Bushnik, Tracey; Cook, Jocelynn L.; Yuzpe, A. Albert; Tough, Suzanne; Collins, John
BACKGROUND Over the past 10 years, there has been a significant increase in the use of assisted reproductive technologies in Canada, however, little is known about the overall prevalence of infertility in the population. The purpose of the present study was to estimate the prevalence of current infertility in Canada according to three definitions of the risk of conception. METHODS Data from the infertility component of the 2009–2010 Canadian Community Health Survey were analyzed for married and common-law couples with a female partner aged 18–44. The three definitions of the risk of conception were derived sequentially starting with birth control use in the previous 12 months, adding reported sexual intercourse in the previous 12 months, then pregnancy intent. Prevalence and odds ratios of current infertility were estimated by selected characteristics. RESULTS Estimates of the prevalence of current infertility ranged from 11.5% (95% CI 10.2, 12.9) to 15.7% (95% CI 14.2, 17.4). Each estimate represented an increase in current infertility prevalence in Canada when compared with previous national estimates. Couples with lower parity (0 or 1 child) had significantly higher odds of experiencing current infertility when the female partner was aged 35–44 years versus 18–34 years. Lower odds of experiencing current infertility were observed for multiparous couples regardless of age group of the female partner, when compared with nulliparous couples. CONCLUSIONS The present study suggests that the prevalence of current infertility has increased since the last time it was measured in Canada, and is associated with the age of the female partner and parity. PMID:22258658
Landsteiner, K.; Chase, M. W.
A method of preparation and a preliminary chemical investigation of the substance present in commercial (pig) pepsin which reacts with human A antiserum are presented. The material offers especial advantage in securing in quantity a serologically highly active preparation suitable for further studies. Active preparations were isolated moreover from commercial (pig) gastric mucin. Some other materials showing group specific reactions are mentioned. PMID:19870506
CHOY, M.; SWITZER, P.; De MARTEL, C.; PARSONNET, J.
SUMMARY We describe a method of working on publicly available data to estimate disease prevalence in small geographic areas using Helicobacter pylori as a model infection. Using data from the Third National Health and Nutrition Examination Survey, risk parameters for H. pylori infection were obtained by logistic regression and validated by predicting 737·5 infections in an independent cohort with 736 observed infections. The prevalence of H. pylori infection in the San Francisco Bay Area was estimated with the probabilities obtained from a predictive logistic model, using risk parameters with individual-level 1990 U.S. Census data as input. Predicted H. pylori prevalence was also compared to gastric cancer incidence obtained from the Northern California Cancer Center and showed a positive correlation with gastric cancer incidence (P<0·001, R2=0·87), and no statistically significant association with other malignancies. By exclusively using publicly available data, these methods may be applied to selected conditions with strong demographic predictors. PMID:18047747
Wolf, Michael; Musch, Jochen; Enczmann, Juergen; Fischer, Johannes
The prevalence of nonpaternity in human societies is difficult to establish. To obtain a current and fairly unbiased estimate of the nonpaternity rate in Germany, we analysed a dataset consisting of 971 children and their parents in whom human leukocyte antigen (HLA) typing had been carried out in the context of bone marrow transplantation. In this sample, nine exclusions (0.93%) could be identified on the basis of more than 300 HLA-haplotypes defined by four HLA genes. Given this number of exclusions, a maximum likelihood estimate of the nonpaternity rate in the population of 0.94% was obtained with asymptotic 95% confidence limits of 0.33% and 1.55%, respectively. This result is in accordance with recent surveys as well as findings from Switzerland for a comparable sample, and it suggests that earlier estimates of the nonpaternity rate which were often in excess of 10% may have been largely exaggerated.
White, Peter J.
Background: Understanding patterns of chlamydia prevalence is important for addressing inequalities and planning cost-effective control programs. Population-based surveys are costly; the best data for England come from the Natsal national surveys, which are only available once per decade, and are nationally representative but not powered to compare prevalence in different localities. Prevalence estimates at finer spatial and temporal scales are required. Methods: We present a method for estimating local prevalence by modeling the infection, testing, and treatment processes. Prior probability distributions for parameters describing natural history and treatment-seeking behavior are informed by the literature or calibrated using national prevalence estimates. By combining them with surveillance data on numbers of chlamydia tests and diagnoses, we obtain estimates of local screening rates, incidence, and prevalence. We illustrate the method by application to data from England. Results: Our estimates of national prevalence by age group agree with the Natsal-3 survey. They could be improved by additional information on the number of diagnosed cases that were asymptomatic. There is substantial local-level variation in prevalence, with more infection in deprived areas. Incidence in each sex is strongly correlated with prevalence in the other. Importantly, we find that positivity (the proportion of tests which were positive) does not provide a reliable proxy for prevalence. Conclusion: This approach provides local chlamydia prevalence estimates from surveillance data, which could inform analyses to identify and understand local prevalence patterns and assess local programs. Estimates could be more accurate if surveillance systems recorded additional information, including on symptoms. See video abstract at, http://links.lww.com/EDE/B211. PMID:28306613
Battaglia, Mario Alberto; Bezzini, Daiana
Italy is a high risk area for multiple sclerosis (MS) as confirmed by the numerous prevalence and incidence studies conducted in several regions/districts of the country. Nevertheless, there are no recent published epidemiological data, nor studies about the total prevalence of MS in Italy. Our aim was to update as of 2015 the prevalence rates of MS in different geographical areas using already published epidemiological studies, and to estimate the overall prevalence of the disease in Italy. We made a search in MEDLINE database of all published studies on epidemiology of MS in Italy. Then, we applied, to the already published prevalence data, the last published incidence and mortality rates to recalculate, as of 2015, the prevalence of MS. So, we calculated the mean prevalence rate from our extrapolations, and we applied it to the population in 2015 to estimate the number of MS patients in Italy. Our prevalence extrapolations ranged from 122 to 232 cases/100,000 in the mainland and Sicily, with an average of 176/100,000, and from 280 to 317 cases/100,000 in Sardinia with an average of 299/100,000. Applying these media to the Italian population in 2015, we obtained an estimate of more than 109,000 MS patients in Italy. Our estimates were higher than the latest published rates but consistent with the annual increase of prevalence due to incidence that exceeds mortality, with the increase of survival and, maybe, with the probable increase of incidence.
Ye, Rong; Gao, Yan-hui; Yang, Yi; Chen, Yue
To estimate the prevalence ratios, using a log-binomial model with or without continuous covariates. Prevalence ratios for individuals' attitude towards smoking-ban legislation associated with smoking status, estimated by using a log-binomial model were compared with odds ratios estimated by logistic regression model. In the log-binomial modeling, maximum likelihood method was used when there were no continuous covariates and COPY approach was used if the model did not converge, for example due to the existence of continuous covariates. We examined the association between individuals' attitude towards smoking-ban legislation and smoking status in men and women. Prevalence ratio and odds ratio estimation provided similar results for the association in women since smoking was not common. In men however, the odds ratio estimates were markedly larger than the prevalence ratios due to a higher prevalence of outcome. The log-binomial model did not converge when age was included as a continuous covariate and COPY method was used to deal with the situation. All analysis was performed by SAS. Prevalence ratio seemed to better measure the association than odds ratio when prevalence is high. SAS programs were provided to calculate the prevalence ratios with or without continuous covariates in the log-binomial regression analysis.
Zheng, Rongshou; Zeng, Hongmei; Zhang, Siwei; Chen, Tianhui; Chen, Wanqing
Little is known about the nationwide cancer prevalence in China. This paper aimed at assessing the 5-year cancer prevalence in China for 25 major cancers. Incidence data were estimated using data from 177 cancer registries and covering 175 million populations. Survival data were from 17 cancer registries diagnosed during 2003-2005 and followed up until 31 December 2010. Standardized protocols for data collection and validation were adopted. Cancer prevalence for 25 major sites was estimated from year-specific incidence rates and survival probabilities according to standardized formula. The estimated 5-year prevalence for all cancers combined in 2011 in China was 7.49 million (3.68 million for men and 3.81 million for women). Cancer prevalence estimates for 5 years varied by cancer sites, ranging from 11,900 for testicular cancer to 1.02 million for women breast cancer. Those most prevalent five cancers (breast, colorectal, lung, stomach and esophageal cancers) covered 56.1% of cancer burden in China. The proportion for the 5-year prevalence was higher in urban areas compared to rural areas (666 per 100,000 versus 440 per 100,000), while cancer prevalence estimates were higher for women compared to men, with the men/women ratio of 5-year cancer prevalence reaching 0.96. This paper provides the first systematic analysis on 5-year cancer prevalence for 25 major cancers in China in 2011, which may serve as a baseline for assessment of the overall effectiveness of cancer health care. The huge number of cancer survivors requires resource allocation to improve health care programs and primary prevention, especially in rural areas. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
Journal of Intellectual and Developmental Disability, 2004
Existing estimates of the prevalence of intellectual disability vary substantially between different studies and among different populations (AIHW: Wen, 1997; Roeleveld, Zielhuis, & Gabreels, 1997; Leonard & Wen, 2002), often affected by differences in operational definitions and methods of estimation. For example, in Australia, operational…
Alonzo, Todd A; Pepe, Margaret Sullivan; Lumley, Thomas
Disease prevalence is ideally estimated using a 'gold standard' to ascertain true disease status on all subjects in a population of interest. In practice, however, the gold standard may be too costly or invasive to be applied to all subjects, in which case a two-phase design is often employed. Phase 1 data consisting of inexpensive and non-invasive screening tests on all study subjects are used to determine the subjects that receive the gold standard in the second phase. Naive estimates of prevalence in two-phase studies can be biased (verification bias). Imputation and re-weighting estimators are often used to avoid this bias. We contrast the forms and attributes of the various prevalence estimators. Distribution theory and simulation studies are used to investigate their bias and efficiency. We conclude that the semiparametric efficient approach is the preferred method for prevalence estimation in two-phase studies. It is more robust and comparable in its efficiency to imputation and other re-weighting estimators. It is also easy to implement. We use this approach to examine the prevalence of depression in adolescents with data from the Great Smoky Mountain Study.
Gatta, G; Mallone, S; van der Zwan, J M; Trama, A; Siesling, S; Capocaccia, R
Complete cancer prevalence data in Europe have never been updated after the first estimates provided by the EUROPREVAL project and referred to the year 1993. This paper provides prevalence estimates for 16 major cancers in Europe at the beginning of the year 2003. We estimated complete prevalence by the completeness index method. We used information on cancer patients diagnosed in 1978-2002 with vital status information available up to 31 December 2003, from 76 European cancer registries. About 11.6 millions of Europeans with a history of one of the major considered cancers were alive on 1 January 2003. For breast and prostate cancers, about 1 out of 73 women and 1 out of 160 men were living with a previous diagnosis of breast and prostate cancers, respectively. The demographic variations alone will increase the number of prevalent cases to nearly 13 millions in 2010. Several factors (early detection, population aging and better treatment) contribute to increase cancer prevalence and push for the need of a continuous monitoring of prevalence indicators to properly plan needs, resource allocation to cancer and for improving health care programs for cancer survivors. Cancer prevalence should be included within the EU official health statistics.
Janssens, Wendy; van der Gaag, Jacques; Rinke de Wit, Tobias F; Tanović, Zlata
In 2007, UNAIDS corrected estimates of global HIV prevalence downward from 40 million to 33 million based on a methodological shift from sentinel surveillance to population-based surveys. Since then, population-based surveys are considered the gold standard for estimating HIV prevalence. However, prevalence rates based on representative surveys may be biased because of nonresponse. This article investigates one potential source of nonresponse bias: refusal to participate in the HIV test. We use the identity of randomly assigned interviewers to identify the participation effect and estimate HIV prevalence rates corrected for unobservable characteristics with a Heckman selection model. The analysis is based on a survey of 1,992 individuals in urban Namibia, which included an HIV test. We find that the bias resulting from refusal is not significant for the overall sample. However, a detailed analysis using kernel density estimates shows that the bias is substantial for the younger and the poorer population. Nonparticipants in these subsamples are estimated to be three times more likely to be HIV-positive than participants. The difference is particularly pronounced for women. Prevalence rates that ignore this selection effect may be seriously biased for specific target groups, leading to misallocation of resources for prevention and treatment.
Harbaugh, Bonnie L; Bounds, Wendy; Kolbo, Jerome; Molaison, Elaine; Zhang, Lei
This study estimates prevalence of overweight and at risk of overweight among low-income predominately non-Hispanic Black Head Start Mississippi preschoolers. A two-stage stratified probability design produced a representative sample of 1,250 preschoolers aged 3 to 5 years. Height, weight, age, gender, and race data were obtained. The prevalence of overweight (20.6%) and at risk of overweight (17.9%) combined was 38.5%. Moreover, highest rates were found in boys, non-Hispanic Blacks, and 5-year-olds. The prevalence of overweight in Mississippi Head Start children exceeds national averages, reinforcing the need for early-childhood health promotion and prevention.
Adeloye, Davies; Chan, Kit Yee; Rudan, Igor; Campbell, Harry
Aim To estimate and compare asthma prevalence in Africa in 1990, 2000, and 2010 in order to provide information that will help inform the planning of the public health response to the disease. Methods We conducted a systematic search of Medline, EMBASE, and Global Health for studies on asthma published between 1990 and 2012. We included cross-sectional population based studies providing numerical estimates on the prevalence of asthma. We calculated weighted mean prevalence and applied an epidemiological model linking age with the prevalence of asthma. The UN population figures for Africa for 1990, 2000, and 2010 were used to estimate the cases of asthma, each for the respective year. Results Our search returned 790 studies. We retained 45 studies that met our selection criteria. In Africa in 1990, we estimated 34.1 million asthma cases (12.1%; 95% confidence interval [CI] 7.2-16.9) among children <15 years, 64.9 million (11.8%; 95% CI 7.9-15.8) among people aged <45 years, and 74.4 million (11.7%; 95% CI 8.2-15.3) in the total population. In 2000, we estimated 41.3 million cases (12.9%; 95% CI 8.7-17.0) among children <15 years, 82.4 million (12.5%; 95% CI 5.9-19.1) among people aged <45 years, and 94.8 million (12.0%; 95% CI 5.0-18.8) in the total population. This increased to 49.7 million (13.9%; 95% CI 9.6-18.3) among children <15 years, 102.9 million (13.8%; 95% CI 6.2-21.4) among people aged <45 years, and 119.3 million (12.8%; 95% CI 8.2-17.1) in the total population in 2010. There were no significant differences between asthma prevalence in studies which ascertained cases by written and video questionnaires. Crude prevalences of asthma were, however, consistently higher among urban than rural dwellers. Conclusion Our findings suggest an increasing prevalence of asthma in Africa over the past two decades. Due to the paucity of data, we believe that the true prevalence of asthma may still be under-estimated. There is a need for national governments in Africa
Richardson, Lisa K.; Frueh, B. Christopher; Acierno, Ronald
Objective To provide a critical review of prevalence estimates of combat-related PTSD among military personnel and veterans, and of the relevant factors that may account for the variability of estimates within and across cohorts, including methodological and conceptual factors accounting for differences in prevalence rates across nations, conflicts/wars, and studies. Method We examined MEDLINE and PsycINFO databases for literature on combat-related PTSD. The following terms were used independently and in combinations in this search: PTSD, combat, veterans, military, epidemiology, prevalence. Results The point prevalence of combat-related PTSD in US military veterans since the Vietnam War ranges from about 2 – 17%. Studies of recent conflicts suggest that combat-related PTSD afflicts between 4 – 17% of US Iraq War veterans, but only 3 – 6% of returning UK Iraq War veterans. Thus, the prevalence range is narrower and tends to have a lower ceiling among combat veterans of non-US Western nations. Variability in prevalence is likely due to differences in sampling strategies; measurement strategies; inclusion and measurement of the DSM-IV clinically significant impairment criterion; timing and latency of assessment and potential for recall bias; and combat experiences. Prevalence rates are also likely affected by issues related to PTSD course, chronicity, and comorbidity; symptom overlap with other psychiatric disorders; and sociopolitical and cultural factors that may vary over time and by nation. Conclusions The disorder represents a significant and costly illness to veterans, their families, and society as a whole. However, further carefully conceptualized research is needed to advance our understanding of disorder prevalence, as well as associated information on course, phenomenology, protective factors, treatment, and economic costs. PMID:20073563
Teixeira, A L; Lisboa, M
Due to globalized migratory processes, female genital mutilation/cutting (FGM/C) has spread to other countries, including countries in Europe, where, with a few exceptions, it remains a concealed problem. To the authors' knowledge, this is the first national extensive study to estimate the prevalence of FGM/C in Portugal. Prevalence estimation. Using extrapolation of country-of-origin prevalence data and the 2011 Census data, this study estimated: the prevalence of FGM/C in Portugal among women of reproductive age (15-49 years) and among all women aged ≥15 years; and the number of girls aged <15 years living in Portugal who have undergone or will probably undergo FGM/C. It is estimated that 6576 women aged ≥15 years living in Portugal have undergone FGM/C, with cases distributed unevenly throughout the national territory. In addition, it is estimated that 1830 girls aged <15 years living in Portugal have undergone or are likely to undergo FGM/C. This study estimated that more than 6000 women living in Portugal have undergone FGM/C, and many girls remain at risk. These two groups need different types of interventions. Awareness of the number and geographical dispersion of cases of FGM/C will enable more informed and targeted definition of public health policies for protection of females who have undergone or are at risk of undergoing FGM/C. Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.
Raso, Giovanna; Vounatsou, Penelope; McManus, Donald P; N'Goran, Eliézer K; Utzinger, Jürg
Models that accurately estimate the age-specific infection prevalence of Schistosoma mansoni can be useful for schistosomiasis control programmes, particularly with regard to whether mass drug administration or selected treatment should be employed. We developed a Bayesian formulation of an immigration-death model that has been previously proposed, which used maximum likelihood inference for estimating the age-specific S. mansoni prevalence in a dataset from Egypt. For comparative purposes, we first applied the Bayesian formulation of the immigration-death model to the dataset from Egypt. We further analysed data obtained from a cross-sectional parasitological survey that determined the infection prevalence of S. mansoni among 447 individuals in a village in Côte d'Ivoire. Three consecutive stool samples were collected from each participant and analysed by the Kato-Katz technique. In the Côte d'Ivoire study, the observed S. mansoni infection prevalence was 41.6% and varied with age. The immigration-death model was able to correctly predict 50% of the observed age group-specific point prevalences. The model presented here can be utilized to estimate S. mansoni community infection prevalences, which in turn helps in the strategic planning of schistosomiasis control.
Ward, Alex; Arrighi, H Michael; Michels, Shannon; Cedarbaum, Jesse M
The purpose of conducting this study was to identify areas of concordance and sources of variation for the published rates of prevalence and incidence associated with various definitions for mild cognitive impairment (MCI). The study used systematic review of studies published in English since 1984. Studies were identified by searching MEDLINE and EMBASE databases. Population-based observational studies of incidence or prevalence of MCI and related terms were eligible for inclusion. A total of 3,705 citations were identified, and 42 were accepted for inclusion; 35 included data on prevalence and 13 on incidence. The following four terms predominated: age-associated memory impairment (AAMI); cognitive impairment no dementia (CIND); MCI; and amnestic MCI (aMCI). Within each term, the operational definition varied. Substantial variation was observed for both incidence (MCI: 21.5-71.3; aMCI: 8.5-25.9 per 1,000 person-years) and prevalence of each definition of cognitive impairment (AAMI 3.6%-38.4%; CIND 5.1%-35.9%; MCI 3%-42%; aMCI 0.5%-31.9%). CIND and MCI showed increasing prevalence among older age groups, whereas age-specific rates of aMCI were lower and without any apparent age relationship. Prevalence and incidence estimates associated with MCI vary greatly both between definitions and within a definition across the 42 publications. These wide differences pose a significant challenge to our understanding of the social burden of this disease. Enhancement and standardization of operational definitions of the subtypes of cognitive impairment could improve estimates of disease burden and provide a mechanism to assist in the identification of individuals at risk for future Alzheimer's disease and other dementias. Copyright © 2012 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.
Much of the debate over how best to estimate the prevalence of problem gambling in the general population is driven by a number of misconceptions, misinterpretations, and questionable, sometimes erroneous assumptions. Among the latter is the failure to understand that what is being validated is not the test but the interpretation of test scores for a specific purpose. In addition there has been a lack of attention to defining the clinical and/or epidemiologic relevance of case definitions in terms of severity and other clinical attributes, a misunderstanding of how test values are interpreted when criterion thresholds or cut-off points are selected, and a failure to replicate the validation of criterion thresholds for defining cases of problem gambling. It is argued further that the distinction between dichotomy and continuum is a false choice, and any emphasis on overestimation is misdirected. Alternative methods for evaluating tests and estimating prevalence are described and a pragmatic empirical approach to the interpretation of prevalence estimates is recommended.
Pritchard, Nicholas A.; Tebbs, Joshua M.
Monitoring populations of hosts as well as insect vectors is an important part of agricultural and public health risk assessment. In applications where pathogen prevalence is likely low, it is common to test pools of subjects for the presence of infection, rather than to test subjects individually. This technique is known as pooled (group) testing. In this paper, we revisit the problem of estimating the population prevalence p from pooled testing, but we consider applications where inverse binomial sampling is used. Our work is unlike previous research in pooled testing, which has largely assumed a binomial model. Inverse sampling is natural to implement when there is a need to report estimates early on in the data collection process and has been used in individual testing applications when disease incidence is low. We consider point and interval estimation procedures for p in this new pooled testing setting, and we use example data sets from the literature to describe and to illustrate our methods. PMID:21743789
Koran, Lorrin M; Faber, Ronald J; Aboujaoude, Elias; Large, Michael D; Serpe, Richard T
Compulsive buying (uncontrolled urges to buy, with resulting significant adverse consequences) has been estimated to affect from 1.8% to 16% of the adult U.S. population. To the authors' knowledge, no study has used a large general population sample to estimate its prevalence. The authors conducted a random sample, national household telephone survey in the spring and summer of 2004 and interviewed 2,513 adults. The interviews addressed buying attitudes and behaviors, their consequences, and the respondents' financial and demographic data. The authors used a clinically validated screening instrument, the Compulsive Buying Scale, to classify respondents as either compulsive buyers or not. The rate of response was 56.3%, which compares favorably with rates in federal national health surveys. The cooperation rate was 97.6%. Respondents included a higher percentage of women and people ages 55 and older than the U.S. adult population. The estimated point prevalence of compulsive buying among respondents was 5.8% (by gender: 6.0% for women, 5.5% for men). The gender-adjusted prevalence rate was 5.8%. Compared with other respondents, compulsive buyers were younger, and a greater proportion reported incomes under 50,000 US dollars. They exhibited more maladaptive responses on most consumer behavior measures and were more than four times less likely to pay off credit card balances in full. A study using clinically valid interviews is needed to evaluate these results. The emotional and functional toll of compulsive buying and the frequency of comorbid psychiatric disorders suggests that studies of treatments and social interventions are warranted.
Rice, Brian D; Bätzing-Feigenbaum, Jörg; Hosegood, Victoria; Tanser, Frank; Hill, Caterina; Barnighausen, Till; Herbst, Kobus; Welz, Tanya; Newell, Marie-Louise
To present and compare population-based and antenatal-care (ANC) sentinel surveillance HIV prevalence estimates among women in a rural South African population where both provision of ANC services and family planning is prevalent and fertility is declining. With a need, in such settings, to understand how to appropriately adjust ANC sentinel surveillance estimates to represent HIV prevalence in general populations, and with evidence of possible biases inherent to both surveillance systems, we explore differences between the two systems. There is particular emphasis on unrepresentative selection of ANC clinics and unrepresentative testing in the population. HIV sero-prevalence amongst blood samples collected from women consenting to test during the 2005 annual longitudinal population-based serological survey was compared to anonymous unlinked HIV sero-prevalence amongst women attending antenatal care (ANC) first visits in six clinics (January to May 2005). Both surveillance systems were conducted as part of the Africa Centre Demographic Information System. Population-based HIV prevalence estimates for all women (25.2%) and pregnant women (23.7%) were significantly lower than that for ANC attendees (37.7%). A large proportion of women attending urban or peri-urban clinics would be predicted to be resident within rural areas. Although overall estimates remained significantly different, presenting and standardising estimates by age and location (clinic for ANC-based estimates and individual-residence for population-based estimates) made some group-specific estimates from the two surveillance systems more predictive of one another. It is likely that where ANC coverage and contraceptive use is widespread and fertility is low, population-based surveillance under-estimates HIV prevalence due to unrepresentative testing by age, residence and also probably by HIV status, and that ANC sentinel surveillance over-estimates prevalence due to selection bias in terms of age of
Vester, Heike; Hammerschmidt, Kurt; Timme, Marc; Hallerberg, Sarah
Recordings of animal vocalization can lack information about sender and context. This is often the case in studies on marine mammals or in the increasing number of automated bioacoustics monitorings. Here, we develop a framework to estimate group specificity without specific sender information. We introduce and apply a bag-of-calls-and-coefficients approach (BOCCA) to study ensembles of cepstral coefficients calculated from vocalization signals recorded from a given animal group. Comparing distributions of such ensembles of coefficients by computing relative entropies reveals group specific differences. Applying the BOCCA to ensembles of calls recorded from group of long-finned pilot whales in northern Norway, we find that differences of vocalizations within social groups of pilot whales (Globicephala melas) are significantly lower than intergroup differences.
Wu, Anise M S; Lai, Mark H C; Tong, Kwok-Kit
An excessive, problematic gambling pattern has been regarded as a mental disorder in the Diagnostic and Statistical Manual for Mental Disorders (DSM) for more than 3 decades (American Psychiatric Association [APA], 1980). In this study, its latest prevalence in Macao (one of very few cities with legalized gambling in China and the Far East) was estimated with 2 major changes in the diagnostic criteria, suggested by the 5th edition of DSM (APA, 2013): (a) removing the "Illegal Act" criterion, and (b) lowering the threshold for diagnosis. A random, representative sample of 1,018 Macao residents was surveyed with a phone poll design in January 2013. After the 2 changes were adopted, the present study showed that the estimated prevalence rate of gambling disorder was 2.1% of the Macao adult population. Moreover, the present findings also provided empirical support to the application of these 2 recommended changes when assessing symptoms of gambling disorder among Chinese community adults. Personal risk factors of gambling disorder, namely being male, having low education, a preference for casino gambling, as well as high materialism, were identified.
Fortea Sevilla, M S; Escandell Bermúdez, M O; Castro Sánchez, J J
To make an initial estimate of the prevalence of autism spectrum disorders (ASDs) among children in the province of Las Palmas (Spain). Descriptive study was conducted on 1,796 children between the ages of 18 and 30 months of age, all part of the Child Health Surveillance of the Canary Islands, more specifically the province of Las Palmas, with a population of 1,090,605. The parents of children involved completed the Spanish version of the Modified Checklist for Autism in Toddlers (M-CHAT/ES) in the paediatric clinic. The positive cases were then diagnosed by experts by means of the Autism Diagnostic Interview-Revised (ADIR) and the Autism Diagnostic Observation Schedule (ADOS). A 0.61% prevalence of ASDs was determined, similar to that reported in previous studies using the same tools. The ratio was six girls for every five boys. This was contrary to the results of previous studies which suggested more boys than girls were affected. This may have been due to the sample size, which will have to be increased in future studies to confirm this outcome. An increased sample size and also spread to other age ranges should be used in order to obtain a more reliable estimate of prevalence. As regards the gender ratio, this could be a result of the small size of the sample researched, and should therefore be confirmed by further studies. Copyright © 2012 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.
Huang, Xuelin; Cortes, Jorge; Kantarjian, Hagop
Background The annual incidence of chronic myeloid leukemia (CML) in the United States is about 4800 cases. With the success of tyrosine kinase inhibitor (TKI) therapy, the all-cause annual mortality rate was reduced to 2%. The prevalence of CML is therefore increasing over time. Estimating the CML prevalence and plateau prevalence is important in the implementation of healthcare strategies and future therapeutic trials. Aims Estimate the increasing prevalence and plateau prevalence of CML in future years. Methods The prevalence of CML was estimated based on several parameters: annual mortality rate on TKI therapy compared to age-matched normal population, incidence of CML, anticipated population growth in the United States, aging of the population. Results Based on these calculations, the mortality ratio of patients with CML compared to an age-matched normal population is about 1.53. The prevalence of CML is estimated to be about 70,000 in 2010, 112,000 in 2020, 144,000 in 2030, 167,000 in 2040 and 181,000 in 2050 when it reaches a near plateau prevalence. Conclusions The prevalence of CML will continue to increase to reach a near plateau prevalence 35 times the annual incidence. These estimates should be considered in healthcare policies and in the design of future studies in CML. PMID:22294282
Estimates of disease prevalence for small areas are increasingly required for the allocation of health funds according to local need. Both individual level and geographic risk factors are likely to be relevant to explaining prevalence variations, and in turn relevant to the procedure for small area prevalence estimation. Prevalence estimates are of particular importance for major chronic illnesses such as cardiovascular disease. A multilevel prevalence model for cardiovascular outcomes is proposed that incorporates both survey information on patient risk factors and the effects of geographic location. The model is applied to derive micro area prevalence estimates, specifically estimates of cardiovascular disease for Zip Code Tabulation Areas in the USA. The model incorporates prevalence differentials by age, sex, ethnicity and educational attainment from the 2005 Behavioral Risk Factor Surveillance System survey. Influences of geographic context are modelled at both county and state level, with the county effects relating to poverty and urbanity. State level influences are modelled using a random effects approach that allows both for spatial correlation and spatial isolates. To assess the importance of geographic variables, three types of model are compared: a model with person level variables only; a model with geographic effects that do not interact with person attributes; and a full model, allowing for state level random effects that differ by ethnicity. There is clear evidence that geographic effects improve statistical fit. Geographic variations in disease prevalence partly reflect the demographic composition of area populations. However, prevalence variations may also show distinct geographic 'contextual' effects. The present study demonstrates by formal modelling methods that improved explanation is obtained by allowing for distinct geographic effects (for counties and states) and for interaction between geographic and person variables. Thus an appropriate
Saad-Roy, C M; van den Driessche, P; Ma, Junling
There currently is a severe Zika Virus (ZIKV) epidemic in Brazil and other South American countries. Due to international travel, this poses severe public health risk of ZIKV importation to other countries. We estimate the prevalence of ZIKV in an import region by the time a microcephaly case is detected, since microcephaly is presently the most significant indication of ZIKV presence. We establish a mathematical model to describe ZIKV spread from a source region to an import region. This model incorporates both vector transmission (between humans and mosquitoes) and sexual transmission (from males to females). We take account of population structure through a contact network for sexually active individuals. Parameter values of our model are either taken from the literature or estimated from travel data. This model gives us the probability distribution of time until detection of the first microcephaly case. Based on current field observations, our results also indicate that the percentage of infected pregnant women that results in fetal abnormalities is more likely to be on the smaller end of the 1%-30% spectrum that is currently hypothesized. Our model predicts that for import regions with at least 250,000 people, on average 1,000-12,000 will have been infected by the time of the first detection of microcephaly, and on average 200-1,500 will be infectious at this time. Larger population sizes do not significantly change our predictions. By the first detection of a microcephaly case, a sizable fraction of the population will have been infected by ZIKV. It is thus clear that adequate surveillance, isolation, and quarantine are needed in susceptible import regions to stop the dissemination of a Zika epidemic.
Shilowich, Bryan E; Biederman, Irving
A web-based survey estimated the distribution of voice recognition abilities with a focus on determining the prevalence of developmental phonagnosia, the inability to identify a familiar person based on their voice. Participants matched clips of 50 celebrity voices to 1-4 named headshots of celebrities whose voices they had previously rated for familiarity. Given a strong correlation between rated familiarity and recognition performance, a residual was calculated based on the average familiarity rating on each trial, which thus constituted each respondent's voice recognition ability that could not be accounted for by familiarity. 3.2% of the respondents (23 of 730 participants) had residual recognition scores 2.28 SDs below the mean (whereas 8 or 1.1% would have been expected from a normal distribution). They also judged whether they could imagine the voice of five familiar celebrities. Individuals who had difficulty in imagining voices were also generally below average in their accuracy of recognition. Copyright © 2016 Elsevier Inc. All rights reserved.
Accetta, Nancy A; Gladstone, Elisa H; DiSogra, Charles; Wright, Elizabeth C; Briggs, Michael; Narva, Andrew S
Routine laboratory reporting of estimated glomerular filtration rate (eGFR) may help clinicians detect kidney disease. The current national prevalence of eGFR reporting in clinical laboratories is unknown; thus, the extent of the situation of laboratories not routinely reporting eGFR with serum creatinine results is not quantified. Observational analysis. National Kidney Disease Education Program survey of clinical laboratories conducted in 2006 to 2007 by mail, web, and telephone follow-up. A national random sample, 6,350 clinical laboratories, drawn from the Federal Clinical Laboratory Improvement Amendments database and stratified by 6 major laboratory types/groupings. Laboratory reports serum creatinine results. Reporting eGFR values with serum creatinine results. Percentage of laboratories reporting eGFR along with reporting serum creatinine values, reporting protocol, eGFR formula used, and style of reporting cutoff values. Of laboratories reporting serum creatinine values, 38.4% report eGFR (physician offices, 25.8%; hospitals, 43.6%; independents, 38.9%; community clinics, 47.2%; health fair/insurance/public health, 45.5%; and others, 43.2%). Physician office laboratories have a reporting prevalence lower than other laboratory types (P < 0.001). Of laboratories reporting eGFR, 66.7% do so routinely with all adult serum creatinine determinations; 71.6% use the 4-variable Modification of Diet in Renal Disease Study equation; and 45.3% use the ">60 mL/min/1.73 m(2)" reporting convention. Independent laboratories are least likely to routinely report eGFR (50.6%; P < 0.05) and most likely to report only when specifically requested (45.4%; P < 0.05). High-volume laboratories across all strata are more likely to report eGFR (P < 0.001). Self-reporting by laboratories, federal database did not have names of laboratory directors/managers (intended respondents), assumed accuracy of federal database for sample purposes. Routine eGFR reporting with serum creatinine
Pantelis, Peter C.; Kennedy, Daniel P.
Two-phase designs in epidemiological studies of autism prevalence introduce methodological complications that can severely limit the precision of resulting estimates. If the assumptions used to derive the prevalence estimate are invalid or if the uncertainty surrounding these assumptions is not properly accounted for in the statistical inference…
Pantelis, Peter C.; Kennedy, Daniel P.
Two-phase designs in epidemiological studies of autism prevalence introduce methodological complications that can severely limit the precision of resulting estimates. If the assumptions used to derive the prevalence estimate are invalid or if the uncertainty surrounding these assumptions is not properly accounted for in the statistical inference…
Pascom, Ana Roberta Pati; Szwarcwald, Célia Landmann; Barbosa Júnior, Aristides
We investigated sampling methods being used to estimate the HIV prevalence rate among female commercial sex workers. The studies were classified according to the adequacy or not of the sample size to estimate HIV prevalence rate and according to the sampling method (probabilistic or convenience). We identified 75 studies that estimated the HIV prevalence rate among female sex workers. Most of the studies employed convenience samples. The sample size was not adequate to estimate HIV prevalence rate in 35 studies. The use of convenience sample limits statistical inference for the whole group. It was observed that there was an increase in the number of published studies since 2005, as well as in the number of studies that used probabilistic samples. This represents a large advance in the monitoring of risk behavior practices and HIV prevalence rate in this group.
Hermes, Kerstin; Poulsen, Michael
Small area estimates (SAEs) can provide information about health behaviour at small area levels that is otherwise not available. Because of its increasing use by policy makers, more attention needs to be paid to the reliability of these estimates. This paper reports on smoking prevalence data generated for London at the neighbourhood level using spatial microsimulation modelling. We test the reliability of smoking prevalence estimates at the neighbourhood level using different input datasets. The paper further underlines the importance of estimating health behaviours at the small area level, particularly in diverse cities such as London, where estimation at the city level can mask significant spatial differences.
Presson, Angela P.; Partyka, Ginger; Jensen, Kristin M.; Devine, Owen J.; Rasmussen, Sonja A.; McCabe, Linda L.; McCabe, Edward R. B.
Objective To calculate a reliable estimate of the population prevalence of Down syndrome in the US. Study design The annual number of births of infants with Down syndrome were estimated by applying published birth prevalence rates of Down syndrome by maternal age to US data from the Centers for Disease Control and Prevention for the years for which births by maternal age were available (1940–2008). Death certificate data for persons with Down syndrome were available for the years 1968–2007. We estimated the number of people with Down syndrome on January 1, 2008, using a life table approach based on proportions of deaths by age. Monte Carlo sampling was used to create 90% uncertainty intervals (UIs) for our estimates. Results We estimated the January 1, 2008, population prevalence of Down syndrome as approximately 250 700 (90% UI, 185 900–321 700) based on proportions of deaths by age from the most recent 2 years (2006–2007) of death certificate data. This estimate corresponds to a prevalence of 8.27 people with Down syndrome per 10 000 population (90% UI, 6.14–10.62). Conclusion Our estimate of Down syndrome prevalence is roughly 25%–40% lower than estimates based solely on current birth prevalence. The results presented here can be considered a starting point for facilitating policy and services planning for persons with Down syndrome. PMID:23885965
Ouellette-Kuntz, Hélène; Coo, Helen; Lloyd, Jennifer E V; Kasmara, Liza; Holden, Jeanette J A; Lewis, M E Suzanne
There is considerable controversy over reasons for observed increases in the prevalence of autism spectrum disorders. We examined trends in British Columbia education database coding of children with autism from 1996 to 2004. There was a significant linear increase in autism prevalence. The proportion of children identified by age 6 increased significantly from 1996 to 1999. When we calculated prevalence assuming onset prior to age 3, previously unidentified cases, particularly among girls in 1996 and 1997, accounted for substantial increases in estimated prevalence. The magnitude of under-identification decreased from 1996 to 2000, and rose slightly in 2001. Analyses of prevalence trends must take into account effects of earlier age at identification and inclusion of previously undetected cases on prevalence estimates.
