The results from comparisons of differentially exposed cousins, especially born to discordant monozygotic twin sisters, provide support for a causal association between MAFB and offspring criminal convictions. The analyses also found little evidence for genetic confounding due to passive gene-environment correlation. Future studies are needed to replicate these findings and to identify environmental risk factors that mediate this causal association.

Adjusting for geographic variation in observational comparative effectiveness studies: a case study of antipsychotics using state Medicaid data.

PubMed

Root, Elisabeth Dowling; Thomas, Deborah S K; Campagna, Elizabeth J; Morrato, Elaine H

2014-08-27

Area-level variation in treatment and outcomes may be a potential source of confounding bias in observational comparative effectiveness studies. This paper demonstrates how to use exploratory spatial data analysis (ESDA) and spatial statistical methods to investigate and control for these potential biases. The case presented compares the effectiveness of two antipsychotic treatment strategies: oral second-generation antipsychotics (SGAs) vs. long-acting paliperiodone palmitate (PP). A new-start cohort study was conducted analyzing patient-level administrative claims data (8/1/2008-4/30/2011) from Missouri Medicaid. ESDA techniques were used to examine spatial patterns of antipsychotic prescriptions and outcomes (hospitalization and emergency department (ED) visits). Likelihood of mental health-related outcomes were compared between patients starting PP (N = 295) and oral SGAs (N = 8,626) using multilevel logistic regression models adjusting for patient composition (demographic and clinical factors) and geographic region. ESDA indicated significant spatial variation in antipsychotic prescription patterns and moderate variation in hospitalization and ED visits thereby indicating possible confounding by geography. In the multilevel models for this antipsychotic case example, patient composition represented a stronger source of confounding than geographic context. Because geographic variation in health care delivery is ubiquitous, it could be a comparative effectiveness research (CER) best practice to test for possible geographic confounding in observational data. Though the magnitude of the area-level geography effects were small in this case, they were still statistically significant and should therefore be examined as part of this observational CER study. More research is needed to better estimate the range of confounding due to geography across different types of observational comparative effectiveness studies and healthcare utilization outcomes.

Good research practices for comparative effectiveness research: approaches to mitigate bias and confounding in the design of nonrandomized studies of treatment effects using secondary data sources: the International Society for Pharmacoeconomics and Outcomes Research Good Research Practices for Retrospective Database Analysis Task Force Report--Part II.

PubMed

Cox, Emily; Martin, Bradley C; Van Staa, Tjeerd; Garbe, Edeltraut; Siebert, Uwe; Johnson, Michael L

2009-01-01

The goal of comparative effectiveness analysis is to examine the relationship between two variables, treatment, or exposure and effectiveness or outcome. Unlike data obtained through randomized controlled trials, researchers face greater challenges with causal inference with observational studies. Recognizing these challenges, a task force was formed to develop a guidance document on methodological approaches to addresses these biases. The task force was commissioned and a Chair was selected by the International Society for Pharmacoeconomics and Outcomes Research Board of Directors in October 2007. This report, the second of three reported in this issue of the Journal, discusses the inherent biases when using secondary data sources for comparative effectiveness analysis and provides methodological recommendations to help mitigate these biases. The task force report provides recommendations and tools for researchers to mitigate threats to validity from bias and confounding in measurement of exposure and outcome. Recommendations on design of study included: the need for data analysis plan with causal diagrams; detailed attention to classification bias in definition of exposure and clinical outcome; careful and appropriate use of restriction; extreme care to identify and control for confounding factors, including time-dependent confounding. Design of nonrandomized studies of comparative effectiveness face several daunting issues, including measurement of exposure and outcome challenged by misclassification and confounding. Use of causal diagrams and restriction are two techniques that can improve the theoretical basis for analyzing treatment effects in study populations of more homogeneity, with reduced loss of generalizability.

Associations of cardiovascular risk factors in Al Ain- United Arab Emirates

PubMed Central

Baynouna, Latifa M; Revel, Anthony D; Nagelkerke, Nico JD; Jaber, Tariq M; Omar, Aziza O; Ahmed, Nader M; Nazirudeen, Mohammad K; Al Sayed, Mamdouh F; Nour, Fuad A; Abdouni, Sameh

2009-01-01

Background Over the last 30 years the citizens of the United Arab Emirates have experienced major changes in life-style secondary to increased affluence. Currently, 1 in 5 adults have diabetes mellitus, but the associations (clustering) among risk factors, as well as the relevance of the concept of the metabolic syndrome, in this population is unknown. Aim To investigate the prevalence and associations among cardiovascular risk factors in this population, and explore to what extent associations can be explained by the metabolic syndrome according to ATP-III criteria. Method A community based survey, of conventional risk factors for cardiovascular disease was conducted among 817 national residents of Al Ain city, UAE. These factors were fasting blood sugar, blood pressure, lipid profile, BMI, waist circumference, smoking, or CHD family history. Odds ratios between risks factors, both unadjusted and adjusted for age and sex as well as adjusted for age, sex, and metabolic syndrome were calculated. Results Various risk factors were positively associated in this population; associations that are mostly unexplained by confounding by age and sex. For example, hypertension and diabetes were still strongly related (OR 2.5; 95% CI 1.7–3.7) after adjustment. An increased waist circumference showed similar relationship with hypertension (OR 2.3; 95% CI 1.5–3.5). Diabetes was related to an increased BMI (OR 1.5; 96% CI 1.0–2.3). Smoking was also associated with diabetes (OR 1.9, 95% CI 1.0–3.3). Further adjustment for metabolic syndrome reduced some associations but several remained. Conclusion In this population risk-factors cluster, but associations do not appear to be explained by the presence/absence of the ATP-III metabolic syndrome. Associations provide valuable information in planning interventions for screening and management. PMID:19371412

Clinical Research Methodology 2: Observational Clinical Research.

PubMed

Sessler, Daniel I; Imrey, Peter B

2015-10-01

Case-control and cohort studies are invaluable research tools and provide the strongest feasible research designs for addressing some questions. Case-control studies usually involve retrospective data collection. Cohort studies can involve retrospective, ambidirectional, or prospective data collection. Observational studies are subject to errors attributable to selection bias, confounding, measurement bias, and reverse causation-in addition to errors of chance. Confounding can be statistically controlled to the extent that potential factors are known and accurately measured, but, in practice, bias and unknown confounders usually remain additional potential sources of error, often of unknown magnitude and clinical impact. Causality-the most clinically useful relation between exposure and outcome-can rarely be definitively determined from observational studies because intentional, controlled manipulations of exposures are not involved. In this article, we review several types of observational clinical research: case series, comparative case-control and cohort studies, and hybrid designs in which case-control analyses are performed on selected members of cohorts. We also discuss the analytic issues that arise when groups to be compared in an observational study, such as patients receiving different therapies, are not comparable in other respects.

Physical work load and psychological stress of daily activities as predictors of disability pension due to musculoskeletal disorders.

PubMed

Ropponen, Annina; Svedberg, Pia; Koskenvuo, Markku; Silventoinen, Karri; Kaprio, Jaakko

2014-06-01

Physical work loading and psychological stress commonly co-occur in working life, hence potentially having an interrelationship that may affect work incapacity. This prospective cohort study aimed to investigate the effect of stability and change in physical work loading and stress on the risk of disability pension (DP) due to musculoskeletal diagnoses (MSD), while accounting for familial confounding in these associations. Data on 12,455 twins born before 1958 were surveyed of their physical work loading and psychological stress of daily activities in 1975 and 1981. The follow-up data was collected from pension registers until 2004. Cox proportional hazards regression models were used. During the follow up, 893 participants were granted DP due to MSD. Stable high (hazard ratio, HR, 2.21), but also increased physical work loading (HR 2.05) and high psychological stress (HR 2.22) were associated with increased risk for DP, and had significant interaction (p=0.032). The associations were confirmed when accounting for several confounding factors. Stable high but also increased physical work loading and psychological stress of daily activities between two timepoints with 6 years apart confirms their predictive role for an increased risk of DP. Both physical work loading and psychological stress seem to be independent from various confounding factors hence suggesting direct effect on risk for DP providing potential for occupational health care to early identification of persons at risk. © 2014 the Nordic Societies of Public Health.

Triple confusion: An interesting case of proteinuria in pregnancy.

PubMed

Guru, Pramod K; Ramaeker, Devon M; Jeybalan, Arundhathi; Shah, Nirav A; Bastacky, Sheldon; Liang, Kelly V

2016-01-01

Pregnancy-related renal diseases are unique and need special attention, both for diagnosis and management. The major confounding factors for diagnosis are the physiological multiorgan changes that occur throughout the gestational period. Proper diagnosis of the renal disease is also important, given the impact of varied management options both on the maternal and fetal health. A young middle-aged female with a long-standing history of diabetes presented to the hospital with worsening proteinuria in her second trimester of pregnancy. Clinical history, examinations, and laboratory analysis did not give any clues for diagnosis of a specific disease entity. This led us to take the risk of renal biopsy for a tissue diagnosis. The odds of renal biopsy favored the management decision in her case, thereby avoiding the confusions prior to biopsy. The pathological diagnosis is a surprise though not a unique entity on its own (minimal change disease in pregnancy). The case illustrates the disparity of clinical presentations and the pathology in patients, and the importance of renal biopsy in pregnant patients in particular.

Disease Ecology, Biodiversity, and the Latitudinal Gradient in Income

PubMed Central

Bonds, Matthew H.; Dobson, Andrew P.; Keenan, Donald C.

2012-01-01

While most of the world is thought to be on long-term economic growth paths, more than one-sixth of the world is roughly as poor today as their ancestors were hundreds of years ago. The majority of the extremely poor live in the tropics. The latitudinal gradient in income is highly suggestive of underlying biophysical drivers, of which disease conditions are an especially salient example. However, conclusions have been confounded by the simultaneous causality between income and disease, in addition to potentially spurious relationships. We use a simultaneous equations model to estimate the relative effects of vector-borne and parasitic diseases (VBPDs) and income on each other, controlling for other factors. Our statistical model indicates that VBPDs have systematically affected economic development, evident in contemporary levels of per capita income. The burden of VBDPs is, in turn, determined by underlying ecological conditions. In particular, the model predicts it to rise as biodiversity falls. Through these positive effects on human health, the model thus identifies measurable economic benefits of biodiversity. PMID:23300379

Depression and cardiovascular disease: Epidemiological evidence on their linking mechanisms.

PubMed

Penninx, Brenda W J H

2017-03-01

Depression's burden of disease goes beyond functioning and quality of life and extends to somatic health. Results from longitudinal cohort studies converge in illustrating that major depressive disorder (MDD) subsequently increases the risk of cardiovascular morbidity and mortality with about 80%. The impact of MDD on cardiovascular health may be partly explained by mediating mechanisms such as unhealthy lifestyle (smoking, excessive alcohol use, physical inactivity, unhealthy diet, therapy non-compliance) and unfavorable pathophysiological disturbances (autonomic, HPA-axis, metabolic and immuno-inflammatory dysregulations). A summary of the literature findings as well as relevant results from the large-scale Netherlands Study of Depression and Anxiety (N=2981) are presented. Persons with MDD have significantly worse lifestyles as well as more pathophysiological disturbances as compared to healthy controls. Some of these differences seem to be specific for (typical versus 'atypical', or antidepressant treated versus drug-naive) subgroups of MDD patients. Alternative explanations are also present, namely undetected confounding, iatrogenic effects or 'third factors' such as genetics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Prolonged recovery of sea otters from the Exxon Valdez oil spill? A re-examination of the evidence.

PubMed

Garshelis, David L; Johnson, Charles B

2013-06-15

Sea otters (Enhydra lutris) suffered major mortality after the Exxon Valdez oil spill in Prince William Sound, Alaska, 1989. We evaluate the contention that their recovery spanned over two decades. A model based on the otter age-at-death distribution suggested a large, spill-related population sink, but this has never been found, and other model predictions failed to match empirical data. Studies focused on a previously-oiled area where otter numbers (~80) stagnated post-spill; nevertheless, post-spill abundance exceeded the most recent pre-spill count, and population trends paralleled an adjacent, unoiled-lightly-oiled area. Some investigators posited that otters suffered chronic effects by digging up buried oil residues while foraging, but an ecological risk assessment indicated that exposure levels via this pathway were well below thresholds for toxicological effects. Significant confounding factors, including killer whale predation, subsistence harvests, human disturbances, and environmental regime shifts made it impossible to judge recovery at such a small scale. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Silhouette scales and body satisfaction in adolescents: a systematic literature review].

PubMed

Côrtes, Marcela Guimarães; Meireles, Adriana Lúcia; Friche, Amélia Augusta de Lima; Caiaffa, Waleska Teixeira; Xavier, César Coelho

2013-03-01

The purpose of this study was to summarize studies on adolescents' body satisfaction, focusing on the use of silhouette scales. A systematic review was carried out on MEDLINE, LILACS, SciELO, and in unpublished papers. The final analysis included 36 studies. The majority adopted the scale proposed by Stunkard et al., self-administered, presented in ascending order and on a single sheet of paper. Most studies compared characteristics on satisfaction and dissatisfaction, used the chi-square test, and did not test for confounding. Among 18 studies included in the meta-analysis, prevalence of body dissatisfaction ranged from 32.2% to 83%. The review showed wide heterogeneity between studies (p-value = 0.000; I(2) = 87.39) even after sub-group analysis and the absence of relevant information for proper comparison of studies. The article concludes by recommending greater rigor in application of the scales and presentation of study methods on body satisfaction assessed by silhouette scales, in addition to new methodological studies and those that elucidate factors related to body satisfaction.

"Care and feeding": the Asian environmental tobacco smoke consultants programme.

PubMed

Assunta, M; Fields, N; Knight, J; Chapman, S

2004-12-01

To review the tobacco industry's Asian environmental tobacco smoke (ETS) consultants programme, focusing on three key nations: China, Hong Kong, and Malaysia. Systematic keyword and opportunistic website searches of formerly private internal industry documents. The release of the 1986 US Surgeon General's report on second hand smoke provoked tobacco companies to prepare for a major threat to their industry. Asian programme activities included conducting national/international symposiums, consultant "road shows" and extensive lobbying and media activities. The industry exploited confounding factors said to be unique to Asian societies such as diet, culture and urban pollution to downplay the health risks of ETS. The industry consultants were said to be "..prepared to do the kinds of things they were recruited to do". The programme was successful in blurring the science on ETS and keeping the controversy alive both nationally and internationally. For the duration of the project, it also successfully dissuaded national policy makers from instituting comprehensive bans on smoking in public places.