Boles, Myde; Fink, Karol; Topol, Rebecca; Fenaughty, Andrea
Although monitoring childhood obesity prevalence is critical for state public health programs to assess trends and the effectiveness of interventions, few states have comprehensive body mass index measurement systems in place. In some states, however, assorted school districts collect measurements on student height and weight as part of annual health screenings. To estimate childhood obesity prevalence in Alaska, we created a logistic regression model using such annual measurements along with public data on demographics and socioeconomic status. Our mixed-effects model-generated prevalence estimates validated well against weighted estimates, with 95% confidence intervals overlapping between methodologies among 7 of 8 participating school districts. Our methodology accounts for variation in school-level and student-level demographic factors across the state, and the approach we describe can be applied by other states that have existing nonrandom student measurement data to estimate childhood obesity prevalence. PMID:27010843
Sari, M.; de Pee, S.; Martini, E.; Herman, S.; Sugiatmi; Bloem, M. W.; Yip, R.
OBJECTIVE: To determine the most effective method for analysing haemoglobin concentrations in large surveys in remote areas, and to compare two methods (indirect cyanmethaemoglobin and HemoCue) with the conventional method (direct cyanmethaemoglobin). METHODS: Samples of venous and capillary blood from 121 mothers in Indonesia were compared using all three methods. FINDINGS: When the indirect cyanmethaemoglobin method was used the prevalence of anaemia was 31-38%. When the direct cyanmethaemoglobin or HemoCue method was used the prevalence was 14-18%. Indirect measurement of cyanmethaemoglobin had the highest coefficient of variation and the largest standard deviation of the difference between the first and second assessment of the same blood sample (10-12 g/l indirect measurement vs 4 g/l direct measurement). In comparison with direct cyanmethaemoglobin measurement of venous blood, HemoCue had the highest sensitivity (82.4%) and specificity (94.2%) when used for venous blood. CONCLUSIONS: Where field conditions and local resources allow it, haemoglobin concentration should be assessed with the direct cyanmethaemoglobin method, the gold standard. However, the HemoCue method can be used for surveys involving different laboratories or which are conducted in relatively remote areas. In very hot and humid climates, HemoCue microcuvettes should be discarded if not used within a few days of opening the container containing the cuvettes. PMID:11436471
Dzekedzeke, Kumbutso; Fylkesnes, Knut
The premise for using antenatal care (ANC) clinic data for estimating HIV prevalence in the general population is the finding from community studies in sub-Saharan Africa that total HIV prevalence in pregnant women attending ANC clinics closely approximate levels in the total general population of both women and men aged 15-49 years. In this study, the validity of national level HIV prevalence estimates for the total general population 15-49 years made from ANC clinic and population survey data was assessed. In 2001-2002, a national population HIV prevalence survey for women 15-49 years and men 15-59 years was conducted in Zambia. In the same period, a national HIV sentinel surveillance survey among pregnant women attending ANC clinics was carried out. The ANC HIV prevalence estimates for age-group 15-49 years (rural: 11.5%; 95% CI, 11.2-11.8; urban: 25.4%; 95% CI, 24.8-26.0; adjusted national: 16.9%; 95% CI, 16.6-17.2) were similar to the population survey estimates (rural: 10.8%; 95% CI, 9.6-12.1; urban: 23.2%; 95% CI 20.7-25.6; national: 15.6%; 95% CI, 14.4-16.9). The HIV prevalence urban to rural ratio was 2.2 in ANC and 2.1 in population survey estimates. The HIV prevalence estimate for the total general population 15-49 years derived from testing both women and men in the population survey was similar to the estimate derived from testing women attending ANC clinics. It shows that national HIV prevalence estimates for adults aged 15-49 years can also be obtained from ANC HIV sentinel surveillance surveys with good coverage when ANC attendance and fertility are high.
Omulo, Sylvia; Lofgren, Eric T; Mugoh, Maina; Alando, Moshe; Obiya, Joshua; Kipyegon, Korir; Kikwai, Gilbert; Gumbi, Wilson; Kariuki, Samuel; Call, Douglas R
Investigators often rely on studies of Escherichia coli to characterize the burden of antibiotic resistance in a clinical or community setting. To determine if prevalence estimates for antibiotic resistance are sensitive to sample handling and interpretive criteria, we collected presumptive E. coli isolates (24 or 95 per stool sample) from a community in an urban informal settlement in Kenya. Isolates were tested for susceptibility to nine antibiotics using agar breakpoint assays and results were analyzed using generalized linear mixed models. We observed a <3-fold difference between prevalence estimates based on freshly isolated bacteria when compared to isolates collected from unprocessed fecal samples or fecal slurries that had been stored at 4°C for up to 7days. No time-dependence was evident (P>0.1). Prevalence estimates did not differ for five distinct E. coli colony morphologies on MacConkey agar plates (P>0.2). Successive re-plating of samples for up to five consecutive days had little to no impact on prevalence estimates. Finally, culturing E. coli under different conditions (with 5% CO2 or micro-aerobic) did not affect estimates of prevalence. For the conditions tested in these experiments, minor modifications in sample processing protocols are unlikely to bias estimates of the prevalence of antibiotic-resistance for fecal E. coli. Copyright © 2017 Elsevier B.V. All rights reserved.
Honeyford, Kate; Baker, Richard; Bankart, M John G; Jones, David R
Objectives To determine to what extent underlying data published as part of Quality and Outcomes Framework (QOF) can be used to estimate smoking prevalence within practice populations and local areas and to explore the usefulness of these estimates. Design Cross-sectional, observational study of QOF smoking data. Smoking prevalence in general practice populations and among patients with chronic conditions was estimated by simple manipulation of QOF indicator data. Agreement between estimates from the integrated household survey (IHS) and aggregated QOF-based estimates was calculated. The impact of including smoking estimates in negative binomial regression models of counts of premature coronary heart disease (CHD) deaths was assessed. Setting Primary care in the East Midlands. Participants All general practices in the area of study were eligible for inclusion (230). 14 practices were excluded due to incomplete QOF data for the period of study (2006/2007–2012/2013). One practice was excluded as it served a restricted practice list. Measurements Estimates of smoking prevalence in general practice populations and among patients with chronic conditions. Results Median smoking prevalence in the practice populations for 2012/2013 was 19.2% (range 5.8–43.0%). There was good agreement (mean difference: 0.39%; 95% limits of agreement (−3.77, 4.55)) between IHS estimates for local authority districts and aggregated QOF register estimates. Smoking prevalence estimates in those with chronic conditions were lower than for the general population (mean difference −3.05%), but strongly correlated (Rp=0.74, p<0.0001). An important positive association between premature CHD mortality and smoking prevalence was shown when smoking prevalence was added to other population and service characteristics. Conclusions Published QOF data allow useful estimation of smoking prevalence within practice populations and in those with chronic conditions; the latter estimates may sometimes be
This paper considers estimation of disease prevalence for small areas (neighbourhoods) when the available observations on prevalence are for an alternative partition of a region, such as service areas. Interpolation to neighbourhoods uses a kernel method extended to take account of two types of collateral information. The first is morbidity and service use data, such as hospital admissions, observed for neighbourhoods. Variations in morbidity and service use are expected to reflect prevalence. The second type of collateral information is ecological risk factors (e.g., pollution indices) that are expected to explain variability in prevalence in service areas, but are typically observed only for neighbourhoods. An application involves estimating neighbourhood asthma prevalence in a London health region involving 562 neighbourhoods and 189 service (primary care) areas. PMID:24129116
Brugal, M. T.; Domingo-Salvany, A.; Maguire, A.; Cayla, J. A.; Villalbi, J. R.; Hartnoll, R.
STUDY OBJECTIVE: To determine the distribution of opioid use prevalence in small areas and its relation with socioeconomic indicators. DESIGN: Capture-recapture was applied using data from the Barcelona Drug Information System for 1993 (treatment demands, hospital emergency room visits, deaths from heroin acute adverse reaction and pre-trial prison admissions). To avoid dependence between sources, a log-linear regression model with interactions was fitted. For small neighbourhoods, where capture-recapture estimates were not obtainable, the Heroin Problem Index (HPI) was used to predict prevalence rates from a regression model. The correlation between estimated opioid use prevalence by neighbourhoods and their socioeconomic level was computed. MAIN RESULTS: The city's estimated prevalence was 12.9 opioid addicts per 1000 inhabitants aged 15 to 44 years (95% CI: 10.1, 17.2), which represents 9176 persons. The highest rate was found in the inner city neighbourhood. Comparing rates obtained for each neighbourhood with their unemployment rates, a high correlation coefficient was obtained (r = 0.80, p < 0.001). CONCLUSION: The main contribution of this study is that of combining capture-recapture with the HPI to produce small area prevalence estimates, which would not have been possible using only one method. Areas with higher socioeconomic status showed proportionally low addiction prevalences, but in depressed areas, prevalences varied widely. PMID:10562867
Mathieu, Els; Amann, Josef; Eigege, Abel; Richards, Frank; Sodahlon, Yao
The lymphatic filariasis elimination program aims not only to stop transmission, but also to alleviate morbidity. Although geographically limited morbidity projects exist, few have been implemented nationally. For advocacy and planning, the program coordinators need prevalence estimates that are currently rarely available. This article compares several approaches to estimate morbidity prevalence: (1) data routinely collected during mapping or sentinel site activities; (2) data collected during drug coverage surveys; and (3) alternative surveys. Data were collected in Plateau and Nasarawa States in Nigeria and in 6 districts in Togo. In both settings, we found that questionnaires seem to underestimate the morbidity prevalence compared with existing information collected through clinical examination. We suggest that program managers use the latter for advocacy and planning, but if not available, questionnaires to estimate morbidity prevalence can be added to existing surveys. Even though such data will most likely underestimate the real burden of disease, they can be useful in resource-limited settings.
REVEILLE, JOHN D.; WITTER, JAMES P.; WEISMAN, MICHAEL H.
Objective The US national prevalence of spondylarthritis (SpA) was estimated for 2 published sets of classification criteria: the Amor criteria and the European Spondylarthropathy Study Group (ESSG) criteria. These 2 SpA criteria sets have been the most widely utilized in previous population-based studies of SpA. Methods The US SpA prevalence estimates were based on a representative sample of 5,013 US adults ages 20 – 69 years who were examined in the US National Health and Nutrition Examination Survey (NHANES) 2009–2010. Results The overall age-adjusted prevalence of definite and probable SpA by the Amor criteria was 0.9% (95% confidence interval [95% CI] 0.7–1.1%), corresponding to an estimated 1.7 million persons (95% CI 1.4–2.1 million persons). The age-adjusted prevalence of SpA by the ESSG criteria was 1.4% (95% CI 1.0–1.9%), corresponding to an estimated 2.7 million persons (95% CI 1.9–3.7 million persons). There were no statistically significant sex differences in SpA prevalence. The SpA prevalence among non-Hispanic white persons was 1.0% (95% CI 0.7–1.5%) by the Amor criteria and 1.5% (95% CI 1.0–2.3%) by the ESSG criteria. SpA prevalence could not be reliably estimated in other race/ethnicity subgroups due to sample size imitations. Conclusion The SpA prevalence estimates are in the range of SpA prevalence estimates reported elsewhere in population-based surveys and it is likely that SpA may affect up to 1% of US adults, a prevalence similar to that reported for rheumatoid arthritis. The current US SpA prevalence estimates may be lower than the true value because the NHANES 2009–2010 data collection did not capture a complete set of the elements specified in the 2 SpA criteria sets. PMID:22275150
Klein, Ronald; Klein, Barbara E. K.
Purpose. To examine prevalence of five age-related eye conditions (age-related cataract, AMD, open-angle glaucoma, diabetic retinopathy [DR], and visual impairment) in the United States. Methods. Review of published scientific articles and unpublished research findings. Results. Cataract, AMD, open-angle glaucoma, DR, and visual impairment prevalences are high in four different studies of these conditions, especially in people over 75 years of age. There are disparities among racial/ethnic groups with higher age-specific prevalence of DR, open-angle glaucoma, and visual impairment in Hispanics and blacks compared with whites, higher prevalence of age-related cataract in whites compared with blacks, and higher prevalence of late AMD in whites compared with Hispanics and blacks. The estimates are based on old data and do not reflect recent changes in the distribution of age and race/ethnicity in the United States population. There are no epidemiologic estimates of prevalence for many visually-impairing conditions. Conclusions. Ongoing prevalence surveys designed to provide reliable estimates of visual impairment, AMD, age-related cataract, open-angle glaucoma, and DR are needed. It is important to collect objective data on these and other conditions that affect vision and quality of life in order to plan for health care needs and identify areas for further research. PMID:24335069
Huemer, Anja Katharina; Vollrath, Mark
Secondary tasks while driving are frequently found in different types of studies from all over the world. For a profound understanding of secondary tasks' impact on road safety it is essential to know in detail what kind of tasks drivers are doing in which situations. In contrast to costly observational studies, interviews may be a suitable access to these data if reporting biases are minimized. In 2009, 289 drivers were interviewed in face-to-face interviews on German motorway service areas as well as in the city of Braunschweig about their secondary task engagement in the last 30 min of driving. Five groups of drivers were examined: (1) truck drivers at the motorway (N=90), (2) car drivers on private trips at the motorway (N=71), (3) car drivers on business trips at the motorway (N=29), (4) car drivers on private trips in town (N=85), (5) car drivers on business trips in town (N=12). The pattern and frequency of engagement in secondary tasks differed between these groups. Overall, about 80% of all drivers conducted one to three secondary tasks. Thus, secondary task engagement is a serious issue in Germany and accident studies are needed to estimate drivers' risk.
Cunningham, Marc; Brown, Niquelle; Sacher, Suzy; Hatch, Benjamin; Inglis, Andrew; Aronovich, Dana
Background: Contraceptive prevalence rate (CPR) is a vital indicator used by country governments, international donors, and other stakeholders for measuring progress in family planning programs against country targets and global initiatives as well as for estimating health outcomes. Because of the need for more frequent CPR estimates than population-based surveys currently provide, alternative approaches for estimating CPRs are being explored, including using contraceptive logistics data. Methods: Using data from the Demographic and Health Surveys (DHS) in 30 countries, population data from the United States Census Bureau International Database, and logistics data from the Procurement Planning and Monitoring Report (PPMR) and the Pipeline Monitoring and Procurement Planning System (PipeLine), we developed and evaluated 3 models to generate country-level, public-sector contraceptive prevalence estimates for injectable contraceptives, oral contraceptives, and male condoms. Models included: direct estimation through existing couple-years of protection (CYP) conversion factors, bivariate linear regression, and multivariate linear regression. Model evaluation consisted of comparing the referent DHS prevalence rates for each short-acting method with the model-generated prevalence rate using multiple metrics, including mean absolute error and proportion of countries where the modeled prevalence rate for each method was within 1, 2, or 5 percentage points of the DHS referent value. Results: For the methods studied, family planning use estimates from public-sector logistics data were correlated with those from the DHS, validating the quality and accuracy of current public-sector logistics data. Logistics data for oral and injectable contraceptives were significantly associated (P<.05) with the referent DHS values for both bivariate and multivariate models. For condoms, however, that association was only significant for the bivariate model. With the exception of the CYP
Cunningham, Marc; Bock, Ariella; Brown, Niquelle; Sacher, Suzy; Hatch, Benjamin; Inglis, Andrew; Aronovich, Dana
Contraceptive prevalence rate (CPR) is a vital indicator used by country governments, international donors, and other stakeholders for measuring progress in family planning programs against country targets and global initiatives as well as for estimating health outcomes. Because of the need for more frequent CPR estimates than population-based surveys currently provide, alternative approaches for estimating CPRs are being explored, including using contraceptive logistics data. Using data from the Demographic and Health Surveys (DHS) in 30 countries, population data from the United States Census Bureau International Database, and logistics data from the Procurement Planning and Monitoring Report (PPMR) and the Pipeline Monitoring and Procurement Planning System (PipeLine), we developed and evaluated 3 models to generate country-level, public-sector contraceptive prevalence estimates for injectable contraceptives, oral contraceptives, and male condoms. Models included: direct estimation through existing couple-years of protection (CYP) conversion factors, bivariate linear regression, and multivariate linear regression. Model evaluation consisted of comparing the referent DHS prevalence rates for each short-acting method with the model-generated prevalence rate using multiple metrics, including mean absolute error and proportion of countries where the modeled prevalence rate for each method was within 1, 2, or 5 percentage points of the DHS referent value. For the methods studied, family planning use estimates from public-sector logistics data were correlated with those from the DHS, validating the quality and accuracy of current public-sector logistics data. Logistics data for oral and injectable contraceptives were significantly associated (P<.05) with the referent DHS values for both bivariate and multivariate models. For condoms, however, that association was only significant for the bivariate model. With the exception of the CYP-based model for condoms, models
Looker, Katharine J.; Magaret, Amalia S.; May, Margaret T.; Turner, Katherine M. E.; Vickerman, Peter; Gottlieb, Sami L.; Newman, Lori M.
Background Herpes simplex virus type 1 (HSV-1) commonly causes orolabial ulcers, while HSV-2 commonly causes genital ulcers. However, HSV-1 is an increasing cause of genital infection. Previously, the World Health Organization estimated the global burden of HSV-2 for 2003 and for 2012. The global burden of HSV-1 has not been estimated. Methods We fitted a constant-incidence model to pooled HSV-1 prevalence data from literature searches for 6 World Health Organization regions and used 2012 population data to derive global numbers of 0-49-year-olds with prevalent and incident HSV-1 infection. To estimate genital HSV-1, we applied values for the proportion of incident infections that are genital. Findings We estimated that 3709 million people (range: 3440–3878 million) aged 0–49 years had prevalent HSV-1 infection in 2012 (67%), with highest prevalence in Africa, South-East Asia and Western Pacific. Assuming 50% of incident infections among 15-49-year-olds are genital, an estimated 140 million (range: 67–212 million) people had prevalent genital HSV-1 infection, most of which occurred in the Americas, Europe and Western Pacific. Conclusions The global burden of HSV-1 infection is huge. Genital HSV-1 burden can be substantial but varies widely by region. Future control efforts, including development of HSV vaccines, should consider the epidemiology of HSV-1 in addition to HSV-2, and especially the relative contribution of HSV-1 to genital infection. PMID:26510007
Thrul, Johannes; Pabst, Alexander; Kraus, Ludwig
The European School Survey Project on Alcohol and Other Drugs (ESPAD) is a survey study that collects comparable data on substance use of students aged 15-16 years old in European countries. The present study aims at investigating the impact of school refusal to participate in ESPAD on substance use prevalence estimates. Data came from the 2007 German ESPAD study; the sample consisted of 12,246 students in 552 schools within seven German federal states. A simulation approach was used in order to study the effects of systematic exclusion of participating schools on prevalence estimates of key ESPAD outcomes including the use of tobacco, alcohol, cannabis, and other illegal drugs. The systematic exclusion of schools based on city-, school-, and class size, school environment, and schools' substance use policies resulted in significant changes in prevalence estimates in 23 of 25 examined combinations of selection criterion and outcome. Yet, these effects were small, with differences remaining below three percentage points around the original estimates. This simulation approach suggests that nonparticipation of schools in surveys on students' substance use in Germany does not largely affect the validity of resulting prevalence estimates. Even a reduced number of schools may be sufficient to gain valid prevalence figures. Copyright © 2015 Elsevier B.V. All rights reserved.
McGovern, Mark E; Bärnighausen, Till; Salomon, Joshua A; Canning, David
Selection bias in HIV prevalence estimates occurs if non-participation in testing is correlated with HIV status. Longitudinal data suggests that individuals who know or suspect they are HIV positive are less likely to participate in testing in HIV surveys, in which case methods to correct for missing data which are based on imputation and observed characteristics will produce biased results. The identity of the HIV survey interviewer is typically associated with HIV testing participation, but is unlikely to be correlated with HIV status. Interviewer identity can thus be used as a selection variable allowing estimation of Heckman-type selection models. These models produce asymptotically unbiased HIV prevalence estimates, even when non-participation is correlated with unobserved characteristics, such as knowledge of HIV status. We introduce a new random effects method to these selection models which overcomes non-convergence caused by collinearity, small sample bias, and incorrect inference in existing approaches. Our method is easy to implement in standard statistical software, and allows the construction of bootstrapped standard errors which adjust for the fact that the relationship between testing and HIV status is uncertain and needs to be estimated. Using nationally representative data from the Demographic and Health Surveys, we illustrate our approach with new point estimates and confidence intervals (CI) for HIV prevalence among men in Ghana (2003) and Zambia (2007). In Ghana, we find little evidence of selection bias as our selection model gives an HIV prevalence estimate of 1.4% (95% CI 1.2% - 1.6%), compared to 1.6% among those with a valid HIV test. In Zambia, our selection model gives an HIV prevalence estimate of 16.3% (95% CI 11.0% - 18.4%), compared to 12.1% among those with a valid HIV test. Therefore, those who decline to test in Zambia are found to be more likely to be HIV positive. Our approach corrects for selection bias in HIV prevalence
Clark, R C; Mytton, J
The prevalence of infectious diseases such as tuberculosis (TB), HIV and hepatitis B in the UK asylum seeker and refugee population is currently uncertain. Systematic review of published and unpublished studies. Five studies met the inclusion criteria. Three studies reported the prevalence of TB with rates ranging from 1.33 to 10.42 per 1000. The three studies reporting hepatitis B estimated rates from 57 to 118 per 1000. One study reported a prevalence rate for HIV of 38.19 per 1000. A small number of studies have been identified reporting prevalence rates for TB, hepatitis B and HIV that vary widely where comparisons are available. These differences may reflect true variation in risk between study populations, but are likely to be affected by sampling difficulties encountered when researching these population groups. Efforts are required to improve these difficulties which are currently limiting the validity of prevalence findings and generalizability to comparable asylum seeker and refugee populations.
de Hoyos-Alonso, M C; Bonis, J; Tapias-Merino, E; Castell, M V; Otero, A
The progressive rise in dementia prevalence increases the need for rapid methods that complement population-based prevalence studies. To estimate the prevalence of dementia in the population aged 65 and older based on use of cholinesterase inhibitors and memantine. Descriptive study of use and prescription of cholinesterase inhibitors and/or memantine in 2011 according to 2 databases: Farm@drid (pharmacy billing records for the Region of Madrid) and BIFAP (database for pharmacoepidemiology research in primary care, with diagnosis and prescription records). We tested the comparability of drug use results from each database using the chi-square test and prevalence ratios. The prevalence of dementia in Madrid was estimated based on the dose per 100 inhabitants/day, adjusting the result for data obtained from BIFAP on combination treatment in the general population (0.37%) and the percentage of dementia patients undergoing treatment (41.13%). Cholinesterase inhibitors and memantine were taken by 2.08% and 0.72% of Madrid residents aged 65 and older was respectively. Both databases displayed similar results for use of these drugs. The estimated prevalence of dementia in individuals aged 65 and older is 5.91% (95% CI%, 5.85-5.95) (52 287 people), and it is higher in women (7.16%) than in men (4.00%). The estimated prevalence of dementia is similar to that found in population-based studies. Analysing consumption of specific dementia drugs can be a reliable and inexpensive means of updating prevalence data periodically and helping rationalise healthcare resources. Copyright © 2014 Sociedad Española de Neurología. Published by Elsevier España, S.L.U. All rights reserved.
Hillis, Susan; Mercy, James; Amobi, Adaugo; Kress, Howard
Evidence confirms associations between childhood violence and major causes of mortality in adulthood. A synthesis of data on past-year prevalence of violence against children will help advance the United Nations' call to end all violence against children. Investigators systematically reviewed population-based surveys on the prevalence of past-year violence against children and synthesized the best available evidence to generate minimum regional and global estimates. We searched Medline, PubMed, Global Health, NBASE, CINAHL, and the World Wide Web for reports of representative surveys estimating prevalences of violence against children. Two investigators independently assessed surveys against inclusion criteria and rated those included on indicators of quality. Investigators extracted data on past-year prevalences of violent victimization by country, age group, and type (physical, sexual, emotional, or multiple types). We used a triangulation approach which synthesized data to generate minimum regional prevalences, derived from population-weighted averages of the country-specific prevalences. Thirty-eight reports provided quality data for 96 countries on past-year prevalences of violence against children. Base case estimates showed a minimum of 50% or more of children in Asia, Africa, and Northern America experienced past-year violence, and that globally over half of all children-1 billion children, ages 2-17 years-experienced such violence. Due to variations in timing and types of violence reported, triangulation could only be used to generate minimum prevalence estimates. Expanded population-based surveillance of violence against children is essential to target prevention and drive the urgent investment in action endorsed in the United Nations 2030 Sustainable Development Agenda. Copyright © 2016 by the American Academy of Pediatrics.
Preisser, John S; Marks, Sarah J; Sanders, Anne E; Akinkugbe, Aderonke A; Beck, James D
Standard partial-mouth estimators of chronic periodontitis (CP) that define an individual's disease status solely in terms of selected sites underestimate prevalence. This study proposes an improved prevalence estimator based on randomly sampled sites and evaluates its accuracy in a well-characterized population cohort. Importantly, this method does not require determination of disease status at the individual level. Instead, it uses a statistical distributional approach to derive a prevalence formula from randomly selected periodontal sites. The approach applies the conditional linear family of distributions for correlated binary data (i.e. the presence or absence of disease at sites within a mouth) with two simple working assumptions: (i) the probability of having disease is the same across all sites; and (ii) the correlation of disease status is the same for all pairs of sites within the mouth. Using oral examination data from 6793 participants in the Arteriolosclerosis Risk in Communities study, the new formula yields CP prevalence estimates that are much closer than standard partial mouth estimates to full mouth estimates. Resampling of the cohort shows that the proposed estimators give good precision and accuracy for as few as six tooth sites sampled per individual. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Polanczyk, Guilherme V; Willcutt, Erik G; Salum, Giovanni A; Kieling, Christian; Rohde, Luis A
Background: Previous studies have identified significant variability in attention-deficit / hyperactivity disorder (ADHD) prevalence estimates worldwide, largely explained by methodological procedures. However, increasing rates of ADHD diagnosis and treatment throughout the past few decades have fuelled concerns about whether the true prevalence of the disorder has increased over time. Methods: We updated the two most comprehensive systematic reviews on ADHD prevalence available in the literature. Meta-regression analyses were conducted to test the effect of year of study in the context of both methodological variables that determined variability in ADHD prevalence (diagnostic criteria, impairment criterion and source of information), and the geographical location of studies. Results: We identified 154 original studies and included 135 in the multivariate analysis. Methodological procedures investigated were significantly associated with heterogeneity of studies. Geographical location and year of study were not associated with variability in ADHD prevalence estimates. Conclusions: Confirming previous findings, variability in ADHD prevalence estimates is mostly explained by methodological characteristics of the studies. In the past three decades, there has been no evidence to suggest an increase in the number of children in the community who meet criteria for ADHD when standardized diagnostic procedures are followed. PMID:24464188
Khan, Suliman; Nabi, Ghulam; Naeem, Muhammad; Ali, Liaqat; Silburn, Peter A; Mellick, George D
Parkinson's disease (PD) occurs in all races and cultures, and population-related differences in frequency may provide etiological clues. The present study was designed to explore the prevalence of PD and Parkinsonism in Pakistan, the world's sixth most populous country, for which no published prevalence data are available. We conducted a three-phase door-to-door survey in two districts of the Khyber Pakhtunkhwa province of Pakistan, to assess the prevalence of PD and Parkinsonism in a sample of 4,000 individuals aged 50 years and above. We identified 14 cases of Parkinsonism, eleven with a diagnosis of idiopathic PD. The overall prevalence estimates were 1.7/100 (95% confidence interval [CI]: 0.9-2.46) for Parkinsonism and 1.28/100 (95% CI: 0.6-1.94) for PD in persons aged 65 years and above. The age-standardized prevalence of PD (aged 65 years and above), normalized to the USA population in 2000, was 1.33/100, which is similar to that observed in other human populations. Of the total 14 cases, five were newly diagnosed and four had a family history of PD. The estimated prevalence rates in Pakistan are similar to those observed in other human populations. The frequency of familial Parkinsonism is also equivalent to previous estimates.
Khan, Suliman; Nabi, Ghulam; Naeem, Muhammad; Ali, Liaqat; Silburn, Peter A; Mellick, George D
Introduction Parkinson’s disease (PD) occurs in all races and cultures, and population-related differences in frequency may provide etiological clues. The present study was designed to explore the prevalence of PD and Parkinsonism in Pakistan, the world’s sixth most populous country, for which no published prevalence data are available. Methods We conducted a three-phase door-to-door survey in two districts of the Khyber Pakhtunkhwa province of Pakistan, to assess the prevalence of PD and Parkinsonism in a sample of 4,000 individuals aged 50 years and above. Results We identified 14 cases of Parkinsonism, eleven with a diagnosis of idiopathic PD. The overall prevalence estimates were 1.7/100 (95% confidence interval [CI]: 0.9–2.46) for Parkinsonism and 1.28/100 (95% CI: 0.6–1.94) for PD in persons aged 65 years and above. The age-standardized prevalence of PD (aged 65 years and above), normalized to the USA population in 2000, was 1.33/100, which is similar to that observed in other human populations. Of the total 14 cases, five were newly diagnosed and four had a family history of PD. Conclusion The estimated prevalence rates in Pakistan are similar to those observed in other human populations. The frequency of familial Parkinsonism is also equivalent to previous estimates. PMID:27382292
Pope, Harrison G.; Kanayama, Gen; Athey, Alison; Ryan, Erin; Hudson, James I.; Baggish, Aaron
Background and Objectives Although various surveys have tracked the prevalence of anabolic-androgenic steroid (AAS) use in American teenagers and young adults, no recent surveys have assessed the lifetime prevalence of AAS use in Americans overall. We therefore analyzed serial youth-survey data to derive estimates of the lifetime prevalence of AAS use in the current American general population. Methods We first determined the distribution of age of onset of AAS use, based on pooled data from nine studies. Using this distribution, we then developed equations to project the eventual lifetime prevalence of AAS use among young survey respondents, once they aged and completed the period of risk for initiating AAS. We similarly calculated the denominator of lifetimes of risk for AAS use in the total American population. We next applied these equations to four independent national youth datasets to derive current American general-population estimates for lifetime AAS use. Finally, using data from 10 pooled studies, we estimated the lifetime prevalence of AAS dependence among AAS users. Results Age-of-onset studies consistently showed that AAS use begins later than most drugs, with only 22% of users (95% confidence interval: 19%–25%) starting before age 20. Applying the age-of-onset findings to national youth datasets, we estimated that among Americans currently age 13 to 50 years, 2.9–4.0 million have used AAS. Within this group, roughly 1 million may have experienced AAS dependence. Conclusions and Scientific Significance Although subject to various limitations, our estimation techniques suggest a surprisinigly high prevalence of AAS use and dependence among Americans. PMID:24112239
Popova, Svetlana; Lange, Shannon; Bekmuradov, Dennis; Mihic, Alanna; Rehm, Jürgen
The objective of this study was to conduct a systematic search of the literature for studies that estimated the prevalence/incidence of Fetal Alcohol Spectrum Disorder (FASD) in correctional systems in different countries and, based on these data, to estimate a) the number of people with Fetal Alcohol Syndrome (FAS)/FASD within the criminal justice system population, and b) the relative risk of becoming imprisoned for individuals with FAS/FASD compared with those without FAS/FASD. A systematic world literature review of published and unpublished studies concerning the prevalence/incidence of FASD in correctional systems was conducted in multiple electronic bibliographic databases. Very little empirical evidence is available on the prevalence of FASD in correctional systems. There were no studies estimating the prevalence/incidence of FASD in correctional systems found for any country other than Canada and the USA. The few studies that have identified incarcerated individuals with FASD estimate that the number of undiagnosed persons in correctional facilities is high. Based on available Canadian data, this study estimates that youths with FASD are 19 times more likely to be incarcerated than youths without FASD in a given year. More studies investigating the prevalence/incidence of alcohol-affected people in the criminal justice system are required. There is an urgent need to raise awareness about the prevalence and disabilities of individuals with FASD in the criminal justice system and about appropriate responses. The criminal justice system is an ideal arena for intervention efforts aimed at the rehabilitation and prevention or reduction of recidivism in this unique population.
Pescatore, Anina M.; Spycher, Ben D.; Beardsmore, Caroline S.; Kuehni, Claudia E.
Background Estimates of prevalence of wheeze depend on questionnaires. However, wording of questions may vary between studies. We investigated effects of alternative wording on estimates of prevalence and severity of wheeze, and associations with risk factors. Methods White and South Asian children from a population-based cohort (UK) were randomly assigned to two groups and followed up at one, four and six years (1998, 2001, 2003). Parents were asked either if their child ever had “attacks of wheeze” (attack group, N=535), or “wheezing or whistling in the chest” (whistling group, N=2859). All other study aspects were identical, including questions about other respiratory symptoms. Results Prevalence of wheeze ever was lower in the attack group than in the whistling group for all surveys (32 vs. 40% in white children aged one year, p<0.001). Prevalence of other respiratory symptoms did not differ between groups. Wheeze tended to be more severe in the attack group. The strength of association with risk factors was comparable in the two groups. Conclusions The wording of questions on wheeze can affect estimates of prevalence, but has less impact on measured associations with risk factors. Question wording is a potential source of between-study-heterogeneity in meta-analyses. PMID:26114296
Seo, Sang Jin; Lee, Yun Ha; Lee, Sang Yeop; Bae, Hyoung Won; Hong, Samin; Seong, Gong Je; Kim, Chan Yun
Purpose. To estimate the prevalence of glaucoma and costs associated with glaucoma care in South Korea between 2008 and 2013 using the Korean national claims database. Design. Retrospective cross-sectional study from a national claims database. Methods. Patients who were diagnosed with glaucoma between 2008 and 2013 were retrospectively identified in the national claims database using glaucoma diagnostic codes. For each year, the prevalence of glaucoma and direct medical costs associated with glaucoma care were estimated. Result. The prevalence of glaucoma in patients ≥40 years of age increased from 0.79% in 2008 to 1.05% in 2013. The number of patients with glaucoma increased by 54% between 2008 and 2013 (9% average annual increase). The prevalence of glaucoma increased with age and was higher in males than in females. The cost to care for glaucoma patients increased from $16.5 million in 2008 to $29.2 million in 2013, which translated into an 81% increase over the 6 years examined (12.7% average annual increase). Conclusion. The estimated prevalence and socioeconomic burden of glaucoma have steadily increased each year in South Korea. Nevertheless, many glaucoma patients remain undiagnosed in the present study using national claims database.
Mora, Nallely; Adams, William H; Kliethermes, Stephanie; Dugas, Lara; Balasubramanian, Neelam; Sandhu, Jasmin; Nde, Helen; Small, Christina; Jose, Joanne; Scaglione, Steven; Layden, Jennifer E
Hepatitis C (HCV) is a deleterious virus that can be cured with new, highly effective anti-viral treatments, yet more than 185 million individuals worldwide remain HCV positive (with the vast majority un-diagnosed or untreated). Of importance, HCV is a leading cause of chronic liver disease and liver cancer, especially in Sub-Saharan Africa (SSA) where the prevalence remains high but uncertain due to little population-based evidence of the epidemic. We aimed to synthesize available data to calculate and highlight the HCV disease burden in SSA. Weighted random-effects generalized linear mixed models were used to estimate prevalence by risk cohort, African region (Southern, Eastern, Western, and Central Africa), type of assay used, publication year, and whether the estimate included children. A pooled prevalence estimate was also calculated. Multi-variable analyses were limited to cohort and region specific prevalence estimates in the adult population due to limited studies including children. Prevalence estimates were additionally weighted using the known adult population size within each region. We included more than 10 years of data. Almost half of the studies on HCV prevalence in SSA were from the Western region (49 %), and over half of all studies were from either blood donor (25 %) or general population cohorts (31 %). In uni-variable analyses, prevalence was lowest in Southern Africa (0.72 %), followed by Eastern Africa at 3.00 %, Western Africa at 4.14 %, and Central Africa at 7.82 %. Blood donors consistently had the lowest prevalence (1.78 %), followed by pregnant women (2.51 %), individuals with comorbid HIV (3.57 %), individuals from the general population (5.41 %), those with a chronic illness (7.99 %), and those at high risk for infection (10.18 %). After adjusting for the population size in each region, the overall adult prevalence of HCV in SSA rose from 3.82 to 3.94 %. This meta-analysis offers a timely update to the HCV disease burden
Adeloye, Davies; Chua, Stephen; Lee, Chinwei; Basquill, Catriona; Papana, Angeliki; Theodoratou, Evropi; Nair, Harish; Gasevic, Danijela; Sridhar, Devi; Campbell, Harry; Chan, Kit Yee; Sheikh, Aziz; Rudan, Igor
Background The burden of chronic obstructive pulmonary disease (COPD) across many world regions is high. We aim to estimate COPD prevalence and number of disease cases for the years 1990 and 2010 across world regions based on the best available evidence in publicly accessible scientific databases. Methods We conducted a systematic search of Medline, EMBASE and Global Health for original, population–based studies providing spirometry–based prevalence rates of COPD across the world from January 1990 to December 2014. Random effects meta–analysis was conducted on extracted crude prevalence rates of COPD, with overall summaries of the meta–estimates (and confidence intervals) reported separately for World Health Organization (WHO) regions, the World Bank's income categories and settings (urban and rural). We developed a meta–regression epidemiological model that we used to estimate the prevalence of COPD in people aged 30 years or more. Findings Our search returned 37 472 publications. A total of 123 studies based on a spirometry–defined prevalence were retained for the review. From the meta–regression epidemiological model, we estimated about 227.3 million COPD cases in the year 1990 among people aged 30 years or more, corresponding to a global prevalence of 10.7% (95% confidence interval (CI) 7.3%–14.0%) in this age group. The number of COPD cases increased to 384 million in 2010, with a global prevalence of 11.7% (8.4%–15.0%). This increase of 68.9% was mainly driven by global demographic changes. Across WHO regions, the highest prevalence was estimated in the Americas (13.3% in 1990 and 15.2% in 2010), and the lowest in South East Asia (7.9% in 1990 and 9.7% in 2010). The percentage increase in COPD cases between 1990 and 2010 was the highest in the Eastern Mediterranean region (118.7%), followed by the African region (102.1%), while the European region recorded the lowest increase (22.5%). In 1990, we estimated about 120.9 million COPD cases
Jensen, Elizabeth T; Cook, Suzanne F; Allen, Jeffery K; Logie, John; Brookhart, Maurice Alan; Kappelman, Michael D; Dellon, Evan S
Considerations for using administrative claims data in research have not been well-described. To increase awareness of how enrollment factors and insurance benefit use may contribute to prevalence estimates, we evaluated how differences in operational definitions of the cohort impact observed estimates. We conducted a cross-sectional study estimating the prevalence of five gastrointestinal conditions using MarketScan claims data for 73.1 million enrollees. We extracted data obtained from 2009 to 2012 to identify cohorts meeting various enrollment, prescription drug benefit, or health care utilization characteristics. Next, we identified patients meeting the case definition for each of the diseases of interest. We compared the estimates obtained to evaluate the influence of enrollment period, drug benefit, and insurance usage. As the criteria for inclusion in the cohort became increasingly restrictive the estimated prevalence increased, as much as 45% to 77% depending on the disease condition and the definition for inclusion. Requiring use of the insurance benefit and a longer period of enrollment had the greatest influence on the estimates observed. Individuals meeting case definition were more likely to meet the more stringent definition for inclusion in the study cohort. This may be considered a form of selection bias, where overly restrictive inclusion criteria definitions may result in selection of a source population that may no longer represent the population from which cases arose. Copyright © 2015 Elsevier Inc. All rights reserved.
Anderson, H. Ross; Butland, Barbara K.; Donkelaar, Aaron Matthew Van; Brauer, Michael; Strachan, David P.; Clayton, Tadd; van Dingenen, Rita; Amann, Marcus; Brunekreef, Bert; Cohen, Aaron; Dentener, Frank; Lai, Christopher; Lamsal, Lok N.; Martin, Randall V.
Background: The effect of ambient air pollution on global variations and trends in asthma prevalence is unclear. Objectives: Our goal was to investigate community-level associations between asthma prevalence data from the International Study of Asthma and Allergies in Childhood (ISAAC) and satellite-based estimates of particulate matter with aerodynamic diameter < 2.5 microm (PM2.5) and nitrogen dioxide (NO2), and modelled estimates of ozone. Methods: We assigned satellite-based estimates of PM2.5 and NO2 at a spatial resolution of 0.1deg × 0.1deg and modeled estimates of ozone at a resolution of 1deg × 1deg to 183 ISAAC centers. We used center-level prevalence of severe asthma as the outcome and multilevel models to adjust for gross national income (GNI) and center- and country-level sex, climate, and population density. We examined associations (adjusting for GNI) between air pollution and asthma prevalence over time in centers with data from ISAAC Phase One (mid-1900s) and Phase Three (2001-2003). Results: For the 13- to 14-year age group (128 centers in 28 countries), the estimated average within-country change in center-level asthma prevalence per 100 children per 10% increase in center-level PM2.5 and NO2 was -0.043 [95% confidence interval (CI): -0.139, 0.053] and 0.017 (95% CI: -0.030, 0.064) respectively. For ozone the estimated change in prevalence per parts per billion by volume was -0.116 (95% CI: -0.234, 0.001). Equivalent results for the 6- to 7-year age group (83 centers in 20 countries), though slightly different, were not significantly positive. For the 13- to 14-year age group, change in center-level asthma prevalence over time per 100 children per 10% increase in PM2.5 from Phase One to Phase Three was -0.139 (95% CI: -0.347, 0.068). The corresponding association with ozone (per ppbV) was -0.171 (95% CI: -0.275, -0.067). Conclusion: In contrast to reports from within-community studies of individuals exposed to traffic pollution, we did not find
Anderson, H Ross; Butland, Barbara K; van Donkelaar, Aaron; Brauer, Michael; Strachan, David P; Clayton, Tadd; van Dingenen, Rita; Amann, Marcus; Brunekreef, Bert; Cohen, Aaron; Dentener, Frank; Lai, Christopher; Lamsal, Lok N; Martin, Randall V; One, Isaac Phase
The effect of ambient air pollution on global variations and trends in asthma prevalence is unclear. Our goal was to investigate community-level associations between asthma prevalence data from the International Study of Asthma and Allergies in Childhood (ISAAC) and satellite-based estimates of particulate matter with aerodynamic diameter < 2.5 µm (PM₂.₅) and nitrogen dioxide (NO₂), and modelled estimates of ozone. We assigned satellite-based estimates of PM₂.₅ and NO₂ at a spatial resolution of 0.1° × 0.1° and modeled estimates of ozone at a resolution of 1° × 1° to 183 ISAAC centers. We used center-level prevalence of severe asthma as the outcome and multilevel models to adjust for gross national income (GNI) and center- and country-level sex, climate, and population density. We examined associations (adjusting for GNI) between air pollution and asthma prevalence over time in centers with data from ISAAC Phase One (mid-1900s) and Phase Three (2001-2003). For the 13- to 14-year age group (128 centers in 28 countries), the estimated average within-country change in center-level asthma prevalence per 100 children per 10% increase in center-level PM₂.₅ and NO₂ was -0.043 [95% confidence interval (CI): -0.139, 0.053] and 0.017 (95% CI: -0.030, 0.064) respectively. For ozone the estimated change in prevalence per parts per billion by volume was -0.116 (95% CI: -0.234, 0.001). Equivalent results for the 6- to 7-year age group (83 centers in 20 countries), though slightly different, were not significantly positive. For the 13- to 14-year age group, change in center-level asthma prevalence over time per 100 children per 10% increase in PM₂.₅ from Phase One to Phase Three was -0.139 (95% CI: -0.347, 0.068). The corresponding association with ozone (per ppbV) was -0.171 (95% CI: -0.275, -0.067). In contrast to reports from within-community studies of individuals exposed to traffic pollution, we did not find evidence of a positive association
Jensen, Elizabeth T.; Martin, Christopher F.; Kappelman, Michael D.; Dellon, Evan S.
Objectives Eosinophilic esophagitis (EoE) is becoming increasingly more common, but the prevalence of other eosinophilic gastrointestinal disorders (EGIDs) is unknown. Our objective was to estimate the prevalence of eosinophilic gastritis, gastroenteritis, and colitis in the U.S.. Methods We used the IMS Health LifeLink™, PharMetrics Plus™Claims Database, data representative of a U.S. national commercially-insured population containing medical and pharmaceutical claims for >75million individuals. We restricted our sample to patients age 0–64 with continuous enrollment between 7/1/2009–6/30/2011. We identified cases of eosinophilic gastritis, gastroenteritis, and colitis as defined by ≥1 instance of the ICD-9 codes 535.70, 558.41, and 558.42, respectively. We calculated the prevalence of the codes in the database and then standardized the estimates to the U.S. population by age and sex. Results The standardized estimated prevalences of eosinophilic gastritis, gastroenteritis, and colitis were 6.3/100,000, 8.4/100,000, and 3.3/100,000, respectively. The prevalence of eosinophilic gastroenteritis was highest among children age < 5 years, whereas eosinophilic gastritis was more prevalent among older age groups. We observed no age differences for eosinophilic colitis. Among affected patients there was a high proportion of co-existing allergic conditions, 38.5% for eosinophilic gastritis, 45.6% for gastroenteritis, and 41.8% for colitis. Concomitant allergic disease was most commonly identified in pediatric patients. Conclusions The prevalence of non-EoE EGIDs remains rare in the U.S., with less than 50,000 total patients affected. There appears to be a female predominance, as well as a high co-occurrence of atopic comorbidities. PMID:25988554
Jensen, Elizabeth T; Martin, Christopher F; Kappelman, Michael D; Dellon, Evan S
Eosinophilic esophagitis (EoE) is becoming increasingly more common, but the prevalence of other eosinophilic gastrointestinal disorders (EGIDs) is unknown. Our objective was to estimate the prevalence of eosinophilic gastritis, gastroenteritis, and colitis in the United States. We used the IMS Health LifeLink PharMetrics Plus Claims Database, data representative of a US national commercially insured population containing medical and pharmaceutical claims for > 75 million individuals. We restricted our sample to patients ages 0 to 64 with continuous enrollment between July 1, 2009, and June 30, 2011. We identified patients with eosinophilic gastritis, gastroenteritis, and colitis as defined by ≥ 1 instance of the International Classification of Diseases, Ninth Revision codes 535.70, 558.41, and 558.42, respectively. We calculated the prevalence of the codes in the database and then standardized the estimates to the US population by age and sex. The standardized estimated prevalences of eosinophilic gastritis, gastroenteritis, and colitis were 6.3/100,000, 8.4/100,000, and 3.3/100,000, respectively. The prevalence of eosinophilic gastroenteritis was the highest among children age < 5 years, whereas eosinophilic gastritis was more prevalent among older age groups. We observed no age differences for eosinophilic colitis. Among affected patients, there was a high proportion of coexisting allergic conditions, 38.5% for eosinophilic gastritis, 45.6% for gastroenteritis, and 41.8% for colitis. Concomitant allergic disease was most commonly identified in pediatric patients. The prevalence of non-EoE EGIDs remains rare in the United States, with < 50,000 total patients affected. There appears to be a female predominance and a high co-occurrence of atopic comorbidities.
NAVAL HEALTH RESEARCH CENTER THE INFLUENCE OF SURVEY METHODOLOGY IN ESTIMATING PREVALENCE RATES OF CHILDHOOD SEXUAL ABUSE AMONG...different results than studies that ask about specific childhood sexual experiences (CSEs) or about experiences with specific types of parental physical... sexually abused. Data from all three sources independently accounted for variability in participants’ symptoms of depression, anxiety, and sexual
Bernstein, Amy B.; Remsburg, Robin E.
Purpose: We address how the national prevalence of cognitive impairment can be estimated from two nationally representative surveys. Design and Methods: Data are from the 1999-2001 National Health Interview Survey (NHIS) and the 1999 National Nursing Home Survey (NNHS). The NHIS represents all community-dwelling people living in the United States,…
Mariano, Andrea; Scalia Tomba, Gianpaolo; Tosti, Maria Elena; Spada, Enea; Mele, Alfonso
Our objective was to estimate HCV clinical burden over time in Italy. A national age-specific HCV prevalence in 1995 was obtained from studies conducted in general population samples and intravenous drug users. Age profile of new HCV infections and trend of incidence since 1985 were derived from a database of reported acute HCV infections. These incidence and prevalence data were used to estimate HCV burden from 1950 to 2030 by mathematical modelling. Different rates of HCV related liver disease progression were tested to assess the robustness of estimates. It is estimated that HCV had a major spread in Italy in 1945-1969. HCV RNA-positive subjects peaked around 1970; their prevalence in 2005 was 3.2%, 58% of them being >65 y of age. The number of individuals with HCV related cirrhosis and that of HCV liver related deaths peaked in 1980-1985. In 2005, they were approximately 230,000 (range 150,000-240,000, according to lower or higher disease progression rates) and approximately 7,000 (range 2200-12,300), respectively: both will be halved by 2025. In conclusion, unlike other industrialized countries, the burden of clinically relevant HCV-positive cases in Italy is already on the decline and will further reduce in the future. This is due to differences in the age-specific prevalence, most of HCV-positive Italians currently being >65 y of age.
Rhodes, Scott D.; McCoy, Thomas P.; Hergenrather, Kenneth C.; Vissman, Aaron T.; Wolfson, Mark; Alonzo, Jorge; Bloom, Fred R.; Alegria-Ortega, Jose; Eng, Eugenia
Purpose: Little is known about the health status of rural immigrant Latino men who have sex with men (MSM). These MSM comprise a subpopulation that tends to remain "hidden" from both researchers and practitioners. This study was designed to estimate the prevalence of tobacco, alcohol, and drug use, and sexual risk behaviors of Latino MSM…
Bernstein, Amy B.; Remsburg, Robin E.
Purpose: We address how the national prevalence of cognitive impairment can be estimated from two nationally representative surveys. Design and Methods: Data are from the 1999-2001 National Health Interview Survey (NHIS) and the 1999 National Nursing Home Survey (NNHS). The NHIS represents all community-dwelling people living in the United States,…
Rhodes, Scott D.; McCoy, Thomas P.; Hergenrather, Kenneth C.; Vissman, Aaron T.; Wolfson, Mark; Alonzo, Jorge; Bloom, Fred R.; Alegría-Ortega, Jose; Eng, Eugenia
Purpose Little is known about the health status of rural immigrant Latino men who have sex with men (MSM). These MSM comprise a subpopulation that tends to remain “hidden” from both researchers and practitioners. This study was designed to estimate the prevalence of tobacco, alcohol, and drug use, and sexual risk behaviors of Latino MSM living in rural North Carolina. Methods A community-based participatory research (CBPR) partnership used respondent-driven sampling (RDS) to identify, recruit, and enroll Latino MSM to participate in an interviewer-administered behavioral assessment. RDS weighted prevalence of risk behaviors was estimated using the RDS Analysis Tool. Data collection occurred in 2008. Results A total of 190 Latino MSM was reached; the average age was 25.5 years old and nearly 80% reported being from Mexico. Prevalence estimates of smoking everyday and past 30-day heavy episodic drinking were 6.5% and 35.0%, respectively. Prevalence estimates of past 12-month marijuana and cocaine use were 56.0% and 27.1%, respectively. Past 3-month prevalence estimates of sex with at least one woman, multiple male partners, and inconsistent condom use were 21.2%, 88.9%, and 54.1%, respectively. Conclusions Respondents had low rates of tobacco use and club drug use, and high rates of sexual risk behaviors. Although this study represents an initial step in documenting the health risk behaviors of immigrant Latino MSM who are part of a new trend in Latino immigration to the southeastern US, a need exists for further research, including longitudinal studies to understand the trajectory of risk behavior among immigrant Latino MSM. PMID:22236317
Rhodes, Scott D; McCoy, Thomas P; Hergenrather, Kenneth C; Vissman, Aaron T; Wolfson, Mark; Alonzo, Jorge; Bloom, Fred R; Alegría-Ortega, Jose; Eng, Eugenia
Little is known about the health status of rural immigrant Latino men who have sex with men (MSM). These MSM comprise a subpopulation that tends to remain "hidden" from both researchers and practitioners. This study was designed to estimate the prevalence of tobacco, alcohol, and drug use, and sexual risk behaviors of Latino MSM living in rural North Carolina. A community-based participatory research (CBPR) partnership used respondent-driven sampling (RDS) to identify, recruit, and enroll Latino MSM to participate in an interviewer-administered behavioral assessment. RDS-weighted prevalence of risk behaviors was estimated using the RDS Analysis Tool. Data collection occurred in 2008. A total of 190 Latino MSM was reached; the average age was 25.5 years and nearly 80% reported being from Mexico. Prevalence estimates of smoking everyday and past 30-day heavy episodic drinking were 6.5% and 35.0%, respectively. Prevalence estimates of past 12-month marijuana and cocaine use were 56.0% and 27.1%, respectively. Past 3-month prevalence estimates of sex with at least one woman, multiple male partners, and inconsistent condom use were 21.2%, 88.9%, and 54.1%, respectively. Respondents had low rates of tobacco use and club drug use, and high rates of sexual risk behaviors. Although this study represents an initial step in documenting the health risk behaviors of immigrant Latino MSM who are part of a new trend in Latino immigration to the southeastern United States, a need exists for further research, including longitudinal studies to understand the trajectory of risk behavior among immigrant Latino MSM. © 2011 National Rural Health Association.
Ishøy, Torben; Haastrup, Lene; Hay, Gordon
Estimates of the prevalence of drug use in Denmark were, until 1999, based on the mortality multiplier method. This paper presents a study estimating the prevalence of problem opioid use in the Greater Copenhagen region using the capture-recapture method. Records from the prehospital mobile emergency care unit, The Copenhagen Prehospital Research Database, were searched with a particular focus on treatment of opioid overdose. In addition, data from The National Register of Drug Users in Treatment in Greater Copenhagen were analysed for the years 1997 and 1998. Four samples were used within the capture-recapture analysis, ie the Prehospital Research Database for 1997/1998 and the Register of Drug Users in Treatment for the same period. The estimates from the stratified capture-recapture analyses, when summed up, suggest that there is a hidden population of 4116 and thus a total population of 6992 opioid users in Greater Copenhagen (population approx 700,000). This corresponds to a rate of 10 per 1000 inhabitants aged 15-54 years. The 95% confidence attached to this estimate is 5787 to 10,885. The prevalence rate of 10 per 1000 inhabitants aged 15-54 years is comparable to figures found in similar cities in Europe. A previous study of Central Copenhagen calculated the rate to be 12.4 per 1000 inhabitants between 15 and 59 years. It seems reasonable that the estimate of prevalence of problem drug use in Greater Copenhagen is lower than the prevalence in Central Copenhagen, as the city area is more urbanised and has a slightly different demographic and socio-economic profile. About 75% of all opioid overdose incidents are assumed to occur in the central district of the city during the observed period.
Trumbo, Paula R; Spungen, Judith H; Dwyer, Johanna T; Carriquiry, Alicia L; Zimmerman, Thea P; Swanson, Christine A; Murphy, Suzanne P
Background: Prevalences of iodine inadequacy and excess are usually evaluated by comparing the population distribution of urinary iodine concentration (UIC) in spot samples with established UIC cutoffs. To our knowledge, until now, dietary intake data have not been assessed for this purpose. Objective: Our objective was to compare 2 methods for evaluating the prevalence of iodine inadequacy and excess in sex- and life stage–specific subgroups of the US population: one that uses UIC cutoffs, and one that uses iodine intake cutoffs. Design: By using the iodine concentrations of foods measured in the US Food and Drug Administration’s Total Diet Study (TDS), dietary intake data from the NHANES 2003–2010, and a file that maps each NHANES food to a TDS food with similar ingredients, we estimated each NHANES participant’s iodine intake from each NHANES food as the mean iodine concentration of the corresponding TDS food in samples gathered over the same 2-y period. We calculated prevalences of iodine inadequacy and excess in each sex- and life stage–specific subgroup by both the UIC cutoff method and the iodine intake cutoff method—using the UIC values and dietary intakes reported for NHANES participants who provided both types of data—and compared the prevalences across methods. Results: We found lower prevalences of iodine inadequacy across all sex- and life stage–specific subgroups with the iodine intake cutoff method than with the UIC cutoff method; for pregnant females, the respective prevalences were 5.0% and 37.9%. For children aged ≤8 y, the prevalence of excessive iodine intake was high by either method. Conclusions: The consideration of dietary iodine intake from all sources may provide a more complete understanding of population prevalences of iodine inadequacy and excess and thus better inform dietary guidance than consideration of UIC alone. Methods of adjusting UIC for within-person variation are needed to improve the accuracy of prevalence
Juan, WenYen; Trumbo, Paula R; Spungen, Judith H; Dwyer, Johanna T; Carriquiry, Alicia L; Zimmerman, Thea P; Swanson, Christine A; Murphy, Suzanne P
Prevalences of iodine inadequacy and excess are usually evaluated by comparing the population distribution of urinary iodine concentration (UIC) in spot samples with established UIC cutoffs. To our knowledge, until now, dietary intake data have not been assessed for this purpose. Our objective was to compare 2 methods for evaluating the prevalence of iodine inadequacy and excess in sex- and life stage-specific subgroups of the US population: one that uses UIC cutoffs, and one that uses iodine intake cutoffs. By using the iodine concentrations of foods measured in the US Food and Drug Administration's Total Diet Study (TDS), dietary intake data from the NHANES 2003-2010, and a file that maps each NHANES food to a TDS food with similar ingredients, we estimated each NHANES participant's iodine intake from each NHANES food as the mean iodine concentration of the corresponding TDS food in samples gathered over the same 2-y period. We calculated prevalences of iodine inadequacy and excess in each sex- and life stage-specific subgroup by both the UIC cutoff method and the iodine intake cutoff method-using the UIC values and dietary intakes reported for NHANES participants who provided both types of data-and compared the prevalences across methods. We found lower prevalences of iodine inadequacy across all sex- and life stage-specific subgroups with the iodine intake cutoff method than with the UIC cutoff method; for pregnant females, the respective prevalences were 5.0% and 37.9%. For children aged ≤8 y, the prevalence of excessive iodine intake was high by either method. The consideration of dietary iodine intake from all sources may provide a more complete understanding of population prevalences of iodine inadequacy and excess and thus better inform dietary guidance than consideration of UIC alone. Methods of adjusting UIC for within-person variation are needed to improve the accuracy of prevalence assessments based on UIC. © 2016 American Society for Nutrition.
Leone, L; Scatigna, M; Donati, A; Pesce, C
Drug supply and demand indicators have mainly been analysed without triangulating information on environmental drug availability and consumption. This study proposes an approach to analyse the prevalence of illicit drug consumption together with indirect indicators of drug supply. Ecological study correlating cocaine seizure data and consumption prevalence estimates at local level, using Italian provinces as the unit of analysis. The amount of cocaine seized in proportion to the number of potential consumers was computed at Italian provincial level from the 2005 database of the Italian Central Directorate for Anti-Drug Services. Indicators of consumption prevalence, at provincial level, in 15-16-year-old students from the 2005 European School Survey Project on Alcohol and Other Drugs (ESPAD) and 15-54-year-old respondents from the 2005 Italian Population Survey on Alcohol and Drugs (IPSAD) were correlated with the population-adjusted amount of total seizures and seizures of different sizes. ESPAD data were also regressed on seizure data after controlling for the prediction accrued by socio-economic variables that might cause covariation of seizure and consumption prevalence data. Regression-predicted prevalence values were computed and correlated with the ESPAD prevalence data for the following year. There was a weak general correlation between the population-adjusted total seizure and IPSAD prevalence indicators, but not ESPAD prevalence indicators. In contrast, ESPAD data were more strongly correlated with small seizures. The regression model yielded significant variance in prevalence data (18% and 23% in small and large provinces, respectively) explained by small seizures, and this remained after removing the percentage of variance explained by socio-economic factors and (particularly) education level. A moderate correlation was found between seizure-based predicted values of consumption prevalence and ESPAD values for the following year. Associating prevalence
Mendez-Luck, Carolyn A; Yu, Hongjian; Meng, Ying-Ying; Jhawar, Mona; Wallace, Steven P
Research Objective To create prevalence estimates of asthma symptoms for California legislative districts. Data Sources. Three main data sources were used for this study: 2001 California Health Interview Survey, 2000 Census, and 2000–2002 March Current Population Surveys. Study Design Secondary data analyses were conducted from cross-sectional data to distribute the joint probability of ever having an asthma diagnosis and symptoms in the last 12 months within an Assembly district. We applied hierarchical logistic regressions to estimate the parameters for selected survey and census data that predicted the probabilities of diagnosed asthmatics with asthma symptoms. Predictors included individual-level variables and contextual variables at zip code levels. Principal Findings Asthma symptom prevalence geographically varied by age within and across Assembly districts throughout California. Conclusions With modest investments in establishing analytic data files and estimating regression parameters for target conditions, small area estimation (SAE) procedures can create health data estimates not otherwise available at the sub-county level. Applying SAE procedures to asthma symptom prevalence suggest that these data can become essential reference tools for advocates and policy makers currently addressing this and other public health concerns in the state. PMID:17995549
Handel, Ian G.; Tanya, Vincent N.; Hamman, Saidou M.; Nfon, Charles; Bergman, Ingrid E.; Malirat, Viviana; Sorensen, Karl J.; Bronsvoort, Barend M. de C.
Herdsman-reported disease prevalence is widely used in veterinary epidemiologic studies, especially for diseases with visible external lesions; however, the accuracy of such reports is rarely validated. Thus, we used latent class analysis in a Bayesian framework to compare sensitivity and specificity of herdsman reporting with virus neutralization testing and use of 3 nonstructural protein ELISAs for estimates of foot-and-mouth disease (FMD) prevalence on the Adamawa plateau of Cameroon in 2000. Herdsman-reported estimates in this FMD-endemic area were comparable to those obtained from serologic testing. To harness to this cost-effective resource of monitoring emerging infectious diseases, we suggest that estimates of the sensitivity and specificity of herdsmen reporting should be done in parallel with serologic surveys of other animal diseases. PMID:25417556
Nagelkerke, N; Heisterkamp, S; Borgdorff, M; Broekmans, J; Van Houwelingen, H
Many infections cause lasting detectable immune responses, whose prevalence can be estimated from cross-sectional surveys. However, such surveys do not provide direct information on the incidence of infection. We address the issue of estimating age and time specific incidence from a series of prevalence surveys under the assumption that incidence changes exponentially with time, but make no assumption about the age specific incidence. We show that these assumptions lead to a proportional hazards model and estimate its parameters using semi-parametric maximum likelihood methods. The method is applied to tuberculin surveys in The Netherlands to explore age dependence of the risk of tuberculous infection in the presence of a strong secular decline in this risk.
Nasirian, Maryam; Baneshi, Mohammd Reza; Kamali, Kianoush; Haghdoost, Ali Akbar
Routine reporting of sexually transmitted infections (STIs) in Iran is one of the main information sources on STIs, endures some diminution under influence of several factors. We aimed to adjust registered STI data with a model-based approach and estimate the incidence and prevalence of STIs in Iran. In this cross-sectional study, we developed a stochastic compartmental model considering effects of influential factors on STI reporting process to adjust registered STI data. We reviewed literature and used Delphi method to collect data and estimate model parameters. We calibrated the model using Monte Carol simulation with 95% confidence interval (CI). Finally, we validated the models by comparing their output with investigational data. The estimated prevalence of male urethral discharge was 0.40% (95% CI: 0.26%, 0.65%); the prevalence of genital ulcers was 3.68% (95% CI: 2.31%, 6.43%) in women and 0.16% (95% CI: 0.10%, 0.27%) in men. The estimated incidence for Neisseria gonorrhoeae, Chlamydia trachoma and syphilis per 1000 women was 2.44 (95% CI: 1.17, 6.65), 5.02 (95% CI: 2.78, 10.16) and 0.04 (95% CI: 0.02, 0.05) respectively; the corresponding figures per 1000 men were 0.43 (95% CI: 0.26, 0.80), 0.82 (95% CI: 0.42, 1.92) and 0.005 (95% CI: 0.003, 0.008). Various factors are responsible for the obvious underestimation in the number of STIs registered in Iran. Notwithstanding this underestimation, our models offer an indirect method of estimating the prevalence of STIs in the country. Providing policymakers and STI experts with more realistic estimates might prompt policymakers and STI experts to recognize the importance of STIs in Iran and help them to develop appropriate prevention and control programs.
Akioyamen, Leo E; Genest, Jacques; Shan, Shubham D; Reel, Rachel L; Albaum, Jordan M; Chu, Anna; Tu, Jack V
Objectives Heterozygous familial hypercholesterolaemia (FH) confers a significant risk for premature cardiovascular disease (CVD). However, the estimated prevalence of FH varies substantially among studies. We aimed to provide a summary estimate of FH prevalence in the general population and assess variations in frequency across different sociodemographic characteristics. Setting, participants and outcome measures We searched MEDLINE, EMBASE, Global Health, the Cochrane Library, PsycINFO and PubMed for peer-reviewed literature using validated strategies. Results were limited to studies published in English between January 1990 and January 2017. Studies were eligible if they determined FH prevalence using clinical criteria or DNA-based analyses. We determined a pooled point prevalence of FH in adults and children and assessed the variation of the pooled frequency by age, sex, geographical location, diagnostic method, study quality and year of publication. Estimates were pooled using random-effects meta-analysis. Differences by study-level characteristics were investigated through subgroups, meta-regression and sensitivity analyses. Results The pooled prevalence of FH from 19 studies including 2 458 456 unique individuals was 0.40% (95% CI 0.29% to 0.52%) which corresponds to a frequency of 1 in 250 individuals. FH prevalence was found to vary by age and geographical location but not by any other covariates. Results were consistent in sensitivity analyses. Conclusions Our systematic review suggests that FH is a common disorder, affecting 1 in 250 individuals. These findings underscore the need for early detection and management to decrease CVD risk. PMID:28864697
Sarkin, J A; Nichols, J F; Sallis, J F; Calfas, K J
Prevalence estimates of meeting the guidelines for physical activity based on various self-report measures were compared, and the effects of various scoring protocols on the estimates were evaluated. A sample of 575 university students aged 24.5 +/- 1.9 yr (56% women, 54% Euro-American) completed the Seven-Day Physical Activity Recall interview (PAR), Youth Risk Behavior Survey (YRBS), and National Health Interview Survey 1991 (NHIS). To determine the prevalence of meeting the ACSM (1990) fitness and the CDC/ACSM (1995) health-related guidelines, various scoring protocols were employed that closely approximated the recommendations. Protocols varied by whether frequency and duration or duration only were considered. For the health-related guidelines, scoring protocols also varied depending on the intensity of activities considered. Depending on the scoring protocol and instrument used, the proportion meeting the fitness guidelines ranged from 32 to 59%. The NHIS, YRBS, and PAR resulted in significantly different proportions of those meeting the health-related guideline, ranging from 4 to 70%. The type of measure as well as the scoring protocol affected prevalence estimates of meeting the physical activity guidelines. This study indicates the difficulty of comparing prevalence rates across studies using different measures.
Kim, Hyunmi; Thurman, David J; Durgin, Tracy; Faught, Edward; Helmers, Sandra
This study aims to determine prevalence and incidence of epilepsy in the US pediatric population. We analyzed commercial claims and Medicaid insurance claims data between 2008 and 2012. Over 8 million continuously enrolled lives aged 0 to 19 years were included. Our definition of a prevalent case of epilepsy was based on International Classification of Diseases-coded diagnoses of epilepsy or seizures and evidence of prescribed antiepileptic drugs. Incident cases were identified in subjects continuously enrolled for ≥2 years of which the first 2 years had no indication of epilepsy or seizures. The overall prevalence estimate for 2012 was 6.8 per 1,000 children. The overall incidence estimate for 2012 was 104 per 100,000 pediatric population. This study provides estimates of the prevalence and incidence of epilepsy in the US pediatric population, using large claims datasets from multiple US population sectors. The findings appear reasonably representative of the US-insured pediatric population. © The Author(s) 2015.
De Santis, Andrea C; Raghavan, Malathi; Caldanaro, Richard J; Glickman, Nita W; Moore, George E; Lewis, Hugh B; Schantz, Peter M; Glickman, Lawrence T
To estimate prevalences of roundworm, hookworm, and whipworm infections in pet cats in the United States and identify risk factors for parasitism. Retrospective period prevalence survey. 356,086 cats examined at 359 private veterinary hospitals during 2003. Electronic medical records were searched to identify cats for which fecal flotation tests had been performed and to determine proportions of test results positive for roundworms, hookworms, and whipworms. Potential risk factors for roundworm and hookworm infection were identified by means of multivariate logistic regression analysis. A total of 80,278 tests were performed on fecal samples from 66,819 cats. Calculated prevalences of roundworm, hookworm, and whipworm infection were 2.92%, 0.63%, and 0.031%, respectively. Age, reproductive status, breed, and season were significant risk factors for roundworm infection, with cats < 4 years old; sexually intact cats; mixed-breed cats; and cats examined during the summer, fall, or winter more likely to be infected. Age, reproductive status, and season were significant risk factors for hookworm infection, with cats < 1 year old, sexually intact cats, and cats examined during the summer more likely to be infected. Regional differences in prevalences of roundworm and hookworm infection were found. Results suggest that prevalences of nematode infections among pet cats in the United States may be lower than previously suspected on the basis of prevalences reported among cats in humane shelters and those reported in more geographically focused studies.
Adeloye, Davies; Basquill, Catriona
Background The burden of hypertension is high in Africa, and due to rapid population growth and ageing, the exact burden on the continent is still far from being known. We aimed to estimate the prevalence and awareness rates of hypertension in Africa based on the cut off “≥140/90 mm Hg”. Methods We conducted a systematic search of Medline, EMBASE and Global Health. Search date was set from January 1980 to December 2013. We included population-based studies on hypertension, conducted among people aged ≥15 years and providing numerical estimates on the prevalence of hypertension in Africa. Overall pooled prevalence of hypertension in mixed, rural and urban settings in Africa were estimated from reported crude prevalence rates. A meta-regression epidemiological modelling, using United Nations population demographics for the years 1990, 2000, 2010 and 2030, was applied to determine the prevalence rates and number of cases of hypertension in Africa separately for these four years. Results Our search returned 7680 publications, 92 of which met the selection criteria. The overall pooled prevalence of hypertension in Africa was 19.7% in 1990, 27.4% in 2000 and 30.8% in 2010, each with a pooled awareness rate (expressed as percentage of hypertensive cases) of 16.9%, 29.2% and 33.7%, respectively. From the modelling, over 54.6 million cases of hypertension were estimated in 1990, 92.3 million cases in 2000, 130.2 million cases in 2010, and a projected increase to 216.8 million cases of hypertension by 2030; each with an age-adjusted prevalence of 19.1% (13.9, 25.5), 24.3% (23.3, 31.6), 25.9% (23.5, 34.0), and 25.3% (24.3, 39.7), respectively. Conclusion Our findings suggest the prevalence of hypertension is increasing in Africa, and many hypertensive individuals are not aware of their condition. We hope this research will prompt appropriate policy response towards improving the awareness, control and overall management of hypertension in Africa. PMID:25090232
Adeloye, Davies; Basquill, Catriona
The burden of hypertension is high in Africa, and due to rapid population growth and ageing, the exact burden on the continent is still far from being known. We aimed to estimate the prevalence and awareness rates of hypertension in Africa based on the cut off "≥140/90 mm Hg". We conducted a systematic search of Medline, EMBASE and Global Health. Search date was set from January 1980 to December 2013. We included population-based studies on hypertension, conducted among people aged ≥15 years and providing numerical estimates on the prevalence of hypertension in Africa. Overall pooled prevalence of hypertension in mixed, rural and urban settings in Africa were estimated from reported crude prevalence rates. A meta-regression epidemiological modelling, using United Nations population demographics for the years 1990, 2000, 2010 and 2030, was applied to determine the prevalence rates and number of cases of hypertension in Africa separately for these four years. Our search returned 7680 publications, 92 of which met the selection criteria. The overall pooled prevalence of hypertension in Africa was 19.7% in 1990, 27.4% in 2000 and 30.8% in 2010, each with a pooled awareness rate (expressed as percentage of hypertensive cases) of 16.9%, 29.2% and 33.7%, respectively. From the modelling, over 54.6 million cases of hypertension were estimated in 1990, 92.3 million cases in 2000, 130.2 million cases in 2010, and a projected increase to 216.8 million cases of hypertension by 2030; each with an age-adjusted prevalence of 19.1% (13.9, 25.5), 24.3% (23.3, 31.6), 25.9% (23.5, 34.0), and 25.3% (24.3, 39.7), respectively. Our findings suggest the prevalence of hypertension is increasing in Africa, and many hypertensive individuals are not aware of their condition. We hope this research will prompt appropriate policy response towards improving the awareness, control and overall management of hypertension in Africa.
False consensus, or the tendency to overestimate the extent to which others share one's own attitudes and behaviors, was investigated in a study of 348 university students classified as non-drug users, cannabis-only users, or amphetamine + cannabis users. Participants estimated the prevalence of cannabis and amphetamine use among students. Cannabis and amphetamine users made significantly higher estimates of cannabis use among students than did nonusers, whereas amphetamine users gave significantly higher estimates of amphetamine use than nonusers and cannabis-only users. Correlations between estimates of use among friends and other students were significantly positive for both drugs. The results suggest that students are motivated to overestimate the commonality of their own position on drug use and that their estimates may also be influenced by selective exposure.
Satcher Johnson, Anna; Song, Ruiguang; Hall, H Irene
The burden of HIV infection and health outcomes for people living with HIV varies across the United States. New methods allow for estimating national and state-level HIV incidence, prevalence, and undiagnosed infections using surveillance data and CD4 values. HIV surveillance data reported to the Centers for Disease Control and Prevention and the first CD4 value after diagnosis were used to estimate the distribution of delay from infection to diagnosis based on a well-characterized CD4 depletion model. This distribution was used to estimate HIV incidence, prevalence, and undiagnosed infections during 2010-2014. Estimated annual percentage changes (EAPCs) were calculated to assess trends. During 2010-2014, HIV incidence decreased 10.3% (EAPC = -3.1%) and the percentage of undiagnosed infection decreased from 17.1% to 15.0% (EAPC = -3.3%) in the United States; HIV prevalence increased 9.1% (EAPC = 2.2%). Among 36 jurisdictions with sufficient data to produce stable estimates, HIV incidence decreased in 3 jurisdictions (Georgia, New York, and District of Columbia) and the percentage of undiagnosed HIV infections decreased in 2 states (Texas and Georgia). HIV prevalence increased in 4 states (California, Florida, Georgia, and Texas). In 2014, southern states accounted for 50% of both new HIV infections and undiagnosed infections. HIV incidence and undiagnosed infection decreased in the United States during 2010-2014; however, outcomes varied by state and region. Progress in national HIV prevention is encouraging but intensified efforts for testing and treatment are needed in the South and states with high percentages of undiagnosed infection.
Liu, Xiao; Cui, Yazhou; Li, Yan; Wang, Chao; Zhao, Heng; Han, Jinxiang
Summary China lacks a registry for most rare diseases, so specific epidemiological data on those diseases are lacking. A strategy involving the DISMOD II model was recently formulated to estimate the epidemiological parameters of rare diseases, and this strategy has been used to study several rare diseases. The current study used this strategy to estimate the prevalence of one such rare disease, Wegener's granulomatosis (WG), in China based on its incidence, mortality, and rate of remission according to the software tool DISMOD II. The incidence of WG was calculated based on inpatient data from 100 hospitals throughout China. The cause-specific mortality from WG was estimated based on data from the National Vital Statistics System of the United States and adjusted for the Chinese population. The rate of disease remission was based on the results of previous study. The current results indicated that the prevalence of WG in China is 1.94/100,000, which is slightly lower than that in Europe and the United States. The mean age at onset of WG in China was calculated to be 38.9 years for males and 39.3 years for females and the duration of disease was 28 years for both male and female patients. These figures are similar to published data from other countries. In conclusion, the DISMOD II model was used to estimate the prevalence of WG in China, providing a basis to evaluate the potential disease burden and orphan drug use by patients with WG. The DISMOD II model could be used to estimate the prevalence of other rare diseases. PMID:26989646
Manzi, Giancarlo; Spiegelhalter, David J; Turner, Rebecca M; Flowers, Julian; Thompson, Simon G
SUMMARY: Combining information from multiple surveys can improve the quality of small area estimates. Customary approaches, such as the multiple-frame and statistical matching methods, require individual level data, whereas in practice often only multiple aggregate estimates are available. Commercial surveys usually produce such estimates without clear description of the methodology that is used. In this context, bias modelling is crucial, and we propose a series of Bayesian hierarchical models which allow for additive biases. Some of these models can also be fitted in a classical context, by using a mixed effects framework. We apply these methods to obtain estimates of smoking prevalence in local authorities across the east of England from seven surveys. All the surveys provide smoking prevalence estimates and confidence intervals at the local authority level, but they vary by time, sample size and transparency of methodology. Our models adjust for the biases in commercial surveys but incorporate information from all the sources to provide more accurate and precise estimates.