Peri-operative hyperglycemia: a consideration for general surgery?

PubMed

Bower, Wendy F; Lee, Ping Yin; Kong, Alice P S; Jiang, Johnny Y; Underwood, Malcolm J; Chan, Juliana C N; van Hasselt, C Andrew

2010-02-01

Intraoperative hyperglycemia in cardiac and neurosurgical patients is significantly associated with morbidity. Little is known about the perioperative glycemic profile or its impact in other surgical populations or in nondiabetic patients. A systematic review of blood glucose values during major general surgical procedures reported since 1980 was conducted. Data extracted included blood glucose measures, study sample size, gender distribution, age grouping, study purpose, surgical procedure, anesthetic details, and infusion regime. Excluded studies were those with subjects with diabetes insipidus, insulin-treated diabetes, renal or hepatic failure, adrenal gland tumors or dysfunction, pregnancy, and emergency or trauma surgery. Blood glucose levels rose significantly with the induction of anesthesia (P < .001) in nondiabetic patients. At incision, 2 hours, 4 hours, and 6 hours, 30%, 40%, 38%, and 40% of studies, respectively, reported hyperglycemia. Factors that confound or protect against significant rises in perioperative glycemic levels in nondiabetic patients were identified. The findings facilitate investigating the impact of hyperglycemia on general surgical outcomes. Copyright 2010 Elsevier Inc. All rights reserved.

Childhood consequences of maternal obesity and excessive weight gain during pregnancy.

PubMed

Gaillard, Romy; Felix, Janine F; Duijts, Liesbeth; Jaddoe, Vincent W V

2014-11-01

Obesity is a major public health concern. In western countries, the prevalence of obesity in pregnant women has strongly increased, with reported prevalence rates reaching 30%. Also, up to 40% of women gain an excessive amount of weight during pregnancy. Recent observational studies and meta-analyses strongly suggest long-term impact of maternal obesity and excessive weight gain during pregnancy on adiposity, cardiovascular and respiratory related health outcomes in their children. These observations suggest that maternal adiposity during pregnancy may program common health problems in the offspring. Currently, it remains unclear whether the observed associations are causal, or just reflect confounding by family-based sociodemographic or lifestyle-related factors. Parent-offspring studies, sibling comparison studies, Mendelian randomization studies and randomized trials can help to explore the causality and underlying mechanisms. Also, the potential for prevention of common diseases in future generations by reducing maternal obesity and excessive weight gain during pregnancy needs to be explored. © 2014 Nordic Federation of Societies of Obstetrics and Gynecology.

"Care and feeding": the Asian environmental tobacco smoke consultants programme

PubMed Central

Assunta, M; Fields, N; Knight, J; Chapman, S

2004-01-01

Study objective: To review the tobacco industry's Asian environmental tobacco smoke (ETS) consultants programme, focusing on three key nations: China, Hong Kong, and Malaysia. Methods: Systematic keyword and opportunistic website searches of formerly private internal industry documents. Main results: The release of the 1986 US Surgeon General's report on second hand smoke provoked tobacco companies to prepare for a major threat to their industry. Asian programme activities included conducting national/international symposiums, consultant "road shows" and extensive lobbying and media activities. The industry exploited confounding factors said to be unique to Asian societies such as diet, culture and urban pollution to downplay the health risks of ETS. The industry consultants were said to be "...prepared to do the kinds of things they were recruited to do". Conclusions: The programme was successful in blurring the science on ETS and keeping the controversy alive both nationally and internationally. For the duration of the project, it also successfully dissuaded national policy makers from instituting comprehensive bans on smoking in public places. PMID:15564219

Medical students perception of test anxiety triggered by different assessment modalities.

PubMed

Guraya, Salman Y; Guraya, Shaista S; Habib, Fawzia; AlQuiliti, Khalid W; Khoshhal, Khalid I

2018-05-06

Test anxiety is well known among medical students. However, little is known about test anxiety produced by different components of exam individually. This study aimed to stratify varying levels of test anxiety provoked by each exam modality and to explore the students perceptions about confounding factors. A self-administered questionnaire was administered to medical students. The instrument contained four main themes; lifestyle, psychological and specific factors of information needs, learning styles, and perceived difficulty level of each assessment tool. A highest test anxiety score of 5 was ranked for "not scheduling available time" and "insufficient exercise" by 28.8 and 28.3% students, respectively. For "irrational thoughts about exam" and "fear to fail", a highest test anxiety score of 5 was scored by 28.8 and 25.7% students, respectively. The highest total anxiety score of 1255 was recorded for long case exam, followed by 975 for examiner-based objective structured clinical examination. Excessive course load and course not well covered by faculty were thought to be the main confounding factors. The examiner-based assessment modalities induced high test anxiety. Faculty is urged to cover core contents within stipulated time and to rigorously reform and update existing curricula to prepare relevant course material.

On the Influence of Confounding Factors in Multisite Brain Morphometry Studies of Developmental Pathologies: Application to Autism Spectrum Disorder.

PubMed

Auzias, G; Takerkart, S; Deruelle, C

2016-05-01

Pooling data acquired on different MR scanners is a commonly used practice to increase the statistical power of studies based on MRI-derived measurements. Such studies are very appealing since they should make it possible to detect more subtle effects related to pathologies. However, the influence of confounds introduced by scanner-related variations remains unclear. When studying brain morphometry descriptors, it is crucial to investigate whether scanner-induced errors can exceed the effect of the disease itself. More specifically, in the context of developmental pathologies such as autism spectrum disorders (ASD), it is essential to evaluate the influence of the scanner on age-related effects. In this paper, we studied a dataset composed of 159 anatomical MR images pooled from three different scanners, including 75 ASD patients and 84 healthy controls. We quantitatively assessed the effects of the age, pathology, and scanner factors on cortical thickness measurements. Our results indicate that scan pooling from different sites would be less fruitful in some cortical regions than in others. Although the effect of age is consistent across scanners, the interaction between the age and scanner factors is important and significant in some specific cortical areas.

Sperm studies in anesthesiologists

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

Wyrobek, A.J.; Brodsky, J.; Gordon, l.

1981-11-01

Semen samples were collected from 46 anesthesiologists each of whom had worked a minimum of one year in hospital operating rooms ventilated with modern gas-scavenging devices. Samples collected from 26 beginning residents in anesthesiology served as controls. Concentrations of sperm and percentage of sperm having abnormal head shapes were determined for each sample. No significant differences were found between anesthesiologists and beginning residents. Limiting the analyses to men having no confounding factors (varicocele, recent illness, medications, heavy smoking, frequent sauna use) did not change the results. The sperm concentration and morphology in 13 men did not change signficantly after onemore » year of exposure to anesthetic gases. However, the group of men who had one or more confounding factors (excluding exposure to anesthetic gases) showed significantly higher percentages of sperm abnormalities than did the group of men without such factors. These results suggest that limited exposure to anesthetic gases does not significantly affect sperm production as judged by changes in sperm concentration and morphology. These data are reassuring, but since the hospitals surveyed used modern gas-scavenging devices, men who are occupationally exposed to anesthetic gases without this protection should be studied for fuller assessment of the possible human spermatotoxic effects.« less

In plastico: laboratory material newness affects growth and reproduction of Daphnia magna reared in 50-ml polypropylene tubes

PubMed Central

Cuhra, Marek; Bøhn, Thomas; Cuhra, Petr

2017-01-01

Plastic laboratory materials are found to affect vital parameters of the waterflea Daphnia magna. The main responsible factor is defined as “newness” of the materials. Juvenile D. magna were raised individually in; a) new laboratory-standard 50 ml polypropylene tubes, and; b) identical tubes which had been washed and aerated for several weeks. Newness had significant effects on growth and fecundity of D. magna. New tubes caused delayed maturation, reduced reproduction and reduced growth when compared to washed and re-used tubes of the same commercial brand. The findings indicate that newness of tubes has inhibiting or toxic effects on D. magna. Often laboratory plastics are intended for single-use due to sterility demands. Newness might be an important confounding factor in research results and should not be disregarded. Disposable plastic utensils may come with a seemingly ignored cost and induce adverse effects in biological test-organisms and systems. The presented findings accentuate continued need for general awareness concerning confounding factors stemming from material laboratory environment. Based on the present findings the authors suggest that plastics intended for use in sensitive research may need to be washed and aerated prior to use. PMID:28425469

An Examination of the Relationship between Motor Coordination and Executive Functions in Adolescents

ERIC Educational Resources Information Center

Rigoli, Daniela; Piek, Jan P.; Kane, Robert; Oosterlaan, Jaap

2012-01-01

Aim: Research suggests important links between motor coordination and executive functions. The current study examined whether motor coordination predicts working memory, inhibition, and switching performance, extending previous research by accounting for attention-deficit-hyperactivity disorder (ADHD) symptomatology and other confounding factors,…

A TIME SERIES ANALYSIS OF AIR POLLUTION AND PRETERM BIRTH IN PENNSYLVANIA, 1997-2001

EPA Science Inventory

Introduction: Small increases in risk for preterm delivery in relation to air pollution have been reported, but prior investigations may have inadequately controlled for individual factors, such as maternal smoking. To eliminate confounding by known and unknown individual risk f...

Effects of Disturbance-induced trauma on foraging by subterranean termites (Isoptera: Rhinotermitidae)

Treesearch

R. J. Woodrow; T. G. Shelton; R. J. Oshiro; J. K. Grace; T. L. Wagner

2008-01-01

Toxicant baiting systems are effective at population suppression against both the Formosan subterranean termite, Coptotermes formosanus Shiraki, and the Eastern subterranean termite, Reticulitermes flavipes (Kollar). However, trap shyness (i.e., station abandonment) is often quoted as a confounding factor affecting their success....

IDENTIFICATION AND INTERPRETATION OF DEVELOPMENTAL NEUROTOXICITY EFFECTS: A REPORT FROM THE ILSI RESEARCH FOUNDATION/RISK SCIENCE INSTITUTE EXPERT WORKING GROUP ON NEURODEVELOPMENTAL ENDPOINTS

EPA Science Inventory

The reliable detection, measurement, and interpretation of treatment-related developmental neurotoxicity (DNT) effects depend on appropriate study design and execution, using scientifically established methodologies, with appropriate controls to minimize confounding factors. App...

Urinary excretion of mutagens in coke oven workers.

PubMed

Clonfero, E; Granella, M; Marchioro, M; Barra, E L; Nardini, B; Ferri, G; Foà, V

1995-03-01

The influence of occupational exposure to polycyclic aromatic hydrocarbons (PAHs) on urinary mutagenic activity was assessed in 75 coke oven workers, using a highly sensitive bacterial mutagen technique (extraction with C18 resin and liquid micro-preincubation test on strain TA98 of Salmonella typhimurium in the presence of metabolizing and deconjugating enzymes). Exposure to PAHs was assessed according to the urinary excretion of 1-pyrenol; the main confounding factors were checked by the number of cigarettes smoked per day and the levels of nicotine and its metabolites in urine, or by ascertaining whether recommended dietary restrictions had been followed. Of the 20 urine samples which turned out to be positive (producing at least double the number of spontaneous revertants), 19 (95%) belonged to smokers. Only one non-smoker had obvious urinary mutagenic activity, and was highly exposed occupationally to PAHs (urinary 1-pyrenol of 3.930 mumol/mol of creatinine). Of the five urine samples from subjects who had not followed the recommended diet, two (40%) were clearly mutagenic. Multiple regression analysis (n = 67) showed that the presence of samples positive for urinary mutagenic activity depended only on smoking habits, if this confounding factor was assessed according to the number of cigarettes smoked per day, while the significant influence of exposure to PAH could be shown when the confounding factor was objectively estimated according to the urinary levels of nicotine and its metabolites. Assessment of the mutagenic potency of urinary extracts (net revertants/mmol creatinine) confirmed the strong influence of smoking habits on urinary mutagenic activity (all smokers 2156 +/- 2691 versus non-smokers 939 +/- 947 net revertants/mmol creatinine; Mann-Whitney test: P < 0.01). In smokers highly exposed to PAHs, greater excretion of mutagens with respect to low-exposure smokers was revealed (3548 +/- 4009 versus 1552 +/- 1227 net revertants/mmol creatinine; Mann-Whitney test: P < 0.01). Multiple regression analysis showed that the mutagenic potency of urinary extracts of coke oven workers depended on exposure to PAHs, tobacco smoking habits, and consumption of fried, grilled or barbecued meat. Increased urinary mutagenic activity strengthens epidemiological evidence of the increased risk of renal and urinary tract tumours in these workers. The presence of mutagenic metabolites in urine as a result of occupational exposure to PAH may be demonstrated only by using highly sensitive techniques for assessing urinary mutagenic activity in studies which include careful checking of the main confounding factors.

Potential confounding in the association between short birth intervals and increased neonatal, infant, and child mortality

PubMed Central

Perin, Jamie; Walker, Neff

2015-01-01

Background Recent steep declines in child mortality have been attributed in part to increased use of contraceptives and the resulting change in fertility behaviour, including an increase in the time between births. Previous observational studies have documented strong associations between short birth spacing and an increase in the risk of neonatal, infant, and under-five mortality, compared to births with longer preceding birth intervals. In this analysis, we compare two methods to estimate the association between short birth intervals and mortality risk to better inform modelling efforts linking family planning and mortality in children. Objectives Our goal was to estimate the mortality risk for neonates, infants, and young children by preceding birth space using household survey data, controlling for mother-level factors and to compare the results to those from previous analyses with survey data. Design We assessed the potential for confounding when estimating the relative mortality risk by preceding birth interval and estimated mortality risk by birth interval in four categories: less than 18 months, 18–23 months, 24–35 months, and 36 months or longer. We estimated the relative risks among women who were 35 and older at the time of the survey with two methods: in a Cox proportional hazards regression adjusting for potential confounders and also by stratifying Cox regression by mother, to control for all factors that remain constant over a woman's childbearing years. We estimated the overall effects for birth spacing in a meta-analysis with random survey effects. Results We identified several factors known for their associations with neonatal, infant, and child mortality that are also associated with preceding birth interval. When estimating the effect of birth spacing on mortality, we found that regression adjustment for these factors does not substantially change the risk ratio for short birth intervals compared to an unadjusted mortality ratio. For birth intervals less than 18 months, standard regression adjustment for confounding factors estimated a risk ratio for neonatal mortality of 2.28 (95% confidence interval: 2.18–2.37). This same effect estimated within mother is 1.57 (95% confidence interval: 1.52–1.63), a decline of almost one-third in the effect on neonatal mortality. Conclusions Neonatal, infant, and child mortality are strongly and significantly related to preceding birth interval, where births within a short interval of time after the previous birth have increased mortality. Previous analyses have demonstrated this relationship on average across all births; however, women who have short spaces between births are different from women with long spaces. Among women 35 years and older where a comparison of birth spaces within mother is possible, we find a much reduced although still significant effect of short birth spaces on child mortality. PMID:26562139

Potential confounding in the association between short birth intervals and increased neonatal, infant, and child mortality.

PubMed

Perin, Jamie; Walker, Neff

2015-01-01

Recent steep declines in child mortality have been attributed in part to increased use of contraceptives and the resulting change in fertility behaviour, including an increase in the time between births. Previous observational studies have documented strong associations between short birth spacing and an increase in the risk of neonatal, infant, and under-five mortality, compared to births with longer preceding birth intervals. In this analysis, we compare two methods to estimate the association between short birth intervals and mortality risk to better inform modelling efforts linking family planning and mortality in children. Our goal was to estimate the mortality risk for neonates, infants, and young children by preceding birth space using household survey data, controlling for mother-level factors and to compare the results to those from previous analyses with survey data. We assessed the potential for confounding when estimating the relative mortality risk by preceding birth interval and estimated mortality risk by birth interval in four categories: less than 18 months, 18-23 months, 24-35 months, and 36 months or longer. We estimated the relative risks among women who were 35 and older at the time of the survey with two methods: in a Cox proportional hazards regression adjusting for potential confounders and also by stratifying Cox regression by mother, to control for all factors that remain constant over a woman's childbearing years. We estimated the overall effects for birth spacing in a meta-analysis with random survey effects. We identified several factors known for their associations with neonatal, infant, and child mortality that are also associated with preceding birth interval. When estimating the effect of birth spacing on mortality, we found that regression adjustment for these factors does not substantially change the risk ratio for short birth intervals compared to an unadjusted mortality ratio. For birth intervals less than 18 months, standard regression adjustment for confounding factors estimated a risk ratio for neonatal mortality of 2.28 (95% confidence interval: 2.18-2.37). This same effect estimated within mother is 1.57 (95% confidence interval: 1.52-1.63), a decline of almost one-third in the effect on neonatal mortality. Neonatal, infant, and child mortality are strongly and significantly related to preceding birth interval, where births within a short interval of time after the previous birth have increased mortality. Previous analyses have demonstrated this relationship on average across all births; however, women who have short spaces between births are different from women with long spaces. Among women 35 years and older where a comparison of birth spaces within mother is possible, we find a much reduced although still significant effect of short birth spaces on child mortality.

Parallel Worlds of Public and Commercial Bioactive Chemistry Data

PubMed Central

2014-01-01

The availability of structures and linked bioactivity data in databases is powerfully enabling for drug discovery and chemical biology. However, we now review some confounding issues with the divergent expansions of public and commercial sources of chemical structures. These are associated with not only expanding patent extraction but also increasingly large vendor collections amassed via different selection criteria between SciFinder from Chemical Abstracts Service (CAS) and major public sources such as PubChem, ChemSpider, UniChem, and others. These increasingly massive collections may include both real and virtual compounds, as well as so-called prophetic compounds from patents. We address a range of issues raised by the challenges faced resolving the NIH probe compounds. In addition we highlight the confounding of prior-art searching by virtual compounds that could impact the composition of matter patentability of a new medicinal chemistry lead. Finally, we propose some potential solutions. PMID:25415348

Environmental risk factors contributing to traffic accidents in children: a case-control study.

PubMed

Jamshidi, Ensiyeh; Moradi, Ali; Majdzadeh, Reza

2017-09-01

The aim of this study is to identify environmental risk factors related to road accidents in children of Tehran. This case-control study was performed in 2013. The cases were injured pedestrians aged 5-15 who were admitted to major hospitals supervised by Tehran University of Medical Sciences. The sample size for the cases was 273 and for the control group was 546. For the completeness of the clusters, 7 extra persons in case (total = 280) and 14 persons (total = 560) in control group were included. The interference of confounding variables assessed through forward conditional logistic regression. Result shows occurrence of traffic accidents was significantly associate with the width of the alleys or (<5 m: OR = 8.4, 95% CI: 3.3-21.5; 5-8 m: OR = 4.7, 95% CI: 1.8-12.2), distance from home to school((<100 m: OR = 1.7, 95% CI: 1.0-2.8), existence of parking lot (OR = 1.5, 95% CI: 1.0-2.3), traffic congestion (OR = 4.1, 95% CI: 2.6-6.4), traffic speed (OR = 2.1, 95% CI: 1.3-3.2) and existence of pedestrian bridges(OR = 4.2, 95% CI: 2.6-6.8). In the light of the important role of environmental factors in the occurrence of child traffic accidents, alleviating structural risk factors in addition to education and enforcement need more systematic efforts and planning by policymakers and urban planners to attain pedestrian safety goals.

Human gut microbiota: does diet matter?

PubMed

Maukonen, Johanna; Saarela, Maria

2015-02-01

The human oro-gastrointestinal (GI) tract is a complex system, consisting of oral cavity, pharynx, oesophagus, stomach, small intestine, large intestine, rectum and anus, which all together with the accessory digestive organs constitute the digestive system. The function of the digestive system is to break down dietary constituents into small molecules and then absorb these for subsequent distribution throughout the body. Besides digestion and carbohydrate metabolism, the indigenous microbiota has an important influence on host physiological, nutritional and immunological processes, and commensal bacteria are able to modulate the expression of host genes that regulate diverse and fundamental physiological functions. The main external factors that can affect the composition of the microbial community in generally healthy adults include major dietary changes and antibiotic therapy. Changes in some selected bacterial groups have been observed due to controlled changes to the normal diet e.g. high-protein diet, high-fat diet, prebiotics, probiotics and polyphenols. More specifically, changes in the type and quantity of non-digestible carbohydrates in the human diet influence both the metabolic products formed in the lower regions of the GI tract and the bacterial populations detected in faeces. The interactions between dietary factors, gut microbiota and host metabolism are increasingly demonstrated to be important for maintaining homeostasis and health. Therefore the aim of this review is to summarise the effect of diet, and especially dietary interventions, on the human gut microbiota. Furthermore, the most important confounding factors (methodologies used and intrinsic human factors) in relation to gut microbiota analyses are elucidated.

Financial Strain, Major Family Life Events, and Parental Academic Involvement During Adolescence.

PubMed

Camacho-Thompson, Daisy E; Gillen-O'Neel, Cari; Gonzales, Nancy A; Fuligni, Andrew J

2016-06-01

Parental academic involvement-whether through school participation and communication, or supervision and assistance at home-often has been cited as a way to enhance academic achievement. Yet, little is known about how the financial and life pressures faced by families can compromise parents' ability to become involved in their adolescents' education. In the current study, these dynamics were examined among Mexican-origin families, who often may face challenging financial and familial circumstances, and whose students may have more difficulty in secondary school. Parents of Mexican-origin ninth and tenth grade students from two high schools in Los Angeles (N = 428; 50 % female) completed quantitative interviews. The results revealed that financial strain predicted less involvement at school, and major family life events predicted less involvement at home, even after controlling for potentially confounding factors. Moreover, both of the associations between parental stress and parental academic involvement were mediated by lower levels of relationship quality between parents and adolescents, but not by conflict within the parent-adolescent dyad or parental depressive and somatic symptoms. The findings suggest that stress may limit parents' ability to become involved their adolescents' education, and highlight the importance of understanding family dynamics when examining parental academic involvement among Mexican-origin families.

Accounting for biases in riboprofiling data indicates a major role for proline in stalling translation.

PubMed

Artieri, Carlo G; Fraser, Hunter B

2014-12-01

The recent advent of ribosome profiling-sequencing of short ribosome-bound fragments of mRNA-has offered an unprecedented opportunity to interrogate the sequence features responsible for modulating translational rates. Nevertheless, numerous analyses of the first riboprofiling data set have produced equivocal and often incompatible results. Here we analyze three independent yeast riboprofiling data sets, including two with much higher coverage than previously available, and find that all three show substantial technical sequence biases that confound interpretations of ribosomal occupancy. After accounting for these biases, we find no effect of previously implicated factors on ribosomal pausing. Rather, we find that incorporation of proline, whose unique side-chain stalls peptide synthesis in vitro, also slows the ribosome in vivo. We also reanalyze a method that implicated positively charged amino acids as the major determinant of ribosomal stalling and demonstrate that it produces false signals of stalling in low-coverage data. Our results suggest that any analysis of riboprofiling data should account for sequencing biases and sparse coverage. To this end, we establish a robust methodology that enables analysis of ribosome profiling data without prior assumptions regarding which positions spanned by the ribosome cause stalling. © 2014 Artieri and Fraser; Published by Cold Spring Harbor Laboratory Press.

A recessive genetic model and runs of homozygosity in major depressive disorder

PubMed Central

Power, Robert A.; Keller, Matthew C.; Ripke, Stephan; Abdellaoui, Abdel; Wray, Naomi R.; Sullivan, Patrick F; Breen, Gerome

2014-01-01

Genome-wide association studies (GWASs) of major depressive disorder (MDD) have yet to identify variants that surpass the threshold for genome-wide significance. A recent study reported that runs of homozygosity (ROH) are associated with schizophrenia, reflecting a novel genetic risk factor resulting from increased parental relatedness and recessive genetic effects. Here we undertake an analysis of ROH for MDD using the 9,238 MDD cases and 9,521 controls reported in a recent mega-analysis of 9 GWAS. Since evidence for association with ROH could reflect a recessive mode of action at loci, we also conducted a genome-wide association analyses under a recessive model. The genome-wide association analysis using a recessive model found no significant associations. Our analysis of ROH suggested that there was significant heterogeneity of effect across studies in effect (p=0.001), and it was associated with genotyping platform and country of origin. The results of the ROH analysis show that differences across studies can lead to conflicting systematic genome-wide differences between cases and controls that are unaccounted for by traditional covariates. They highlight the sensitivity of the ROH method to spurious associations, and the need to carefully control for potential confounds in such analyses. We found no strong evidence for a recessive model underlying MDD. PMID:24482242

Laser Treatment of Peri-Implantitis: A Literature Review

PubMed Central

Ashnagar, Sajjad; Nowzari, Hessam; Nokhbatolfoghahaei, Hanieh; Yaghoub Zadeh, Behnoush; Chiniforush, Nasim; Choukhachi Zadeh, Nastaran

2014-01-01

Peri-implantitis is a state defined as an inflammatory reaction around osseointegrated implants, leading to progressive loss of supporting bone. Various treatment methods are suggested in the treatment of peri-implantitis and clinicians have to choose a method over a large number of treatment protocols. Lasers have shown promising therapeutic effect in treatment of peri-implantitis. However, some controversies have been found in clinical outcomes after using lasers. Therefore, we aimed to review the current literature over the past ten years for the use of lasers in treatment of peri-implantitis, via the Pubmed electronic database of the US National Library of Medicine. Fifteen human studies were reviewed. Er:YAG (Erbium-Doped Yttrium Aluminum Garnet), CO2(Carbon Dioxide Laser) and Diode lasers were used. Despite inconsistencies and disharmonies among studies in terms of study design, positive treatment outcomes were obvious among the majority of them. However, short period of follow-ups and poor control of plaque index, as a critical confounding factor, were the major problems which these studies suffered from. It seems that one session laser therapy is not adequate for achieving optimal clinical outcome. Further studies with longer periods of follow-ups, intense control of plaque index, and various sessions of laser treatments are needed to clearly illustrate the clinical privilege of laser therapy. PMID:25653815

Financial Strain, Major Family Life Events, and Parental Academic Involvement during Adolescence

PubMed Central

Camacho-Thompson, Daisy E.; Gillen-O’Neel, Cari; Gonzales, Nancy A.; Fuligni, Andrew J.

2017-01-01

Parental academic involvement—whether through school participation and communication, or supervision and assistance at home—often has been cited as a way to enhance academic achievement. Yet, little is known about how the financial and life pressures faced by families can compromise parents’ ability to become involved in their adolescents’ education. In the current study, these dynamics were examined among Mexican-origin families, who often may face challenging financial and familial circumstances, and whose students may have more difficulty in secondary school. Parents of Mexican-origin ninth and tenth grade students from two high schools in Los Angeles (N = 428; 49% female) completed quantitative interviews. The results revealed that financial strain predicted less involvement at school, and major family life events predicted less involvement at home, even after controlling for potentially confounding factors. Moreover, both of the associations between parental stress and parental academic involvement were mediated by lower levels of relationship quality between parents and adolescents, but not by conflict within the parent-adolescent dyad or parental depressive and somatic symptoms. The findings suggest that stress may limit parents’ ability to become involved their adolescents’ education, and highlight the importance of understanding family dynamics when examining parental academic involvement among Mexican-origin families. PMID:26951508

Relationship between major dietary patterns and sarcopenia among menopausal women.

PubMed

Mohseni, Reza; Aliakbar, Sima; Abdollahi, Afsoun; Yekaninejad, Mir Saeed; Maghbooli, Zhila; Mirzaei, Khadijeh

2017-12-01

Dietary habits have been associated with the prevalence of the sarcopenia and limited data are available in this field for menopausal women. This study focused on the relationship between dietary patterns and prevalence of the sarcopenia in menopausal women. This cross-sectional study was done in 250 menopausal women 45 years old or older. Dietary data were collected using a food-frequency questionnaire and physical activity was assessed by International Physical Activity Questionnaire (IPAQ). Height, weight, skeletal muscle mass, hand grip, and gait speed were measured and sarcopenia was defined based on European Working Group on Sarcopenia in Older People (EWGSOP) guidelines. Using factor analysis, two major dietary patterns were found: a Western pattern (high in commercial beverage, sugar and dessert, snacks, solid fat, potato, high fat dairy, legume, organ meat, fast food, and sweets) and a Mediterranean pattern (high in olive, low-fat dairy, vegetable, fish, nut, and vegetable oil). After adjusting for confounding variables, for the highest vs the lowest tertiles, the Odds Ratio (OR) for sarcopenia was 1.06 [95% confidence interval (CI), 0.47-2.37] in the Western pattern and 0.40 [95% confidence interval (CI), 0.17-0.89] in the Mediterranean pattern. Our findings suggest that Mediterranean dietary pattern has a favorable role in the prevention of sarcopenia.