Vizcaya, M A; Romero, J L; Gamero, J J; Arufe, M I
The genetic polymorphism of group-specific component (GC) was analysed in a sample of 443 healthy unrelated subjects of both sexes resident in the province of Cádiz (Southern Spain). Isoelectric focusing was carried out in polyacrylamide gels followed by staining with coomassie blue R 250. The estimated gene frequencies were as follows: GC*1S = 0.6185; GC*1F = 0.1162; GC*2 = 0.2652.
Adeloye, Davies; Basquill, Catriona; Aderemi, Adewale V; Thompson, Jacqueline Y; Obi, Felix A
Hypertension is a leading cause of morbidity and mortality in Africa, and Nigeria, the most populous country in the continent, hugely contributes to this burden. To provide an improved estimate of the prevalence and number of cases of hypertension in Nigeria based on the cut-off 'at least 140/90 mmHg', towards ensuring better awareness, control and policy response in the country. We conducted a systematic search of Medline, EMBASE and Global Health from January 1980 to December 2013 for population-based studies providing estimates on the prevalence of hypertension in Nigeria. From the extracted crude prevalence rates, we conducted a random-effects meta-analysis, and further estimated the overall awareness rate of hypertension in Nigeria, expressed as percentage of all hypertension cases. We applied a meta-regression epidemiological modelling, using United Nations population demographics for the years 2010 and 2030, to determine the prevalence and number of cases of hypertension in Nigeria for the 2 years. Our search returned 2260 publications, 27 of which met our selection criteria. From the random-effects meta-analysis, we estimated an overall hypertension prevalence of 28.9% (25.1, 32.8), with a prevalence of 29.5% (24.8, 34.3) among men and 25.0% (20.2, 29.7) among women. We estimated a prevalence of 30.6% (24.5, 36.6) and 26.4% (19.4, 33.4) among urban and rural dwellers, respectively. The pooled awareness rate of hypertension was 17.4% (11.4, 23.3). The overall mean SBP was 128.6 (125.5, 130.8) mmHg, and the DBP was 80.6 (78.5, 82.7) mmHg. From our modelling, we estimated about 20.8 million cases of hypertension in Nigeria among people aged at least 20 years in 2010, with a prevalence of 28.0% (24.6, 31.9) in both sexes - 30.7% (24.9, 33.7) among men and 25.2% (22.7, 31.9) among women. By 2030, we projected an increase to 39.1 million cases of hypertension among people aged at least 20 years with a prevalence of 30.8% (24.5, 33.7) in both sexes - 32.6% (27
Background The nationwide dementia prevalence is usually calculated by applying the results of local surveys to countries’ populations. To evaluate the reliability of such estimations in developing countries, we chose Brazil as an example. We carried out a systematic review of dementia surveys, ascertained their risk of bias, and present the best estimate of occurrence of dementia in Brazil. Methods and Findings We carried out an electronic search of PubMed, Latin-American databases, and a Brazilian thesis database for surveys focusing on dementia prevalence in Brazil. The systematic review was registered at PROSPERO (CRD42014008815). Among the 35 studies found, 15 analyzed population-based random samples. However, most of them utilized inadequate criteria for diagnostics. Six studies without these limitations were further analyzed to assess the risk of selection, attrition, outcome and population bias as well as several statistical issues. All the studies presented moderate or high risk of bias in at least two domains due to the following features: high non-response, inaccurate cut-offs, and doubtful accuracy of the examiners. Two studies had limited external validity due to high rates of illiteracy or low income. The three studies with adequate generalizability and the lowest risk of bias presented a prevalence of dementia between 7.1% and 8.3% among subjects aged 65 years and older. However, after adjustment for accuracy of screening, the best available evidence points towards a figure between 15.2% and 16.3%. Conclusions The risk of bias may strongly limit the generalizability of dementia prevalence estimates in developing countries. Extrapolations that have already been made for Brazil and Latin America were based on a prevalence that should have been adjusted for screening accuracy or not used at all due to severe bias. Similar evaluations regarding other developing countries are needed in order to verify the scope of these limitations. PMID:26131563
Long, M W; Ward, Z J; Resch, S C; Cradock, A L; Wang, Y C; Giles, C M; Gortmaker, S L
State-specific obesity prevalence data are critical to public health efforts to address the childhood obesity epidemic. However, few states administer objectively measured body mass index (BMI) surveillance programs. This study reports state-specific childhood obesity prevalence by age and sex correcting for parent-reported child height and weight bias. As part of the Childhood Obesity Intervention Cost Effectiveness Study (CHOICES), we developed childhood obesity prevalence estimates for states for the period 2005-2010 using data from the 2010 US Census and American Community Survey (ACS), 2003-2004 and 2007-2008 National Survey of Children's Health (NSCH) (n=133 213), and 2005-2010 National Health and Nutrition Examination Surveys (NHANES) (n=9377; ages 2-17). Measured height and weight data from NHANES were used to correct parent-report bias in NSCH using a non-parametric statistical matching algorithm. Model estimates were validated against surveillance data from five states (AR, FL, MA, PA and TN) that conduct censuses of children across a range of grades. Parent-reported height and weight resulted in the largest overestimation of childhood obesity in males ages 2-5 years (NSCH: 42.36% vs NHANES: 11.44%). The CHOICES model estimates for this group (12.81%) and for all age and sex categories were not statistically different from NHANES. Our modeled obesity prevalence aligned closely with measured data from five validation states, with a 0.64 percentage point mean difference (range: 0.23-1.39) and a high correlation coefficient (r=0.96, P=0.009). Estimated state-specific childhood obesity prevalence ranged from 11.0 to 20.4%. Uncorrected estimates of childhood obesity prevalence from NSCH vary widely from measured national data, from a 278% overestimate among males aged 2-5 years to a 44% underestimate among females aged 14-17 years. This study demonstrates the validity of the CHOICES matching methods to correct the bias of parent-reported BMI data and
Erdes, Svetlana I.; Antishin, Anton S.
Celiac disease (CD) is an autoimmune enteropathy triggered by the ingestion of dietary gluten from some cereals mainly in individuals carrying the HLA-DQ2 and/or HLA-DQ8 haplotypes. As an autoimmune disease, CD is manifested in the small intestine in the form of a progressive and reversible inflammatory lesion due to immune response to self-antigens. Indeed, CD is one of the most challenging medicosocial problems in current gastroenterology. At present, the global CD prevalence is estimated at approximately 1% based on data sent from different locations and available CD screening strategies used. However, it is impossible to estimate global CD prevalence without all the data from the world, including Russia. In this review, we summarize the data on the incidence and prevalence of CD across geographically distinct regions of Russia, which are mostly present in local Russian scientific sources. Our conclusion is that the situation of CD prevalence in Russia is higher than is commonly believed and follows global tendencies that correspond to the epidemiologic situation in Europe, America, and Southwest Asia. PMID:28316996
Wisco, Blair E; Miller, Mark W; Wolf, Erika J; Kilpatrick, Dean; Resnick, Heidi S; Badour, Christal L; Marx, Brian P; Keane, Terence M; Rosen, Raymond C; Friedman, Matthew J
The World Health Organization's posttraumatic stress disorder (PTSD) work group has published a proposal for the forthcoming edition of the International Classification of Diseases (ICD-11) that would yield a very different diagnosis relative to DSM-5. This study examined the impact of the proposed ICD-11 changes on PTSD prevalence relative to the ICD-10 and DSM-5 definitions and also evaluated the extent to which these changes would accomplish the stated aim of reducing the comorbidity associated with PTSD. Diagnostic prevalence estimates were compared using a U.S. national community sample and two U.S. Department of Veterans Affairs clinical samples. The ICD-11 definition yielded prevalence estimates 10-30% lower than DSM-5 and 25% and 50% lower than ICD-10 with no reduction in the prevalence of common comorbidities. Findings suggest that by constraining the diagnosis to a narrower set of symptoms, the proposed ICD-11 criteria set would substantially reduce the number of individuals with the disorder. These findings raise doubt about the extent to which the ICD-11 proposal would achieve the aim of reducing comorbidity associated with PTSD and highlight the public health and policy implications of such a redefinition.
Many HIV prevalence surveys are plagued by the problem that a sizeable number of surveyed individuals do not consent to contribute blood samples for testing. One can ignore this problem, as is often done, but the resultant bias can be of sufficient magnitude to invalidate the results of the survey, especially if the number of non-responders is high and the reason for refusing to participate is related to the individual’s HIV status. One reason for refusing to participate may be for reasons of privacy. For those individuals, we suggest offering the option of being tested in a pool. This form of testing is less certain than individual testing, but, if it convinces more people to submit to testing, it should reduce the potential for bias and give a cleaner answer to the question of prevalence. This paper explores the logistics of implementing a combined individual and pooled testing approach and evaluates the analytical advantages to such a combined testing strategy. We quantify improvements in a prevalence estimator based on this combined testing strategy, relative to an individual testing only approach and a pooled testing only approach. Minimizing non-response is key for reducing bias, and, if pooled testing assuages privacy concerns, offering a pooled testing strategy has the potential to substantially improve HIV prevalence estimates. PMID:23446064
Savvateeva, Lyudmila V; Erdes, Svetlana I; Antishin, Anton S; Zamyatnin, Andrey A
Celiac disease (CD) is an autoimmune enteropathy triggered by the ingestion of dietary gluten from some cereals mainly in individuals carrying the HLA-DQ2 and/or HLA-DQ8 haplotypes. As an autoimmune disease, CD is manifested in the small intestine in the form of a progressive and reversible inflammatory lesion due to immune response to self-antigens. Indeed, CD is one of the most challenging medicosocial problems in current gastroenterology. At present, the global CD prevalence is estimated at approximately 1% based on data sent from different locations and available CD screening strategies used. However, it is impossible to estimate global CD prevalence without all the data from the world, including Russia. In this review, we summarize the data on the incidence and prevalence of CD across geographically distinct regions of Russia, which are mostly present in local Russian scientific sources. Our conclusion is that the situation of CD prevalence in Russia is higher than is commonly believed and follows global tendencies that correspond to the epidemiologic situation in Europe, America, and Southwest Asia.
Montiel-Nava, C; Peña, J A; López, M; Salas, M; Zurga, J R; Montiel-Barbero, I; Pirela, D; Cardozo, J J
This study reports the findings of research aimed at determining the rate of prevalence of attention deficit hyperactivity disorder (ADHD) in children of school age. The epidemiological study was conducted using a community sample extracted by means of multi stage stratified sampling according to socio economic level and schooling and consisted in 1,141 children of both sexes of school age from the city of Maracaibo. The revised Conners scales were used to collect data. The estimated prevalence of ADHD was 7.19% and we also obtained 0.35% for the hyperactive type, 1.14% for the disattentional subtype, and 5.70% for the combined type. Contrary to what was expected, prevalence was higher for females. It was found that 7.45% of the general sample scored higher on the academic problems scales, whereas for the sample identified as having ADHD, academic problems were 50% and the comorbidity between ADHD and academic problems was confirmed. The estimates for prevalence found in this study are consistent with those reported in the literature, which suggests that ADHD is a valid diagnosis for Marabino children.
Wisco, Blair E.; Miller, Mark W.; Wolf, Erika J.; Kilpatrick, Dean; Resnick, Heidi S.; Badour, Christal L.; Marx, Brian P.; Keane, Terence M.; Rosen, Raymond C.; Friedman, Matthew J.
The World Health Organization's posttraumatic stress disorder (PTSD) work group has published a proposal for the forthcoming edition of the International Classification of Diseases (ICD-11) that would yield a very different diagnosis relative to DSM-5. This study examined the impact of the proposed ICD-11 changes on PTSD prevalence relative to the ICD-10 and DSM-5 definitions and also evaluated the extent to which these changes would accomplish the stated aim of reducing the comorbidity associated with PTSD. Diagnostic prevalence estimates were compared using a U.S. national community sample and two U.S. Department of Veterans Affairs clinical samples. The ICD-11 definition yielded prevalence estimates 10 to 30 percent lower than DSM-5 and 25 and 50 percent lower than ICD-10 with no reduction in the prevalence of common comorbidities. Findings suggest that by constraining the diagnosis to a narrower set of symptoms, the proposed ICD-11 criteria set would substantially reduce the number of individuals with the disorder. These findings raise doubt about the extent to which the ICD-11 proposal would achieve the aim of reducing comorbidity associated with PTSD and highlight the public health and policy implications of such a redefinition. PMID:27124207
Finucane, Mariel M.; Rowley, Christopher F.; Paciorek, Christopher J.; Essex, Max; Pagano, Marcello
In many resource-poor countries, hiv-infected patients receive a standardized antiretroviral (art) cocktail. In these settings, population-level surveillance of drug resistance is needed to characterize the prevalence of resistance mutations and to enable art programs to select the optimal regimen for their local population. The surveillance strategy currently recommended by the World Health Organization is prohibitively expensive in some settings and may not provide a sufficiently precise rendering of the emergence of drug resistance. By using a novel assay on pooled sera samples, we decrease surveillance costs while simultaneously increasing the accuracy of drug resistance prevalence estimates for an important mutation that impacts first-line antiretroviral therapy. We present a Bayesian model for pooled-testing data that garners more information from each resistance assay conducted, compared with individual testing. We expand on previous pooling methods to account for uncertainty about the population distribution of within-subject resistance levels. In addition, our model accounts for measurement error of the resistance assay, and this added uncertainty naturally propagates through the Bayesian model to our inference on the prevalence parameter. We conduct a simulation study that informs our pool size recommendations and that shows that this model renders the prevalence parameter identifiable in instances when an existing non-model-based estimator fails. PMID:23376965
Finucane, Mariel M; Rowley, Christopher F; Paciorek, Christopher J; Essex, Max; Pagano, Marcello
In many resource-poor countries, hiv-infected patients receive a standardized antiretroviral cocktail. In these settings, population-level surveillance of drug resistance is needed to characterize the prevalence of resistance mutations and to enable antiretroviral therapy programs to select the optimal regimen for their local population. The surveillance strategy currently recommended by the World Health Organization is prohibitively expensive in some settings and may not provide a sufficiently precise rendering of the emergence of drug resistance. By using a novel assay on pooled sera samples, we decrease surveillance costs while simultaneously increasing the accuracy of drug resistance prevalence estimates for an important mutation that impacts first-line antiretroviral therapy. We present a Bayesian model for pooled-testing data that garners more information from each resistance assay conducted, compared with individual testing. We expand on previous pooling methods to account for uncertainty about the population distribution of within-subject resistance levels. In addition, our model accounts for measurement error of the resistance assay, and this added uncertainty naturally propagates through the Bayesian model to our inference on the prevalence parameter. We conduct a simulation study that informs our pool size recommendations and that shows that this model renders the prevalence parameter identifiable in instances when an existing non-model-based estimator fails. © The Author(s) 2013.
Lee, Seo-Young; Chung, Soo-Eun; Kim, Dong Wook; Eun, So-Hee; Kang, Hoon Chul; Cho, Yong Won; Yi, Sang Do; Kim, Heung Dong
Background and Purpose Few of the epidemiologic studies of epilepsy have utilized well-validated nationwide databases. We estimated the nationwide prevalence of treated epilepsy based on a comprehensive medical payment database along with diagnostic validation. Methods We collected data on patients prescribed of antiepileptic drugs (AEDs) from the Health Insurance Review and Assessment service, which covers the entire population of Korea. To assess the diagnostic validity, a medical records survey was conducted involving 6,774 patients prescribed AEDs from 43 institutions based on regional clusters and referral levels across the country. The prevalence of treated epilepsy was estimated by projecting the diagnostic validity on the number of patients prescribed AEDs. Results The mean positive predictive value (PPV) for epilepsy was 0.810 for those prescribed AEDs with diagnostic codes that indicate epilepsy or seizure (Diagnosis-E), while it was 0.066 for those without Diagnosis-E. The PPV tended to decrease with age in both groups, with lower values seen in females. The prevalence was 3.84 per 1,000, and it was higher among males, children, and the elderly. Conclusions The prevalence of epilepsy in Korea was comparable to that in other East Asian countries. The diagnostic validity of administrative health data varies depending on the method of case ascertainment, age, and sex. The prescriptions of AEDs even without relevant diagnostic codes should be considered as a tracer for epilepsy. PMID:27273925
Jeong, Jin-Young; Lee, Jin Yong; Chung, Byung-Suk; Choi, Younghyun; Alley, Allison Baer; Kim, Hyun Joo
Abstract South Korea presently uses an arbitrary sampling method to monitor the prevalence of Clonorchis sinensis infection in the endemic areas of the country. However, the present method is not standardized and focuses primarily on individuals who reside nearest to the mainstream river. We propose a new sampling method that combines cluster sampling with proportionate quota sampling to ensure that the entire endemic area is accurately represented. We tested the new method in Okcheon-gun, South Korea, and determined that the C sinensis infection prevalence (8.9%) in 2013 was higher than that (6.9%) estimated in 2012 when the arbitrary method was used. Additionally, no difference was observed in the prevalence based on the distance from the riverside areas, including branches and creeks, between the areas <1 and >1 km away from the riversides. Therefore, health authorities should place equal emphasis on all regions within the endemic areas. Based on the findings, we recommend the following: the clonorchiasis prevalence rate must be measured using probability sampling, (clear guidelines on survey coverage should be provided to include the riverside areas and all areas nearby branch streams, and regional cohorts should be created for continuous monitoring of prevalence rates across the region. PMID:28353615
Health data may be collected across one spatial framework (e.g. health provider agencies), but contrasts in health over another spatial framework (neighbourhoods) may be of policy interest. In the UK, population prevalence totals for chronic diseases are provided for populations served by general practitioner practices, but not for neighbourhoods (small areas of circa 1500 people), raising the question whether data for one framework can be used to provide spatially interpolated estimates of disease prevalence for the other. A discrete process convolution is applied to this end and has advantages when there are a relatively large number of area units in one or other framework. Additionally, the interpolation is modified to take account of the observed neighbourhood indicators (e.g. hospitalisation rates) of neighbourhood disease prevalence. These are reflective indicators of neighbourhood prevalence viewed as a latent construct. An illustrative application is to prevalence of psychosis in northeast London, containing 190 general practitioner practices and 562 neighbourhoods, including an assessment of sensitivity to kernel choice (e.g. normal vs exponential). This application illustrates how a zero-inflated Poisson can be used as the likelihood model for a reflective indicator.
Arsenault, Joanne E.; Smith, Matthew R.
Understanding dietary patterns is vital to reducing the number of people experiencing hunger (about 795 million), micronutrient deficiencies (2 billion), and overweight or obesity (2.1 billion). We characterize global trends in dietary quality by estimating micronutrient density of the food supply, prevalence of inadequate intake of 14 micronutrients, and average prevalence of inadequate intake of these micronutrients for all countries between 1961 and 2011. Over this 50-year period, the estimated prevalence of inadequate intakes of micronutrients has declined in all regions due to increased total production of food and/or micronutrient density. This decline has been particularly strong in East and Southeast Asia and weaker in South Asia and sub-Saharan Africa. Sub-Saharan Africa is the only region where dietary micronutrient density has declined over this 50-year period. At the global level, micronutrients with the lowest levels of adequate estimated intake are calcium, iron, vitamin A, and zinc, but there are strong differences between countries and regions. Fortification has reduced the estimated prevalence of inadequate micronutrient intakes in all low-income regions, except South Asia. The food supply in many countries is still far below energy requirements, which suggests a need to increase the availability and accessibility of nutritious foods. Countries where the food energy supply is adequate show a very large variation in dietary quality, and in many of these countries people would benefit from more diverse diets with a greater proportion of micronutrient-dense foods. Dietary quality can be improved through fortification, biofortification, and agricultural diversification, as well as efforts to improve access to and use of micronutrient-dense foods and nutritional knowledge. Reducing poverty and increasing education, especially of women, are integral to sustainably addressing malnutrition. PMID:28399168
Objective: There is evidence of substantial subnational variation in the HIV epidemic. However, robust spatial HIV data are often only available at high levels of geographic aggregation and not at the finer resolution needed for decision making. Therefore, spatial analysis methods that leverage available data to provide local estimates of HIV prevalence may be useful. Such methods exist but have not been formally compared when applied to HIV. Design/methods: Six candidate methods – including those used by the Joint United Nations Programme on HIV/AIDS to generate maps and a Bayesian geostatistical approach applied to other diseases – were used to generate maps and subnational estimates of HIV prevalence across three countries using cluster level data from household surveys. Two approaches were used to assess the accuracy of predictions: internal validation, whereby a proportion of input data is held back (test dataset) to challenge predictions; and comparison with location-specific data from household surveys in earlier years. Results: Each of the methods can generate usefully accurate predictions of prevalence at unsampled locations, with the magnitude of the error in predictions similar across approaches. However, the Bayesian geostatistical approach consistently gave marginally the strongest statistical performance across countries and validation procedures. Conclusions: Available methods may be able to furnish estimates of HIV prevalence at finer spatial scales than the data currently allow. The subnational variation revealed can be integrated into planning to ensure responsiveness to the spatial features of the epidemic. The Bayesian geostatistical approach is a promising strategy for integrating HIV data to generate robust local estimates. PMID:26919737
Beal, Ty; Massiot, Eric; Arsenault, Joanne E; Smith, Matthew R; Hijmans, Robert J
Understanding dietary patterns is vital to reducing the number of people experiencing hunger (about 795 million), micronutrient deficiencies (2 billion), and overweight or obesity (2.1 billion). We characterize global trends in dietary quality by estimating micronutrient density of the food supply, prevalence of inadequate intake of 14 micronutrients, and average prevalence of inadequate intake of these micronutrients for all countries between 1961 and 2011. Over this 50-year period, the estimated prevalence of inadequate intakes of micronutrients has declined in all regions due to increased total production of food and/or micronutrient density. This decline has been particularly strong in East and Southeast Asia and weaker in South Asia and sub-Saharan Africa. Sub-Saharan Africa is the only region where dietary micronutrient density has declined over this 50-year period. At the global level, micronutrients with the lowest levels of adequate estimated intake are calcium, iron, vitamin A, and zinc, but there are strong differences between countries and regions. Fortification has reduced the estimated prevalence of inadequate micronutrient intakes in all low-income regions, except South Asia. The food supply in many countries is still far below energy requirements, which suggests a need to increase the availability and accessibility of nutritious foods. Countries where the food energy supply is adequate show a very large variation in dietary quality, and in many of these countries people would benefit from more diverse diets with a greater proportion of micronutrient-dense foods. Dietary quality can be improved through fortification, biofortification, and agricultural diversification, as well as efforts to improve access to and use of micronutrient-dense foods and nutritional knowledge. Reducing poverty and increasing education, especially of women, are integral to sustainably addressing malnutrition.
Sørensen, L L; Wachmann, H; Alban, L
since 2001. The estimated conversion factor and accept of pooling samples do not necessarily apply to a population with a higher prevalence or to other types of samples (e.g. faeces or lymph nodes) or diagnostic procedures.
Ringeisen, Heather; Aldworth, Jeremy; Colpe, Lisa J; Pringle, Beverly; Simile, Catherine
This study investigates whether the six-item Strengths and Difficulties Questionnaire SDQ (five symptoms and one impact item) included in the National Health Interview Survey (NHIS) can be used to construct models that accurately estimate the prevalence of any impairing mental disorder among children 4-17 years old as measured by a shortened Child/Adolescent or Preschool Age Psychiatric Assessment (CAPA or PAPA). A subsample of 217 NHIS respondents completed a follow-up CAPA or PAPA interview. Logistic regression models were developed to model presence of any child mental disorder with impairment (MDI) or with severe impairment (MDSI). Models containing only the SDQ impact item exhibited highly biased prevalence estimates. The best-performing model included information from both the five symptom SDQ items and the impact item, where absolute bias was reduced and sensitivity and concordance were increased. This study illustrates the importance of using all available information from the six-item SDQ to accurately estimate the prevalence of any impairing childhood mental disorder from the NHIS. Copyright © 2015 John Wiley & Sons, Ltd.
Maenner, Matthew J.; Rice, Catherine E.; Arneson, Carrie L.; Cunniff, Christopher; Schieve, Laura A.; Carpenter, Laura A.; Van Naarden Braun, Kim; Kirby, Russell S.; Bakian, Amanda V.; Durkin, Maureen S.
IMPORTANCE The DSM-5 contains revised diagnostic criteria for autism spectrum disorder (ASD) from the DSM-IV-TR. Potential impacts of the new criteria on ASD prevalence are unclear. OBJECTIVE To assess potential effects of the DSM-5 ASD criteria on ASD prevalence estimation by retrospectively applying the new criteria to population-based surveillance data collected for previous ASD prevalence estimation. DESIGN, SETTING, AND PARTICIPANTS Cross-sectional, population-based ASD surveillance based on clinician review of coded behaviors documented in children’s medical and educational evaluations from 14 geographically defined areas in the United States participating in the Autism and Developmental Disabilities Monitoring (ADDM) Network in 2006 and 2008. This study included 8-year-old children living in ADDM Network study areas in 2006 or 2008, including 644 883 children under surveillance, of whom 6577 met surveillance ASD case status based on the DSM-IV-TR. MAIN OUTCOMES AND MEASURES Proportion of children meeting ADDM Network ASD criteria based on the DSM-IV-TR who also met DSM-5 criteria; overall prevalence of ASD using DSM-5 criteria. RESULTS Among the 6577 children classified by the ADDM Network as having ASD based on the DSM-IV-TR, 5339 (81.2%) met DSM-5 ASD criteria. This percentage was similar for boys and girls but higher for those with than without intellectual disability (86.6% and 72.5%, respectively; P < .001). A total of 304 children met DSM-5 ASD criteria but not current ADDM Network ASD case status. Based on these findings, ASD prevalence per 1000 for 2008 would have been 10.0 (95% CI, 9.6–10.3) using DSM-5 criteria compared with the reported prevalence based on DSM-IV-TR criteria of 11.3 (95% CI, 11.0–11.7). CONCLUSIONS AND RELEVANCE Autism spectrum disorder prevalence estimates will likely be lower under DSM-5 than under DSM-IV-TR diagnostic criteria, although this effect could be tempered by future adaptation of diagnostic practices and
Gao, W L; Lin, H; Liu, X N; Ren, X W; Li, J S; Shen, X P; Zhu, S L
To evaluate the estimation of prevalence ratio (PR) by using bayesian log-binomial regression model and its application, we estimated the PR of medical care-seeking prevalence to caregivers' recognition of risk signs of diarrhea in their infants by using bayesian log-binomial regression model in Openbugs software. The results showed that caregivers' recognition of infant' s risk signs of diarrhea was associated significantly with a 13% increase of medical care-seeking. Meanwhile, we compared the differences in PR's point estimation and its interval estimation of medical care-seeking prevalence to caregivers' recognition of risk signs of diarrhea and convergence of three models (model 1: not adjusting for the covariates; model 2: adjusting for duration of caregivers' education, model 3: adjusting for distance between village and township and child month-age based on model 2) between bayesian log-binomial regression model and conventional log-binomial regression model. The results showed that all three bayesian log-binomial regression models were convergence and the estimated PRs were 1.130(95%CI: 1.005-1.265), 1.128(95%CI: 1.001-1.264) and 1.132(95%CI: 1.004-1.267), respectively. Conventional log-binomial regression model 1 and model 2 were convergence and their PRs were 1.130(95% CI: 1.055-1.206) and 1.126(95% CI: 1.051-1.203), respectively, but the model 3 was misconvergence, so COPY method was used to estimate PR, which was 1.125 (95%CI: 1.051-1.200). In addition, the point estimation and interval estimation of PRs from three bayesian log-binomial regression models differed slightly from those of PRs from conventional log-binomial regression model, but they had a good consistency in estimating PR. Therefore, bayesian log-binomial regression model can effectively estimate PR with less misconvergence and have more advantages in application compared with conventional log-binomial regression model.
Estrada-Parra, Sergio; Zamora, Abel; Bojalil, L. F.
Estrada-Parra, Sergio (Escuela Nacional de Ciencias Biológicas, México, D.F., México), Abel Zamora, and L. F. Bojalil. Immunochemistry of the group-specific polysaccharide of Nocardia brasiliensis. J. Bacteriol. 90:571–574. 1965.—The group-specific polysaccharide of Nocardia brasiliensis was further purified, yielding an amorphous white material with the following characteristics: [α]D20 = + 48; nitrogen, 0.5%; phosphorus, 0.1%; and ash as sodium, 0.8%. The polymer is made of d-arabinose and d-galactose in a molar ratio of 3:1, and no other sugars were detected. Mild hydrolysis liberates mainly arabinose. The polysaccharide consumes 3.46 μmoles of periodate per mg of polymer in 15 days at 4 C (this value remains constant after 4 more days). Oxidation results in destruction of two of the arabinose, with the formation of two glycerols after borohydride reduction and hydrolysis. The polysaccharide oxidized by periodate and reduced under mild acid hydrolysis at 20 C yields glycerol and a polymer formed by galactose and arabinose (in a ratio of 1:1) which is resistant to a second oxidation. Therefore, the polysaccharide is probably formed by a main chain of glactose linked 1,3 and arabinose linked 1,2 or 1,3 or both, and nonreducing side chains of arabofuranose residues. The intact polysaccharide cross-reacts with sera from patients with active tuberculosis, and this, as well as the homologous reaction, is abolished by oxidation with periodate. PMID:16562050
van Hulzen, K J E; Nielen, M; Koets, A P; de Jong, G; van Arendonk, J A M; Heuven, H C M
Worldwide, classical control strategies based on hygiene and culling of infected animals have been implemented to eradicate Johne's disease. Breeding for disease resistance may be a useful additional tool to control the disease. The aim of this study was to estimate genetic parameters for the presence of a Mycobacterium avium ssp. paratuberculosis specific antibody response in milk of Dutch Holstein-Friesian cows using subsets of data based on within-herd test prevalence. The analyzed data set consisted of milk samples of 684,364 animals from 12,077 herds collected during the routine milk production scheme. Milk samples were tested for antibodies specific for Johne's disease by an ELISA test. Heritability estimates were calculated for 4 different subsets of data to determine the sensitivity of heritability for within-herd test prevalence. Results expressed as percentage of the sample to positive ratio were analyzed with a sire-maternal grandsire model with fixed effects for parity, year of birth, lactation stage, and herd; a covariate for milk yield at test day; and random effects for sire, maternal grandsire, and error. The estimated heritability ranged from 0.031 for the complete data set to 0.097 for herds with a test prevalence of at least 10%. Cross-validation was applied to determine which of the subsets of data produced the most accurate estimated breeding values. Results showed that for genetic selection to contribute to disease control, breeding values were estimated most accurately from herds with at least 2 animals that tested positive. In this subset the heritability was 0.041. Copyright Â© 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Adler, A J; Ronsmans, C; Calvert, C; Filippi, V
Obstetric fistula is a severe condition which has devastating consequences for a woman's life. The estimation of the burden of fistula at the population level has been impaired by the rarity of diagnosis and the lack of rigorous studies. This study was conducted to determine the prevalence and incidence of fistula in low and middle income countries. Six databases were searched, involving two separate searches: one on fistula specifically and one on broader maternal and reproductive morbidities. Studies including estimates of incidence and prevalence of fistula at the population level were included. We conducted meta-analyses of prevalence of fistula among women of reproductive age and the incidence of fistula among recently pregnant women. Nineteen studies were included in this review. The pooled prevalence in population-based studies was 0.29 (95% CI 0.00, 1.07) fistula per 1000 women of reproductive age in all regions. Separated by region we found 1.57 (95% CI 1.16, 2.06) in sub Saharan Africa and South Asia, 1.60 (95% CI 1.16, 2.10) per 1000 women of reproductive age in sub Saharan Africa and 1.20 (95% CI 0.10, 3.54) per 1000 in South Asia. The pooled incidence was 0.09 (95% CI 0.01, 0.25) per 1000 recently pregnant women. Our study is the most comprehensive study of the burden of fistula to date. Our findings suggest that the prevalence of fistula is lower than previously reported. The low burden of fistula should not detract from their public health importance, however, given the preventability of the condition, and the devastating consequences of fistula.
Background Obstetric fistula is a severe condition which has devastating consequences for a woman’s life. The estimation of the burden of fistula at the population level has been impaired by the rarity of diagnosis and the lack of rigorous studies. This study was conducted to determine the prevalence and incidence of fistula in low and middle income countries. Methods Six databases were searched, involving two separate searches: one on fistula specifically and one on broader maternal and reproductive morbidities. Studies including estimates of incidence and prevalence of fistula at the population level were included. We conducted meta-analyses of prevalence of fistula among women of reproductive age and the incidence of fistula among recently pregnant women. Results Nineteen studies were included in this review. The pooled prevalence in population-based studies was 0.29 (95% CI 0.00, 1.07) fistula per 1000 women of reproductive age in all regions. Separated by region we found 1.57 (95% CI 1.16, 2.06) in sub Saharan Africa and South Asia, 1.60 (95% CI 1.16, 2.10) per 1000 women of reproductive age in sub Saharan Africa and 1.20 (95% CI 0.10, 3.54) per 1000 in South Asia. The pooled incidence was 0.09 (95% CI 0.01, 0.25) per 1000 recently pregnant women. Conclusions Our study is the most comprehensive study of the burden of fistula to date. Our findings suggest that the prevalence of fistula is lower than previously reported. The low burden of fistula should not detract from their public health importance, however, given the preventability of the condition, and the devastating consequences of fistula. PMID:24373152
Adeloye, Davies; Basquill, Catriona; Papana, Angeliki; Chan, Kit Yee; Rudan, Igor; Campbell, Harry
Chronic obstructive pulmonary disease (COPD) is among the leading causes of death globally, accounting for about 3 million deaths worldwide in 2011. We aimed to estimate the prevalence of COPD in Africa in the year 2010 to provide the information that could assist health policy in the region. We conducted a systematic review of Medline, EMBASE and Global Health for studies on COPD published between 1990 and 2012. We included original population based studies providing estimates of the prevalence of COPD. We considered the reported estimates in terms of the mean age of the sample, sex ratio, the year of study and the country of the study as possible covariates. RESULTS from two different types of studies, i.e., based on spirometric and non-spirometric diagnosis of COPD, were further compared. The United Nation Population Division's population figures were used to estimate the number of COPD cases in the year 2010. Our search returned 243 studies, from which only 13 met our selection criteria and only five were based on spirometry. The difference in the median prevalence of COPD in persons aged 40 years or older based on spirometry data (13.4%; IQR: 9.4%-22.1%) and non-spirometry data (4.0%; IQR: 2.1%-8.9%) was statistically significant (p = 0.001). There was no significant effect of the gender or the year of the study on the reported prevalence of COPD in either set of studies. The prevalence of COPD increased with age in spirometry-based studies (p = 0.017), which is a plausible finding suggesting internal consistency of spirometry-based estimates, while this trend was not observed in studies using other case definitions. When applied to the appropriate age group (40 years or more), which accounted for 196.4 million people in Africa in 2010, the estimated prevalence translates into 26.3 million (18.5-43.4 million) cases of COPD. Comparable figures for the year 2000 based on the same prevalence rates would amount to 20.0 million (14.1-33.1), suggesting an increase
Novakovic, Daniel; Cheng, Alan T L; Baguley, Katherine; Walker, Paul; Harrison, Henley; Soma, Marlene; Malloy, Michael; Brotherton, Julia M L
To estimate the prevalence of juvenile onset recurrent respiratory papillomatosis (RRP) in Australia, describe its epidemiological profile, and assess the positive predictive value of International Classification of Disease, 10th revision (ICD-10) code D14.1 (benign neoplasm of larynx) in children for hospitalization due to RRP. Retrospective case series. Retrospective case review undertaken at the three tertiary pediatric hospitals in New South Wales (Australia's largest state), by reviewing medical records of patients aged 0 to 16 years admitted during 2000-2009 containing the ICD-10 Australian modification code D14.1 or other possible disease (D14.2-4, D14.3, D14.4) and RRP-related procedure codes. For RRP diagnoses, we recorded treatment dates, length of stay, extent of disease, and surgical and adjuvant treatments. The positive predictive value (PPV) of code D14.1 and median number of hospitalizations per year were applied to national hospital separations data from 2000/2001 to 2012/2013 to estimate disease prevalence. We identified 30 cases of RRP using code D14.1, which had a PPV of 98.1%, with no further cases identified using other codes. Fifty-seven percent of cases were female, median age of onset was 36 months, and median treatment duration was 36 months (mean = 40 months, range = 1-118). There was one patient death. Between 2000 and 2013, the estimated national prevalence rate was 0.81 per 100,000 aged < 15 years, peaking at age 5 to 9 years (1.1 per 100,000). RRP prevalence can be monitored after human papillomavirus vaccination programs using routine hospital data. 4 Laryngoscope, 126:2827-2832, 2016. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.
Morimoto, Juliana Masami; Marchioni, Dirce Maria Lobo; Cesar, Chester Luiz Galvão; Fisberg, Regina Mara
The objective of this study was to estimate the prevalence of inadequate micronutrient intake and excess sodium intake among adults age 19 years and older in the city of São Paulo, Brazil. Twenty-four-hour dietary recall and sociodemographic data were collected from each participant (n=1,663) in a cross-sectional study, Inquiry of Health of São Paulo, of a representative sample of the adult population of the city of São Paulo in 2003 (ISA-2003). The variability in intake was measured through two replications of the 24-hour recall in a subsample of this population in 2007 (ISA-2007). Usual intake was estimated by the PC-SIDE program (version 1.0, 2003, Department of Statistics, Iowa State University), which uses an approach developed by Iowa State University. The prevalence of nutrient inadequacy was calculated using the Estimated Average Requirement cut-point method for vitamins A and C, thiamin, riboflavin, niacin, copper, phosphorus, and selenium. For vitamin D, pantothenic acid, manganese, and sodium, the proportion of individuals with usual intake equal to or more than the Adequate Intake value was calculated. The percentage of individuals with intake equal to more than the Tolerable Upper Intake Level was calculated for sodium. The highest prevalence of inadequacy for males and females, respectively, occurred for vitamin A (67% and 58%), vitamin C (52% and 62%), thiamin (41% and 50%), and riboflavin (29% and 19%). The adjustment for the within-person variation presented lower prevalence of inadequacy due to removal of within-person variability. All adult residents of São Paulo had excess sodium intake, and the rates of nutrient inadequacy were high for certain key micronutrients.
Adler, Alma J; Fox, Samantha; Campbell, Oona M R; Kuper, Hannah
Obstetric fistula is a severe condition which can have devastating consequences for a woman's life. Despite a considerable literature, very little is known about its prevalence. This project was conducted to carry out a situational analysis of fistula services in South Sudan and to pilot test the Key Informant Method (KIM) to estimate the prevalence of fistula in a region of South Sudan. Key stakeholder interviews, document reviews and fistula surgery record reviews were undertaken. A KIM survey was conducted in a district of Western Bahr-el-Ghazal in January 2012. One hundred sixty-six community-based distributors, traditional birth attendants and village midwives were trained as key informants to identify women with fistula in the community. Women identified were subsequently examined by an obstetrician and nurse to verify whether they had a fistula. There were limited fistula repair services in South Sudan. Approximately 50-80 women per year attend periodic campaigns, with around half having a fistula and receiving a repair. On average a further 5 women a year received fistula repair from hospital services. Ten women with potential fistula were identified via KIM; all confirmed by the obstetrician. Of these, three were from the survey area, which had 8,865 women of reproductive age (15-49 years). This gives a minimal estimated prevalence of at least 30 fistulas per 100,000 women of reproductive age (95% CI 10-100). Routine fistula repair services available do not meet the population's needs. The pilot study suggests that KIM can be used to identify women with fistula in the community. Data on fistula are generally poor; the KIM methodology we used in South Sudan yielded a lower fistula prevalence than estimates reported previously in the region.
Background Obstetric fistula is a severe condition which can have devastating consequences for a woman’s life. Despite a considerable literature, very little is known about its prevalence. This project was conducted to carry out a situational analysis of fistula services in South Sudan and to pilot test the Key Informant Method (KIM) to estimate the prevalence of fistula in a region of South Sudan. Methods Key stakeholder interviews, document reviews and fistula surgery record reviews were undertaken. A KIM survey was conducted in a district of Western Bahr-el-Ghazal in January 2012. One hundred sixty-six community-based distributors, traditional birth attendants and village midwives were trained as key informants to identify women with fistula in the community. Women identified were subsequently examined by an obstetrician and nurse to verify whether they had a fistula. Results There were limited fistula repair services in South Sudan. Approximately 50–80 women per year attend periodic campaigns, with around half having a fistula and receiving a repair. On average a further 5 women a year received fistula repair from hospital services. Ten women with potential fistula were identified via KIM; all confirmed by the obstetrician. Of these, three were from the survey area, which had 8,865 women of reproductive age (15–49 years). This gives a minimal estimated prevalence of at least 30 fistulas per 100,000 women of reproductive age (95% CI 10–100). Conclusions Routine fistula repair services available do not meet the population’s needs. The pilot study suggests that KIM can be used to identify women with fistula in the community. Data on fistula are generally poor; the KIM methodology we used in South Sudan yielded a lower fistula prevalence than estimates reported previously in the region. PMID:23497241
Paul, Abigail; Adeloye, Davies; George-Carey, Rhiannon; Kolčić, Ivana; Grant, Liz; Chan, Kit Yee
Background Epilepsy is a leading serious neurological condition worldwide and has particularly significant physical, economic and social consequences in Sub–Saharan Africa. This paper aims to contribute to the understanding of epilepsy prevalence in this region and how this varies by age and sex so as to inform understanding of the disease characteristics as well as the development of infrastructure, services and policies. Methods A parallel systematic analysis of Medline, Embase and Global Health returned 32 studies that satisfied pre–defined quality criteria. Relevant data was extracted, tabulated and analyzed. We modelled the available information and used the UN population figures for Africa to determine the age–specific and overall burden of epilepsy. Results Active epilepsy was estimated to affect 4.4 million people in Sub–Saharan Africa, whilst lifetime epilepsy was estimated to affect 5.4 million. The prevalence of active epilepsy peaks in the 20–29 age group at 11.5/1000 and again in the 40–49 age group at 8.2/1000. The lowest prevalence value of 3.1/1000 is seen in the 60+ age group. This binomial pattern is also seen in both men and women, with the second peak more pronounced in women at 14.6/1000. Conclusion The high prevalence of epilepsy, especially in young adults, has important consequences for both the workforce and community structures. An estimation of disease burden would be a beneficial outcome of further research, as would research into appropriate methods of improving health care for and tackling discrimination against people with epilepsy. PMID:23289080
Cox, Andrew P; Tosas, Olga; Tilley, Aimee; Picozzi, Kim; Coleman, Paul; Hide, Geoff; Welburn, Susan C
In East Africa, animal trypanosomiasis is caused by many tsetse transmitted protozoan parasites including Trypanosoma vivax, T. congolense and subspecies of T. brucei s.l. (T. b. brucei and zoonotic human infective T. b. rhodesiense) that may co-circulate in domestic and wild animals. Accurate species-specific prevalence measurements of these parasites in animal populations are complicated by mixed infections of trypanosomes within individual hosts, low parasite densities and difficulties in conducting field studies. Many Polymerase Chain Reaction (PCR) based diagnostic tools are available to characterise and quantify infection in animals. These are important for assessing the contribution of infections in animal reservoirs and the risk posed to humans from zoonotic trypanosome species. New matrices for DNA capture have simplified large scale field PCR analyses but few studies have examined the impact of these techniques on prevalence estimations. The Whatman FTA matrix has been evaluated using a random sample of 35 village zebu cattle from a population naturally exposed to trypanosome infection. Using a generic trypanosome-specific PCR, prevalence was systematically evaluated. Multiple PCR samples taken from single FTA cards demonstrated that a single punch from an FTA card is not sufficient to confirm the infectivity status of an individual animal as parasite DNA is unevenly distributed across the card. At low parasite densities in the host, this stochastic sampling effect results in underestimation of prevalence based on single punch PCR testing. Repeated testing increased the estimated prevalence of all Trypanosoma spp. from 9.7% to 86%. Using repeat testing, a very high prevalence of pathogenic trypanosomes was detected in these local village cattle: T. brucei (34.3%), T. congolense (42.9%) and T. vivax (22.9%). These results show that, despite the convenience of Whatman FTA cards and specific PCR based detection tools, the chronically low parasitaemias in
Martín-Sánchez, J; Gállego, M; Barón, S; Castillejo, S; Morillas-Marquez, F
Prevalence studies of infection in the sandfly vector can be used as an indicator of a change in the intensity of Leishmania transmission. However, these studies are difficult to carry out as prevalence in the vector is usually low and its estimation requires a large number of sandflies to be dissected. Our objective was to establish whether a L. infantum-specific PCR-ELISA applied to pools of female sandflies and a previously described algorithm could be useful tools to study the prevalence of infection by this parasite in natural vector populations. We collected sandflies from six collection points in two stable foci of leishmaniasis in southern (N=3) and north-eastern (N=3) Spain, following standard procedures. A fraction of the collected females was dissected and morphologically identified. Another fraction was used for pool screening. In total, 127 pools of 30 females (3810 specimens) were studied by PCR-ELISA and 1764 specimens were individually dissected. The prevalence of infection determined by dissection does not differ from that determined by pool screen PCR. The results suggest that pool screen PCR can be of practical use in the epidemiological surveillance of leishmaniasis in European countries of the western Mediterranean basin, associated with control interventions or global change.
Mar, Javier; Sainz-Ezkerra, María; Moler-Cuiral, Jose Antonio
Neurological diseases now make up 6.3% of the global burden of disease mainly because they cause disability. To assess disability, prevalence estimates are needed. The objective of this study is to apply a method based on differential equations to calculate the prevalence of stroke-related disability. On the basis of a flow diagram, a set of differential equations for each age group was constructed. The linear system was solved analytically and numerically. The parameters of the system were obtained from the literature. The model was validated and calibrated by comparison with previous results. The stroke prevalence rate per 100,000 men was 828, and the rate for stroke-related disability was 331. The rates steadily rose with age, but the group between the ages of 65 and 74 years had the highest total number of individuals. Differential equations are useful to represent the natural history of neurological diseases and to make possible the calculation of the prevalence for the various states of disability. In our experience, when compared with the results obtained by Markov models, the benefit of the continuous use of time outweighs the mathematical requirements of our model. (c) 2008 S. Karger AG, Basel.
Azzato, E M; Greenberg, D; Shah, M; Blows, F; Driver, K E; Caporaso, N E; Pharoah, P D P
Observational epidemiological studies often include prevalent cases recruited at various times past diagnosis. This left truncation can be dealt with in non-parametric (Kaplan–Meier) and semi-parametric (Cox) time-to-event analyses, theoretically generating an unbiased hazard ratio (HR) when the proportional hazards (PH) assumption holds. However, concern remains that inclusion of prevalent cases in survival analysis results inevitably in HR bias. We used data on three well-established breast cancer prognosticators – clinical stage, histopathological grade and oestrogen receptor (ER) status – from the SEARCH study, a population-based study including 4470 invasive breast cancer cases (incident and prevalent), to evaluate empirically the effectiveness of allowing for left truncation in limiting HR bias. We found that HRs of prognostic factors changed over time and used extended Cox models incorporating time-dependent covariates. When comparing Cox models restricted to subjects ascertained within six months of diagnosis (incident cases) to models based on the full data set allowing for left truncation, we found no difference in parameter estimates (P=0.90, 0.32 and 0.95, for stage, grade and ER status respectively). Our results show that use of prevalent cases in an observational epidemiological study of breast cancer does not bias the HR in a left truncation Cox survival analysis, provided the PH assumption holds true. PMID:19401693
Mueller, Astrid; Mitchell, James E; Crosby, Ross D; Gefeller, Olaf; Faber, Ronald J; Martin, Alexandra; Bleich, Stefan; Glaesmer, Heide; Exner, Cornelia; de Zwaan, Martina
The aim of this study was to estimate the prevalence of compulsive buying and its association with sociodemographic characteristics and depressive symptoms in a nationally representative sample of the German population using the validated German version of the Compulsive Buying Scale (CBS; Faber and O'Guinn, 1992) in order to have a direct comparison with U.S. findings. The point prevalence of compulsive buying in the weighted representative sample (N=2,350) was estimated to be 6.9%. This was somewhat higher than the percentage in the American sample assessed in 2004 (5.8%). No significant difference was found between women and men (6.9% and 6.8%, respectively). Age was inversely related to the prevalence of compulsive buying. Individuals with compulsive buying reported more depressive symptoms assessed via the German version of the Brief Patient Health Questionnaire Mood Scale (PHQ-9). Further research on this topic is needed to establish a clearer delineation of when excessive buying is clinically significant and should be treated and how it could be prevented. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.
Guo, H R; Tanaka, S; Halperin, W E; Cameron, L L
OBJECTIVES: Back pain is the most common reason for filing workers' compensation claims and often causes lost workdays. Data from the 1988 National Health Interview Survey were analyzed to identify high-risk industries and to estimate the prevalence of work-related back pain and number of workdays lost. METHODS: Analyses included 30074 respondents who worked during the 12 months before the interview. A case patient was defined as a respondent who had back pain every day for a week or more during that period. RESULTS: The prevalence of lost-workday back pain was 4.6%, and individuals with work-related cases lost 101.8 million workdays owing to back pain. Male and female case patients lost about the same number of workdays. Industries in high-risk categories were also identified for future research and intervention, including those seldom studied. CONCLUSIONS: This study provides statistically reliable national estimates of the prevalence of back pain among workers and the enormous effect of this condition on American industry in terms of lost workdays. PMID:10394311
Fernández, O; Fernández, V; Guerrero, M; León, A; López-Madrona, J C; Alonso, A; Bustamante, R; Tamayo, J A; Romero, F; Bravo, M; Luque, G; García, L; Sanchís, G; San Roman, C; Romero, M; Papais-Alvarenga, M; de Ramon, E
Although not definitively proven, there is commonly accepted to be a latitudinal gradient in the distribution of multiple sclerosis (MS), which is more frequent in temperate zones. The European Mediterranean countries are situated in a zone of median frequency, although ever increasing figures have been noted in the last decades. The objective of this study was to assess the current prevalence rate of MS in the province of Malaga, Southern Spain. The capture-recapture method (CRM) uses independent sources of data and permits the number of non-registered cases of a given disease to be estimated, and by doing so, to avoid ascertainment bias. Use of this method showed the estimated prevalence rate of MS in the province of Malaga, Southern Spain, to be 125/10(5) (95% confidence interval: 102/10(5)-169/10(5)), higher than the figures published previously. Although we recognize that these data need to be confirmed in further studies and in other areas of the country using a similar method, we believe this study is the first to find such high figure of prevalence, being very similar to the figures reported in recent years in other southern European countries.
Holzer, Barbara M; Siebenhuener, Klarissa; Bopp, Matthias; Minder, Christoph E
In aging populations, multimorbidity causes a disease burden of growing importance and cost. However, estimates of the prevalence of multimorbidity (prevMM) vary widely across studies, impeding valid comparisons and interpretation of differences. With this study we pursued two research objectives: (1) to identify a set of study design and demographic factors related to prevMM, and (2) based on (1), to formulate design recommendations for future studies with improved comparability of prevalence estimates. Study data were obtained through systematic review of the literature. UsingPubMed/MEDLINE, Embase, CINAHL, Web of Science, BIOSIS, and Google Scholar, we looked for articles with the terms "multimorbidity," "comorbidity," "polymorbidity," and variations of these published in English or German in the years 1990 to 2011. We selected quantitative studies of the prevalence of multimorbidity (two or more chronic medical conditions) with a minimum sample size of 50 and a study population with a majority of Caucasians. Our database consisted of prevalence estimates in 108 age groups taken from 45 studies. To assess the effects of study design variables, we used meta regression models. In 58% of the studies, there was only one age group, i.e., no stratification by age. The number of persons per age group ranged from 136 to 5.6 million. Our analyses identified the following variables as highly significant: "mean age," "number of age groups", and "data reporting quality" (all p < 0.0001). "Setting," "disease classification," and "number of diseases in the classification" were significant (0.01 < p ≤ 0.03), and "data collection period" and "data source" were non-significant. A separate analysis showed that prevMM was significantly higher in women than men (sign test, p = 0.0015). Comparable prevalence estimates are urgently needed for realistic description of the magnitude of the problem of multimorbidity. Based on the results of our analyses of variables
Roberts, David L; St John, Freya A V
Misconduct in academic research is undoubtedly increasing, but studies estimating the prevalence of such behaviour suffer from biases inherent in researching sensitive topics. We compared the unmatched-count technique (UCT) and the crosswise-model (CM), two methods specifically designed to increase honest reporting to sensitive questions, with direct questioning (DQ) for five types of misconduct in the biological sciences. UCT performed better than CM and either outperformed or produced similar estimates to DQ depending on the question. Estimates of academic misconduct increased with decreasing seriousness of the behaviour, from c. 0% for data fabrication to >68% for inappropriate co-authorship. Results show that research into even minor issues of misconduct, is sensitive, suggesting that future studies should consider using specialised questioning techniques as they are more likely to yield accurate figures.
Busanello, Marcos; Rossi, Rodolfo S; Cassoli, Laerte D; Pantoja, José C F; Machado, Paulo F
The objectives of this study were to estimate the prevalence and incidence of subclinical mastitis (SM) in a large population of Brazilian dairy herds and to describe how these indices changed over time. A data set comprising individual cow somatic cell counts (SCC) from 18,316 test days (TD) of 1,809 herds that participated in a Dairy Herd Improvement Association (DHIA) program between January 2011 and May 2015 was available for analysis. Only tests that had ≥10 lactating cows and that were performed at 30 ± 10-d intervals were used for analysis. The final data set included 8,285 TD from 517 herds located in 5 regions of the country. Prevalence (%) of SM was defined as the number of cows with SCC ≥200,000 cells/mL divided by the total number of tested cows on a given TD. The incidence of SM was defined as the number of cows whose SCC increased from <200,000 to ≥200,000 cells/mL over 2 consecutive TD divided by the sum of each cow's days at risk during this interval, expressed as new cases per cow month at risk. Prevalence and incidence of SM were compared among years, regions, herd size categories, and frequency of DHIA testing during the study period. The overall mean prevalence and incidence of SM including all tests performed during the study period was 46.4% and 0.17 new cases per cow month at risk, respectively. The prevalence of SM varied little from 2011 to 2015, and an increasing trend was observed over the years. Prevalence was lower in herds that performed ≥60 DHIA tests during the study period than in those that performed fewer tests and was not different among regions or herd size categories. Incidence of SM varied little over the years and was not different among the regions studied. Prevalence and incidence of SM in the 517 herds studied were high and did not improve over the years. These trends were observed across all herd size categories and regions studied. Producers who had more DHIA tests performed per herd during the study period had
Lasarte-Velillas, J J; Hernández-Aguilar, M T; Martínez-Boyero, T; Soria-Cabeza, G; Soria-Ruiz, D; Bastarós-García, J C; Gil-Hernández, I; Pastor-Arilla, C; Lasarte-Sanz, I
To investigate the prevalence of overweight and obesity among our pediatric population and observe whether the use of different growth references for classification produce significant differences. A total of 35824 boys and girls aged between 2 and 14 years were included. Body mass index (BMI) was used to calculate the prevalence of overweight-obesity by age and sex. Prevalence was obtained by using a set of national references (Hernández's standards) and the references of World Health Organization (WHO standards). Prevalences were compared for each age and sex subset, as well as with the percentage of patients who had an overweight-obesity diagnosis in the clinical record. The overall prevalence of overweight-obesity among children aged 2 to 14 years was 17.0% (95% CI; 16.1%-18.0%) according to the Hernández standards vs 30.8% (95% CI; 29.9%-31.7%) according to WHO standards (10.1% vs 12.2% obese, and 6.9% vs 18.6% overweight). It was significantly higher in boys, by both standards, due to the higher prevalence of obesity. By using the Hernández standards the prevalence was significantly lower than by using WHO standards for all ages and for both sexes. A low percentage of patients were found to have an obesity-overweight diagnosis in the clinical record (from 3% to 22% at the ages of 2 and 14 years, respectively). The prevalence of overweight-obesity in our population is high, especially among boys. Using Hernández standards leads to an under-estimation of the problem, especially because it detects less overweight patients, thus we recommend using the WHO standards in our daily practice. The low number of overweight-obesity diagnoses in the clinical records might reflect that there is little awareness of the problem by the professionals. Copyright © 2013 Asociación Española de Pediatría. Published by Elsevier España, S.L.U. All rights reserved.
Wessells, K. Ryan; Singh, Gitanjali M.; Brown, Kenneth H.
Background The prevalence of inadequate zinc intake in a population can be estimated by comparing the zinc content of the food supply with the population’s theoretical requirement for zinc. However, assumptions regarding the nutrient composition of foods, zinc requirements, and zinc absorption may affect prevalence estimates. These analyses were conducted to: (1) evaluate the effect of varying methodological assumptions on country-specific estimates of the prevalence of dietary zinc inadequacy and (2) generate a model considered to provide the best estimates. Methodology and Principal Findings National food balance data were obtained from the Food and Agriculture Organization of the United Nations. Zinc and phytate contents of these foods were estimated from three nutrient composition databases. Zinc absorption was predicted using a mathematical model (Miller equation). Theoretical mean daily per capita physiological and dietary requirements for zinc were calculated using recommendations from the Food and Nutrition Board of the Institute of Medicine and the International Zinc Nutrition Consultative Group. The estimated global prevalence of inadequate zinc intake varied between 12–66%, depending on which methodological assumptions were applied. However, country-specific rank order of the estimated prevalence of inadequate intake was conserved across all models (r = 0.57–0.99, P<0.01). A “best-estimate” model, comprised of zinc and phytate data from a composite nutrient database and IZiNCG physiological requirements for absorbed zinc, estimated the global prevalence of inadequate zinc intake to be 17.3%. Conclusions and Significance Given the multiple sources of uncertainty in this method, caution must be taken in the interpretation of the estimated prevalence figures. However, the results of all models indicate that inadequate zinc intake may be fairly common globally. Inferences regarding the relative likelihood of zinc deficiency as a public health
Membré, J M; Amézquita, A; Bassett, J; Giavedoni, P; Blackburn, C de W; Gorris, L G M
The survival of spore-forming bacteria is linked to the safety and stability of refrigerated processed foods of extended durability (REPFEDs). A probabilistic modeling approach was used to assess the prevalence and concentration of Bacillus cereus spores surviving heat treatment for a semiliquid chilled food product. This product received heat treatment to inactivate nonproteolytic Clostridium botulinum during manufacture and was designed to be kept at refrigerator temperature postmanufacture. As key inputs for the modeling, the assessment took into consideration the following factors: (i) contamination frequency (prevalence) and level (concentration) of both psychrotrophic and mesophilic strains of B. cereus, (ii) heat resistance of both types (expressed as decimal reduction times at 90 degrees C), and (iii) intrapouch variability of thermal kinetics during heat processing (expressed as the time spent at 90 degrees C). These three inputs were established as statistical distributions using expert opinion, literature data, and specific modeling, respectively. They were analyzed in a probabilistic model in which the outputs, expressed as distributions as well, were the proportion of the contaminated pouches (the likely prevalence) and the number of spores in the contaminated pouches (the likely concentration). The prevalence after thermal processing was estimated to be 11 and 49% for psychrotrophic and mesophilic strains, respectively. In the positive pouches, the bacterial concentration (considering psychrotrophic and mesophilic strains combined) was estimated to be 30 CFU/g (95th percentile). Such a probabilistic approach seems promising to help in (i) optimizing heat processes, (ii) identifying which key factor(s) to control, and (iii) providing information for subsequent assessment of B. cereus resuscitation and growth.
Knodel, J; Lewis, G
Data collected in contraceptive prevalence surveys for Korea, Sri Lanka, Thailand, Barbados, Colombia, Costa Rica, and Peru on how soon following childbirth menstruation returned provide the basis for national level estimates of the duration of postpartum amenorrhea. 2 somewhat different techniques are used for estimating median and mean durations of postpartum amenorrhea. The results are compared with information indicating patterns of breastfeeding. The analysis indicates considerable cross-national variation in the mean and median duration of postpartum amenorrhea and suggests that estimating postpartum amenorrhea from information on breastfeeding alone could be misleading. What is most striking about the results is how quickly postpartum amenorrhea appears to terminate in most of the countries. Only for Korean women is the median duration substantially above 1/2 a year. The results suggest that at least for most of the limited number of developing countries for which Westinghouse Contraceptive Prevalence Survey data are available, postpartum nonsusceptibility is providing protection against a new pregnancy for only a relatively short period following a birth for the majority of women. In all the countries with available data except Costa Rica, breastfeeding is close to universal, involving at least 90% of all children; in Costa Rica, only about 3/4 of children are ever breastfed. The average duration of breastfeeding is noticeably longer in the 3 Asian countries than in the Latin American ones.
Hoover, Melanie; Rotermann, Michelle; Sanmartin, Claudia; Bernier, Julie
This study validates cut-points for a frailty index (FI) to identify seniors at risk of a hospital-related event and estimates the number of frail seniors living in the community. The FI developed by Rockwood and Mitnitski defines levels of frailty based on scores of 0 to 1.0. The cut-point validation was conducted using Stratum-Specific Likelihood Ratios applied to combined 2003 and 2005 Canadian Community Health Survey (CCHS) data, linked to hospital records from the Discharge Abstract Database (2002 to 2007). Based on the validated cut-points, frailty prevalence was estimated using 2009/2010 CCHS data. Seniors scoring more than 0.21 on the FI were considered to be at elevated risk of hospital-related events. Four additional frailty levels were identified: non-frail (0 to ≤0.1), pre-frail (>0.1 to ≤0.21), more frail (>0.30 to ≤0.35) (women only), and most frail (frail-group subset) (0.45 or more). The number of community-dwelling seniors considered to be frail was estimated at about 1 million (24%) in 2009/2010; another 1.4 million (32%) could be considered pre-frail. Frailty prevalence rose with age; was higher among women than among men; and varied by geographic location. A cut-point of more than 0.21 can be used to identify frail seniors living in the community.
Armour, Brian S; Courtney-Long, Elizabeth; Campbell, Vincent A; Wethington, Holly R
Obesity is associated with adverse health outcomes in people with and without disabilities; however, little is known about disability prevalence among people who are obese. The purpose of this study was to determine the prevalence and type of disability among obese adults in the United States. We analyzed pooled data from sample adult modules of the 2003-2009 National Health Interview Survey (NHIS) to obtain national prevalence estimates of disability, disability type, and obesity by using 30 questions that screened for activity limitations, vision and hearing impairment, and cognitive, movement, and emotional difficulties. We stratified disability prevalence by category of body mass index (BMI, measured as kg/m(2)): underweight, less than 18.5; normal weight, 18.5 to 24.9; overweight, 25.0 to 29.9; and obese, 30.0 or higher. Among the 25.3% of adult men and 24.6% of women in our pooled sample who were obese, 35.2% and 46.9%, respectively, reported a disability. In contrast, 26.7% of men and 26.8% women of normal weight reported a disability. Disability was much higher among obese women than among obese men (46.9% vs 35.2%, P < .001). Movement difficulties were the most common disabilities among obese men and women, affecting 25.3% of men and 37.9% of women. This research contributes to the literature on obesity by including disability as a demographic in characterizing people by body mass index. Because of the high prevalence of disability among those who are obese, public health programs should consider the needs of those with disabilities when designing obesity prevention and treatment programs.
Courtney-Long, Elizabeth; Campbell, Vincent A.; Wethington, Holly R.
Introduction Obesity is associated with adverse health outcomes in people with and without disabilities; however, little is known about disability prevalence among people who are obese. The purpose of this study was to determine the prevalence and type of disability among obese adults in the United States. Methods We analyzed pooled data from sample adult modules of the 2003–2009 National Health Interview Survey (NHIS) to obtain national prevalence estimates of disability, disability type, and obesity by using 30 questions that screened for activity limitations, vision and hearing impairment, and cognitive, movement, and emotional difficulties. We stratified disability prevalence by category of body mass index (BMI, measured as kg/m2): underweight, less than 18.5; normal weight, 18.5 to 24.9; overweight, 25.0 to 29.9; and obese, 30.0 or higher. Results Among the 25.3% of adult men and 24.6% of women in our pooled sample who were obese, 35.2% and 46.9%, respectively, reported a disability. In contrast, 26.7% of men and 26.8% women of normal weight reported a disability. Disability was much higher among obese women than among obese men (46.9% vs 35.2%, P < .001). Movement difficulties were the most common disabilities among obese men and women, affecting 25.3% of men and 37.9% of women. Conclusion This research contributes to the literature on obesity by including disability as a demographic in characterizing people by body mass index. Because of the high prevalence of disability among those who are obese, public health programs should consider the needs of those with disabilities when designing obesity prevention and treatment programs. PMID:23270667
Lek, Dysoley; Popovici, Jean; Ariey, Frederic; Vinjamuri, Seshu Babu; Meek, Sylvia; Bruce, Jan; Taylor, Walter R J; Socheat, Duong; Menard, Didier; Rogers, William O
Accurate information regarding malaria prevalence at national level is required to design and assess malaria control/elimination efforts. Although many comparisons of microscopy and polymerase chain reaction (PCR)-based methods have been conducted, there is little published literature covering such comparisons in southeast Asia especially at the national level. Both microscopic examination and PCR detection were performed on blood films and dried blood spots samples collected from 8,067 individuals enrolled in a nationwide, stratified, multistage, cluster sampling malaria prevalence survey conducted in Cambodia in 2007. The overall malaria prevalence and prevalence rates of Plasmodium falciparum, Plasmodium vivax, and Plasmodium malariae infections estimated by microscopy (N = 8,067) were 2.74% (95% confidence interval [CI]: 2.39-3.12%), 1.81% (95% CI: 1.53-2.13%), 1.14% (95% CI: 0.92-1.40%), and 0.01% (95% CI: 0.003-0.07%), respectively. The overall malaria prevalence based on PCR detection (N = 7,718) was almost 2.5-fold higher (6.31%, 95% CI: 5.76-6.89%, P < 0.00001). This difference was significantly more pronounced for P. falciparum (4.40%, 95% CI: 3.95-4.90%, P < 0.00001) compared with P. vivax (1.89%, 95% CI: 1.60-2.22%, P < 0.001) and P. malariae infections (0.22%, 95% CI: 0.13-0.35%, P < 0.0001). The significant proportion of microscopy-negative but PCR-positive individuals (289/7,491, 3.85%) suggest microscopic examination frequently underestimated malaria infections and that active case detection based on microscopy may miss a significant reservoir of infection, especially in low-transmission settings.
Brook, M O; Bottomley, M J; Mevada, C; Svistunova, A; Bielinska, A-M; James, T; Kalachik, A; Harden, P N
Investigations into chronic kidney disease (CKD) and cardiovascular disease in the CKD population may be misleading as they are often based on a single test of kidney function. To determine whether repeat testing at 3 months to confirm a diagnosis of CKD impacts on the estimated prevalence of CKD and the estimated 10-year general cardiovascular risk of the CKD population. Blood and urine samples from presumed healthy volunteers were analysed for evidence of CKD on recruitment and again 3 months later. Estimated 10-year cardiovascular risk was calculated using criteria determined by the Framingham study. Preliminary study: 512 volunteers were screened for CKD. Of the initial results, 206 indicated CKD or eGFR within one standard deviation of abnormal, and 142 (69%) of these were retested. Validation study: 528 volunteers were recruited and invited to return for repeat testing. A total of 214 (40.5%) participants provided repeat samples. A single test indicating CKD had a positive predictive value of 0.5 (preliminary) and 0.39 (validation) for repeat abnormalities 3 months later. Participants with CKD confirmed on repeat testing had a significant increase in estimated 10-year cardiovascular risk over the population as a whole (preliminary: 16.5 vs. 11.9%, P < 0.05; validation: 18.1 vs. 9.2%, P < 0.01). Participants with a solitary test indicating CKD had no elevation in cardiovascular risk. Repeat testing for CKD after 3 months significantly reduces the estimated prevalence of disease and identifies a population with true CKD and a cardiovascular risk significantly in excess of the general population.
Barros, Aluisio J D; Boerma, Ties; Hosseinpoor, Ahmad R; Restrepo-Méndez, María C; Wong, Kerry L M; Victora, Cesar G
Contraception is one of the most important health interventions currently available and yet, many women and couples still do not have reliable access to modern contraceptives. The best indicator for monitoring family planning is the proportion of women using contraception among those who need it. This indicator is frequently called demand for family planning satisfied and we argue that it should be called family planning coverage (FPC). This indicator is complex to calculate and requires a considerable number of questions to be included in a household survey. We propose a model that can predict FPC from a much simpler indicator - contraceptive use prevalence - for situations where it cannot be derived directly. Using 197 Multiple Indicator Cluster Surveys and Demographic and Health Surveys from 82 countries, we explored least-squares regression models that could be used to predict FPC. Non-linearity was expected in this situation and we used a fractional polynomial approach to find the best fitting model. We also explored the effect of calendar time and of wealth on the models explored. Given the high correlation between the variables involved in FPC, we managed to derive a relatively simple model that depends only on contraceptive use prevalence but explains 95% of the variability of the outcome, with high precision for the estimated regression line. We also show that the relationship between the two variables has not changed with time. A concordance analysis showed agreement between observed and fitted results within a range of ±9 percentage points. We show that it is possible to obtain fairly good estimates of FPC using only contraceptive prevalence as a predictor, a strategy that is useful in situations where it is not possible to estimate FPC directly.
Brooker, S.; Donnelly, C. A.; Guyatt, H. L.
INTRODUCTION: The prevalence of infection with helminths is markedly dependent on age, yet estimates of the total number of infections are typically based on data only from school-aged children. Such estimates, although useful for advocacy, provide inadequate information for planning control programmes and for quantifying the burden of disease. Using readily available data on the prevalence of infection in schoolchildren, the relation between the prevalence of infection in school-aged children and prevalence in the wider community can be adequately described using species-specific models. This paper explores the reliability of this approach to predict the prevalence infection in the community and provides a model for estimating the total number of people infected in the Republic of Cameroon. METHODS: Using data on the prevalence of helminthic infection in school-aged children in Cameroon, the prevalence of infection in pre-school children and adults was estimated from species-specific linear and logistic regression models developed previously. The model predictions were then used to estimate the number of people infected in each district in each age group in Cameroon. RESULTS: For Cameroon, if only the prevalence of infection in schoolchildren is used, the number of people infected with each helminthic species will be overestimated by up to 32% when compared with the estimates provided by the species-specific models. The calculation of confidence intervals supports the statistical reliability of the model since a narrow range of parameter estimates is evident. Furthermore, this work suggests that estimation of national prevalence of infection and the number infected will be enhanced if data are stratified by age; this model represents a useful planning tool for obtaining more accurate estimates. Estimates based on data aggregated from three geographical levels (district, regional, and national) show that summarizing prevalence data at the national level will result
Pence, Brian Wells; Miller, William C.; Gaynes, Bradley N.
Prevalence and validation studies rely on imperfect reference standard (RS) diagnostic instruments that can bias prevalence and test characteristic estimates. The authors illustrate 2 methods to account for RS misclassification. Latent class analysis (LCA) combines information from multiple imperfect measures of an unmeasurable latent condition to…
Pence, Brian Wells; Miller, William C.; Gaynes, Bradley N.
Prevalence and validation studies rely on imperfect reference standard (RS) diagnostic instruments that can bias prevalence and test characteristic estimates. The authors illustrate 2 methods to account for RS misclassification. Latent class analysis (LCA) combines information from multiple imperfect measures of an unmeasurable latent condition to…
Nielsen, T D; Nielsen, L R; Toft, N
Specialised veal producers that purchase and raise calves from several dairy herds are potentially at high risk of delivering Salmonella-infected animals to slaughter. However, the true prevalence of Salmonella infected veal producing herds and the prevalence of infected calves delivered to slaughter from infected herds are unknown in Denmark. Due to uncertainties about test sensitivity and specificity, these prevalences are not straightforward to assess. The objective of this study was to estimate the within-herd- and between-herd prevalence of Salmonella in veal calves delivered for slaughter to abattoirs in Denmark. Furthermore, it was investigated to which extent the estimates differed between a setup using both serological tests and faecal culture, compared to just serological tests, and whether the applied sampling scheme in the national surveillance programme in Denmark was sufficient to establish high posterior estimates of freedom from infection in individual herds. We used Bayesian analysis to avoid bias as a result of fixed test validity estimates. Serological test results from 753 animals and faecal culture from 1233 animals from 68 randomly selected Danish veal producing herds that delivered more than 100 calves to slaughter per year were used to estimate the prevalences and estimates of freedom from Salmonella. Serological test results of 7726 animals from 185 herds were used to compare the difference in prevalence estimates between serology alone vs. faecal culture combined with serology. We estimated that 34-57% of specialised veal producing herds were infected with Salmonella. Within the infected herds, 21-49% of the animals were infected. Few herds obtained high posterior estimates for the probability of freedom from infection given the collected data, with only six of 68 herds obtaining posterior probability of being infected less than 10%. Furthermore, this study indicated that serology is sufficiently sensitive and specific to be used for
Villa, Antonio R; Escobedo, Michelle H; Méndez-Sánchez, Nahum
The pandemy of obesity is affecting more than 300 millions of adults in the world. The trend is increasing. Diabetes, coronary hearth disease, hypertension, cerebrovascular disease and dyslipidemia are chronic diseases associated with obesity. The methodology of this paper is proposed as an alternative resource based in mortality data to quantify the magnitude of chronic diseases in developing countries. Deaths for Mexico registered in 2000, according to selected causes, were taken to derive indirectly the prevalence of obesity in years 2000, 2005, and 2010, both males and females > or = 35 years-old. In 2010, an estimation of 8 million of Mexican with obesity is made. This methodology is referred to be probed in the quantification and projection of chronic diseases. According with our estimation, we hope in Mexico at 2010 to have between 8 and 14 millions of people > or = 35 years-old with obesity.
Markin, V A
Estimation of the minimum human infective doses of HIV is essential to the prediction of its infection prevalence, including in bioterrorism. Information on the epidemiology and pathogenesis of HIV infection and on the biological properties of the pathogen may serve as reference data for the theoretical determination of a rough infective dose of HIV. The most common route of virus infection is parenteral transmission. The likelihood of HIV transmission through blood depends on the frequency of transfusions, the stage of HIV infection in a donor and the amount of blood given to a recipient. The author has analyzed the data available in the literature on the epidemiology and pathogenesis of the infection, on the properties of the pathogen, and on the risks of HIV infection in different groups and summarized information on the infection among injecting drug users, which could roughly estimate the level of sensitivity in man as a biological species to this virus.