Soil bacterial communities are shaped by temporal and environmental filtering: evidence from a long-term chronosequence.

PubMed

Freedman, Zachary; Zak, Donald R

2015-09-01

Soil microbial communities are abundant, hyper-diverse and mediate global biogeochemical cycles, but we do not yet understand the processes mediating their assembly. Current hypothetical frameworks suggest temporal (e.g. dispersal limitation) and environmental (e.g. soil pH) filters shape microbial community composition; however, there is limited empirical evidence supporting this framework in the hyper-diverse soil environment, particularly at large spatial (i.e. regional to continental) and temporal (i.e. 100 to 1000 years) scales. Here, we present evidence from a long-term chronosequence (4000 years) that temporal and environmental filters do indeed shape soil bacterial community composition. Furthermore, nearly 20 years of environmental monitoring allowed us to control for potentially confounding environmental variation. Soil bacterial communities were phylogenetically distinct across the chronosequence. We determined that temporal and environmental factors accounted for significant portions of bacterial phylogenetic structure using distance-based linear models. Environmental factors together accounted for the majority of phylogenetic structure, namely, soil temperature (19%), pH (17%) and litter carbon:nitrogen (C:N; 17%). However, of all individual factors, time since deglaciation accounted for the greatest proportion of bacterial phylogenetic structure (20%). Taken together, our results provide empirical evidence that temporal and environmental filters act together to structure soil bacterial communities across large spatial and long-term temporal scales. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Hurricane exposure and county fetal death rates, utilization of a county environmental quality index for confounding control.

EPA Science Inventory

The effects of natural disasters on public health are a rising concern, with increasing severity of disaster events. Many disaster studies utilize county-level analysis, however most do not control for county level environmental factors. Hurricane exposure during pregnancy could ...

Assessment Intelligence in Small Group Learning

ERIC Educational Resources Information Center

Xing, Wanli; Wu, Yonghe

2014-01-01

Assessment of groups in CSCL context is a challenging task fraught with many confounding factors collected and measured. Previous documented studies are by and large summative in nature and some process-oriented methods require time-intensive coding of qualitative data. This study attempts to resolve these problems for teachers to assess groups…

ISSUES AND RECCOMMENDATIONS FOR POREWATER TOXCITY TESTING: METHODOLOGICAL UNCERTAINTIES, CONFOUNDING FACTORS AND TOXCITY IDENTIFICATION EVALUATION PROCEDURES

EPA Science Inventory

During the last decade porewater toxicity tests have gained popularity among researchers and managers as tools for the assessment of the presence and biological effects of bioavailable contaminants in aquatic sediments. However, there are a number of information gaps in our know...

Selecting Evaluation Comparison Groups: A Cluster Analytic Approach.

ERIC Educational Resources Information Center

Davis, Todd Mclin; McLean, James E.

A persistent problem in the evaluation of field-based projects is the lack of no-treatment comparison groups. Frequently, potential comparison groups are confounded by socioeconomic, racial, or other factors. Among the possible methods for dealing with this problem are various matching procedures, but they are cumbersome to use with multiple…

Age of Acquisition and Imageability: A Cross-Task Comparison

ERIC Educational Resources Information Center

Ploetz, Danielle M.; Yates, Mark

2016-01-01

Previous research has reported an imageability effect on visual word recognition. Words that are high in imageability are recognised more rapidly than are those lower in imageability. However, later researchers argued that imageability was confounded with age of acquisition. In the current research, these two factors were manipulated in a…

It Ain't over 'til It's Over: On Foreign Language Anxiety, First Language Deficits, and the Confounding of Variables.

ERIC Educational Resources Information Center

Horwitz, Elaine K.

2000-01-01

Replies on behalf of the authors of a previous article to a critique of their study on foreign language anxiety. Argues that factors other than cognitive-linguistic deficits contribute to problems in foreign language achievement. (Author/VWL)

Hierarchical analysis of forest bird species-environment relationships in the Oregon Coast Range

Treesearch

Samuel A. Cushman; Kevin McGarigal

2004-01-01

Species in biological communities respond to environmental variation simultaneously across a range of organizational levels. Accordingly, it is important to quantify the effects of environmental factors at multiple levels on species distribution and abundance. Hierarchical methods that explicitly separate the independent and confounded influences of environmental...

EFFECT OF ARSENICALS ON ULTRAVIOLET-RADIATION-INDUCED GROWTH ARREST AND RELATED SIGNALING EVENTS IN HUMAN KERATINOCYTES

EPA Science Inventory

The molecular mechanisms mediating arsenic-induced carcinogenesis are not well understood. The role of confounding factors such as ultraviolet radiation (UV), add another level of complexity to the study of arsenic carcinogenesis and the cancer risk assessment to humans. We hypot...

Examining the Intergenerational Transmission of Violence in a New Zealand Birth Cohort

ERIC Educational Resources Information Center

Fergusson, David M.; Boden, Joseph M.; Horwood, L. John

2006-01-01

Objective: This paper examines whether exposure to interparental violence in childhood predicts subsequent involvement in interpartner violence and violent crime after controlling for potentially confounding factors. Method: The investigation analyses data from the Christchurch Health and Development Study, a prospective, longitudinal study of a…

Problems in Psychiatric Genetic Research: A Reply to Faraone and Biederman.

ERIC Educational Resources Information Center

Joseph, Jay

2000-01-01

Answers the most important criticisms by Faraone and Biederman in their critique of Joseph's analysis of evidence supporting a genetic basis of attention deficit hyperactivity disorder. Argues that possible genetic and environmental influences in ADHD twin studies are confounded, obscuring inferences about genetic factors. (JPB)

Measuring Systematic Long-Term Trajectories of School Effectiveness Improvement

ERIC Educational Resources Information Center

Valenzuela, Juan Pablo; Bellei, Cristián; Allende, Claudio

2016-01-01

The objective of this study was to identify trajectories of school improvement experienced by Chilean elementary schools over the last decade. Using econometric analysis and controlling for potential confounding factors, we created an index of school performance combining outcome indicators focused on different school dimensions, and estimated the…

Inverse Association between Fruit and Vegetable Intake and BMI even after Controlling for Demographic, Socioeconomic and Lifestyle Factors

PubMed Central

Heo, Moonseong; Kim, Ryung S.; Wylie-Rosett, Judith; Allison, David B.; Heymsfield, Steve B.; Faith, Myles S.

2011-01-01

Objective To estimate fruit and vegetable (FV) intake levels of US adult population and evaluate the association between FV intake and BMI status after controlling for confounding demographic, socioeconomic and lifestyle factors. We also sought to identify moderating factors. Methods We used 2007 Behavior Risk Factors Surveillance System (N > 400,000) data. FV intake was dichotomized as ≥5 servings (FV5+) versus <5 servings/day. BMI status was categorized as normal, overweight, and obese. Identification of moderators was performed by testing interactions between BMI status and other variables using bivariate analyses followed by multiple logistic regression analysis incorporating complex survey sampling design features. Results Only 24.6% of US adults consumed ≥5 servings per day and less than 4% consumed 9 or more servings. Overweight (% FV5+ = 23.9%) and obese (21.9%) groups consumed significantly less FV than the normal-weight (27.4%) group (p < 0.0001). This inverse association remained significant even after controlling for potential confounding factors. Multivariate analysis identified five significant moderators (p < 0.0001) after controlling for all evaluated variables: race, sex, smoking status, health coverage, and physical activity. Notably, physically inactive obese males tended to consume the least FV (% FV5+ = 14.7%). Conclusion Current US population FV intake level is below recommended levels. The inverse association between FV intake and obesity was significant and was moderated by demographic, socioeconomic status, and lifestyle factors. These factors should be considered when developing policies and interventions to increase FV intake. PMID:22248995

Repeated electromagnetic induction measurements for mapping soil moisture at the field scale: validation with data from a wireless soil moisture monitoring network

NASA Astrophysics Data System (ADS)

Martini, Edoardo; Werban, Ulrike; Zacharias, Steffen; Pohle, Marco; Dietrich, Peter; Wollschläger, Ute

2017-01-01

Electromagnetic induction (EMI) measurements are widely used for soil mapping, as they allow fast and relatively low-cost surveys of soil apparent electrical conductivity (ECa). Although the use of non-invasive EMI for imaging spatial soil properties is very attractive, the dependence of ECa on several factors challenges any interpretation with respect to individual soil properties or states such as soil moisture (θ). The major aim of this study was to further investigate the potential of repeated EMI measurements to map θ, with particular focus on the temporal variability of the spatial patterns of ECa and θ. To this end, we compared repeated EMI measurements with high-resolution θ data from a wireless soil moisture and soil temperature monitoring network for an extensively managed hillslope area for which soil properties and θ dynamics are known. For the investigated site, (i) ECa showed small temporal variations whereas θ varied from very dry to almost saturation, (ii) temporal changes of the spatial pattern of ECa differed from those of the spatial pattern of θ, and (iii) the ECa-θ relationship varied with time. Results suggest that (i) depending upon site characteristics, stable soil properties can be the major control of ECa measured with EMI, and (ii) for soils with low clay content, the influence of θ on ECa may be confounded by changes of the electrical conductivity of the soil solution. Further, this study discusses the complex interplay between factors controlling ECa and θ, and the use of EMI-based ECa data with respect to hydrological applications.

[Epidemiologic and medical sociological aspects of hypertension].

PubMed

Siegrist, J

1995-10-01

Cardiovascular diseases are a major determinant of overall and premature mortality in advanced and in rapidly developing societies. In view of their importance it is mandatory to identify underlying risk factors and to guide preventive and therapeutic actions accordingly. Hypertension is one of the most prevalent and well-established cardiovascular risk factors. This paper briefly summarizes some major determinants of high blood pressure from an epidemiologic and sociomedical point of view. Determinants include age, overweight, physical inactivity, salt and alcohol intake, family history of hypertension, race and socio-economic status. The complexity of these influences is discussed by pointing to interactions between genetic and socio-environmental influences, e.g. in the case of age, bodyweight and salt intake. Based on experimental animal research there is now solid evidence on direct links between psychosocial stress, patterns of neuroendocrine activation and elevation of blood pressure. Four theoretical concepts are described which identify conditions of chronic psychosocial vulnerability or protection in man, and their role in explaining the prevalence of hypertension in epidemiologic studies is discussed. The four concepts are labelled "socioemotional support", "lifestyle incongruity", "job strain" and "effort-reward-imbalance at work". Special emphasis is given to the two latter concepts in view of the potential role of occupational life in triggering high blood pressure during middle adulthood. For instance, Table 1 indicates that high job strain, i.e. high demands in combination with low control at work, is associated with a relative risk of 3 of being hypertensive, after adjusting for important confounders.(ABSTRACT TRUNCATED AT 250 WORDS)

High Triglycerides Predicts Arteriogenic Erectile Dysfunction and Major Adverse Cardiovascular Events in Subjects With Sexual Dysfunction.

PubMed

Corona, Giovanni; Cipriani, Sarah; Rastrelli, Giulia; Sforza, Alessandra; Mannucci, Edoardo; Maggi, Mario

2016-09-01

The atherogenic role of triglycerides (TG) remains controversial. The aim of the present study is to analyze the contribution of TG in the pathogenesis of erectile dysfunction (ED) and to verify the value of elevated TG in predicting major adverse cardiovascular events (MACE). An unselected series of 3,990 men attending our outpatient clinic for sexual dysfunction was retrospectively studied. A subset of this sample (n = 1,687) was enrolled in a longitudinal study. Several clinical, biochemical, and instrumental (penile color Doppler ultrasound; PCDU) factors were evaluated. Among the patients studied, after adjustment for confounders, higher TG levels were associated with arteriogenic ED and a higher risk of clinical and biochemical hypogonadism. Conversely, no association between TG and other sexual dysfunctions was observed. When pathological PCDU parameters-including flaccid acceleration (<1.17 m/sec(2)) or dynamic peak systolic velocity (PSV <35 cm/sec)-were considered, the negative association between impaired penile flow and higher TG levels was confirmed, even when subjects taking lipid-lowering drugs or those with diabetes were excluded from the analysis (OR = 6.343 [1.243;32.362], P = .026 and 3.576 [1.104;11.578]; P = .34 for impaired acceleration and PSV, respectively). Similarly, when the same adjusted models were applied, TG levels were associated with a higher risk of hypogonadism, independently of the definition criteria (OR = 2.892 [1.643;5.410], P < .0001 and 4.853 [1.965;11.990]; P = .001 for total T <12 and 8 nM, respectively). In the longitudinal study, after adjusting for confounders, elevated TG levels (upper quartile: 162-1686 mg/dL) were independently associated with a higher incidence of MACE (HR = 2.469 [1.019;5.981]; P = .045), when compared to the rest of the sample. Our data suggest an association between elevated TG and arteriogenic ED and its cardiovascular (CV) risk stratification. Whether the use of TG lowering drugs might improve ED and its associated CV risk must be confirmed through specific trials. Copyright © 2016 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Poor response to alprostadil ICI test is associated with arteriogenic erectile dysfunction and higher risk of major adverse cardiovascular events.

PubMed

Rastrelli, Giulia; Corona, Giovanni; Monami, Matteo; Melani, Cecilia; Balzi, Daniela; Sforza, Alessandra; Forti, Gianni; Mannucci, Edoardo; Maggi, Mario

2011-12-01

Intracavernous alprostadil injection (ICI) test has been considered useless in assessing the vascular status of subjects with erectile dysfunction (ED). To analyze the clinical correlates of ICI test in patients with ED and to verify the value of this test in predicting major adverse cardiovascular events (MACE). A consecutive series of 2,396 men (mean age 55.9 ± 11.9 years) attending our outpatient clinic for sexual dysfunction was retrospectively studied. A subset of this sample (N = 1,687) was enrolled in a longitudinal study. Several clinical, biochemical, and instrumental (penile color Doppler ultrasound; PCDU) factors were evaluated. All patients underwent an ICI test, and responses were recorded on a four-point scale ranging from 1 = no response to 4 = full erection. Among the patients studied, 16.4%, 41.2%, 40.2% and 2.2% showed grade 4, 3, 2, and 1 ICI test response, respectively. After adjusting for confounders, subjects with grade 1 ICI test response showed reduced perceived sleep-related, masturbation-related, and sexual-related erections when compared with the rest of the sample. In addition, a worse response to ICI test was associated with a higher prevalence of hypogonadism-related symptoms and signs along with lower testosterone levels. The prevalence of both diabetes mellitus and metabolic syndrome was inversely related to ICI test response. Accordingly, dynamic and basal peak systolic velocity (PSV), as well as acceleration at PCDU, decreased as a function of ICI test response. In the longitudinal study, after adjusting for confounders, grade 1 response was independently associated with a higher incidence of MACE (hazard ratio = 2.745 [1.200-6.277]; P < 0.05). These data were confirmed even when only subjects with normal PSV (>25 cm/s) were considered. Our results demonstrate that poor ICI test response is associated with several metabolic disturbances and higher incidence of MACE. We strongly recommend performing ICI test with alprostadil in all ED subjects. © 2011 International Society for Sexual Medicine.

Factors confounding the assessment of reflection: a critical review

PubMed Central

2011-01-01

Background Reflection on experience is an increasingly critical part of professional development and lifelong learning. There is, however, continuing uncertainty about how best to put principle into practice, particularly as regards assessment. This article explores those uncertainties in order to find practical ways of assessing reflection. Discussion We critically review four problems: 1. Inconsistent definitions of reflection; 2. Lack of standards to determine (in)adequate reflection; 3. Factors that complicate assessment; 4. Internal and external contextual factors affecting the assessment of reflection. Summary To address the problem of inconsistency, we identified processes that were common to a number of widely quoted theories and synthesised a model, which yielded six indicators that could be used in assessment instruments. We arrived at the conclusion that, until further progress has been made in defining standards, assessment must depend on developing and communicating local consensus between stakeholders (students, practitioners, teachers, supervisors, curriculum developers) about what is expected in exercises and formal tests. Major factors that complicate assessment are the subjective nature of reflection's content and the dependency on descriptions by persons being assessed about their reflection process, without any objective means of verification. To counter these validity threats, we suggest that assessment should focus on generic process skills rather than the subjective content of reflection and where possible to consider objective information about the triggering situation to verify described reflections. Finally, internal and external contextual factors such as motivation, instruction, character of assessment (formative or summative) and the ability of individual learning environments to stimulate reflection should be considered. PMID:22204704

Anger is a distinctive feature of epilepsy patients with depression.

PubMed

Mori, Yasuhiro; Kanemoto, Kousuke; Onuma, Teiichi; Tanaka, Masaki; Oshima, Tomohiro; Kato, Hiroko; Tachimori, Hisateru; Wada, Kazumaru; Kikuchi, Takashi; Tomita, Tetsu; Chen, Lei; Fang, Liu; Yoshida, Shuichi; Kato, Masaaki; Kaneko, Sunao

2014-02-01

Controversy exists regarding the similarity between depression as seen in patients with epilepsy and in those with idiopathic major depression. The objective of this study was to examine whether anger is a distinctive feature of depression in epilepsy. Participants included 487 adult patients with epilepsy (study group) and 85 patients with idiopathic major depression according to Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV) criteria, and without other neurological complications (control group). All participants completed the Inventory of Depressive Symptomatology Self-Report (IDS-SR) and the Buss-Perry Aggression Questionnaire (BAQ). The IDS-SR is a self-report questionnaire that measures depression severity and assesses all symptoms of depression as defined by the DSM-IV. The BAQ is a self-rating scale designed for assessing aggression. After examining potential confounding factors (i.e., demographic and clinical variables) using a multivariate linear regression model, BAQ scores were compared between the study (n = 85) and control groups (n = 54) for patients with moderate or severe depression using established cut-off points (IDS-SR score > 25). BAQ scores were significantly higher in the study group (P = 0.009). Among the BAQ subscales, only anger showed a statistically significant difference (P = 0.013). Although a significant correlation was revealed between the IDS-SR and BAQ scores in the study group, no such correlation was found in the control group. Thus, anger might be a constituent component of depression among epilepsy patients, but not among idiopathic major depression patients.

Elevated maternal placental protein 13 serum levels at term of pregnancy in postpartum major hemorrhage (>1000 mLs). A prospective cohort study.

PubMed

Farina, Antonio; Bernabini, Dalila; Zucchini, Cinzia; De Sanctis, Paola; Quezada, Maria Soledad; Mattioli, Mara; Rizzo, Nicola

2017-09-01

To compare placental protein 13 (PP13) levels in the serum of women with primary postpartum hemorrhage (PPH) with a control population. A prospective cohort study was conducted between May 2014 and May 2016 and included 435 pregnant women at term (38 weeks gestation) without any known risk factor and with normal labor. Multiples of median (MoM) were used to evaluate differences of the PP13 values between cases and controls. PP13 concentrations were adjusted for maternal and neonatal weight. Multivariable analysis was used to detect independent contribution of predictors of PPH. Fifteen had a major PPH >1000 mLs and represented the cases of the study. They were matched with 399 controls. Twenty-one patients who had a minor PPH (500-1000 mLs) were excluded. The mean observed rank in the PPH group was higher than that of controls (28.5 vs 13.5, P-value=.01). PP13 MoM values adjusted for maternal weight were higher than expected being 1.44±0.45 in PPH cases and 1.00±0.59 in controls (P-value .008). This difference was still significant even after adjustment for neonatal weight that represented a confounding variable. Higher PP13 levels are independently associated with major PPH >1000 mLs. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The Problem of Confounding in Studies of the Effect of Maternal Drug Use on Pregnancy Outcome

PubMed Central

Källén, Bengt

2012-01-01

In most epidemilogical studies, the problem of confounding adds to the uncertainty in conclusions drawn. This is also true for studies on the effect of maternal drug use on birth defect risks. This paper describes various types of such confounders and discusses methods to identify and adjust for them. Such confounders can be found in maternal characteristics like age, parity, smoking, use of alcohol, and body mass index, subfertility, and previous pregnancies including previous birth of a malformed child, socioeconomy, race/ethnicity, or country of birth. Confounding by concomitant maternal drug use may occur. A geographical or seasonal confounding can exist. In rare instances, infant sex and multiple birth can appear as confounders. The most difficult problem to solve is often confounding by indication. The problem of confounding is less important for congenital malformations than for many other pregnancy outcomes. PMID:22190949

Does Metformin Reduce Cancer Risks? Methodologic Considerations.

PubMed

Golozar, Asieh; Liu, Shuiqing; Lin, Joeseph A; Peairs, Kimberly; Yeh, Hsin-Chieh

2016-01-01

The substantial burden of cancer and diabetes and the association between the two conditions has been a motivation for researchers to look for targeted strategies that can simultaneously affect both diseases and reduce their overlapping burden. In the absence of randomized clinical trials, researchers have taken advantage of the availability and richness of administrative databases and electronic medical records to investigate the effects of drugs on cancer risk among diabetic individuals. The majority of these studies suggest that metformin could potentially reduce cancer risk. However, the validity of this purported reduction in cancer risk is limited by several methodological flaws either in the study design or in the analysis. Whether metformin use decreases cancer risk relies heavily on the availability of valid data sources with complete information on confounders, accurate assessment of drug use, appropriate study design, and robust analytical techniques. The majority of the observational studies assessing the association between metformin and cancer risk suffer from methodological shortcomings and efforts to address these issues have been incomplete. Future investigations on the association between metformin and cancer risk should clearly address the methodological issues due to confounding by indication, prevalent user bias, and time-related biases. Although the proposed strategies do not guarantee a bias-free estimate for the association between metformin and cancer, they will reduce synthesis of and reporting of erroneous results.

Does exposure to aircraft noise increase the mortality from cardiovascular disease in the population living in the vicinity of airports? Results of an ecological study in France.

PubMed

Evrard, Anne-Sophie; Bouaoun, Liacine; Champelovier, Patricia; Lambert, Jacques; Laumon, Bernard

2015-01-01

The impact of aircraft noise on health is of growing concern. We investigated the relationship between this exposure and mortality from cardiovascular disease, coronary heart disease, myocardial infarction, and stroke. We performed an ecological study on 161 communes (commune being the smallest administrative unit in France) close to the following three major French airports: Paris-Charles de Gaulle, Lyon Saint-Exupéry, and Toulouse-Blagnac. The mortality data were provided by the French Center on Medical Causes of Death for the period 2007-2010. Based on the data provided by the French Civil Aviation Authority, a weighted average exposure to aircraft noise (L den AEI) was computed at the commune level. A Poisson regression model with commune-specific random intercepts, adjusted for potential confounding factors including air pollution, was used to investigate the association between mortality rates and L den AEI. Positive associations were observed between L den AEI and mortality from cardiovascular disease [adjusted mortality rate ratio (MRR) per 10 dB(A) increase in L den AEI = 1.18; 95% confidence interval (CI): 1.11-1.25], coronary heart disease [MRR = 1.24 (1.12-1.36)], and myocardial infarction [MRR = 1.28 (1.11-1.46]. Stroke mortality was more weakly associated with L den AEI [MRR = 1.08 (0.97-1.21]. These significant associations were not attenuated after the adjustment for air pollution. The present ecological study supports the hypothesis of an association between aircraft noise exposure and mortality from cardiovascular disease, coronary heart disease, and myocardial infarction. However, the potential for ecological bias and the possibility that this association could be due to residual confounding cannot be excluded.

Does exposure to aircraft noise increase the mortality from cardiovascular disease in the population living in the vicinity of airports? Results of an ecological study in France

PubMed Central

Evrard, Anne-Sophie; Bouaoun, Liacine; Champelovier, Patricia; Lambert, Jacques; Laumon, Bernard

2015-01-01

The impact of aircraft noise on health is of growing concern. We investigated the relationship between this exposure and mortality from cardiovascular disease, coronary heart disease, myocardial infarction, and stroke. We performed an ecological study on 161 communes (commune being the smallest administrative unit in France) close to the following three major French airports: Paris-Charles de Gaulle, Lyon Saint-Exupéry, and Toulouse-Blagnac. The mortality data were provided by the French Center on Medical Causes of Death for the period 2007-2010. Based on the data provided by the French Civil Aviation Authority, a weighted average exposure to aircraft noise (Lden AEI) was computed at the commune level. A Poisson regression model with commune-specific random intercepts, adjusted for potential confounding factors including air pollution, was used to investigate the association between mortality rates and Lden AEI. Positive associations were observed between Lden AEI and mortality from cardiovascular disease [adjusted mortality rate ratio (MRR) per 10 dB(A) increase in Lden AEI = 1.18; 95% confidence interval (CI): 1.11-1.25], coronary heart disease [MRR = 1.24 (1.12-1.36)], and myocardial infarction [MRR = 1.28 (1.11-1.46]. Stroke mortality was more weakly associated with Lden AEI [MRR = 1.08 (0.97-1.21]. These significant associations were not attenuated after the adjustment for air pollution. The present ecological study supports the hypothesis of an association between aircraft noise exposure and mortality from cardiovascular disease, coronary heart disease, and myocardial infarction. However, the potential for ecological bias and the possibility that this association could be due to residual confounding cannot be excluded. PMID:26356375

Study design and statistical analysis of data in human population studies with the micronucleus assay.

PubMed

Ceppi, Marcello; Gallo, Fabio; Bonassi, Stefano

2011-01-01

The most common study design performed in population studies based on the micronucleus (MN) assay, is the cross-sectional study, which is largely performed to evaluate the DNA damaging effects of exposure to genotoxic agents in the workplace, in the environment, as well as from diet or lifestyle factors. Sample size is still a critical issue in the design of MN studies since most recent studies considering gene-environment interaction, often require a sample size of several hundred subjects, which is in many cases difficult to achieve. The control of confounding is another major threat to the validity of causal inference. The most popular confounders considered in population studies using MN are age, gender and smoking habit. Extensive attention is given to the assessment of effect modification, given the increasing inclusion of biomarkers of genetic susceptibility in the study design. Selected issues concerning the statistical treatment of data have been addressed in this mini-review, starting from data description, which is a critical step of statistical analysis, since it allows to detect possible errors in the dataset to be analysed and to check the validity of assumptions required for more complex analyses. Basic issues dealing with statistical analysis of biomarkers are extensively evaluated, including methods to explore the dose-response relationship among two continuous variables and inferential analysis. A critical approach to the use of parametric and non-parametric methods is presented, before addressing the issue of most suitable multivariate models to fit MN data. In the last decade, the quality of statistical analysis of MN data has certainly evolved, although even nowadays only a small number of studies apply the Poisson model, which is the most suitable method for the analysis of MN data.

A Prospective Investigation of Coffee Drinking and Bladder Cancer Incidence in the United States.

PubMed

Loftfield, Erikka; Freedman, Neal D; Inoue-Choi, Maki; Graubard, Barry I; Sinha, Rashmi

2017-09-01

In 1991, coffee was classified as a group 2B carcinogen, possibly carcinogenic to humans, based on limited epidemiologic evidence of a positive association with bladder cancer. In 2016, the International Agency for Research on Cancer downgraded this classification due to lack of evidence from prospective studies particularly for never smokers. Baseline coffee drinking was assessed with a food frequency questionnaire in the NIH-AARP prospective cohort study. Among 469,047 US adults, who were cancer free at baseline, 6,012 bladder cancer cases (5,088 men and 924 women) were identified during >6.3 million person-years of follow-up. Multivariable-adjusted Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI), with non-coffee drinkers as the reference group. Coffee drinking was positively associated with bladder cancer in models adjusted for age and sex (HR for ≥4 cups/d relative to coffee nondrinkers = 1.91, 95% CI = 1.70, 2.14; P trend < 0.0001). However, the association was substantially attenuated after adjustment for cigarette smoking and other potential confounders (HR for ≥4 cups/d relative to coffee nondrinkers = 1.18, 95% CI = 1.05, 1.33; P trend = 0.0007). Associations were further attenuated after additional adjustment for lifetime smoking patterns among the majority of the cohort with this available data (P trend = 0.16). There was no evidence of an association among never smokers (P trend = 0.84). Positive associations between coffee drinking and bladder cancer among ever smokers but not never smokers suggest that residual confounding from imperfect measurement of smoking or unmeasured risk factors may be an explanation for our positive findings.