Olotu, Ally; Fegan, Gregory; Wambua, Juliana; Nyangweso, George; Ogada, Edna; Drakeley, Chris; Marsh, Kevin; Bejon, Philip
Background Heterogeneity in malaria exposure complicates survival analyses of vaccine efficacy trials and confounds the association between immune correlates of protection and malaria infection in longitudinal studies. Analysis may be facilitated by taking into account the variability in individual exposure levels, but it is unclear how exposure can be estimated at an individual level. Method and Findings We studied three cohorts (Chonyi, Junju and Ngerenya) in Kilifi District, Kenya to assess measures of malaria exposure. Prospective data were available on malaria episodes, geospatial coordinates, proximity to infected and uninfected individuals and residence in predefined malaria hotspots for 2,425 individuals. Antibody levels to the malaria antigens AMA1 and MSP1142 were available for 291 children from Junju. We calculated distance-weighted local prevalence of malaria infection within 1 km radius as a marker of individual's malaria exposure. We used multivariable modified Poisson regression model to assess the discriminatory power of these markers for malaria infection (i.e. asymptomatic parasitaemia or clinical malaria). The area under the receiver operating characteristic (ROC) curve was used to assess the discriminatory power of the models. Local malaria prevalence within 1 km radius and AMA1 and MSP1142 antibodies levels were independently associated with malaria infection. Weighted local malaria prevalence had an area under ROC curve of 0.72 (95%CI: 0.66–0.73), 0.71 (95%CI: 0.69–0.73) and 0.82 (95%CI: 0.80–0.83) among cohorts in Chonyi, Junju and Ngerenya respectively. In a small subset of children from Junju, a model incorporating weighted local malaria prevalence with AMA1 and MSP1142 antibody levels provided an AUC of 0.83 (95%CI: 0.79–0.88). Conclusion We have proposed an approach to estimating the intensity of an individual's malaria exposure in the field. The weighted local malaria prevalence can be used as individual marker of malaria
Background Estimation of pre-immunisation prevalence of HPV and distribution of HPV types is fundamental to understanding the subsequent impact of HPV vaccination. We describe the type specific prevalence of HPV in females aged 20–21 in Scotland who attended or defaulted from cervical screening using three specimen types; from attenders liquid based cytology and from defaulters urine or self-taken swabs. Methods Residual liquid based cytology samples (n = 2148), collected from women aged 20–21 attending for their first smear were genotyped for HPV. A sample (n = 709) from women who had defaulted from screening was also made available for HPV testing through the use of postal testing kits (either urine samples (n = 378) or self-taken swabs (n = 331)). Estimates of prevalence weighted by deprivation, and for the postal testing kit, also by reminder status and specimen type were calculated for each HPV type. The distribution of HPV types were compared between specimen types and the occurrence of multiple high-risk infections examined. The influence of demographic factors on high-risk HPV positivity and multiple infections was examined via logistic regression. Results The prevalence of any HPV in young women aged 20–21 was 32.2% for urine, 39.5% for self-taken swab, and 49.4% for LBC specimens. Infection with vaccine specific types (HPV 16, 18) or those associated with cross-protection (HPV 31, 33, 45, 51) was common. Individuals were more likely to test positive for high-risk HPV if they resided in an area of high deprivation or in a rural area. The overall distribution of HPV types did not vary between defaulters and attenders. Multiple infections occurred in 48.1% of high-risk HPV positive individuals. Excluding vaccine types the most common pairing was HPV 56 and 66. Conclusions Understanding of the pre-immunisation prevalence of HPV in young women puts Scotland in a prime position to assess the early effect of vaccination as the first highly
Edlin, Brian R; Eckhardt, Benjamin J; Shu, Marla A; Holmberg, Scott D; Swan, Tracy
Data from the 2003-2010 National Health and Nutrition Examination Survey (NHANES) indicate that about 3.6 million people in the United States have antibodies to the hepatitis C virus, of whom 2.7 million are currently infected. NHANES, however, excludes several high-risk populations from its sampling frame, including people who are incarcerated, homeless, or hospitalized; nursing home residents; active-duty military personnel; and people living on Indian reservations. We undertook a systematic review of peer-reviewed literature and sought out unpublished presentations and data to estimate the prevalence of hepatitis C in these excluded populations and in turn improve the estimate of the number of people with hepatitis C in the United States. The available data do not support a precise result, but we estimated that 1.0 million (range 0.4 million-1.8 million) persons excluded from the NHANES sampling frame have hepatitis C virus antibody, including 500,000 incarcerated people, 220,000 homeless people, 120,000 people living on Indian reservations, and 75,000 people in hospitals. Most are men. An estimated 0.8 million (range 0.3 million-1.5 million) are currently infected. Several additional sources of underestimation, including nonresponse bias and the underrepresentation of other groups at increased risk of hepatitis C that are not excluded from the NHANES sampling frame, were not addressed in this study. The number of US residents who have been infected with hepatitis C is unknown but is probably at least 4.6 million (range 3.4 million-6.0 million), and of these, at least 3.5 million (range 2.5 million-4.7 million) are currently infected; additional sources of potential underestimation suggest that the true prevalence could well be higher. © 2015 by the American Association for the Study of Liver Diseases.
Cooper, Hannah L F; Brady, Joanne E; Friedman, Samuel R; Tempalski, Barbara; Gostnell, Karla; Flom, Peter L
No adequate data exist on patterns of injection drug use (IDU) prevalence over time within racial/ethnic groups in U.S. geographic areas. The absence of such prevalence data limits our understanding of the causes and consequences of IDU and hampers planning efforts for IDU-related interventions. Here, we (1) describe a method of estimating IDU prevalence among non-Hispanic Black and non-Hispanic White adult residents of 95 large U.S. metropolitan statistical areas (MSAs) annually over an 11-year period (1992--2002); (2) validate the resulting prevalence estimates; and (3) document temporal trends in these prevalence estimates. IDU prevalence estimates for Black adults were calculated in several steps: we (1) created estimates of the proportion of injectors who were Black in each MSA and year by analyzing databases documenting injectors' encounters with the healthcare system; (2) multiplied the resulting proportions by previously calculated estimates of the total number of injectors in each MSA and year (Brady et al., 2008); (3) divided the result by the number of Black adults living in each MSA each year; and (4) validated the resulting estimates by correlating them cross-sectionally with theoretically related constructs (Black- and White-specific prevalences of drug-related mortality and of mortality from hepatitis C). We used parallel methods to estimate and validate White IDU prevalence. We analyzed trends in the resulting racial/ethnic-specific IDU prevalence estimates using measures of central tendency and hierarchical linear models (HLM). Black IDU prevalence declined from a median of 279 injectors per 10,000 adults in 1992 to 156 injectors per 10,000 adults in 2002. IDU prevalence for White adults remained relatively flat over time (median values ranged between 86 and 97 injectors per 10,000 adults). HLM analyses described similar trends and suggest that declines in Black IDU prevalence decelerated over time. Both sets of IDU estimates correlated cross
Jenness, Samuel M; Neaigus, Alan; Wendel, Travis; Gelpi-Acosta, Camila; Hagan, Holly
Respondent-driven sampling (RDS) is a study design used to investigate populations for which a probabilistic sampling frame cannot be efficiently generated. Biases in parameter estimates may result from systematic non-random recruitment within social networks by geography. We investigate the spatial distribution of RDS recruits relative to an inferred social network among heterosexual adults in New York City in 2010. Mean distances between recruitment dyads are compared to those of network dyads to quantify bias. Spatial regression models are then used to assess the impact of spatial structure on risk and prevalence outcomes. In our primary distance metric, network dyads were an average of 1.34 (95 % CI 0.82–1.86) miles farther dispersed than recruitment dyads, suggesting spatial bias. However, there was no evidence that demographic associations with HIV risk or prevalence were spatially confounded. Therefore, while the spatial structure of recruitment may be biased in heterogeneous urban settings, the impact of this bias on estimates of outcome measures appears minimal.
Tomasallo, Carrie D.; Hanrahan, Lawrence P.; Tandias, Aman; Chang, Timothy S.; Cowan, Kelly J.
Objectives. We compared a statewide telephone health survey with electronic health record (EHR) data from a large Wisconsin health system to estimate asthma prevalence in Wisconsin. Methods. We developed frequency tables and logistic regression models using Wisconsin Behavioral Risk Factor Surveillance System and University of Wisconsin primary care clinic data. We compared adjusted odds ratios (AORs) from each model. Results. Between 2007 and 2009, the EHR database contained 376 000 patients (30 000 with asthma), and 23 000 (1850 with asthma) responded to the Behavioral Risk Factor Surveillance System telephone survey. AORs for asthma were similar in magnitude and direction for the majority of covariates, including gender, age, and race/ethnicity, between survey and EHR models. The EHR data had greater statistical power to detect associations than did survey data, especially in pediatric and ethnic populations, because of larger sample sizes. Conclusions. EHRs can be used to estimate asthma prevalence in Wisconsin adults and children. EHR data may improve public health chronic disease surveillance using high-quality data at the local level to better identify areas of disparity and risk factors and guide education and health care interventions. PMID:24228643
Berger, Anke; Bachmann, Nicole; Signorell, Andri; Erdin, Rebekka; Oelhafen, Stephan; Reich, Oliver; Cignacco, Eva
Perinatal mental disorders (PMDs) are the most common complication of pregnancy and the first postpartum year. Since PMD prevalence and use of mental-health services by perinatal women in Switzerland are unknown, we analysed existing health statistics. We used statistics from a large health insurance company, hospitals and freelance midwives. We assessed the annual rates of mental-healthcare use in perinatal women (n = 13 969). We ascertained the annual rates of PMD treatment in obstetric inpatients (n = 89 699), and annual rates of PMD records by freelance midwives (n = 57 951). In 15 104 women who gave birth in 2012 or 2013, we assessed use of mental healthcare before and during pregnancy, and in the postpartum year. For the same sample, we determined proportions of medication and consultation treatments. We used multiple regression analysis to estimate the influence of PMD on overall healthcare costs of mandatory health insurance. The annual rate of mental-healthcare use by perinatal women was 16.7%. The annual rate of PMD treatment in obstetric inpatients was 1.1%. The annual rate of PMD records in the midwifery care setting was 2.9%. Women with PMD use mental health services mainly in non-obstetric outpatient settings. Medication was the most frequent treatment. Primary care providers and mental health specialists contributed almost equally to consultation treatments. PMD during pregnancy raised overall costs of healthcare in the postpartum year by 1214 Swiss francs. Health-system research and perinatal healthcare should take into consideration the high prevalence of PMD. Real PMD prevalence may be even higher than our data suggest and could be assessed with a survey using our model of PMD prevalence.
Ohmura, Hirotoshi; Fukushima, Yoshifumi; Mizuno, Atsushi; Niwa, Koichiro; Kobayashi, Yohei; Ebina, Toshiaki; Kimura, Kazuo; Ishibashi, Shun; Daida, Hiroyuki
Heterozygous familial hypercholesterolemia (FH) represents a strong risk for development of premature coronary artery disease (CAD). However, the majority of patients with FH are undiagnosed and the prevalence likely represents an underestimate in most countries. In Japan, the possible contribution of FH to the development of CAD may be higher because of the low incidence of CAD among the general population. We estimated the prevalence of heterozygous FH by measuring Achilles tendon thickness (ATT) in patients with acute coronary syndrome (ACS).A total of 359 patients suffering from ACS were enrolled in this multicenter registration study. Heterozygous FH was defined according to the diagnostic criteria proposed by the Japan Atherosclerosis Society. After excluding 63 patients because of missing ATT data or plasma triglyceride levels that were 4.5 mmol/L or more, 296 patients were eligible for inclusion in the study. The number of patients with ATT of 9 mm or more was 53 (17.9%). They were significantly younger and had significantly higher LDL cholesterol levels than patients with an ATT less than 9 mm. The prevalence of heterozygous FH was 5.7% (1/17.5) and more prominent in younger patients who were less than 60 years old (7.8%). In patients with ATT of 9 mm or more, approximately 1 in 3.5 fulfilled the criteria for heterozygous FH.We demonstrated the usefulness of measuring ATT by radiography and the high prevalence of heterozygous FH in patients with ACS in Japan, especially in younger patients who were less than 60 years old.
Henderson, Joan; Miller, Graeme; Britt, Helena
Objectives To estimate the prevalence of common chronic conditions and multimorbidity among patients at GP encounters and among people in the Australian population. To assess the extent to which use of each individual patient’s GP attendance over the previous year, instead of the average for their age-sex group, affects the precision of national population prevalence estimates of diagnosed chronic conditions. Design, setting and participants A sub-study (between November 2012 and March 2016) of the Bettering the Evaluation and Care of Health program, a continuous national study of GP activity. Each of 1,449 GPs provided data for about 30 consecutive patients (total 43,501) indicating for each, number of GP attendances in previous year and all diagnosed chronic conditions, using their knowledge of the patient, patient self-report, and patient's health record. Results Hypertension (26.5%) was the most prevalent diagnosed chronic condition among patients surveyed, followed by osteoarthritis (22.7%), hyperlipidaemia (16.6%), depression (16.3%), anxiety (11.9%), gastroesophageal reflux disease (GORD) (11.3%), chronic back pain (9.7%) and Type 2 diabetes (9.6%). After adjustment, we estimated population prevalence of hypertension as 12.4%, 9.5% osteoarthritis, 8.2% hyperlipidaemia, 8.0% depression, 5.8% anxiety and 5.2% asthma. Estimates were significantly lower than those derived using the previous method. About half (51.6%) the patients at GP encounters had two or more diagnosed chronic conditions and over one third (37.4%) had three or more. Population estimates were: 25.7% had two or more diagnosed chronic conditions and 15.8% had three or more. Conclusions Of the three approaches we have tested to date, this study provides the most accurate method for estimation of population prevalence of chronic conditions using the GP as an expert interviewer, by adjusting for each patient’s reported attendance. PMID:28278241
Jawad, Issrah; Lukšić, Ivana; Rafnsson, Snorri Bjorn
Objective Sepsis is a complex and hard-to-define condition with many different interactions with other disorders. Presently, there are no estimates of the burden of sepsis and septicaemia at the global level and it was not included in the initial Global Burden of Disease study. Non-maternal sepsis has only recently received attention as a substantial global public health problem. The aim of this study was to assess available data on the burden of non-maternal sepsis, severe sepsis and septic shock in the community and to identify key gaps in information needed to estimate the global burden of sepsis. Methods Literature review of English language-based studies reporting on the incidence, prevalence, mortality or case-fatality of sepsis, severe sepsis and septic shock. The available literature was searched using the MEDLINE database of citations and abstracts of biomedical research articles published between 1980 and 2008. Findings 8 studies reported incidence of sepsis, severe sepsis or septic shock at the national level (4 from the USA and 1 from Brazil, the UK, Norway and Australia). No studies on the incidence, prevalence, mortality or case-fatality from sepsis in developing countries were found. The population sepsis incidence ranged from 22 to 240/100 000 (most plausible estimates ranged from 149 to 240/100 000); of severe sepsis from 13 to 300/100 000 (most of the estimates were between 56 and 91/100 000); and of septic shock 11/100 000. Case-fatality rate depends on the setting and severity of disease. It can reach up to 30% for sepsis, 50% for severe sepsis and 80% for septic shock. While the data were compiled using strict inclusion and exclusion criteria, a degree of uncertainty still exists regarding the reported estimates. Conclusion The few national-level reports available allow only a very crude estimation of the incidence of sepsis in developed countries while there is apparent lack of data from developing countries. A clear and universal
McGovern, Mark E.; Marra, Giampiero; Radice, Rosalba; Canning, David; Newell, Marie-Louise; Bärnighausen, Till
Introduction HIV testing is a cornerstone of efforts to combat the HIV epidemic, and testing conducted as part of surveillance provides invaluable data on the spread of infection and the effectiveness of campaigns to reduce the transmission of HIV. However, participation in HIV testing can be low, and if respondents systematically select not to be tested because they know or suspect they are HIV positive (and fear disclosure), standard approaches to deal with missing data will fail to remove selection bias. We implemented Heckman-type selection models, which can be used to adjust for missing data that are not missing at random, and established the extent of selection bias in a population-based HIV survey in an HIV hyperendemic community in rural South Africa. Methods We used data from a population-based HIV survey carried out in 2009 in rural KwaZulu-Natal, South Africa. In this survey, 5565 women (35%) and 2567 men (27%) provided blood for an HIV test. We accounted for missing data using interviewer identity as a selection variable which predicted consent to HIV testing but was unlikely to be independently associated with HIV status. Our approach involved using this selection variable to examine the HIV status of residents who would ordinarily refuse to test, except that they were allocated a persuasive interviewer. Our copula model allows for flexibility when modelling the dependence structure between HIV survey participation and HIV status. Results For women, our selection model generated an HIV prevalence estimate of 33% (95% CI 27–40) for all people eligible to consent to HIV testing in the survey. This estimate is higher than the estimate of 24% generated when only information from respondents who participated in testing is used in the analysis, and the estimate of 27% when imputation analysis is used to predict missing data on HIV status. For men, we found an HIV prevalence of 25% (95% CI 15–35) using the selection model, compared to 16% among those who
Benício, Maria Helena D'Aquino; Martins, Ana Paula Bortoletto; Venancio, Sonia Isoyama; Barros, Aluísio Jardim Dornellas de
To estimate the prevalence of malnutrition in children for all Brazilian municipalities. A multilevel logistic regression model was used to estimate the individual probability of malnutrition in 5,507 Brazilian municipalities in 2006, in terms of predictive factors grouped according to hierarchical levels. The response variable was child malnutrition (children aged from six to 59 months with height for age and sex below -2 z-scores, according to the World Health Organization standard). The predictive variables were determinants of malnutrition measured similarly by the National Demographics and Health Survey-2006 and the Sample from the 2000 Demographic Census. At level 1 (individual): sex and age, level 2 (household): socioeconomic variables, water and indoor plumbing, urban or rural area and level 3 (municipal): location of the municipality and coverage of the Family Health Strategy (FHS) in 2006. The study detected a statistically significant chance of malnutrition in male children, those living in households with two or more individuals per room, those belonging to the lowest quintiles of the socioeconomic score, those with three or more children under five in the household, those with no access to running water or located in the North. There was a negative dose-response association between FHS coverage and the chance of malnutrition (p = 0.007). FHS coverage in the municipality equal to or greater than 70% showed a 45% reduction in the chance of infant malnutrition. Estimates of the prevalence of child malnutrition show that most of the cities have the risk of malnutrition under control, very low or low. Risks of greater magnitude exist only in 158 municipalities in the North Region. Childhood malnutrition as a public health problem is concentrated in the cities of the North region, where FHS coverage is lower. A protective effect of FHS in relation to child malnutrition was found in the country as a whole, irrespective of other determinants of the problem.
Stewart, Barclay; Pathak, John; Gupta, Shailvi; Shrestha, Sunil; Groen, Reinou S.; Nwomeh, Benedict C.; Kushner, Adam L; McIntyre, Thomas
Background Herniorrhaphy is one of the most frequently performed general surgical operations worldwide. However, most low- and middle-income countries (LMICs) are unable to provide this essential surgery to the general public, resulting in considerable morbidity and mortality. This study aimed to estimate the prevalence, barriers to care and disability of untreated hernias in Nepal. Methods Nepal is a low-income country in South Asia with rugged terrain, infrastructure deficiencies and a severely under-resourced healthcare system resulting in substantial unmet surgical need. A cluster randomized, cross-sectional household survey was performed using the validated Surgeons OverSeas Assessment of Surgical (SOSAS) tool. Fifteen randomized clusters consisting of 30 households with two randomly selected respondents each were sampled to estimate surgical need. The prevalence of and disability from groin hernias and barriers to herniorrhaphy were assessed. Results The survey sampled 1,350 households, totaling 2,695 individuals (97% response rate). There were 1,434 males (53%) with 1.5% having a mass or swelling in the groin at time of survey (95% CI 0.8 – 3.0). The age-standardized rate for inguinal hernias in men ranged from 1,144 per 100,000 persons between age 5 and 49 years and 2,941 per 100,000 persons age ≥50 years. Extrapolating nationally, there are nearly 310,000 individuals with groin masses and 66,000 males with soft/reducible groin masses in need of evaluation in Nepal. Twenty-nine respondents were not able to have surgery due to lack of surgical services (31%), fear or mistrust of the surgical system (31%) and inability to afford care (21%). Twenty percent were unable to work as previous or perform self-care due to their hernia. Conclusions Despite the lower than expected prevalence of inguinal hernias, hundreds of thousands of people in Nepal are currently in need of surgical evaluation. Given that essential surgery is a necessary component in health
Kong, Kyoung Ae; Jung-Choi, Kyung-Hee; Lim, Dohee; Lee, Hye Ah; Lee, Won Kyung; Baik, Sun Jung; Park, Su Hyun; Park, Hyesook
Background Smoking is a major modifiable risk factor for premature mortality. Estimating the smoking-attributable burden is important for public health policy. Typically, prevalence- or smoking impact ratio (SIR)-based methods are used to derive estimates, but there is controversy over which method is more appropriate for country-specific estimates. We compared smoking-attributable fractions (SAFs) of deaths estimated by these two methods. Methods To estimate SAFs in 2012, we used several different prevalence-based approaches using no lag and 10- and 20-year lags. For the SIR-based method, we obtained lung cancer mortality rates from the Korean Cancer Prevention Study (KCPS) and from the United States-based Cancer Prevention Study-II (CPS-II). The relative risks for the diseases associated with smoking were also obtained from these cohort studies. Results For males, SAFs obtained using KCPS-derived SIRs were similar to those obtained using prevalence-based methods. For females, SAFs obtained using KCPS-derived SIRs were markedly greater than all prevalence-based SAFs. Differences in prevalence-based SAFs by time-lag period were minimal among males, but SAFs obtained using longer-lagged prevalence periods were significantly larger among females. SAFs obtained using CPS-II-based SIRs were lower than KCPS-based SAFs by >15 percentage points for most diseases, with the exceptions of lung cancer and chronic obstructive pulmonary disease. Conclusions SAFs obtained using prevalence- and SIR-based methods were similar for males. However, neither prevalence-based nor SIR-based methods resulted in precise SAFs among females. The characteristics of the study population should be carefully considered when choosing a method to estimate SAF. PMID:26477995
Davila-Payan, Carlo; DeGuzman, Michael; Johnson, Kevin; Serban, Nicoleta
Introduction Interventions for pediatric obesity can be geographically targeted if high-risk populations can be identified. We developed an approach to estimate the percentage of overweight or obese children aged 2 to 17 years in small geographic areas using publicly available data. We piloted our approach for Georgia. Methods We created a logistic regression model to estimate the individual probability of high body mass index (BMI), given data on the characteristics of the survey participants. We combined the regression model with a simulation to sample subpopulations and obtain prevalence estimates. The models used information from the 2001–2010 National Health and Nutrition Examination Survey, the 2010 Census, and the 2010 American Community Survey. We validated our results by comparing 1) estimates for adults in Georgia produced by using our approach with estimates from the Centers for Disease Control and Prevention (CDC) and 2) estimates for children in Arkansas produced by using our approach with school examination data. We generated prevalence estimates for census tracts in Georgia and prioritized areas for interventions. Results In DeKalb County, the mean prevalence among census tracts varied from 27% to 40%. For adults, the median difference between our estimates and CDC estimates was 1.3 percentage points; for Arkansas children, the median difference between our estimates and examination-based estimates data was 1.7 percentage points. Conclusion Prevalence estimates for census tracts can be different from estimates for the county, so small-area estimates are crucial for designing effective interventions. Our approach validates well against external data, and it can be a relevant aid for planning local interventions for children. PMID:25764138
Meza, Benjamin P.L.; Lohrke, Britta; Wilkinson, Robert; Pitman, John P.; Shiraishi, Ray W.; Bock, Naomi; Lowrance, David W.; Kuehnert, Matthew J.; Mataranyika, Mary; Basavaraju, Sridhar V.
Background Acute transfusion reactions are probably common in sub-Saharan Africa, but transfusion reaction surveillance systems have not been widely established. In 2008, the Blood Transfusion Service of Namibia implemented a national acute transfusion reaction surveillance system, but substantial under-reporting was suspected. We estimated the actual prevalence and rate of acute transfusion reactions occurring in Windhoek, Namibia. Methods The percentage of transfusion events resulting in a reported acute transfusion reaction was calculated. Actual percentage and rates of acute transfusion reactions per 1,000 transfused units were estimated by reviewing patients’ records from six hospitals, which transfuse >99% of all blood in Windhoek. Patients’ records for 1,162 transfusion events occurring between 1st January – 31st December 2011 were randomly selected. Clinical and demographic information were abstracted and Centers for Disease Control and Prevention National Healthcare Safety Network criteria were applied to categorize acute transfusion reactions1. Results From January 1 – December 31, 2011, there were 3,697 transfusion events (involving 10,338 blood units) in the selected hospitals. Eight (0.2%) acute transfusion reactions were reported to the surveillance system. Of the 1,162 transfusion events selected, medical records for 785 transfusion events were analysed, and 28 acute transfusion reactions were detected, of which only one had also been reported to the surveillance system. An estimated 3.4% (95% confidence interval [CI]: 2.3–4.4) of transfusion events in Windhoek resulted in an acute transfusion reaction, with an estimated rate of 11.5 (95% CI: 7.6–14.5) acute transfusion reactions per 1,000 transfused units. Conclusion The estimated actual rate of acute transfusion reactions is higher than the rate reported to the national haemovigilance system. Improved surveillance and interventions to reduce transfusion-related morbidity and mortality
Meza, Benjamin P L; Lohrke, Britta; Wilkinson, Robert; Pitman, John P; Shiraishi, Ray W; Bock, Naomi; Lowrance, David W; Kuehnert, Matthew J; Mataranyika, Mary; Basavaraju, Sridhar V
Acute transfusion reactions are probably common in sub-Saharan Africa, but transfusion reaction surveillance systems have not been widely established. In 2008, the Blood Transfusion Service of Namibia implemented a national acute transfusion reaction surveillance system, but substantial under-reporting was suspected. We estimated the actual prevalence and rate of acute transfusion reactions occurring in Windhoek, Namibia. The percentage of transfusion events resulting in a reported acute transfusion reaction was calculated. Actual percentage and rates of acute transfusion reactions per 1,000 transfused units were estimated by reviewing patients' records from six hospitals, which transfuse >99% of all blood in Windhoek. Patients' records for 1,162 transfusion events occurring between 1(st) January - 31(st) December 2011 were randomly selected. Clinical and demographic information were abstracted and Centers for Disease Control and Prevention National Healthcare Safety Network criteria were applied to categorize acute transfusion reactions. From January 1 - December 31, 2011, there were 3,697 transfusion events (involving 10,338 blood units) in the selected hospitals. Eight (0.2%) acute transfusion reactions were reported to the surveillance system. Of the 1,162 transfusion events selected, medical records for 785 transfusion events were analysed, and 28 acute transfusion reactions were detected, of which only one had also been reported to the surveillance system. An estimated 3.4% (95% confidence interval [CI]: 2.3-4.4) of transfusion events in Windhoek resulted in an acute transfusion reaction, with an estimated rate of 11.5 (95% CI: 7.6-14.5) acute transfusion reactions per 1,000 transfused units. The estimated actual rate of acute transfusion reactions is higher than the rate reported to the national haemovigilance system. Improved surveillance and interventions to reduce transfusion-related morbidity and mortality are required in Namibia.
Wirth, Kathleen E.; Agniel, Denis; Barr, Christopher D.; Austin, Matthew D.; DeGruttola, Victor
Since 1990 the World Health Organization (WHO) has recommended HIV surveillance among pregnant women as an essential surveillance activity for countries with generalized HIV epidemics. Despite the widespread availability and potential usefulness of antenatal HIV surveillance, analyses of such data present important challenges. Within an individual clinic, the HIV status of its attendees may be correlated due to similarities in HIV risk among women close in age. Between-clinic correlation may also arise as women often seek antenatal care at clinics located close to their home and individuals living in nearby communities may share important characteristics or behaviours related to susceptibility. A general estimating equations-based approach for spatially-correlated, binary data such as that antenatal HIV surveillance based on a pairwise composite likelihood has been described. We present an extended version of this model that can accommodate penalized spline estimators and apply it to antenatal HIV surveillance data collected in 2011 in Botswana to estimate the effects of proximity to the “hotspot” of the country’s HIV epidemic and age on HIV prevalence. Finally, we compare the results to a logistic regression analysis which ignores potential correlation of responses. PMID:26215657
Gupta, Soma; Saha, Pradip Kumar; Mukhopadhyay, Ashish
The coexistence of hypothroidism and depression is already reported and both of these conditions are known to share some common clinical symptoms. Serum cholesterol level is known to be altered in either condition considered separately. But, no report is obtained regarding serum cholesterol level when both the conditions coexist. In this study, 78 patients (61 females and 17 males, age ranged 19 to 67 years) suffering from major depressive disorder were included. Serum T3, T4, TSH and cholesterol levels were estimated in all of them. Sixty-two patients were found to be euthyroid and 16 patients (11 females, 5 males) were found to be hypothyroid. Among female patients, 6 had subclinical hypothyroidism and 5 had overt hypothyroidism. Among male patients 3 had subclinical hypothyroidism and 2 had overt hypothyroidism. The overall prevalence of hypothyroidism in major depressive disorder was estimated as 20.5%. Mean serum cholesterol level in 62 euthyroid patients was found to be 150.9% +/- 16 mg% and that of 16 hypothyroid patients to be 190.7 +/- 12 mg% showing a significant difference (p < 0.01). Thus estimation of cholesterol in major depressive disorder patients may give an idea regarding their thyroid status and vice-versa.
Ng, T P; Tan, W C
We conducted a population-based study involving a stratified cluster disproportionate random sample of 2868 adults aged 20 to 74 years selected from five housing estates (Yishun, Toa Payoh, Jurong East, Geylang/Eunos and Bukit Merah). Chronic rhinitis was defined as the usual presence of symptoms of blocked or running nose, apart from colds or the flu, lasting for more than a year. Allergic rhinitis was considered to be present if these symptoms were associated with conjunctivitis or recognisable provocation by commonly known allergens, namely house dust, dogs, cats, birds, pollen, or medicines. The estimated general population prevalence of chronic rhinitis was 10.8% (95% confidence interval (CI) 8.8-12.7). Higher prevalences were noted in males, in younger adults, in Indians and Chinese, in those with higher socio-economic status, and in Toa Payoh, Jurong East and Geylang/Eunos. The prevalence of allergic rhinitis was 5.5% (95% CI 4.5-6.5). The most common 'allergenic' factor in allergic rhinitis was house dust (73%); provocation by birds, cats or dogs (5%), grass or tree pollens (5%), and medicine (5%) was less common but likely to have been under-recognised. Provocation by change in temperature (54%) and early in the morning (64%) was equally frequent in both 'allergic' and 'non-allergic' rhinitis; cigarette smoke, petrol and diesel fumes, food and work environment were less common (4-12%). Allergic rhinitis was highly significantly associated with asthma (13.9% in allergic rhinitis, 4.4% in non-allergic rhinitis, and 2.2% in non-rhinitic subjects).
Patel, Hiten D; Groen, Reinou S; Kamara, Thaim B; Samai, Mohamed; Farahzad, Mina M; Cassidy, Laura D; Kushner, Adam L; Wren, Sherry M
Purpose A large number of unrepaired inguinal hernias is expected in sub-Saharan Africa where late presentation often results in incarceration, strangulation, or giant scrotal hernias. However, no representative population-based data is available to quantify the prevalence of hernias. We present data on groin masses in Sierra Leone to estimate prevalence, barriers to care, and associated disability. Methods A cluster randomized, cross-sectional household survey of 75 clusters of 25 households with 2 respondents each was designed to calculate the prevalence of and disability caused by groin hernias in Sierra Leone using a verbal head-to-toe examination. Barriers to hernia repairs were assessed by asking participants the main reason for delay in surgical care. Results Information was obtained from 3645 respondents in 1843 households, of which 1669 (46%) were male and included in the study. In total, 117 males or 7.01% (95% CI 5.64-8.38) reported a soft or reducible swelling likely representing a hernia with four men having two masses. Of the 93.2% who indicated the need for health care, only 22.2% underwent a procedure, citing limited funds (59.0%) as the major barrier to care. On disability assessment, 20.2% were not able to work secondary to the groin swelling. Conclusions The results indicate groin masses represent a major burden for the male population in Sierra Leone. Improving access to surgical care for adult patients with hernias and early intervention for children will be vital to address the burden of disease and prevent complications or limitations of daily activity. PMID:24241327
Kiffer, Carlos Roberto Veiga; Conceição, Orlando Jorge; Santos, Edgar Bortholi; Sabino, Ester; Focaccia, Roberto
Objectives. Estimate the prevalence of immunity to poliomyelitis (anti-polio antibodies) in the city of São Paulo/Brazil through a population-based survey. Methods. A quantitative and inductive method was used to draw a representative sample of the population. Randomization and stratification (based on sex, age and residence region) was done, and 1,059 individuals were studied on a home-visit basis (structured questionnaires and blood samples). A microneutralization test was performed to detect anti-polio antibodies against serotypes 1, 2 and 3. Results. The estimated prevalence of immunity to poliomyelitis was high, with 94.6% prevalence of anti-polio 1 antibodies, 98.8% anti-polio 2 and 91.9% anti-polio 3. Despite this high prevalence, there were significantly lower prevalence levels in some groups, specially among age and residence region groups. Discussion. Routine child immunization and NIDs with OPV have provided excellent levels of serological immunity to poliomyelitis in the population of the city of São Paulo, Brazil. However, there may be specific groups with a lower prevalence of immunity. Estimations of the prevalence of immunity to poliomyelitis were made in a population-based survey, which could be used as an auxiliary tool for supporting the polio eradication program.
Chinomona, Amos; Mwambi, Henry
Missing data are a common feature in many areas of research especially those involving survey data in biological, health and social sciences research. Most of the analyses of the survey data are done taking a complete-case approach, that is taking a list-wise deletion of all cases with missing values assuming that missing values are missing completely at random (MCAR). Methods that are based on substituting the missing values with single values such as the last value carried forward, the mean and regression predictions (single imputations) are also used. These methods often result in potential bias in estimates, in loss of statistical information and in loss of distributional relationships between variables. In addition, the strong MCAR assumption is not tenable in most practical instances. Since missing data are a major problem in HIV research, the current research seeks to illustrate and highlight the strength of multiple imputation procedure, as a method of handling missing data, which comes from its ability to draw multiple values for the missing observations from plausible predictive distributions for them. This is particularly important in HIV research in sub-Saharan Africa where accurate collection of (complete) data is still a challenge. Furthermore the multiple imputation accounts for the uncertainty introduced by the very process of imputing values for the missing observations. In particular national and subgroup estimates of HIV prevalence in Zimbabwe were computed using multiply imputed data sets from the 2010-11 Zimbabwe Demographic and Health Surveys (2010-11 ZDHS) data. A survey logistic regression model for HIV prevalence and demographic and socio-economic variables was used as the substantive analysis model. The results for both the complete-case analysis and the multiple imputation analysis are presented and discussed. Across different subgroups of the population, the crude estimates of HIV prevalence are generally not identical but their
Irwin, R J; Poppe, C; Messier, S; Finley, G G; Oggel, J
In 1990-1991, a national survey was conducted to estimate the prevalence of Salmonella species among Canadian commercial turkey flocks. Two hundred and seventy flocks were randomly selected across Canada. The proportion sampled from each province was selected according to each province's share of the national turkey market. Samples, consisting of 12 pooled litter and four pooled dust samples, were used to determine the Salmonella status of the environment of each flock. Additionally, a one kilogram sample of feed was taken from each flock premise. Salmonella was recovered from environmental samples in 234/270 (86.7%) of flocks and from feed samples in 26/266 (9.8%) of flocks. Forty-eight different Salmonella serovars were isolated from flock environmental samples. The most prevalent serovars were S. anatum, S. hadar, S. agona, S. heidelberg and S. saintpaul which were isolated from 53/270 (19.6%), 49/270 (18.1%), 49/270 (18.1%), 42/270 (15.6%) and 34/270 (12.6%) flocks, respectively. PMID:7889457
Karlsson, Maria A; Lindelöf, Bernt; Wahlgren, Carl-Fredrik; Wiklund, Kerstin; Rodvall, Ylva
The prevalence of melanocytic naevi in children correlates with sun exposure and may serve as an objective population risk indicator of future melanoma incidence. The aim was to investigate if mobile teledermatology could offer a valid methodology compared with standard manual, face-to-face counting of naevi on the back of children. Ninety-seven children aged 7-16 years were enrolled. One dermatologist performed manual naevi counting and imaging of the child's back using an iPhone 4S comprising a safe-coded mobile application. Two other dermatologists independently counted naevi from the images. Cohen's weighted kappa (κw) coefficient demonstrated substantial agreement for both dermatologists: κw = 0.69 (0.57-0.81 [95% confidence intervals]) and κw = 0.78 (0.70-0.86), compared with the manual assessment. Inter-rater reliability was also substantial (κw = 0.80 [0.73-0.87]). Use of mobile teledermatology proved valid for estimating naevi prevalence on the back and could provide a more feasible methodology following trends in sun exposure in children.
Mentzoni, Rune Aune; Brunborg, Geir Scott; Molde, Helge; Myrseth, Helga; Skouverøe, Knut Joachim Mår; Hetland, Jørn; Pallesen, Ståle
A nationwide survey was conducted to investigate the prevalence of video game addiction and problematic video game use and their association with physical and mental health. An initial sample comprising 2,500 individuals was randomly selected from the Norwegian National Registry. A total of 816 (34.0 percent) individuals completed and returned the questionnaire. The majority (56.3 percent) of respondents used video games on a regular basis. The prevalence of video game addiction was estimated to be 0.6 percent, with problematic use of video games reported by 4.1 percent of the sample. Gender (male) and age group (young) were strong predictors for problematic use of video games. A higher proportion of high frequency compared with low frequency players preferred massively multiplayer online role-playing games, although the majority of high frequency players preferred other game types. Problematic use of video games was associated with lower scores on life satisfaction and with elevated levels of anxiety and depression. Video game use was not associated with reported amount of physical exercise.
Lyahyai, Jaber; Sbiti, Aziza; Barkat, Amina; Ratbi, Ilham; Sefiani, Abdelaziz
Spinal muscular atrophy (SMA) is one of the most common autosomal recessive diseases caused by homozygous deletion of exon 7 of the survival motor neuron 1 (SMN1) gene in approximately 95% of SMA patients. Carrier frequency studies of SMA have been reported for various populations. The aim of our study was to estimate the carrier frequency of the common SMN1 exon 7 deletion in the Moroccan population to achieve an insight into the prevalence of SMA in Morocco. In this study, we used a reliable quantitative real-time polymerase chain reaction assay with SYBR Green I dye to determine the copy number of the SMN1 gene. Analysis of 150 Moroccan newborns predicts a carrier frequency of approximately 1:25, which would mean a calculated SMA prevalence of 1:1800 after correction due to consanguinity. These results show as expected that the SMA carrier frequency in Morocco is higher than in the European populations and is close to those of Middle Eastern countries. Genetic carrier testing for genetic counseling should be recommended particularly to families with a clear clinical history of SMA.
Schwarz, B; Ertl, R; Zimmer, S; Netzmann, Y; Klein, D; Schwendenwein, I; Hoven, R V D
The aim of this study was to determine the occurrence and frequency of a mutation in the gene coding for skeletal muscle glycogen synthase type 1 (GYS-1), which is the cause of equine polysaccharide storage myopathy (PSSM) type 1 in a population of 50 Haflingers. GYS-1 genotyping of 50 Haflingers was performed with a validated restriction fragment length polymorphism (RFLP) assay. The second aim was to compare resting and post-exercise muscle enzyme activities as well as parameters of glucose metabolism in blood between horses with and without the mutation. Nine of the 50 Haflingers were identified to be heterozygous for the mutation (HR). None was homozygous (HH). The estimated HR prevalence was 18 per cent in this herd. Mean aspartate aminotransferase (AST) activity at rest and mean creatine kinase and AST activity after exercise were significantly higher in HR compared with RR (homozygote normal) horses. No significant differences could be found in the other parameters.