Health effects resulting from exercise versus those from body fat loss.

PubMed

Williams, P T

2001-06-01

The purpose of this review was to assess whether body weight confounds the relationships between physical activity and its health benefits. The review includes 80 reports from population-based studies (Evidence Category C) of physical activity or fitness and cardiovascular disease (CVD) or coronary heart disease (CHD). Eleven of 64 reports on activity found no relationship between physical activity and disease. Of the remaining 53 reports, 11 did not address the possible confounding effects of body weight, nine cited reasons that weight differences should not explain their observed associations, and 33 statistically adjusted for weight (as required). Only three of these changed their associations from significant to nonsignificant when adjusted. Ten of 16 reports on cardiorespiratory fitness and CHD or CVD used statistical adjustment, and none of these changed their findings to nonsignificant. Population studies show that vigorously active individuals also have higher high-density lipoprotein (HDL)-cholesterol concentration, a major risk factor for CHD and CVD, than sedentary individuals when statistically adjusted for weight. In contrast, intervention studies, which relate dynamic changes in weight and HDL, suggest that adjustment for weight loss largely eliminates the increase in HDL-cholesterol in sedentary men who begin exercising vigorously. Adjusting the cross-sectional HDL-cholesterol differences for the dynamic effects of weight loss eliminates most of the HDL-cholesterol difference between active and sedentary men. Population studies show that the lower incidence of CHD and CVD and higher HDL of fit, active individuals are not because of lean, healthy individuals choosing to be active (i.e., self-selection bias). Nevertheless, metabolic processed associated weight loss may be primarily responsible for the HDL differences between active and sedentary men, and possibly also their differences in CHD and CVD.

Associations between prenatal cigarette smoke exposure and externalized behaviors at school age among Inuit children exposed to environmental contaminants.

PubMed

Desrosiers, Caroline; Boucher, Olivier; Forget-Dubois, Nadine; Dewailly, Eric; Ayotte, Pierre; Jacobson, Sandra W; Jacobson, Joseph L; Muckle, Gina

2013-01-01

Smoking during pregnancy is common among Inuit women from the Canadian Arctic. Yet prenatal cigarette smoke exposure (PCSE) is seen as a major risk factor for childhood behavior problems. Recent data also suggest that co-exposure to neurotoxic environmental contaminants can exacerbate the effects of PCSE on behavior. This study examined the association between PCSE and behavior at school age in a sample of Inuit children from Nunavik, Québec, where co-exposure to environmental contaminants is also an important issue. Interactions with lead (Pb) and mercury (Hg), two contaminants associated with behavioral problems, were also explored. Participants were 271 children (mean age=11.3years) involved in a prospective birth-cohort study. PCSE was assessed through maternal recall. Assessment of child behavior was obtained from the child's classroom teacher on the Teacher Report Form (TRF) and the Disruptive Behavior Disorders Rating Scale (DBD). Exposure to contaminants was assessed from umbilical cord and child blood samples. Other confounders were documented by maternal interview. After control for contaminants and confounders, PCSE was associated with increased externalizing behaviors and attention problems on the TRF and higher prevalence of attention deficit hyperactivity disorder (ADHD) assessed on the DBD. No interactions were found with contaminants. This study extends the existing empirical evidence linking PCSE to behavioral problems in school-aged children by reporting these effects in a population where tobacco use is normative rather than marginal. Co-exposure to Pb and Hg do not appear to exacerbate tobacco effects, suggesting that these substances act independently. © 2013. Published by Elsevier Inc. All rights reserved.

Prevalence and associated factors for temporomandibular disorders in Chinese civilian pilots.

PubMed

Yu, Qing; Liu, Yang; Chen, Xi; Chen, Duanjing; Xie, Lu; Hong, Xiao; Wang, Xingyuan; Huang, Haili; Yu, Haiyang

2015-10-01

Piloting is a special profession with prolonged stress, which could induce the occurrence of TMD. This sample is useful to reduce the effect of confounders in the analyses. Based on this, the present study aims to determine the prevalence and associated factors for TMD in civilian pilots of China. A cross-sectional epidemiological survey was carried out in 616 male subjects (aged 23-52 years). The questionnaire included general information, chewing preference (bilateral or unilateral), and Trait Anxiety section of Spielberger State-Trait Anxiety Inventory (STAI-T). The clinical examination contained TMD screening per research diagnostic criteria for TMD and diagnosis of sleep bruxism per American Academy of Sleep Medicine standards. The level of statistical significance was set at P ≤ 0.05. The program was conducted from June 2012 to April 2013, in which period, and the percentage of TMD in the samples we examined was 33.3 % (=205/616). Only high anxiety (OR 2.48; 95 % CI 1.25-4.90) and unilateral chewing preference (OR 12.67; 95 % CI 7.77-20.65) were the most significant associated factors with TMD. Also, salivary cortisol and the STAI-T score had a significant correlation (r = 0.47, P < 0.001). It was more reliable to study the associated factors on TMD with the exclusion of the possible confounding factors, and only unilateral chewing preference and psychological stress had a significant association with TMD. In addition, the salivary cortisol levels might assist to assess psychological stress in epidemiological research.

Self-reported neck pain is associated with migraine but not with tension-type headache in adolescents.

PubMed

Blaschek, Astrid; Decke, Siona; Albers, Lucia; Schroeder, Andreas Sebastian; Lehmann, Steffi; Straube, Andreas; Landgraf, Mirjam N; Heinen, Florian; von Kries, Rüdiger

2014-10-01

The aim of the present analysis is to confirm or refute the association of neck pain to migraine or tension-type headache and to assess whether this association is independent of other risk factors for headache. Secondary school students were invited to complete a questionnaire on headache and lifestyle factors in a cross-sectional study. Neck pain was assessed via (a) a screening question concerning neck pain and (b) denoting affected areas in schematic drawings of the human body. Absolute increment in prevalence of headache with pain in the shoulder-neck region was between 7.5% and 9.6%. Gender, grade, stress and lifestyle factors were assessed as potential confounding factors. Nearly all factors were associated with shoulder-neck pain and most with headache. After adjustment for confounders, the association of neck pain with headache was almost completely confined to migraine (OR 2.39; 95% CI 1.48-3.85) and migraine + tension-type headache (OR 2.12; 95% CI 1.50-2.99), whereas the association with isolated tension-type headache was negligible (OR 1.22, 95% CI 0.87-1.69). Neck pain is associated with migraine but not with tension-type headache. A possible link between migraine and neck pain may be the cervico-trigeminal convergence of neck and meningeal sensory afferents or a disturbed descending inhibition in migraine. © International Headache Society 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Evaluating the impact of implementation factors on family-based prevention programming: methods for strengthening causal inference.

PubMed

Crowley, D Max; Coffman, Donna L; Feinberg, Mark E; Greenberg, Mark T; Spoth, Richard L

2014-04-01

Despite growing recognition of the important role implementation plays in successful prevention efforts, relatively little work has sought to demonstrate a causal relationship between implementation factors and participant outcomes. In turn, failure to explore the implementation-to-outcome link limits our understanding of the mechanisms essential to successful programming. This gap is partially due to the inability of current methodological procedures within prevention science to account for the multitude of confounders responsible for variation in implementation factors (i.e., selection bias). The current paper illustrates how propensity and marginal structural models can be used to improve causal inferences involving implementation factors not easily randomized (e.g., participant attendance). We first present analytic steps for simultaneously evaluating the impact of multiple implementation factors on prevention program outcome. Then, we demonstrate this approach for evaluating the impact of enrollment and attendance in a family program, over and above the impact of a school-based program, within PROSPER, a large-scale real-world prevention trial. Findings illustrate the capacity of this approach to successfully account for confounders that influence enrollment and attendance, thereby more accurately representing true causal relations. For instance, after accounting for selection bias, we observed a 5% reduction in the prevalence of 11th grade underage drinking for those who chose to receive a family program and school program compared to those who received only the school program. Further, we detected a 7% reduction in underage drinking for those with high attendance in the family program.

Associations of work stress with hair cortisol concentrations - initial findings from a prospective study.

PubMed

Herr, Raphael M; Almer, Christian; Loerbroks, Adrian; Barrech, Amira; Elfantel, Irina; Siegrist, Johannes; Gündel, Harald; Angerer, Peter; Li, Jian

2018-03-01

There is ample evidence supporting the link between stress at the workplace and physical and mental health. One of the pathways potentially mediating those associations may involve the hypothalamic-pituitary-adrenal (HPA) axis, with cortisol as an end product. While theoretically plausible, findings on the association of self-reported work stress with hair cortisol concentrations (HCC) are inconclusive, being potentially biased by omitted pertinent factors. This issue can be addressed, among others, by eliminating time-invariant factors through consideration of variation within persons over time. To this end, the present study examined the association between variation in HCC and perceived work stress - as assessed by the Effort-Reward-Imbalance (ERI) model - between two points in time (t1 and t2) over one year in a sample of 40 male factory workers. Neither a cross-sectional association, nor a link between change in ERI and HCC levels at t2 was observed. There was however a robust association of the change in ERI with the change of HCC. This effect was independent of baseline HCC and other confounders (Beta = 0.414, S.E. = 0.155, p = 0.012). Accordingly, this is the first study revealing prospective evidence for the associations of work stress with HCC, while excluding potentially time-stable confounding factors, like genetic factors or phenotypic hair color. Copyright © 2018 Elsevier Ltd. All rights reserved.

Socioeconomic Factors and Women's Use of Complementary and Alternative Medicine in Four Racial/Ethnic Groups

PubMed Central

Chao, Maria T.; Wade, Christine M.

2014-01-01

Objective Higher socioeconomic status (SES) is associated with using complementary and alternative medicine (CAM) in national surveys. Less is known about how socioeconomic factors affect CAM use in US subpopulations. We examined whether the relationship between SES and CAM use differs by racial/ethnic groups. Methods Using national survey data, we assessed education and income effects on women's CAM use in four racial/ethnic groups (Whites, Blacks, Mexican Americans, and Chinese Americans), controlling for age, health status, and geographic region. CAM use was defined as using any of 11 domains in the prior year. Results Adjusted effects of SES on CAM use were similar among Mexican American and non-Hispanic White women—education had a distinct gradient effect, with each increasing level of education significantly more likely to use CAM; household income ≥$60,000 was associated with CAM use compared to income <$20,000. For Chinese American women, socioeconomic factors were not associated with CAM use when controlling for confounders. Although income was not associated with CAM use among African American women, college graduates were three times more likely to use CAM than those with less than a high school education, adjusting for confounders. Conclusion SES effects on CAM use are not uniform across racial/ethnic populations. Other factors, such as culture and social networks, may interact with SES to influence CAM use in minority populations. PMID:18447102

Rumination, anxiety, depressive symptoms and subsequent depression in adolescents at risk for psychopathology: a longitudinal cohort study

PubMed Central

2013-01-01

Background A ruminative style of responding to low mood is associated with subsequent high depressive symptoms and depressive disorder in children, adolescents and adults. Scores on self-report rumination scales correlate strongly with scores on anxiety and depression symptom scales. This may confound any associations between rumination and subsequent depression. Methods Our sample comprised 658 healthy adolescents at elevated risk for psychopathology. This study applied ordinal item (non-linear) factor analysis to pooled items from three self-report questionnaires to explore whether there were separate, but correlated, constructs of rumination, depression and anxiety. It then tested whether rumination independently predicted depressive disorder and depressive symptoms over the subsequent 12 months, after adjusting for confounding variables. Results We identified a single rumination factor, which was correlated with factors representing cognitive symptoms of depression, somatic symptoms of depression and anxiety symptoms; and one factor representing adaptive responses to low mood. Elevated rumination scores predicted onset of depressive disorders over the subsequent year (p = 0.035), and levels of depressive symptoms 12 months later (p < 0.0005), after adjustment for prior levels of depressive and anxiety symptoms. Conclusion High rumination predicts onset of depressive disorder in healthy adolescents. Therapy that reduces rumination and increases distraction/problem-solving may reduce onset and relapse rates of depression. PMID:24103296

The association of lifetime education with the prevalence of myocardial infarction: an analysis of the 2006 Behavioral Risk Factor Surveillance System.

PubMed

Kelly, Michael J; Weitzen, Sherry

2010-02-01

Socioeconomic status is likely an independent risk factor for coronary heart disease but little research has been done in the United States to study this association in a nationally representative sample. We sought to determine the association between lifetime education and the prevalence of myocardial infarction (MI) among adults over the age of 39 in the US. A cross sectional study was conducted using the 2006 Behavioral Risk Factor Surveillance System (BRFSS). A multivariable logistic regression was performed. The analysis was conducted in 2008. Among respondents aged 40 years and older to the 2006 BRFSS survey those with less than a high school education had 3.09 (95% CI: 2.79-3.43) times the odds of having had an MI compared to college graduates. After adjusting for confounders, respondents with less than a high school education had 1.61 (95% CI: 1.41-1.83) times the odds of having had an MI compared to college graduates. Both those with a high school education and those who completed some college or technical school had 1.22 times the odds of having had an MI compared to college graduates after adjusting for confounders. This study suggests that education is a risk factor for MI. More national prospective studies are needed in the US to better understand the link between socioeconomic status and coronary heart disease.

Concurrent and Sustained Cumulative Effects of Adolescent Marijuana Use on Subclinical Psychotic Symptoms.

PubMed

Bechtold, Jordan; Hipwell, Alison; Lewis, David A; Loeber, Rolf; Pardini, Dustin

2016-08-01

Adolescents who regularly use marijuana may be at heightened risk of developing subclinical and clinical psychotic symptoms. However, this association could be explained by reverse causation or other factors. To address these limitations, the current study examined whether adolescents who engage in regular marijuana use exhibit a systematic increase in subclinical psychotic symptoms that persists during periods of sustained abstinence. The sample comprised 1,009 boys who were recruited in 1st and 7th grades. Self-reported frequency of marijuana use, subclinical psychotic symptoms, and several time-varying confounds (e.g., other substance use, internalizing/externalizing problems) were recorded annually from age 13 to 18. Fixed-effects (within-individual change) models examined whether adolescents exhibited an increase in their subclinical psychotic symptoms as a function of their recent and/or cumulative history of regular marijuana use and whether these effects were sustained following abstinence. Models controlled for all time-stable factors (default) and several time-varying covariates as potential confounds. For each year adolescent boys engaged in regular marijuana use, their expected level of subsequent subclinical psychotic symptoms rose by 21% and their expected odds of experiencing subsequent subclinical paranoia or hallucinations rose by 133% and 92%, respectively. The effect of prior regular marijuana use on subsequent subclinical psychotic symptoms persisted even when adolescents stopped using marijuana for a year. These effects were after controlling for all time-stable and several time-varying confounds. No support was found for reverse causation. These results suggest that regular marijuana use may significantly increase the risk that an adolescent will experience persistent subclinical psychotic symptoms.

Gestational diabetes predicts the risk of childhood overweight and abdominal circumference independent of maternal obesity.

PubMed

Nehring, I; Chmitorz, A; Reulen, H; von Kries, R; Ensenauer, R

2013-12-01

Gestational diabetes mellitus is believed to be a risk factor for childhood overweight/obesity. We aimed to assess whether this association is either a reflection or independent of confounding by maternal BMI. Data from 7355 mother-child dyads of the German Perinatal Prevention of Obesity cohort with full anthropometric information on mothers and children, gestational diabetes and confounding factors were obtained at school entry health examination. We calculated crude and adjusted logistic regression models for the association of gestational diabetes and childhood overweight/obesity and abdominal adiposity defined by age- and sex-specific percentiles for BMI and waist circumference. Among all children (mean age 5.8 years), 8.1% were overweight, 2.6% were obese and 15.5% had abdominal adiposity. The prevalence of overweight (obesity) was 21% (8.2%) in children of mothers with gestational diabetes and 10.4% (2.4%) in children of healthy mothers. Analyses with adjustment for maternal BMI and other potential confounders yielded an odds ratio of 1.81 (95% CI 1.23-2.65) and 2.80 (95% CI 1.58-4.99) for the impact of gestational diabetes on childhood overweight and obesity, respectively. Similar results were obtained for the risk of childhood abdominal adiposity (odds ratio 1.64, 95% CI 1.16-2.33) by maternal gestational diabetes. The postulated increased risk of overweight and abdominal adiposity in offspring of mothers with gestational diabetes cannot be explained by maternal BMI alone and may be stronger for childhood obesity than for overweight. © 2013 The Authors. Diabetic Medicine © 2013 Diabetes UK.

Educational gains in cause-specific mortality: Accounting for cognitive ability and family-level confounders using propensity score weighting.

PubMed

Bijwaard, Govert E; Myrskylä, Mikko; Tynelius, Per; Rasmussen, Finn

2017-07-01

A negative educational gradient has been found for many causes of death. This association may be partly explained by confounding factors that affect both educational attainment and mortality. We correct the cause-specific educational gradient for observed individual background and unobserved family factors using an innovative method based on months lost due to a specific cause of death re-weighted by the probability of attaining a higher educational level. We use data on men with brothers from the Swedish Military Conscription Registry (1951-1983), linked to administrative registers. This dataset of some 700,000 men allows us to distinguish between five education levels and many causes of death. The empirical results reveal that raising the educational level from primary to tertiary would result in an additional 20 months of survival between ages 18 and 63. This improvement in mortality is mainly attributable to fewer deaths from external causes. The highly educated gain more than nine months due to the reduction in deaths from external causes, but gain only two months due to the reduction in cancer mortality and four months due to the reduction in cardiovascular mortality. Ignoring confounding would lead to an underestimation of the gains by educational attainment, especially for the less educated. Our results imply that if the education distribution of 50,000 Swedish men from the 1951 cohort were replaced with that of the corresponding 1983 cohort, 22% of the person-years that were lost to death between ages 18 and 63 would have been saved for this cohort. Copyright © 2017 Elsevier Ltd. All rights reserved.

Decreased Brain pH as a Shared Endophenotype of Psychiatric Disorders

PubMed Central

Hagihara, Hideo; Catts, Vibeke S; Katayama, Yuta; Shoji, Hirotaka; Takagi, Tsuyoshi; Huang, Freesia L; Nakao, Akito; Mori, Yasuo; Huang, Kuo-Ping; Ishii, Shunsuke; Graef, Isabella A; Nakayama, Keiichi I; Shannon Weickert, Cynthia; Miyakawa, Tsuyoshi

2018-01-01

Although the brains of patients with schizophrenia and bipolar disorder exhibit decreased brain pH relative to those of healthy controls upon postmortem examination, it remains controversial whether this finding reflects a primary feature of the diseases or is a result of confounding factors such as medication and agonal state. To date, systematic investigation of brain pH has not been undertaken using animal models that can be studied without confounds inherent in human studies. In the present study, we first reevaluated the pH of the postmortem brains of patients with schizophrenia and bipolar disorder by conducting a meta-analysis of existing data sets from 10 studies. We then measured pH, lactate levels, and related metabolite levels in brain homogenates from five neurodevelopmental mouse models of psychiatric disorders, including schizophrenia, bipolar disorder, and autism spectrum disorder. All mice were drug naive with the same agonal state, postmortem interval, and age within each strain. Our meta-analysis revealed that brain pH was significantly lower in patients with schizophrenia and bipolar disorder than in control participants, even when a few potential confounding factors (postmortem interval, age, and history of antipsychotic use) were considered. In animal experiments, we observed significantly lower pH and higher lactate levels in the brains of model mice relative to controls, as well as a significant negative correlation between pH and lactate levels. Our findings suggest that lower pH associated with increased lactate levels is not a mere artifact, but rather implicated in the underlying pathophysiology of schizophrenia and bipolar disorder. PMID:28776581

Associations between poor sleep quality and psychosocial stress with obesity in reproductive-age women of lower socioeconomic status.

PubMed

Tom, Sarah E; Berenson, Abbey B

2013-01-01

Prior studies have not examined the role of psychosocial stress in the relationship between poor sleep quality and obesity among women of lower socioeconomic status (SES). We tested the following hypotheses in a sample of reproductive-age women of lower SES: 1) Poor sleep quality is related to increased risk of obesity, and 2) psychosocial stress confounds this association between poor sleep quality and obesity. A total of 927 women age 16 to 40 years attending public health clinics in Southeastern Texas provided information on the Pittsburgh Sleep Quality Index and sociodemographic and health characteristics, including the Perceived Stress Scale. Height, weight, and waist circumference (WC) were measured in clinic. A series of models examined the associations between sleep disturbance, perceived stress, and weight outcomes, accounting for potential confounding factors. Nearly 30% of women were overweight, and 35% were obese. Half of women had a WC of greater than 35 inches. Most women had poor sleep quality and high levels of stress. Sleep quality and perceived stress were not related to body mass index category or WC in models that adjusted for age and race/ethnicity. Adjusting for potential confounding factors did not alter results. Perceived stress did not modify the association between sleep quality and weight outcomes. Poor sleep quality and psychosocial stress were not related to weight in reproductive-aged women of lower SES. However, poor sleep quality, high stress, overweight, and obesity were common in this group. Copyright © 2013 Jacobs Institute of Women's Health. Published by Elsevier Inc. All rights reserved.

Increased popliteal circumferential wall tension induced by orthostatic body posture is associated with local atherosclerotic plaques.

PubMed

Gemignani, Tiago; Azevedo, Renata C; Higa, Celina M; Coelho, Otávio R; Matos-Souza, José R; Nadruz, Wilson

2012-09-01

Lower limb arteries are exposed to higher hemodynamic burden in erectile posture. This study evaluated the effects of body posture on popliteal, carotid and brachial circumferential wall tension (CWT) and investigated the relationship between local CWT and atherosclerotic plaques in subjects with cardiovascular risk factors. Two hundred and three subjects (118 women and 85 men) with cardiovascular risk factors (smoking, hypertension or diabetes mellitus) underwent clinical and laboratory analysis and had their blood pressure measured in the arm and calf in supine and orthostatic positions. Arteries were evaluated by ultrasound analysis, while CWT was calculated according to Laplace's law. Among the enrolled participants, 47%, 29% and none presented popliteal, carotid and brachial plaques, respectively. Carotid CWT measurements were not associated with local plaques after adjustment for potential confounders. Conversely, general linear model and logistic regression analyses adjusted for potential confounders demonstrated that peak orthostatic CWT was the only local hemodynamic parameter showing significant relationship with popliteal plaques in the whole sample. In gender-specific analyses, although positively correlated with popliteal plaques in both genders, local peak orthostatic CWT exhibited an independent association with popliteal plaques after adjustment for potential confounders only in women. Popliteal CWT measured in orthostatic posture, rather than in supine position, is associated with popliteal atherosclerotic plaques, particularly in women. These findings suggest that erectile posture might play a role in the atherogenesis of leg arteries by modifying local hemodynamic forces and that there may be gender differences in this regard. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Physical and psychosocial factors in the prevention of chronic pain in older age.

PubMed

Fancourt, D; Steptoe, A

2018-06-24

Chronic pain is recognised as a major challenge as people age. Yet, despite growing research on chronic pain management, there is little research into chronic pain prevention. So there is a clear need to identify multimodal activities that could be encouraged amongst older adults as part of a healthy lifestyle to reduce the incidence risk of chronic pain. Using data from the English Longitudinal Study of Ageing we tracked 2,631 adults aged 50+ who were free from chronic pain at baseline across a decade and explore whether physical or psychosocial factors reduced the risk of developing chronic pain. In relation to physical factors, engaging in vigorous weekly activity was protective against the development of chronic pain (OR=0.74, SE=0.07, CI=0.62 to 0.89) when controlling for all identified socio-economic, health and social confounders. But no effects were found for moderate weekly activity. In relation to psychosocial factors, cultural engagement was also protective against the development of chronic pain (OR=0.75, SE=0.07, CI=0.63 to 0.91), but community group participation was not. These findings extend previous work showing that physical activity and psychosocial factors such as positive affect are key factors in the long-term success of chronic pain self-management. Future interventional studies for chronic pain are encouraged. Perspective This article explores whether physical and psychosocial activities could reduce the risk of developing chronic pain in older age. These results could potentially help clinicians to recommend multimodal activities as part of a broader healthy lifestyle for those aged 50+ to reduce the incidence rate of chronic pain. Copyright © 2018. Published by Elsevier Inc.

Urbanicity and lifestyle risk factors for cardiometabolic diseases in rural Uganda: a cross-sectional study.

PubMed

Riha, Johanna; Karabarinde, Alex; Ssenyomo, Gerald; Allender, Steven; Asiki, Gershim; Kamali, Anatoli; Young, Elizabeth H; Sandhu, Manjinder S; Seeley, Janet

2014-07-01

Urban living is associated with unhealthy lifestyles that can increase the risk of cardiometabolic diseases. In sub-Saharan Africa (SSA), where the majority of people live in rural areas, it is still unclear if there is a corresponding increase in unhealthy lifestyles as rural areas adopt urban characteristics. This study examines the distribution of urban characteristics across rural communities in Uganda and their associations with lifestyle risk factors for chronic diseases. Using data collected in 2011, we examined cross-sectional associations between urbanicity and lifestyle risk factors in rural communities in Uganda, with 7,340 participants aged 13 y and above across 25 villages. Urbanicity was defined according to a multi-component scale, and Poisson regression models were used to examine associations between urbanicity and lifestyle risk factors by quartile of urbanicity. Despite all of the villages not having paved roads and running water, there was marked variation in levels of urbanicity across the villages, largely attributable to differences in economic activity, civil infrastructure, and availability of educational and healthcare services. In regression models, after adjustment for clustering and potential confounders including socioeconomic status, increasing urbanicity was associated with an increase in lifestyle risk factors such as physical inactivity (risk ratio [RR]: 1.19; 95% CI: 1.14, 1.24), low fruit and vegetable consumption (RR: 1.17; 95% CI: 1.10, 1.23), and high body mass index (RR: 1.48; 95% CI: 1.24, 1.77). This study indicates that even across rural communities in SSA, increasing urbanicity is associated with a higher prevalence of lifestyle risk factors for cardiometabolic diseases. This finding highlights the need to consider the health impact of urbanization in rural areas across SSA. Please see later in the article for the Editors' Summary.

The association between risk factors and hypertension in perak, malaysia.

PubMed

Loh, K W; Rani, F; Chan, T C; Loh, H Y; Ng, C W; Moy, F M

2013-08-01

Hypertension is a major public health problem in Malaysia. A survey was initiated to examine the association of modifiable and non-modifiable risk factors for hypertension in Perak, Malaysia. A total of 2025 respondents aged 30 years and above were recruited using a multi-stage sampling method. Hypertension was defined as self-reported hypertension and/or average of two blood pressure readings at single occasion with SBP ≥ 140mmHg or DBP ≥ 90 mmHg. Body mass index (BMI) was defined using the Asian criteria and International Physical Activity Questionnaire (IPAQ) was used to evaluate physical activity. Body weight, height and blood pressure were obtained using standard procedures. Univariate analyses were conducted to examine the associations between risk factors and hypertension. Multiple logistic regression was used to examine each significant risk factor on hypertension after adjusted for confounders. In total, 1076 (54.9%) respondents were found to be hypertensive. Significant associations (p <0.001) with hypertension were noted for increasing age, low physical activity, obese BMI, no education background and positive family history of hypertension. After adjusting for age, sex, ethnicity, education background, family history, BMI, physical activity, smoking and diet, respondents who were obese and had positive family history had higher odds for hypertension (OR:2.34; 95% CI:1.84-3.17 and 1.96 (1.59-2.42) respectively. A significant increase (p <0.001) in risk for hypertension was noted for age. Those with moderate physical activities were 1.40 (1.04-1.78) times more of having hypertension than those active. Poor diet score and smoking were not significantly associated with increased risk for hypertension. In conclusion, modifiable risk factors such as BMI and physical activity are important risk factors to target in reducing the risk for hypertension.

Examining the role of unmeasured confounding in mediation analysis with genetic and genomic applications.