Background To provide a clear picture of the current hepatitis B situation, the authors performed a systematic review to estimate the age- and region-specific prevalence of chronic hepatitis B (CHB) in Turkey. Methods A total of 339 studies with original data on the prevalence of hepatitis B surface antigen (HBsAg) in Turkey and published between 1999 and 2009 were identified through a search of electronic databases, by reviewing citations, and by writing to authors. After a critical assessment, the authors included 129 studies, divided into categories: 'age-specific'; 'region-specific'; and 'specific population group'. To account for the differences among the studies, a generalized linear mixed model was used to estimate the overall prevalence across all age groups and regions. For specific population groups, the authors calculated the weighted mean prevalence. Results The estimated overall population prevalence was 4.57, 95% confidence interval (CI): 3.58, 5.76, and the estimated total number of CHB cases was about 3.3 million. The outcomes of the age-specific groups varied from 2.84, (95% CI: 2.60, 3.10) for the 0-14-yearolds to 6.36 (95% CI: 5.83, 6.90) in the 25-34-year-old group. Conclusion There are large age-group and regional differences in CHB prevalence in Turkey, where CHB remains a serious health problem. PMID:22151620
Kurth, Ann E.; Cleland, Charles M.; Des Jarlais, Don C.; Musyoki, Helgar; Lizcano, John A.; Chhun, Nok; Cherutich, Peter
Objective HIV infection in sub-Saharan Africa increasingly occurs among people who inject drugs (PWID). Kenya is one of the first to implement a national needle and syringe program (NSP). Our study undertook a baseline assessment as part of evaluating NSP in a seek, test, treat, and retain approach. Methods Participants enrolled May–December 2012 from 10 sites. Respondent-driven sampling was used to reach n=1,785 PWID for HIV-1 prevalence and viral load determination and survey data. Results Estimated HIV prevalence, adjusted for differential network size and recruitment relationships, was 14.5% in Nairobi (95% CI 10.8–18.2) and 20.5% in the Coast region (95% CI 17.3–23.6). Viral load (log10 transformed) in Nairobi ranged from 1.71 to 6.12 (median 4.41; IQR 3.51–4.94) and in the Coast from 1.71 to 5.88 (median 4.01; IQR 3.44–4.72). Using log10 viral load 2.6 as a threshold for HIV viral suppression, the percentage of HIV-infected participants with viral suppression was 4.2% in Nairobi and 4.6% in the Coast. Heroin was the most commonly injected drug in both regions, used by 93% of participantsin the past month typically injecting 2–3 times/day. Receptive needle/syringe sharing at last injection was more common in Nairobi (23%) than the Coast (4%). Estimated incidence among new injectors was 2.5/100 person-years in Nairobi and 1.6/100 person-years in the Coast. Conclusion The HIV epidemic is well-established among PWID in both Nairobi and Coast regions. Public health scale implementation of combination HIV prevention has the potential to greatly limit the epidemic in this vulnerable and bridging population. PMID:26226249
Background Despite concerns about its health and social consequences, little is known about the prevalence of illicit opioid use in New York City. Individuals who misuse heroin and prescription opioids are known to bear a disproportionate burden of morbidity and mortality. Service providers and public health authorities are challenged to provide appropriate interventions in the absence of basic knowledge about the size and characteristics of this population. While illicit drug users are underrepresented in population-based surveys, they may be identified in multiple administrative data sources. Methods We analyzed large datasets tracking hospital inpatient and emergency room admissions as well as drug treatment and detoxification services utilization. These were applied in combination with findings from a large general population survey and administrative records tracking prescriptions, drug overdose deaths, and correctional health services, to estimate the prevalence of heroin and non-medical prescription opioid use among New York City residents in 2006. These data were further applied to a descriptive analysis of opioid users entering drug treatment and hospital-based medical care. Results These data sources identified 126,681 cases of opioid use among New York City residents in 2006. After applying adjustment scenarios to account for potential overlap between data sources, we estimated over 92,000 individual opioid users. By contrast, just 21,600 opioid users initiated drug treatment in 2006. Opioid users represented 4 % of all individuals hospitalized, and over 44,000 hospitalizations during the calendar year. Conclusions Our findings suggest that innovative approaches are needed to provide adequate services to this sizeable population of opioid users. Given the observed high rates of hospital services utilization, greater integration of drug services into medical settings could be one component of an effective approach to expanding both the scope and reach
Nourzad, Susan; Jenkins, Helen E.; Milstein, Meredith; Mitnick, Carole D.
SUMMARY Background Multidrug-resistant tuberculosis (MDR-TB) burden estimates are based on incomplete, infrequently updated data among a limited pool of cases: notified or incident, pulmonary TB patients. Methods Using WHO data reported by 217 countries/territories in 2014, we calculated MDR-TB burdens among prevalent TB cases and compared these with estimates among incident and notified TB patients. We also compared treatment coverage across estimates. Findings Among prevalent TB patients globally in 2014, we estimate that 555,545 (95% credible bounds: 499,340–617,391) MDR-TB cases occurred. This is 85% more than the 300,000 estimated among notified cases, and 16% more than the 480,000 among incident cases. Only 20% of MDR-TB cases among prevalent—compared to 37% of MDR-TB among notified—TB patients had access to MDR-TB treatment. Applying prior estimates, only 10% of MDR-TB cases will have successful outcomes. Interpretation Estimates based on likely-to-be-diagnosed cases of MDR-TB overlook a significant proportion of morbidity, mortality, and transmission: that occur in undiagnosed, untreated, prevalent TB patients. Still likely underestimating the true disease burden, MDR-TB among patients with prevalent TB represents a closer approximation of disease burden than currently reported indicators. Progress toward elimination—or control—depends on policies guided by a more complete representation of the disease burden. PMID:28157458
Foley, Norine C; Salter, Katherine L; Robertson, James; Teasell, Robert W; Woodbury, M Gail
The reported prevalence of malnutrition after stroke varies widely, whereas it remains unclear which of the estimates is most accurate. The aim of this review was to explore possible sources of this heterogeneity among studies and to evaluate whether the nutritional assessment techniques used were valid. A literature search was conducted to identify all studies in which the nutritional state of patients was assessed after inpatient admission for stroke. The percentages of patients identified as malnourished in each study and method of nutritional assessment are reported. For the purposes of this study, an assessment technique was considered valid if at least one form of validity had been demonstrated previously through psychometric evaluation. Eighteen studies meeting inclusion criteria were identified. The reported frequency of malnutrition ranged from 6.1% to 62%. Seventeen different methods of nutritional assessment were used. Four trials used previously validated assessment methods: Subjective Global Assessment, "an informal assessment," and Mini Nutritional Assessment. The nutritional assessment methods used in the remaining studies used had not been validated previously. The use of a wide assortment of nutritional assessment tools, many of which have not been validated, may have contributed to the wide range of estimates of malnutrition. If so, this underscores the need for valid and reliable assessment tools to further our understanding of the relationship between stroke and nutritional status.
Gamblin, Jenny; Jefferies, Johanna M; Harris, Scott; Ahmad, Nusreen; Marsh, Peter; Faust, Saul N; Fraser, Simon; Moore, Michael; Roderick, Paul; Blair, Iain; Clarke, Stuart C
Staphylococcus aureus remains a significant cause of morbidity and mortality and, therefore, a burden on healthcare systems. Our aim was to estimate the current rate of nasal S. aureus carriage in the general population and to determine the feasibility of nasal self-swabbing as a means of detection. Two thousand people (1200 adults and 800 children) from a single NHS general practice in Southampton, UK, were randomly selected from a general practice age sex register, stratified by age and sex, and invited to undertake nasal self-swabbing in their own home. Overall, 362 (32.5%) swabs from adults and 168 (22%) from children were returned. Responses were greater for adults and those of increased age, female gender and decreasing socio-economic deprivation. The overall estimated practice carriage rate of S. aureus directly standardized for age sex was 28% [95% confidence interval (CI) 26.1-30.2%]. Carriage of meticillin-susceptible S. aureus was 27% (95% CI 26.1-30.2%), whilst that of meticillin-resistant S. aureus was 1.9% (95% CI 0.7-3.1%). Although nasal self-swabbing rates were relatively low, they are comparable to other studies and may allow large population-based carriage studies to be undertaken at relatively low cost. Importantly, this study updates prevalence data for S. aureus carriage in the community.
Nguyen, Thin; Larsen, Mark E; O'Dea, Bridianne; Phung, Dinh; Venkatesh, Svetha; Christensen, Helen
This work aims to estimate the degree of adverse drug reactions (ADR) for psychiatric medications from social media, including Twitter, Reddit, and LiveJournal. Advances in lightning-fast cluster computing was employed to process large scale data, consisting of 6.4 terabytes of data containing 3.8 billion records from all the media. Rates of ADR were quantified using the SIDER database of drugs and side-effects, and an estimated ADR rate was based on the prevalence of discussion in the social media corpora. Agreement between these measures for a sample of ten popular psychiatric drugs was evaluated using the Pearson correlation coefficient, r, with values between 0.08 and 0.50. Word2vec, a novel neural learning framework, was utilized to improve the coverage of variants of ADR terms in the unstructured text by identifying syntactically or semantically similar terms. Improved correlation coefficients, between 0.29 and 0.59, demonstrates the capability of advanced techniques in machine learning to aid in the discovery of meaningful patterns from medical data, and social media data, at scale. Copyright © 2017 Elsevier B.V. All rights reserved.
Dingus, Thomas A.
By using in situ naturalistic driving data, estimates of prevalence and risk can be made regarding driver populations’ secondary task distractions and crash rates. Through metadata analysis, three populations of drivers (i.e., adult light vehicle, teenaged light vehicle, and adult heavy vehicle) were compared regarding frequency of secondary task behavior and the associated risk for safety-critical incidents. Relative risk estimates provide insight into the risk associated with engaging in a single task. When such risk is considered in combination with frequency of use, it sheds additional light on those secondary tasks that create the greatest overall risk to driving safety. The results show that secondary tasks involving manual typing, texting, dialing, reaching for an object, or reading are dangerous for all three populations. Additionally, novice teen drivers have difficulty in several tasks that the other two populations do not, including eating and external distractions. Truck drivers also perform a number of risky “mobile office” types of tasks, including writing, not seen in the other populations. Implications are described for policy makers and designers of in-vehicle and nomadic, portable systems. PMID:24776227
Havlir, D V; Eastman, S; Gamst, A; Richman, D D
The nonnucleoside reverse transcriptase inhibitor nevirapine rapidly selects for mutant human immunodeficiency virus (HIV) in vivo. The most common mutation occurs at amino acid residue 181 in patients receiving monotherapy. After the initiation of nevirapine therapy, plasma and peripheral blood mononuclear cell samples were collected at frequent intervals and assayed for HIV RNA levels and the proportion of virus containing a mutation at residue 181. HIV RNA levels remained stable for the first 24 h after initiation of therapy and rapidly declined between 1 and 7 days. There was a consistent maximum decrease of 2 log10 HIV RNA copies per ml of plasma (range, 1.96 to 2.43) from baseline after 2 weeks in all monotherapy subjects. The estimated median half-life of HIV RNA was 1.11 days (range, 0.63 to 1.61). After 14 days of therapy, HIV RNA levels began to increase and 181 mutant virus was detected. The estimated doubling time of the emerging virus population ranged from 1.80 to 5.73 days. Viral DNA in peripheral blood mononuclear cells turned over from wild type to the mutant with a mutation at residue 181 significantly more slowly than did HIV RNA in plasma. In two subjects, the calculated prevalence of the 181 mutant virus prior to treatment was 7 and 133 per 10,000 copies of plasma HIV RNA. PMID:8892912
Dowling, Russell; Caravanos, Jack; Grigsby, Patrick; Rivera, Anthony; Ericson, Bret; Amoyaw-Osei, Yaw; Akuffo, Bennett; Fuller, Richard
then allocated these sites to each region. Both methods used cluster random sampling principles. The investigators identified 72 sites in the sampled quadrats. Extrapolating from these findings to the entire country, the first methodology estimated that there are 1561 sites contaminated by heavy metals in Ghana (confidence interval [CI]: 1134-1987), whereas the second estimated 1944 sites (CI: 812-3075). The estimated total number of contaminated sites in Ghana is thus 7-9 times the number of sites captured through TSIP. On a population basis, it was estimated that there are between 31 and 115 contaminated sites per million inhabitants in Ghana. The findings of this study indicate that the TSIP methodology provides a sound statistical basis for policy formulation. The statistical approaches used in this study can be replicated in other countries to improve estimates of the prevalence of contaminated sites. This information provides important input to calculations of the global burden of disease attributable to hazardous exposures at contaminated sites. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.
Pieroni, Luca; Muzi, Giacomo; Quercia, Augusto; Lanari, Donatella; Rundo, Carmen; Minelli, Liliana; Salmasi, Luca; dell'Omo, Marco
We evaluated the effects of the Italian 2005 smoking ban in public places on the prevalence of smoking, quitting and cigarette consumption of young workers. The dataset was obtained from non-computerized registers of medical examinations for a population of workers with apprenticeship contracts residing in the province of Viterbo, Italy, in the period 1996-2007. To estimate the effects of the ban, a segmented regression approach was used, exploiting the discontinuity introduced by the application of the law on apprentices' smoking behavior. It is estimated that the Italian smoking ban generally had no effect on smoking prevalence, quitting ratio, or cigarette consumption of apprentices. However, when the estimates were applied to subpopulations, significant effects were found: -1% in smoking prevalence, +2% in quitting, and -3% in smoking intensity of apprentices with at least a diploma.
Pieroni, Luca; Muzi, Giacomo; Quercia, Augusto; Lanari, Donatella; Rundo, Carmen; Minelli, Liliana; Salmasi, Luca; dell’Omo, Marco
Objectives: We evaluated the effects of the Italian 2005 smoking ban in public places on the prevalence of smoking, quitting and cigarette consumption of young workers. Data and Methods: The dataset was obtained from non-computerized registers of medical examinations for a population of workers with apprenticeship contracts residing in the province of Viterbo, Italy, in the period 1996–2007. To estimate the effects of the ban, a segmented regression approach was used, exploiting the discontinuity introduced by the application of the law on apprentices’ smoking behavior. Results: It is estimated that the Italian smoking ban generally had no effect on smoking prevalence, quitting ratio, or cigarette consumption of apprentices. However, when the estimates were applied to subpopulations, significant effects were found: −1% in smoking prevalence, +2% in quitting, and −3% in smoking intensity of apprentices with at least a diploma. PMID:26287220
McDonald, Douglas C.; Carlson, Kenneth E.
Background Abuse of prescription opioid analgesics is a serious threat to public health, resulting in rising numbers of overdose deaths and admissions to emergency departments and treatment facilities. Absent adequate patient information systems, “doctor shopping” patients can obtain multiple opioid prescriptions for nonmedical use from different unknowing physicians. Our study estimates the prevalence of doctor shopping in the US and the amounts and types of opioids involved. Methods and Findings The sample included records for 146.1 million opioid prescriptions dispensed during 2008 by 76% of US retail pharmacies. Prescriptions were linked to unique patients and weighted to estimate all prescriptions and patients in the nation. Finite mixture models were used to estimate different latent patient populations having different patterns of using prescribers. On average, patients in the extreme outlying population (0.7% of purchasers), presumed to be doctor shoppers, obtained 32 opioid prescriptions from 10 different prescribers. They bought 1.9% of all opioid prescriptions, constituting 4% of weighed amounts dispensed. Conclusions Our data did not provide information to make a clinical diagnosis of individuals. Very few of these patients can be classified with certainty as diverting drugs for nonmedical purposes. However, even patients with legitimate medical need for opioids who use large numbers of prescribers may signal dangerously uncoordinated care. To close the information gap that makes doctor shopping and uncoordinated care possible, states have created prescription drug monitoring programs to collect records of scheduled drugs dispensed, but the majority of physicians do not access this information. To facilitate use by busy practitioners, most monitoring programs should improve access and response time, scan prescription data to flag suspicious purchasing patterns and alert physicians and pharmacists. Physicians could also prevent doctor shopping by
Background The basis for this study is the fact that instrument error increases the variance of the distribution of body mass index (BMI). Combined with a defined cut-off value this may impact upon the estimated proportion of overweight and obesity. It is important to ensure high quality surveillance data in order to follow trends of estimated prevalence of overweight and obesity. The purpose of the study was to assess the impact of instrument error, due to uncalibrated scales and stadiometers, on prevalence estimates of overweight and obesity. Methods Anthropometric measurements from a nationally representative sample were used; the Norwegian Child Growth study (NCG) of 3474 children. Each of the 127 participating schools received a reference weight and a reference length to determine the correction value. Correction value corresponds to instrument error and is the difference between the true value and the measured, uncorrected weight and height at local scales and stadiometers. Simulations were used to determine the expected implications of instrument errors. To systematically investigate this, the coefficient of variation (CV) of instrument error was used in the simulations and was increased successively. Results Simulations showed that the estimated prevalence of overweight and obesity increased systematically with the size of instrument error when the mean instrument error was zero. The estimated prevalence was 16.4% with no instrument error and was, on average, overestimated by 0.5 percentage points based on observed variance of instrument error from the NCG-study. Further, the estimated prevalence was 16.7% with 1% CV of instrument error, and increased to 17.8%, 19.5% and 21.6% with 2%, 3% and 4% CV of instrument error, respectively. Conclusions Failure to calibrate measuring instruments is likely to lead to overestimation of the prevalence of overweight and obesity in population-based surveys. PMID:23413839
distribution is unlimited. Aldehyde Recognition and Discrimination by Mammalian Odorant Receptors via Functional Group-Specific Hydration Chemistry The...Recognition and Discrimination by Mammalian Odorant Receptors via Functional Group-Specific Hydration Chemistry Report Title The mammalian odorant receptors...octanal. Aldehyde Recognition and Discrimination by Mammalian Odorant Receptors via Functional Group-Specific Hydration Chemistry Approved for public
Pouget, Enrique R; Friedman, Samuel R; Cleland, Charles M; Tempalski, Barbara; Cooper, Hannah L F
Little information exists on the population prevalence or geographic distribution of injection drug users (IDUs) who are Hispanic in the USA. Here, we present yearly estimates of IDU population prevalence among Hispanic residents of the 96 most populated US metropolitan statistical areas (MSAs) for 1992-2002. First, yearly estimates of the proportion of IDUs who were Hispanic in each MSA were created by combining data on (1) IDUs receiving drug treatment services in Substance Abuse and Mental Health Services Administration (SAMHSA)'s Treatment Entry Data System, (2) IDUs being tested in the Centers for Disease Control and Prevention (CDC) HIV-Counseling and Testing System, and (3) incident AIDS diagnoses among IDUs, supplemented by (4) data on IDUs who were living with AIDS. Then, the resulting proportions were multiplied by published yearly estimates of the number of IDUs of all racial/ethnic groups in each MSA to produce Hispanic IDU population estimates. These were divided by Hispanic population data to produce population prevalence rates. Time trends were tested using mixed-effects regression models. Hispanic IDU prevalence declined significantly on average (1992 mean = 192, median = 133; 2002 mean = 144, median = 93; units are per 10,000 Hispanics aged 15-64). The highest prevalence rates across time tended to be in smaller northeastern MSAs. Comparing the last three study years to the first three, prevalence decreased in 82% of MSAs and increased in 18%. Comparisons with data on drug-related mortality and hepatitis C mortality supported the validity of the estimates. Generally, estimates of Hispanic IDU population prevalence were higher than published estimates for non-Hispanic White residents and lower than published estimates for non-Hispanic Black residents. Further analysis indicated that the proportion of IDUs that was Hispanic decreased in 52% and increased in 48% of MSAs between 2002 and 2007. The estimates resulting from this study can
Park, Jung Hwan; Kim, Yong Chul; Koo, Ho Seok; Oh, Se Won; Kim, Suhnggwon; Chin, Ho Jun
Stomach cancer is one of the most common cancers in Korea. The aim of this study was to identify the association between the prevalence of cancer, particularly stomach cancer, and the amount of 24-hr urine sodium excretion estimated from spot urine specimens. The study included 19,083 subjects who took part in the Korean National Health and Nutritional Examination Survey between 2009 and 2011. The total amount of urine sodium excreted in a 24-hr period was estimated by using two equations based on the values for spot urine sodium and creatinine. In subjects who had an estimated 24-hr urine sodium excretion of more than two standard deviations above the mean (group 2), the prevalence of stomach cancer was higher than in subjects with lower 24-hr sodium excretion (group 1). By using the Tanaka equation to estimate it, the prevalence of stomach cancer was 0.6% (114/18,331) in group 1, whereas it was 1.6% (9/568) in group 2 (P=0.006). By using the Korean equation, the prevalence was 0.6% (115/18,392) in group 1, and 1.6% in group 2 (8/507) (P=0.010). By using the Tanaka equation, breast cancer in women is more prevalent in group 2 (1.9%, 6/324) than group 1 (0.8%, 78/9,985, P=0.039). Higher salt intake, as defined by the estimated amount of 24-hr urine sodium excretion, is positively correlated with a higher prevalence of stomach or breast cancer in the Korean population.
Sun, Zhuoyu; Gilbert, Lucy; Ciampi, Antonio; Kaufman, Jay S; Basso, Olga
Diagnostic testing is recommended in women with "ovarian cancer symptoms." However, these symptoms are nonspecific. The ongoing Diagnosing Ovarian Cancer Early (DOVE) Study in Montreal, Quebec, Canada, provides diagnostic testing to women aged 50 years or older with symptoms lasting for more than 2 weeks and less than 1 year. The prevalence of ovarian cancer in DOVE is 10 times that of large screening trials, prompting us to estimate the prevalence of these symptoms in this population. We sent a questionnaire to 3,000 randomly sampled women in 2014-2015. Overall, 833 women responded; 81.5% reported at least 1 symptom, and 59.7% reported at least 1 symptom within the duration window specified in DOVE. We explored whether such high prevalence resulted from low survey response by applying inverse probability weighting to correct the estimates. Older women and those from deprived areas were less likely to respond, but only age was associated with symptom reporting. Prevalence was similar in early and late responders. Inverse probability weighting had a minimal impact on estimates, suggesting little evidence of nonresponse bias. This is the first study investigating symptoms that have proven to identify a subset of women with a high prevalence of ovarian cancer. However, the high frequency of symptoms warrants further refinements before symptom-triggered diagnostic testing can be implemented.
VILLARROEL, MARIA A.; TURNER, CHARLES F.; EGGLESTON, ELIZABETH; AL-TAYYIB, ALIA; ROGERS, SUSAN M.; ROMAN, ANTHONY M.; COOLEY, PHILIP C.; GORDEK, HARPER
Well-conducted telephone surveys provide an economical means of estimating the prevalence of sexual and reproductive behaviors in a population. There is, however, a nontrivial potential for bias since respondents must report sensitive information to a human interviewer. The National STD and Behavior Measurement Experiment (NSBME) evaluates a new survey technology—telephone audio computer-assisted self-interviewing (T-ACASI)—that eliminates this requirement. The NSBME embedded a randomized experiment in a survey of probability samples of 1,543 U.S. and 744 Baltimore adults ages 18 to 45. Compared with NSBME respondents interviewed by human interviewers, respondents interviewed by T-ACASI were 1.5 to 1.6 times more likely to report same-gender sexual attraction, experience, and genital contact. The impact of T-ACASI was more pronounced (odds ratio = 2.5) for residents of locales that have historically been less tolerant of same-gender sexual behaviors and for respondents in households with children (odds ratio = 3.0). PMID:21998488
Pels, Elmar G M; Aarnoutse, Erik J; Ramsey, Nick F; Vansteensel, Mariska J
People who suffer from paralysis have difficulties participating in society. Particularly burdensome is the locked-in syndrome (LIS). LIS patients are not able to move and speak but are cognitively healthy. They rely on assistive technology to interact with the world and may benefit from neurotechnological advances. Optimal research and design of such aids requires a well-defined target population. However, the LIS population is poorly characterized and the number of patients in this condition is unknown. Here we estimated and described the LIS patient population in the Netherlands to define the target population for assistive (neuro)technology. We asked physicians in the Netherlands if they had patients suffering from severe paralysis and communication problems in their files. Physicians responding affirmatively were asked to fill out a questionnaire on the patients' status. We sent out 9570 letters to general practitioners (GPs), who reported 83 patients. After first screening, the GPs of 46 patients received the questionnaire. Based on the responses, 26 patients were classified as having LIS. Extrapolation of these numbers resulted in a prevalence of 0.73 patients per 100 000 inhabitants. Notable results from the questionnaire were the percentage of patients with neuromuscular disease (>50%) and living at home (>70%). We revealed an etiologically diverse group of LIS patients. The functioning and needs of these patients were, however, similar and many relied on assistive technology. By characterizing the LIS population, our study may contribute to optimal development of assistive (neuro)technology.
Rebollar, Eria A; Woodhams, Douglas C; LaBumbard, Brandon; Kielgast, Jos; Harris, Reid N
The ribosomal gene complex is a multi-copy region that is widely used for phylogenetic analyses of organisms from all 3 domains of life. In fungi, the copy number of the internal transcribed spacer (ITS) is used to detect abundance of pathogens causing diseases such as chytridiomycosis in amphibians and white nose syndrome in bats. Chytridiomycosis is caused by the fungi Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal), and is responsible for declines and extinctions of amphibians worldwide. Over a decade ago, a qPCR assay was developed to determine Bd prevalence and pathogen load. Here, we demonstrate the effect that ITS copy number variation in Bd strains can have on the estimation of prevalence and pathogen load. We used data sets from different amphibian species to simulate how ITS copy number affects prevalence and pathogen load. In addition, we tested 2 methods (gBlocks® synthetic standards and digital PCR) to determine ITS copy number in Bd strains. Our results show that assumptions about the ITS copy number can lead to under- or overestimation of Bd prevalence and pathogen load. The use of synthetic standards replicated previously published estimates of ITS copy number, whereas dPCR resulted in estimates that were consistently lower than previously published estimates. Standardizing methods will assist with comparison across studies and produce reliable estimates of prevalence and pathogen load in the wild, while using the same Bd strain for exposure experiments and zoospore standards in qPCR remains the best method for estimating parameters used in epidemiological studies.
Barros, Aluísio JD; Hirakata, Vânia N
Background Cross-sectional studies with binary outcomes analyzed by logistic regression are frequent in the epidemiological literature. However, the odds ratio can importantly overestimate the prevalence ratio, the measure of choice in these studies. Also, controlling for confounding is not equivalent for the two measures. In this paper we explore alternatives for modeling data of such studies with techniques that directly estimate the prevalence ratio. Methods We compared Cox regression with constant time at risk, Poisson regression and log-binomial regression against the standard Mantel-Haenszel estimators. Models with robust variance estimators in Cox and Poisson regressions and variance corrected by the scale parameter in Poisson regression were also evaluated. Results Three outcomes, from a cross-sectional study carried out in Pelotas, Brazil, with different levels of prevalence were explored: weight-for-age deficit (4%), asthma (31%) and mother in a paid job (52%). Unadjusted Cox/Poisson regression and Poisson regression with scale parameter adjusted by deviance performed worst in terms of interval estimates. Poisson regression with scale parameter adjusted by χ2 showed variable performance depending on the outcome prevalence. Cox/Poisson regression with robust variance, and log-binomial regression performed equally well when the model was correctly specified. Conclusions Cox or Poisson regression with robust variance and log-binomial regression provide correct estimates and are a better alternative for the analysis of cross-sectional studies with binary outcomes than logistic regression, since the prevalence ratio is more interpretable and easier to communicate to non-specialists than the odds ratio. However, precautions are needed to avoid estimation problems in specific situations. PMID:14567763
Background Prevalence rates for overweight and obesity based on self-reported height and weight are underestimated, whereas the prevalence rate for underweight is slightly overestimated. Therefore a correction is needed. Aim of this study is to apply correction procedures to the prevalence rates developed on basis of (self-reported and measured) data from the representative German National Health Interview and Examination Survey for Children and Adolescents (KiGGS) to (self-reported) data from the German Health Behaviour in School Aged Children (HBSC) study to determine whether correction leads to higher prevalence estimates of overweight and obesity as well as lower prevalence rates for underweight. Methods BMI classifications based on self-reported and measured height and weight from a subsample of the KiGGS study (2,565 adolescents aged 11–15) were used to estimate two different correction formulas. The first and the second correction function are described. Furthermore, the both formulas were applied to the prevalence rates from the HBSC study (7,274 adolescents aged 11–15) which are based on self-reports collected via self-administered questionnaires. Results After applying the first correction function to self-reported data of the HBSC study, the prevalence rates of overweight and obesity increased from 5.5% to 7.8% (compared to 10.4% in the KiGGS study) and 2.7% to 3.8% (compared to 7.8% in the KiGGS study), respectively, whereas the corrected prevalence rates of underweight and severe underweight decreased from 8.0% to 6.7% (compared to 5.7% in the KiGGS study) and from 5.5% to 3.3% (compared to 2.4% in the KiGGS study), respectively. Application of the second correction function, which additionally considers body image, led to further slight corrections with an increase of the prevalence rates for overweight to 7.9% and for obese to 3.9%. Conclusion Subjective BMI can be used to determine the prevalence of overweight and obesity among children and
McAloon, Conor G; Doherty, Michael L; Whyte, Paul; O'Grady, Luke; More, Simon J; Messam, Locksley L McV; Good, Margaret; Mullowney, Peter; Strain, Sam; Green, Martin J
Bovine paratuberculosis is a disease characterised by chronic granulomatous enteritis which manifests clinically as a protein-losing enteropathy causing diarrhoea, hypoproteinaemia, emaciation and, eventually death. Some evidence exists to suggest a possible zoonotic link and a national voluntary Johne's Disease Control Programme was initiated by Animal Health Ireland in 2013. The objective of this study was to estimate herd-level true prevalence (HTP) and animal-level true prevalence (ATP) of paratuberculosis in Irish herds enrolled in the national voluntary JD control programme during 2013-14. Two datasets were used in this study. The first dataset had been collected in Ireland during 2005 (5822 animals from 119 herds), and was used to construct model priors. Model priors were updated with a primary (2013-14) dataset which included test records from 99,101 animals in 1039 dairy herds and was generated as part of the national voluntary JD control programme. The posterior estimate of HTP from the final Bayesian model was 0.23-0.34 with a 95% probability. Across all herds, the median ATP was found to be 0.032 (0.009, 0.145). This study represents the first use of Bayesian methodology to estimate the prevalence of paratuberculosis in Irish dairy herds. The HTP estimate was higher than previous Irish estimates but still lower than estimates from other major dairy producing countries.
Mann, Robert E.; Paglia-Boak, Angela; Adlaf, Edward M.; Beitchman, Joseph; Wolfe, David; Wekerle, Christine; Hamilton, Hayley A.; Rehm, Jurgen
Anxiety and mood disorders (AMD) may be more common among adolescents than previously thought, and epidemiological research would benefit from an easily-administered measure of AMD. We assessed the ability of the GHQ12 to estimate the prevalence of AMD in a representative sample of Ontario adolescents. Data were based on self-administered…
Jaffee, Sara R.; Gallop, Robert
Objective: To estimate the prevalence and stability of social, emotional, and academic competence in a nationally representative sample of children involved with child protective services. Method: Children were assessed as part of the National Survey of Child and Adolescent Well-Being. Children (N = 2,065) ranged in age from 8 to 16 years and were…
Eaton, Danice K.; Brener, Nancy D.; Kann, Laura; Denniston, Maxine M.; McManus, Tim; Kyle, Tonja M.; Roberts, Alice M.; Flint, Katherine H.; Ross, James G.
The authors examined whether paper-and-pencil and Web surveys administered in the school setting yield equivalent risk behavior prevalence estimates. Data were from a methods study conducted by the Centers for Disease Control and Prevention (CDC) in spring 2008. Intact classes of 9th- or 10th-grade students were assigned randomly to complete a…
Mann, Robert E.; Paglia-Boak, Angela; Adlaf, Edward M.; Beitchman, Joseph; Wolfe, David; Wekerle, Christine; Hamilton, Hayley A.; Rehm, Jurgen
Anxiety and mood disorders (AMD) may be more common among adolescents than previously thought, and epidemiological research would benefit from an easily-administered measure of AMD. We assessed the ability of the GHQ12 to estimate the prevalence of AMD in a representative sample of Ontario adolescents. Data were based on self-administered…
Barkley, Jonathan S; Kendrick, Katherine L; Codling, Karen; Muslimatun, Siti; Pachón, Helena
To summarize anaemia prevalence data for children, women, and men using data from the second, third and fourth waves of the Indonesia Family Life Surveys (IFLS), which were conducted in 1997/8, 2000, and 2007/8, respectively. Anaemia prevalence was determined for children 0 to 5 years, 5 to 12 years, 12 to 15 years, non-pregnant women at least 15 years, pregnant women at least 15 years, and men at least 15 years, based on haemoglobin adjusted for altitude and smoking status. Compared with 1997/8 estimates, anaemia prevalence estimates were lower in 2007/8 for all groups, with the greatest relative decline occurring in children 5 to 12 years (25.4%). Trend analysis found anaemia significantly declined over the survey years for all groups (χ² p=0.005 for pregnant women, χ² p<0.001 for all other groups). IFLS anaemia estimates for different population groups decreased between 1997/8 and 2007/8 and were consistent with estimates from Southeast Asia, and with other studies conducted in Indonesia. While the prevalence of anaemia consistently decreased in all groups, anaemia remains a moderate public health problem for children 0 to 5 years, children 5 to 12 years, and non-pregnant and pregnant women.
Jaffee, Sara R.; Gallop, Robert
Objective: To estimate the prevalence and stability of social, emotional, and academic competence in a nationally representative sample of children involved with child protective services. Method: Children were assessed as part of the National Survey of Child and Adolescent Well-Being. Children (N = 2,065) ranged in age from 8 to 16 years and were…
Sinnott, Sarah-Jo; McHugh, Sheena; Whelton, Helen; Layte, Richard; Barron, Steve; Kearney, Patricia M
Objective To estimate the prevalence and incidence of type 2 diabetes using a national pharmacy claims database. Research design and methods We used data from the Health Service Executive-Primary Care Reimbursement Service database in Ireland for this cross-sectional study. Prevalent cases of type 2 diabetes were individuals using an oral hypoglycemic agent, irrespective of insulin use, in 2012. Incident cases were individuals using an oral hypoglycemic agent in 2012 who had not used one in the past. Population level estimates were calculated and stratified by age and sex. Results In 2012, there were 114 957 prevalent cases of type 2 diabetes giving a population prevalence of 2.51% (95% CI 2.49% to 2.52%). Among adults (≥15yrs), this was 3.16% (95% CI 3.15% to 3.18%). The highest prevalence was in those aged 70+ years (12.1%). 21 574 people developed type 2 diabetes in 2012 giving an overall incidence of 0.48% (95% CI 0.48% to 0.49%). In adults, this was 0.60% (95% CI 0.60% to 0.61%). Incidence rose with age to a maximum of 2.08% (95% CI 2.02% to 2.15%) in people aged 65–69 years. Men had a higher prevalence (2.96% vs 2.04%) and incidence (0.54% vs 0.41%) of type 2 diabetes than women. Conclusions Pharmacy claims data allow estimates of objectively defined type 2 diabetes at the population level using up-to-date data. These estimates can be generated quickly to inform health service planning or to evaluate the impact of population level interventions. PMID:28123753
Youssef, G. J.; Jackson, A. C.; Pennay, D. W.; Francis, K. L.; Pennay, A.; Lubman, D. I.