PubMed

Lutz, Sharon M; Thwing, Annie; Schmiege, Sarah; Kroehl, Miranda; Baker, Christopher D; Starling, Anne P; Hokanson, John E; Ghosh, Debashis

2017-07-19

In mediation analysis if unmeasured confounding is present, the estimates for the direct and mediated effects may be over or under estimated. Most methods for the sensitivity analysis of unmeasured confounding in mediation have focused on the mediator-outcome relationship. The Umediation R package enables the user to simulate unmeasured confounding of the exposure-mediator, exposure-outcome, and mediator-outcome relationships in order to see how the results of the mediation analysis would change in the presence of unmeasured confounding. We apply the Umediation package to the Genetic Epidemiology of Chronic Obstructive Pulmonary Disease (COPDGene) study to examine the role of unmeasured confounding due to population stratification on the effect of a single nucleotide polymorphism (SNP) in the CHRNA5/3/B4 locus on pulmonary function decline as mediated by cigarette smoking. Umediation is a flexible R package that examines the role of unmeasured confounding in mediation analysis allowing for normally distributed or Bernoulli distributed exposures, outcomes, mediators, measured confounders, and unmeasured confounders. Umediation also accommodates multiple measured confounders, multiple unmeasured confounders, and allows for a mediator-exposure interaction on the outcome. Umediation is available as an R package at https://github.com/SharonLutz/Umediation A tutorial on how to install and use the Umediation package is available in the Additional file 1.

In vivo preclinical cancer and tissue engineering applications of absolute oxygen imaging using pulse EPR

NASA Astrophysics Data System (ADS)

Epel, Boris; Kotecha, Mrignayani; Halpern, Howard J.

2017-07-01

The value of any measurement and a fortiori any measurement technology is defined by the reproducibility and the accuracy of the measurements. This implies a relative freedom of the measurement from factors confounding its accuracy. In the past, one of the reasons for the loss of focus on the importance of imaging oxygen in vivo was the difficulty in obtaining reproducible oxygen or pO2 images free from confounding variation. This review will briefly consider principles of electron paramagnetic oxygen imaging and describe how it achieves absolute oxygen measurements. We will provide a summary review of the progress in biomedical EPR imaging, predominantly in cancer biology research, discuss EPR oxygen imaging for cancer treatment and tissue graft assessment for regenerative medicine applications.

Survey material choices in haematology EQA: a confounding factor in automated counting performance assessment.

PubMed

De la Salle, Barbara

2017-02-15

The complete blood count (CBC) is one of the most frequently requested tests in laboratory medicine, performed in a range of healthcare situations. The provision of an ideal assay material for external quality assessment is confounded by the fragility of the cellular components of blood, the lack of commutability of stabilised whole blood material and the lack of certified reference materials and methods to which CBC results can be traced. The choice of assay material between fresh blood, extended life assay material and fully stabilised, commercially prepared, whole blood material depends upon the scope and objectives of the EQA scheme. The introduction of new technologies in blood counting and the wider clinical application of parameters from the extended CBC will bring additional challenges for the EQA provider.

Diversity of gastrointestinal helminths in Dall's sheep and the negative association of the abomasal nematode, Marshallagia marshalli, with fitness indicators

USDA-ARS?s Scientific Manuscript database

Gastrointestinal helminths can have a detrimental effect on the fitness of wild ungulates. Arctic and Subarctic ecosystems are ideal for the study of host-parasite interactions due to the comparatively simple ecological interactions and limited confounding factors. We used a unique dataset collected...

Unique Contributions of Maternal Reading Proficiency to Predicting Children's Preschool Receptive Vocabulary and Reading Proficiency

ERIC Educational Resources Information Center

Phillips, Linda M.; Norris, Stephen P.; Hayward, Denyse V.; Lovell, Meridith A.

2017-01-01

This study investigated whether mothers' measured reading proficiency and their educational level predict, over and above each other, their children's receptive vocabulary and reading proficiency when confounding factors of speaking a minority language, ethnicity, number of children in the family, and marital and employment status are controlled.…

"Fundamental Causes" of Social Inequalities in Mortality: A Test of the Theory

ERIC Educational Resources Information Center

Phelan, Jo C.; Link, Bruce G.; Diez-Roux, Ana; Kawachi, Ichiro; Levin, Bruce

2004-01-01

Medicine and epidemiology currently dominate the study of the strong association between socioeconomic status and mortality. Socioeconomic status typically is viewed as a causally irrelevant "confounding variable" or as a less critical variable marking only the beginning of a causal chain in which intervening risk factors are given prominence. Yet…

The Relationship between Frequency of Family Dinner and Adolescent Problem Behaviors after Adjusting for Other Family Characteristics

ERIC Educational Resources Information Center

Sen, Bisakha

2010-01-01

Objective: To examine the association between frequency of family dinners (FFD) and selected problem behaviors for adolescents after adjusting for family connectedness, parental awareness, other family activities, and other potentially confounding factors. Methods: Data are drawn from the National Longitudinal Survey of Youth, 1997. The primary…

The Impact of Coaching on New African-American Female Principals

ERIC Educational Resources Information Center

King, Chanel

2012-01-01

This is cross-case analysis of four new African American female principals who reported that coaching was critical to their success. They described the challenges inherent to all newcomers with particular attention to how their professional socialization was further confounded by factors of race and gender. The conceptual framework used for this…

Characteristics of Teacher Induction Programs and Turnover Rates of Beginning Teachers

ERIC Educational Resources Information Center

Kang, Seok; Berliner, David C.

2012-01-01

The federal School and Staffing Survey (SASS) and Teacher Follow-up Survey (TFS) were used to examine the impacts of induction activities on beginning teacher turnover. This study excluded those teachers who moved or left schools for unavoidable and involuntary reasons, a confounding factor in previous research. This analysis revealed that three…

Situational Determinants of Personal Validation of General Personality Interpretations

ERIC Educational Resources Information Center

Hinrichsen, James J.; Bradley, Laurence A.

1974-01-01

Determines whether kind of test used in personality assessment is an important factor in influencing the extent to which subjects accept the interpretation made by a psychologist and clarifies the importance of the status of the test-interpreter by eliminating a status-experimenter confound contained within the Snyder and Larsen (1972) study.…

Above- and belowground competition from longleaf pine plantations limits performance of reintroduced herbaceous species

Treesearch

Timothy B. Harrington; Christa M. Dagley; M. Boyd Edwards

2002-01-01

Although overstory trees limit the abundance and species richness of herbaceous vegetation in longleaf pine (Pinus palustris Mill.) plantations, the responsible mechanisms are poorly understood because of confounding among limiting factors. In fall 1998, research was initiated to determine the separate effects of above- and belowground competition...

Use of combined biogeochemical model approaches and empirical data to assess critical loads of nitrogen

Treesearch

Mark Fenn; Charles Driscoll; Quingtao Zhou; Leela Rao; Thomas Meixner; Edith Allen; Fengming Yuan; Timothy Sullivan

2015-01-01

Empirical and dynamic biogeochemical modelling are complementary approaches for determining the critical load (CL) of atmospheric nitrogen (N) or other constituent deposition that an ecosystem can tolerate without causing ecological harm. The greatest benefits are obtained when these approaches are used in combination. Confounding environmental factors can complicate...

Is Childhood Physical Abuse Associated with Peptic Ulcer Disease? Findings from a Population-Based Study

ERIC Educational Resources Information Center

Fuller-Thomson, Esme; Bottoms, Jennifer; Brennenstuhl, Sarah; Hurd, Marion

2011-01-01

This study investigated childhood physical abuse and ulcers in a regionally representative community sample. Age, race and sex were controlled for in addition to five clusters of potentially confounding factors: adverse childhood conditions, adult socioeconomic status, current health behaviors, current stress and marital status, and history of…

Local-scale and watershed-scale determinants of summertime urban stream temperatures

Treesearch

Derek B. Booth; Kristin A. Kraseski; C. Rhett Jackson

2014-01-01

The influence of urbanization on the temperature of small streams is widely recognized, but these effects are confounded by the great natural variety of their contributing watersheds. To evaluate the relative importance of local-scale and watershed-scale factors on summer temperatures in urban streams, hundreds of near-instantaneous temperature measurements throughout...

Sensory imbalance as mechanism of orientation disruption in the leafminer, Phyllocnistis citrella: Elucidation by multivariate geometric designs and response surface models

USDA-ARS?s Scientific Manuscript database

Experimental designs developed to address mixtures are ideally suited for many areas of experimental biology including pheromone blend studies because they address the confounding of proportionality and concentration intrinsic to factorial and one-factor-at-a-time designs. Geometric multivariate des...

Land surface controls on afternoon precipitation diagnosed from observational data: Uncertainties and confounding factors

USDA-ARS?s Scientific Manuscript database

The feedback between soil moisture and precipitation has long been a topic of interest due to its potential for improving weather and seasonal forecasts. The generally proposed mechanism assumes a control of soil moisture on precipitation via the partitioning of the surface fluxes (the Evaporative F...

Pre- and Postnatal Influences on Preschool Mental Health: A Large-Scale Cohort Study

ERIC Educational Resources Information Center

Robinson, Monique; Oddy, Wendy H.; Li, Jianghong; Kendall, Garth E.; de Klerk, Nicholas H.; Silburn, Sven R.; Zubrick, Stephen R.; Newnham, John P.; Stanley, Fiona J.; Mattes, Eugen

2008-01-01

Background: Methodological challenges such as confounding have made the study of the early determinants of mental health morbidity problematic. This study aims to address these challenges in investigating antenatal, perinatal and postnatal risk factors for the development of mental health problems in pre-school children in a cohort of Western…

Children's Comprehension and Local-to-Global Recall of Narrative and Expository Texts

ERIC Educational Resources Information Center

Romero, Fernando; Paris, Scott G.; Brem, Sarah K.

2005-01-01

We examined underlying mechanisms for comprehension differences across expository and narrative text while controlling for factors confounded in the extant literature. Fourth grade students (n=32) read both an expository and a narrative text, and completed both a local comprehension assessment, and a global retelling assessment for each text.…

Does Pollution Increase School Absences? NBER Working Paper No. 13252

ERIC Educational Resources Information Center

Currie, Janet; Hanushek, Eric; Kahn, E. Megan; Neidell, Matthew; Rivkin, Steven

2007-01-01

We examine the effect of air pollution on school absences using unique administrative data for elementary and middle school children in the 39 largest school districts in Texas. These data are merged with information from monitors maintained by the Environmental Protection Agency. To control for potentially confounding factors, we adopt a…

Protection from livestock fails to deter shrub proliferation in a desert landscape with a history of heavy grazing

USDA-ARS?s Scientific Manuscript database

Desertification is often characterized by the replacement of mesophytic grasses with xerophytic shrubs. Livestock grazing is considered a key driver of shrub encroachment, although most evidence is anecdotal or confounded by other factors. Mapping of velvet mesquite (Prosopis velutina) shrubs in and...

Eco-Health Linkages: evidence base and socio-economic considerations for linking ecosystem goods and services to human health

EPA Science Inventory

Ecosystem goods and services (EGS) are thought to play a role in protecting human health, but the empirical evidence directly linking EGS to human health outcomes is limited, and our ability to detect Eco-Health linkages is confounded by socio-economic factors. These limitations ...

Random measurement error: Why worry? An example of cardiovascular risk factors.

PubMed

Brakenhoff, Timo B; van Smeden, Maarten; Visseren, Frank L J; Groenwold, Rolf H H

2018-01-01

With the increased use of data not originally recorded for research, such as routine care data (or 'big data'), measurement error is bound to become an increasingly relevant problem in medical research. A common view among medical researchers on the influence of random measurement error (i.e. classical measurement error) is that its presence leads to some degree of systematic underestimation of studied exposure-outcome relations (i.e. attenuation of the effect estimate). For the common situation where the analysis involves at least one exposure and one confounder, we demonstrate that the direction of effect of random measurement error on the estimated exposure-outcome relations can be difficult to anticipate. Using three example studies on cardiovascular risk factors, we illustrate that random measurement error in the exposure and/or confounder can lead to underestimation as well as overestimation of exposure-outcome relations. We therefore advise medical researchers to refrain from making claims about the direction of effect of measurement error in their manuscripts, unless the appropriate inferential tools are used to study or alleviate the impact of measurement error from the analysis.

Abortion in young women and subsequent mental health.

PubMed

Fergusson, David M; Horwood, L John; Ridder, Elizabeth M

2006-01-01

The extent to which abortion has harmful consequences for mental health remains controversial. We aimed to examine the linkages between having an abortion and mental health outcomes over the interval from age 15-25 years. Data were gathered as part of the Christchurch Health and Development Study, a 25-year longitudinal study of a birth cohort of New Zealand children. Information was obtained on: a) the history of pregnancy/abortion for female participants over the interval from 15-25 years; b) measures of DSM-IV mental disorders and suicidal behaviour over the intervals 15-18, 18-21 and 21-25 years; and c) childhood, family and related confounding factors. Forty-one percent of women had become pregnant on at least one occasion prior to age 25, with 14.6% having an abortion. Those having an abortion had elevated rates of subsequent mental health problems including depression, anxiety, suicidal behaviours and substance use disorders. This association persisted after adjustment for confounding factors. The findings suggest that abortion in young women may be associated with increased risks of mental health problems.

The relationship between frequency of family dinner and adolescent problem behaviors after adjusting for other family characteristics.

PubMed

Sen, Bisakha

2010-02-01

To examine the association between frequency of family dinners (FFD) and selected problem behaviors for adolescents after adjusting for family connectedness, parental awareness, other family activities, and other potentially confounding factors. Data are drawn from the National Longitudinal Survey of Youth, 1997. The primary variable of interest is self-reported FFD in a typical week. Problem behaviors studied are substance-use, physical violence, property-destruction, stealing, running away from home, andgang membership. Multivariate logistic models are estimated for each behaviors. Linear regression models are estimated for behavior-frequency for the sub-samples engaging in them. Analysis is done separately by gender. FFD is negatively associated with substance-use and running away for females; drinking, physical violence, property-destruction, stealing and running away for males. Family meals are negatively associated to certain problem behaviors for adolescents even after controlling rigorously for potentially confounding factors. Thus, programs that promote family meals are beneficial. Copyright (c) 2009 The Association for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.