Abstract Background, aims and design The increase in mobile telephone‐only households may be a source of bias for traditional landline gambling prevalence surveys. Aims were to: (1) identify Australian gambling participation and problem gambling prevalence using a dual‐frame (50% landline and 50% mobile telephone) computer‐assisted telephone interviewing methodology; (2) explore the predictors of sample frame and telephone status; and (3) explore the degree to which sample frame and telephone status moderate the relationships between respondent characteristics and problem gambling. Setting and participants A total of 2000 adult respondents residing in Australia were interviewed from March to April 2013. Measurements Participation in multiple gambling activities and Problem Gambling Severity Index (PGSI). Findings Estimates were: gambling participation [63.9%, 95% confidence interval (CI) = 61.4–66.3], problem gambling (0.4%, 95% CI = 0.2–0.8), moderate‐risk gambling (1.9%, 95% CI = 1.3–2.6) and low‐risk gambling (3.0%, 95% CI = 2.2–4.0). Relative to the landline frame, the mobile frame was more likely to gamble on horse/greyhound races [odds ratio (OR) = 1.4], casino table games (OR = 5.0), sporting events (OR = 2.2), private games (OR = 1.9) and the internet (OR = 6.5); less likely to gamble on lotteries (OR = 0.6); and more likely to gamble on five or more activities (OR = 2.4), display problem gambling (OR = 6.4) and endorse PGSI items (OR = 2.4‐6.1). Only casino table gambling (OR = 2.9) and internet gambling (OR = 3.5) independently predicted mobile frame membership. Telephone status (landline frame versus mobile dual users and mobile‐only users) displayed similar findings. Finally, sample frame and/or telephone status moderated the relationship between gender, relationship status, health and problem gambling (OR = 2.9–7.6). Conclusion Given expected future increases in the
James, Spencer L; Romero, Minerva; Ramírez-Villalobos, Dolores; Gómez, Sara; Pierce, Kelsey; Flaxman, Abraham; Serina, Peter; Stewart, Andrea; Murray, Christopher J L; Gakidou, Emmanuela; Lozano, Rafael; Hernandez, Bernardo
Easy-to-collect epidemiological information is critical for the more accurate estimation of the prevalence and burden of different non-communicable diseases around the world. Current measurement is restricted by limitations in existing measurement systems in the developing world and the lack of biometry tests for non-communicable diseases. Diagnosis based on self-reported signs and symptoms ("Symptomatic Diagnosis," or SD) analyzed with computer-based algorithms may be a promising method for collecting timely and reliable information on non-communicable disease prevalence. The objective of this study was to develop and assess the performance of a symptom-based questionnaire to estimate prevalence of non-communicable diseases in low-resource areas. As part of the Population Health Metrics Research Consortium study, we collected 1,379 questionnaires in Mexico from individuals who suffered from a non-communicable disease that had been diagnosed with gold standard diagnostic criteria or individuals who did not suffer from any of the 10 target conditions. To make the diagnosis of non-communicable diseases, we selected the Tariff method, a technique developed for verbal autopsy cause of death calculation. We assessed the performance of this instrument and analytical techniques at the individual and population levels. The questionnaire revealed that the information on health care experience retrieved achieved 66.1% (95% uncertainty interval [UI], 65.6-66.5%) chance corrected concordance with true diagnosis of non-communicable diseases using health care experience and 0.826 (95% UI, 0.818-0.834) accuracy in its ability to calculate fractions of different causes. SD is also capable of outperforming the current estimation techniques for conditions estimated by questionnaire-based methods. SD is a viable method for producing estimates of the prevalence of non-communicable diseases in areas with low health information infrastructure. This technology can provide higher
Crowe, Sonya; Seal, Andrew; Grijalva-Eternod, Carlos; Kerac, Marko
Tackling childhood malnutrition is a global health priority. A key indicator is the estimated prevalence of malnutrition, measured by nutrition surveys. Most aspects of survey design are standardised, but data 'cleaning criteria' are not. These aim to exclude extreme values which may represent measurement or data-entry errors. The effect of different cleaning criteria on malnutrition prevalence estimates was unknown. We applied five commonly used data cleaning criteria (WHO 2006; EPI-Info; WHO 1995 fixed; WHO 1995 flexible; SMART) to 21 national Demographic and Health Survey datasets. These included a total of 163,228 children, aged 6-59 months. We focused on wasting (low weight-for-height), a key indicator for treatment programmes. Choice of cleaning criteria had a marked effect: SMART were least inclusive, resulting in the lowest reported malnutrition prevalence, while WHO 2006 were most inclusive, resulting in the highest. Across the 21 countries, the proportion of records excluded was 3 to 5 times greater when using SMART compared to WHO 2006 criteria, resulting in differences in the estimated prevalence of total wasting of between 0.5 and 3.8%, and differences in severe wasting of 0.4-3.9%. The magnitude of difference was associated with the standard deviation of the survey sample, a statistic that can reflect both population heterogeneity and data quality. Using these results to estimate case-loads for treatment programmes resulted in large differences for all countries. Wasting prevalence and caseload estimations are strongly influenced by choice of cleaning criterion. Because key policy and programming decisions depend on these statistics, variations in analytical practice could lead to inconsistent and potentially inappropriate implementation of malnutrition treatment programmes. We therefore call for mandatory reporting of cleaning criteria use so that results can be compared and interpreted appropriately. International consensus is urgently needed
McGovern, Mark E.; Bärnighausen, Till; Marra, Giampiero; Radice, Rosalba
Background Heckman-type selection models have been used to control HIV prevalence estimates for selection bias, when participation in HIV testing and HIV status are correlated after controlling for observed variables. These models typically rely on the strong assumption that the error terms in the participation and the outcome equations that comprise the model are distributed as bivariate normal. Methods We introduce a novel approach for relaxing the bivariate normality assumption in selection models using non-linear copula functions. We apply this method to estimating HIV prevalence and new confidence intervals (CI) in the 2007 Zambian Demographic and Health Survey (DHS), using interviewer identity as the selection variable that predicts participation (consent to test) but not the outcome (HIV status). Results We show in a simulation study that selection models can generate biased results when the bivariate normality assumption is violated. In the 2007 Zambia DHS, HIV prevalence estimates are similar irrespective of the structure of the association assumed between participation and outcome. For men, we estimate a population HIV prevalence of 21% (95% = CI 16% to 25%), compared with 12% (11% to 13%) among those who consented to be tested; for women, the corresponding figures are 19% (13% to 24%) and 16% (15% to 17%). Conclusions Copula approaches to Heckman-type selection models are a useful addition to the methodological toolkit of HIV epidemiology, and of epidemiology in general. We develop the use of this approach to systematically evaluate the robustness of HIV prevalence estimates based on selection models, both empirically and in a simulation study. PMID:25643102
Accurate estimation of the incidence and prevalence of each subtype of epidermolysis bullosa (EB) is essential before clinical trials can be designed and sufficient funding allocated by government agencies and third-party insurers for the care of these individuals. To determine the incidence and prevalence of inherited EB stratified by subtype in the United States during a 16-year period. Prospective cross-sectional and longitudinal study. Data were obtained from 3271 patients consecutively enrolled in the National Epidermolysis Bullosa Registry from January 1, 1986, through December 31, 2002, using a detailed instrument created with the assistance of the National Institutes of Health. Analyses were performed in January 1999 and April 2015. Participants were patients of all ages with EB. Extensive clinical and laboratory data were collected on patients who were subclassified and serially revalidated based on published diagnostic recommendations by an international panel of experts. Pertinent to this report, estimates were made of the incidence and prevalence during 2 time frames. During the first 5 years of funding of the registry, the overall incidence and prevalence of inherited EB were 19.60 and 8.22 per 1 million live births, respectively. When reassessed over the entire 16 years of the study, the prevalence rose to 11.07, whereas the overall incidence remained unchanged at 19.57 cases. Changes were also observed within some disease subsets as increased numbers of patients were identified, recruited, followed up longitudinally, and resubclassified as needed over time. For example, in 2002, the prevalence of EBS overall and localized EBS had increased considerably by 30.4% and 25.5%, respectively, whereas the prevalence of generalized intermediate EBS declined by 76.7% as a result of later subclassification of some of those patients into other subtypes. In contrast, no significant change was noted in the overall prevalence of JEB or generalized severe JEB
Schur, Nadine; Hürlimann, Eveline; Garba, Amadou; Traoré, Mamadou S.; Ndir, Omar; Ratard, Raoult C.; Tchuem Tchuenté, Louis-Albert; Kristensen, Thomas K.; Utzinger, Jürg; Vounatsou, Penelope
Background Schistosomiasis is a water-based disease that is believed to affect over 200 million people with an estimated 97% of the infections concentrated in Africa. However, these statistics are largely based on population re-adjusted data originally published by Utroska and colleagues more than 20 years ago. Hence, these estimates are outdated due to large-scale preventive chemotherapy programs, improved sanitation, water resources development and management, among other reasons. For planning, coordination, and evaluation of control activities, it is essential to possess reliable schistosomiasis prevalence maps. Methodology We analyzed survey data compiled on a newly established open-access global neglected tropical diseases database (i) to create smooth empirical prevalence maps for Schistosoma mansoni and S. haematobium for individuals aged ≤20 years in West Africa, including Cameroon, and (ii) to derive country-specific prevalence estimates. We used Bayesian geostatistical models based on environmental predictors to take into account potential clustering due to common spatially structured exposures. Prediction at unobserved locations was facilitated by joint kriging. Principal Findings Our models revealed that 50.8 million individuals aged ≤20 years in West Africa are infected with either S. mansoni, or S. haematobium, or both species concurrently. The country prevalence estimates ranged between 0.5% (The Gambia) and 37.1% (Liberia) for S. mansoni, and between 17.6% (The Gambia) and 51.6% (Sierra Leone) for S. haematobium. We observed that the combined prevalence for both schistosome species is two-fold lower in Gambia than previously reported, while we found an almost two-fold higher estimate for Liberia (58.3%) than reported before (30.0%). Our predictions are likely to overestimate overall country prevalence, since modeling was based on children and adolescents up to the age of 20 years who are at highest risk of infection. Conclusion/Significance We
Vanasse, Alain; Courteau, Josiane; Fleury, Marie-Josée; Grégoire, Jean-Pierre; Lesage, Alain; Moisan, Jocelyne
Using a population health services perspective, this article defines and assesses an efficient criteria-based algorithm to identify treatment prevalent and incident cases of schizophrenia. We refer here "treatment" prevalence and incidence since its evaluation depends on a patient receiving a health care service with a diagnosis of schizophrenia. A population-based cohort study was conducted among all adults having a hospital discharge or a physician claim for schizophrenia in the public health plan databases between January 1996 and December 2006. Four algorithms to characterize patients with schizophrenia were defined. To identify treatment incident cases in 2006, we removed from the treatment prevalent pool patients with a previous record of schizophrenia between 1996 and 2006 (10-year clearance period). Using this 10-year period as reference, Kappa coefficients (KC) and positive predictive values (PPV) were calculated to determine the "optimal" length of clearance period to identify incident cases. The lifetime treatment prevalence and incidence of schizophrenia varied from 0.59 to 1.46% and from 42 to 94 per 100,000, respectively. When compared to the 10-year clearance period, the KC is excellent in a clearance period of 6-7 years. To achieve a PPV of 90%, a clearance period of 7-8 years would be necessary. With an appropriate algorithm, treatment prevalence and incidence of schizophrenia can be conveniently estimated using administrative data. These estimates are a vital step toward appropriate planning of services for schizophrenia.
Azevedo, Tiago Castro Lopes; Zwahlen, Marcel; Rauch, Andri; Egger, Matthias; Wandeler, Gilles
Introduction Although hepatitis C virus (HCV) screening is recommended for all HIV-infected patients initiating antiretroviral therapy, data on epidemiologic characteristics of HCV infection in resource-limited settings are scarce. Methods We searched PubMed and EMBASE for studies assessing the prevalence of HCV infection among HIV-infected individuals in Africa and extracted data on laboratory methods used. Prevalence estimates from individual studies were combined for each country using random-effects meta-analysis. The importance of study design, population and setting as well as type of test (anti-HCV antibody tests and polymerase chain reactions) was examined with meta-regression. Results Three randomized controlled trials, 28 cohort studies and 121 cross-sectional analyses with 108,180 HIV-infected individuals from 35 countries were included. The majority of data came from outpatient populations (55%), followed by blood donors (15%) and pregnant women (14%). Based on estimates from 159 study populations, anti-HCV positivity prevalence ranged between 3.3% (95% confidence interval (CI) 1.8–4.7) in Southern Africa and 42.3% (95% CI 4.1–80.5) in North Africa. Study design, type of setting and age distribution did not influence this prevalence significantly. The prevalence of replicating HCV infection, estimated from data of 29 cohorts, was 2.0% (95% CI 1.5–2.6). Ten studies from nine countries reported the HCV genotype of 74 samples, 53% were genotype 1, 24% genotype 2, 14% genotype 4 and 9% genotypes 3, 5 or 6. Conclusions The prevalence of anti-HCV antibodies is high in HIV-infected patients in Africa, but replicating HCV infection is rare and varies widely across countries. PMID:27293220
Azevedo, Tiago Castro Lopes; Zwahlen, Marcel; Rauch, Andri; Egger, Matthias; Wandeler, Gilles
Although hepatitis C virus (HCV) screening is recommended for all HIV-infected patients initiating antiretroviral therapy, data on epidemiologic characteristics of HCV infection in resource-limited settings are scarce. We searched PubMed and EMBASE for studies assessing the prevalence of HCV infection among HIV-infected individuals in Africa and extracted data on laboratory methods used. Prevalence estimates from individual studies were combined for each country using random-effects meta-analysis. The importance of study design, population and setting as well as type of test (anti-HCV antibody tests and polymerase chain reactions) was examined with meta-regression. Three randomized controlled trials, 28 cohort studies and 121 cross-sectional analyses with 108,180 HIV-infected individuals from 35 countries were included. The majority of data came from outpatient populations (55%), followed by blood donors (15%) and pregnant women (14%). Based on estimates from 159 study populations, anti-HCV positivity prevalence ranged between 3.3% (95% confidence interval (CI) 1.8-4.7) in Southern Africa and 42.3% (95% CI 4.1-80.5) in North Africa. Study design, type of setting and age distribution did not influence this prevalence significantly. The prevalence of replicating HCV infection, estimated from data of 29 cohorts, was 2.0% (95% CI 1.5-2.6). Ten studies from nine countries reported the HCV genotype of 74 samples, 53% were genotype 1, 24% genotype 2, 14% genotype 4 and 9% genotypes 3, 5 or 6. The prevalence of anti-HCV antibodies is high in HIV-infected patients in Africa, but replicating HCV infection is rare and varies widely across countries.
Duryea, Elias J.; Herrera, Denise; Parkes, Jay
Surveyed ninth graders regarding the prevalence of nonverbal pressures in their daily experiences, noting gender differences. Students reported high levels of exposure to and conformity with nonverbal pressure, with differences in prevalence of receiving threatening gestures, space invasion from males, trust toward deceptive smiles from males, and…
Nogareda, F; Le Strat, Y; Villena, I; De Valk, H; Goulet, V
Toxoplasmosis is a worldwide zoonosis due to Toxoplasma gondii, a ubiquitous protozoan parasite of warm-blooded animals including humans. In pregnant women, primary infection can cause congenital toxoplasmosis resulting in severe malformations in the newborn. Since 1978, public health authorities in France have implemented a congenital toxoplasmosis prevention programme, including monthly serological screening of all seronegative pregnant women, and treatment in case of seroconversion. However, this programme does not produce systematic surveillance data on incidence and prevalence. Our objective was to estimate the incidence and prevalence of T. gondii infection, and the incidence of seroconversion during pregnancy in women in France. We used a catalytic model to estimate incidence and prevalence of Toxoplasma infection between 1980 and 2020 in women of childbearing age. We used age- and time-specific seroprevalence data obtained from the National Perinatal Surveys (NPS) conducted in 1995, 2003 and 2010. We assumed that incidence depends both on age and calendar time, and can be expressed as the product of two unknown functions. We also estimated incidence of seroconversion during pregnancy in 2010 from the NPS and the National Surveillance of Congenital Toxoplasmosis (ToxoSurv). We combined data of 42208 women aged 15-45 years with serology available from the three NPS. For women aged 30 years the modelled incidence decreased from 7·5/1000 susceptible women in 1980 to 3·5/1000 in 2000. In 2010 the incidence was 2·4/1000. The predicted incidence and prevalence for 2020 was 1·6/1000 and 27%, respectively. The incidence of seroconversion during pregnancy in 2010 was estimated at 2·1/1000 susceptible pregnant women (95% CI 1·3-3·1) from the NPS and 1·9 (95% CI 1·8-2·1) from ToxoSurv. Incidence and prevalence of Toxoplasma infection has decreased markedly during the last 30 years. This decrease may be explained by a lower exposure to the parasite by changes
Seliske, L; Norwood, T A; McLaughlin, J R; Wang, S; Palleschi, C; Holowaty, E
An important public health goal is to decrease the prevalence of key behavioural risk factors, such as tobacco use and obesity. Survey information is often available at the regional level, but heterogeneity within large geographic regions cannot be assessed. Advanced spatial analysis techniques are demonstrated to produce sensible micro area estimates of behavioural risk factors that enable identification of areas with high prevalence. A spatial Bayesian hierarchical model was used to estimate the micro area prevalence of current smoking and excess bodyweight for the Erie-St. Clair region in southwestern Ontario. Estimates were mapped for male and female respondents of five cycles of the Canadian Community Health Survey (CCHS). The micro areas were 2006 Census Dissemination Areas, with an average population of 400-700 people. Two individual-level models were specified: one controlled for survey cycle and age group (model 1), and one controlled for survey cycle, age group and micro area median household income (model 2). Post-stratification was used to derive micro area behavioural risk factor estimates weighted to the population structure. SaTScan analyses were conducted on the granular, postal-code level CCHS data to corroborate findings of elevated prevalence. Current smoking was elevated in two urban areas for both sexes (Sarnia and Windsor), and an additional small community (Chatham) for males only. Areas of excess bodyweight were prevalent in an urban core (Windsor) among males, but not females. Precision of the posterior post-stratified current smoking estimates was improved in model 2, as indicated by narrower credible intervals and a lower coefficient of variation. For excess bodyweight, both models had similar precision. Aggregation of the micro area estimates to CCHS design-based estimates validated the findings. This is among the first studies to apply a full Bayesian model to complex sample survey data to identify micro areas with variation in risk
McLean, Susannah; Barbour, Victoria; Wild, Sarah; Simpson, Colin; Sheikh, Aziz
Epidemiological models for estimating the prevalence and burden of disease inform health policy and service planning decisions. Our aim was to describe the challenges in evaluating such models using the example of epidemiological models for chronic obstructive pulmonary disease (COPD). Two reviewers searched Medline, Embase, CAB Abstracts and World Health Organization (WHO) Databases from 1980 to November 2013 for epidemiological models of COPD prevalence and burden. Two reviewers extracted data and assessed the quality of the studies. We then undertook a descriptive and narrative synthesis of data. We identified 22 models employing a variety of techniques to calculate the prevalence and/or burden of COPD. Models calculated prevalence and/or mortality or other facet of disease burden using demographics and risk factors or trends, Markov-type modelling and microsimulation modelling. The six models which scored highly on the quality framework were: the Peabody model, which generated estimates of COPD prevalence; the WHO DISMOD II model which produced burden estimates in terms of disability adjusted life years with COPD and life years lost to COPD; the Atsou model which gave the life expectancy gains of individual smokers who quit smoking and associated costs; two Dutch COPD models which produced estimates of mortality and health care costs related to COPD; and the Pichon-Riviere model which gave the costs and cost effectiveness of smoking quit programmes. The field of chronic disease modelling is burgeoning. As a result, policy makers need to understand how to interpret epidemiological models and their data sources. © The Author(s) 2015.
Langeland, Willemien; Hoogendoorn, Adriaan W; Mager, Daniel; Smit, Jan H; Draijer, Nel
Estimates of the extent of childhood sexual abuse (CSA) within in the Roman Catholic Church (RCC) in the general population are difficult to find. The independent Commission of Inquiry into sexual abuse of minors in the RCC in the Netherlands collected population-based data to estimate its prevalence. A large random online population sample was surveyed using a two-phase stratified sampling procedure. In Phase 1, 34,267 subjects aged 40 years and older were screened for childhood exposure to sexual abuse by non-family members, a history of institutionalization and a Roman Catholic upbringing. In Phase 2, a stratified subset of 2,462 subjects was assessed to obtain more detailed target information about sexual abuse reports within the RCC. We employed multiple imputation for the estimation of RCC CSA in the original Phase 1 sample. The prevalence of non-familial CSA in general (14.0%) was higher among women (17.2%) than among men (10.6%). The prevalence of CSA within the Dutch RCC (1.7%) was higher among men (2.7%) than among women (0.7%). As expected, older subjects reported more often CSA in the RCC than their younger counterparts. Respondents who stayed for some time in RCC run institutions for education or child protection had a higher risk to report sexual abuse. Although sexual abuse of minors by representatives of the RCC was a structural problem during a period that the Church was highly influential in the Netherlands, the estimated prevalence of the phenomenon is only a fraction of the prevalence rate of non-familial CSA.
Altman, Barbara M; Gulley, Stephen P
An analysis of data from the Joint Canada/United States Survey of Health (JCUSH), allows us to compare prevalence estimates that result from four different question sets designed to assess disability from a group of respondents residing in either Canada or the United States. Depending upon the question set used and the coding applied to the responses, age-standardized prevalence estimates varied widely in both countries. In the U.S. noninstitutionalized adult population, disability prevalence estimates ranged from as low as 15.3% to as high as 36.4%, while in Canada the estimates ranged from 13.4% to 37.3%. Concordance and discordance in identification as disabled among these question sets were also examined. In both countries, less than 20% of those identified as disabled by any question set were identified as disabled on all four question sets when using conservative response coding to define disability. Concordance in answers to these questions was also found to be associated with older age, single marital status, low education and low income in both countries. Discordance between question set pairs was similar across both countries whether among measures based on the same domains of disability or different domains of disability. The theory, methods and future of disability measurement in health surveys are discussed in light of these findings. We conclude that understanding and interpreting national prevalence estimates requires more thoughtful attention to the purposes for which data are being collected, the specific definition and operationalizations of disability for those purposes, the methodology used in the data collection and analysis process and the areas of both commonality and difference in the populations identified by each question set. In terms of cross-cultural comparisons, the use of a common set of questions and answer categories and similar survey methodologies provides much more robust results.
Huang, Chiung-Yu; Qin, Jing
The Canadian Study of Health and Aging (CSHA) employed a prevalent cohort design to study survival after onset of dementia, where patients with dementia were sampled and the onset time of dementia was determined retrospectively. The prevalent cohort sampling scheme favors individuals who survive longer. Thus, the observed survival times are subject to length bias. In recent years, there has been a rising interest in developing estimation procedures for prevalent cohort survival data that not only account for length bias but also actually exploit the incidence distribution of the disease to improve efficiency. This article considers semiparametric estimation of the Cox model for the time from dementia onset to death under a stationarity assumption with respect to the disease incidence. Under the stationarity condition, the semiparametric maximum likelihood estimation is expected to be fully efficient yet difficult to perform for statistical practitioners, as the likelihood depends on the baseline hazard function in a complicated way. Moreover, the asymptotic properties of the semiparametric maximum likelihood estimator are not well-studied. Motivated by the composite likelihood method (Besag 1974), we develop a composite partial likelihood method that retains the simplicity of the popular partial likelihood estimator and can be easily performed using standard statistical software. When applied to the CSHA data, the proposed method estimates a significant difference in survival between the vascular dementia group and the possible Alzheimer’s disease group, while the partial likelihood method for left-truncated and right-censored data yields a greater standard error and a 95% confidence interval covering 0, thus highlighting the practical value of employing a more efficient methodology. To check the assumption of stable disease for the CSHA data, we also present new graphical and numerical tests in the article. The R code used to obtain the maximum composite partial
Robertson, L; Gregson, S; Madanhire, C; Walker, N; Mushati, P; Garnett, G; Nyamukapa, C
Objectives: Model-based estimates of maternal (but not paternal) orphanhood are higher than those based on data from demographic and health surveys (DHS). We investigate the consistency of reporting of parental survival status in data from Manicaland, Zimbabwe. Methods: We compared estimates of paternal and maternal orphan prevalence in three rounds of a prospective household census in Manicaland (1998–2005) with estimates from DHS surveys and UNAIDS model projections. We investigated the consistency of reporting of parental survival status across the three rounds and compared estimates of adult mortality from the orphan data with direct estimates from concurrent follow-up of a general population cohort. Qualitative data were collected on possible reasons for misreporting. Results: Paternal and maternal orphan prevalence is increasing in Zimbabwe. Mothers reported as deceased in round 1 of the Manicaland survey were more likely than fathers to be reported as alive in rounds 2 or 3 (33.3% vs 13.4%). This pattern was most apparent among younger children. The qualitative findings suggest that foster parents sometimes claim adopted children as their natural children. Conclusions: These results are consistent with misreporting of foster parents as natural parents. This appears to be particularly common among foster mothers and could partly explain the discrepancy between mathematical model and DHS estimates of maternal orphanhood. PMID:18647868
Fraser, Simon D S; Aitken, Grant; Taal, Maarten W; Mindell, Jennifer S; Moon, Graham; Day, Julie; O'Donoghue, Donal; Roderick, Paul J
Chronic kidney disease (CKD) diagnosis relies on glomerular filtration rate (eGFR) estimation, traditionally using the creatinine-based Modification of Diet in Renal Disease (MDRD) equation. The Chronic Kidney Disease Epidemiology Collaboration (CKDEPI) equation performs better in estimating eGFR and predicting mortality and CKD progression risk. Cystatin C is an alternative glomerular filtration marker less influenced by muscle mass. CKD risk stratification is improved by combining creatinine eGFR with cystatin C and urinary albumin to creatinine ratio (uACR). We aimed to identify the impact of introducing CKDEPI and cystatin C on the estimated prevalence and risk stratification of CKD in England and to describe prevalence and associations of cystatin C. Cross sectional study of 5799 people in the nationally representative 2009 and 2010 Health Surveys for England. prevalence of MDRD, CKDEPI and cystatin C-defined eGFR<60 ml/min/1.73 m(2); prevalence of CKD biomarker combinations (creatinine, cystatin C, uACR). Using CKDEPI instead of MDRD reduced the prevalence of eGFR<60 ml/min/1.73 m(2) from 6.0% (95% CI 5.4-6.6%) to 5.2% (4.7-5.8%) equivalent to around 340,000 fewer individuals in England. Those reclassified as not having CKD evidenced a lower risk profile. Prevalence of cystatin C eGFR<60 ml/min/1.73 m(2) was 7.7% and independently associated with age, lack of qualifications, being an ex-smoker, BMI, hypertension, and albuminuria. Measuring cystatin C in the 3.9% people with CKDEPI-defined eGFR<60 ml/min/1.73 m(2) without albuminuria (CKD Category G3a A1) reclassified about a third into a lower risk group with one of three biomarkers and two thirds into a group with two of three. Measuring cystatin C in the 6.7% people with CKDEPI eGFR >60 ml/min/1.73 m(2) with albuminuria (CKD Category G1-2) reclassified almost a tenth into a higher risk group. Cross sectional study, single eGFR measure, no measured ('true') GFR. Introducing the CKDEPI equation and targeted
Ramírez-Backhaus, M; Arlandis Guzmán, S; García Fadrique, G; Agulló, Martínez; Martínez García, R; Jiménez-Cruz, J F
Nocturnal enuresis is a disorder with a maintained historical interest. Not only the multifactorial etiopathology, also its prevalence. We consider reviewing the literature for knowing the problematic in the calculation of the prevalence of this disease. We searched in Pubmed database with Mesh terms: "Enuresis", "Nocturnal Enuresis", we added in the search box terms bedwetting and epidemiology or prevalence. We included manuscripts in English and Spanish with more than 1000 patients as sample, we also included review papers. We analyzed the methodology and the prevalence, when it was possible, we stratified results in age, sex and the frequency of wet nights. The analyzed study's methodology is heterogeneous. Therefore comparisons are difficult. Due to the difficulty within the interpretation of the overall frequency, the results are not interesting unless methodology, age range of the sample and diagnosis criteria are previously detailed. An own epidemiology study is necessary in order to solve our problematic.
Otsa, K; Tammaru, M; Vorobjov, S; Esko, M; Pärsik, E; Lang, K
Sound epidemiological data are a basic requirement for decision making on the allocation of health care resources. Unfortunately, this is not the case in Estonia, where the paucity of epidemiological data has impeded health care planning for rheumatic conditions. The current paper presents the first effort to explore the epidemiology of rheumatoid arthritis (RA) in Estonia. Electronic databases of all rheumatology units of Harju County, three national and one private, were searched for the records of RA (ICD-10 diagnoses M05 and M06.0) patients who had visited a rheumatologist during 2006 or 2007. Prevalence of RA was calculated for the age 20 years and older and for subsets according to age and gender, using the numbers from the patients' database in the numerator and the corresponding population numbers in the denominator. The total number of prevalent RA cases was 1,897, of which 85 % (n = 1,605) were women. The overall crude period prevalence 2006-2007 of RA in Harju County for the age group 20 years and older was 0.46 %. RA prevalence for both sexes increased with age until the age of 70-79 years and decreased subsequently. Prevalence of RA was significantly higher for women compared with men in all age groups. The prevalence of RA among women and men 20 years and older was 0.70 % (6.68-7.37) and 0.16 % (1.42, 1.79), respectively. Age-standardized (European population) prevalence rate was 0.44 %. The results are concordant with epidemiological data on RA prevalence derived recently in other European countries.
Sousa, Tanara; Lunnen, Jeffrey C; Gonçalves, Veralice; Schmitz, Aurinez; Pasa, Graciela; Bastos, Tamires; Sripad, Pooja; Chandran, Aruna; Pechansky, Flavio
Drunk driving is an important risk factor for road traffic crashes, injuries and deaths. After June 2008, all drivers in Brazil were subject to a "Zero Tolerance Law" with a set breath alcohol concentration of 0.1 mg/L of air. However, a loophole in this law enabled drivers to refuse breath or blood alcohol testing as it may self-incriminate. The reported prevalence of drunk driving is therefore likely a gross underestimate in many cities. To compare the prevalence of drunk driving gathered from police reports to the prevalence gathered from self-reported questionnaires administered at police sobriety roadblocks in two Brazilian capital cities, and to estimate a more accurate prevalence of drunk driving utilizing three correction techniques based upon information from those questionnaires. In August 2011 and January-February 2012, researchers from the Centre for Drug and Alcohol Research at the Universidade Federal do Rio Grande do Sul administered a roadside interview on drunk driving practices to 805 voluntary participants in the Brazilian capital cities of Palmas and Teresina. Three techniques which include measures such as the number of persons reporting alcohol consumption in the last six hours but who had refused breath testing were used to estimate the prevalence of drunk driving. The prevalence of persons testing positive for alcohol on their breath was 8.8% and 5.0% in Palmas and Teresina respectively. Utilizing a correction technique we calculated that a more accurate prevalence in these sites may be as high as 28.2% and 28.7%. In both cities, about 60% of drivers who self-reported having drank within six hours of being stopped by the police either refused to perform breathalyser testing; fled the sobriety roadblock; or were not offered the test, compared to about 30% of drivers that said they had not been drinking. Despite the reduction of the legal limit for drunk driving stipulated by the "Zero Tolerance Law," loopholes in the legislation permit many
Kruijshaar, Michelle E; Barendregt, Jan J; Van De Poll-Franse, Lonneke V
BACKGROUND: Health policy and planning depend on quantitative data of disease epidemiology. However, empirical data are often incomplete or are of questionable validity. Disease models describing the relationship between incidence, prevalence and mortality are used to detect data problems or supplement missing data. Because time trends in the data affect their outcome, we compared the extent to which trends and known data problems affected model outcome for breast cancer. METHODS: We calculated breast cancer prevalence from Dutch incidence and mortality data (the Netherlands Cancer Registry and Statistics Netherlands) and compared this to regionally available prevalence data (Eindhoven Cancer Registry, IKZ). Subsequently, we recalculated the model adjusting for 1) limitations of the prevalence data, 2) a trend in incidence, 3) secondary primaries, and 4) excess mortality due to non-breast cancer deaths. RESULTS: There was a large discrepancy between calculated and IKZ prevalence, which could be explained for 60% by the limitations of the prevalence data plus the trend in incidence. Secondary primaries and excess mortality had relatively small effects only (explaining 17% and 6%, respectively), leaving a smaller part of the difference unexplained. CONCLUSION: IPM models can be useful both for checking data inconsistencies and for supplementing incomplete data, but their results should be interpreted with caution. Unknown data problems and trends may affect the outcome and in the absence of additional data, expert opinion is the only available judge.
Kilpatrick, Dean G; Resnick, Heidi S; Milanak, Melissa E; Miller, Mark W; Keyes, Katherine M; Friedman, Matthew J
Prevalence of posttraumatic stress disorder (PTSD) defined according to the American Psychiatric Association's Diagnostic and Statistical Manual fifth edition (DSM-5; 2013) and fourth edition (DSM-IV; 1994) was compared in a national sample of U.S. adults (N = 2,953) recruited from an online panel. Exposure to traumatic events, PTSD symptoms, and functional impairment were assessed online using a highly structured, self-administered survey. Traumatic event exposure using DSM-5 criteria was high (89.7%), and exposure to multiple traumatic event types was the norm. PTSD caseness was determined using Same Event (i.e., all symptom criteria met to the same event type) and Composite Event (i.e., symptom criteria met to a combination of event types) definitions. Lifetime, past-12-month, and past 6-month PTSD prevalence using the Same Event definition for DSM-5 was 8.3%, 4.7%, and 3.8% respectively. All 6 DSM-5 prevalence estimates were slightly lower than their DSM-IV counterparts, although only 2 of these differences were statistically significant. DSM-5 PTSD prevalence was higher among women than among men, and prevalence increased with greater traumatic event exposure. Major reasons individuals met DSM-IV criteria, but not DSM-5 criteria were the exclusion of nonaccidental, nonviolent deaths from Criterion A, and the new requirement of at least 1 active avoidance symptom.
Kilpatrick, Dean G.; Resnick, Heidi S.; Milanak, Melissa E.; Miller, Mark W.; Keyes, Katherine M.; Friedman, Matthew J.
Prevalence of posttraumatic stress disorder (PTSD) defined according to the American Psychiatric Association’s Diagnostic and Statistical Manual fifth edition (DSM-5; 2013) and fourth edition (DSM-IV; 1994) was compared in a national sample of U.S. adults (N = 2,953) recruited from an online panel. Exposure to traumatic events, PTSD symptoms, and functional impairment were assessed online using a highly structured, self-administered survey. Traumatic event exposure using DSM-5 criteria was high (89.7%), and exposure to multiple traumatic event types was the norm. PTSD caseness was determined using Same Event (i.e., all symptom criteria met to the same event type) and Composite Event (i.e., symptom criteria met to a combination of event types) definitions. Lifetime, past-12-month, and past 6-month PTSD prevalence using the Same Event definition for DSM-5 was 8.3%, 4.7%, and 3.8% respectively. All 6 DSM-5 prevalence estimates were slightly lower than their DSM-IV counterparts, although only 2 of these differences were statistically significant. DSM-5 PTSD prevalence was higher among women than among men, and prevalence increased with greater traumatic event exposure. Major reasons individuals met DSM-IV criteria, but not DSM-5 criteria were the exclusion of nonaccidental, nonviolent deaths from Criterion A, and the new requirement of at least 1 active avoidance symptom. PMID:24151000
Nelson, Robert G.; Brinks, Ralph
The objective was to estimate chronic kidney disease (CKD) incidence rates from prevalence and mortality data, and compare the estimates with observed (true) incidence rates in a well-characterized population with diabetes. Pima Indians aged 20 years and older with type 2 diabetes were followed from 1982 through 2007. CKD was defined by estimated GFR (eGFR) <60 ml/min/1.72 m2 or albumin-to-creatinine ratio (ACR) ≥30 mg/g. True CKD incidence and mortality rates were computed for the whole study period, and prevalence for the intervals 1982–1994 and 1995–2007. Estimated age-sex stratified CKD incidence rates were computed using illness-death models of the observed prevalences, and of the whole-period mortality rate ratio of CKD to non-CKD persons. Among 1201 participants, 616 incident events of CKD occurred during a median follow-up of 5.6 years. Observed CKD prevalence was 56.9% (95%CI 53.7–60.0) and 48.0% (95%CI 45.2–50.8) in women; 54.0% (95%CI 49.9–58.1) and 49.6% (95%CI 46.0–53.3) in men, across the two periods. Mortality rate was 2.5 (95%CI 1.9–3.3) times as high in women with CKD and 1.6 (95%CI 1.3–2.1) times as high in men with CKD, compared to women or men without CKD. In women, estimated CKD incidence increased linearly from 25.6 (95%CI 4.2–53.0) to 128.6 (95%CI 77.1–196.6) with each 5-year age group up to 69 years, and to 99.8 (95%CI 38.7–204.7) at age ≥70. In men, estimated CKD incidence increased form 28.5 (95%CI 3.8–71.2) at age 20–24 years to 118.7 (95%CI 23.6–336.7) at age ≥70. Age-sex-stratified estimated incidence reflected the magnitude and directional trend of the true incidence and were similar to the true incidence rates (p>0.05 for difference) except for age 20–24 in women (p = 0.008) and age 25–29 in men (p = 0.002). In conclusion, the estimated and observed incidence rates of CKD agree well over 25 years of observation in this well characterized population with type 2 diabetes. PMID:28166298
Chien, Meng-Yueh; Huang, Ta-Yi; Wu, Ying-Tai
To compare a bioelectrical impedance analysis (BIA) prediction equation for estimating skeletal muscle mass (SM) with magnetic resonance imaging (MRI)-measured SM and to investigate the prevalence of sarcopenia in community-dwelling elderly people in Taiwan. Cross-sectional survey. Communities in the district of Zhongzheng, Taipei. Forty-one volunteers (aged 22-90) for BIA equation validation; 302 individuals aged 65 and older and 200 adults aged 18 to 40 for the investigation of the prevalence of sarcopenia. Skeletal muscle mass was estimated using a BIA prediction equation and measured using MRI. No statistical difference between MRI-measured and BIA-derived SM was observed (difference of -0.44 +/- 1.55 kg, P=.08). The prevalence of sarcopenia in was 18.6% in elderly women and 23.6% in elderly men. Estimation of SM using a BIA equation was validated in Taiwanese volunteers. It was confirmed that sarcopenia is an emerging health problem in the aging population in Taiwan.
Miramontes, Roque; Hill, Andrew N.; Yelk Woodruff, Rachel S.; Lambert, Lauren A.; Navin, Thomas R.; Castro, Kenneth G.; LoBue, Philip A.
Background Reexamining the prevalence of persons infected with tuberculosis (TB) is important to determine trends over time. In 2011–2012 a TB component was included in the National Health and Nutrition Examination Survey (NHANES) to estimate the reservoir of persons infected with TB. Methods Civilian, noninstitutionalized U.S. population survey participants aged 6 years and older were interviewed regarding their TB history and eligibility for the tuberculin skin test (TST) and interferon gamma release assay (IGRA) blood test. Once eligibility was confirmed, both tests were conducted. Prevalence and numbers of TST positive (10 mm or greater), IGRA positive, and both TST and IGRA positive were calculated by adjusting for the complex survey design after applying corrections for item nonresponse and digit preference in TST induration measurements. To examine TST positivity over time, data from NHANES 1999–2000 were reanalyzed using the same statistical methods. The TST was performed using Tubersol, a commercially available purified protein derivative (PPD), rather than PPD-S, which was the antigen used in NHANES 1999–2000. Prior patient history of TB vaccination was not collected in this study nor were patients examined for the presence of a Bacillus of Calmette and Guerin (BCG) vaccine scar. Results For NHANES 2011–2012, TST and IGRA results were available for 6,128 (78.4%) and 7,107 (90.9%) eligible participants, respectively. There was no significant difference between the percentage of the U.S. population that was TST positive in 2011–2012 (4.7% [95% CI 3.4–6.3]; 13,276,000 persons) compared with 1999–2000 (4.3%; 3.5–5.3). In 2011–2012 the percentage that was IGRA positive was 5.0% (4.2–5.8) and double TST and IGRA positivity was 2.1% (1.5–2.8). The point estimate of IGRA positivity prevalence in foreign-born persons (15.9%; 13.5–18.7) was lower than for TST (20.5%; 16.1–25.8) in 2011–2012. The point estimate of IGRA positivity
Steppan, Martin; Kraus, Ludwig; Piontek, Daniela; Siciliano, Valeria
Prevalence estimation of cannabis use is usually based on self-report data. Although there is evidence on the reliability of this data source, its cross-cultural validity is still a major concern. External objective criteria are needed for this purpose. In this study, cannabis-related search engine query data are used as an external criterion. Data on cannabis use were taken from the 2007 European School Survey Project on Alcohol and Other Drugs (ESPAD). Provincial data came from three Italian nation-wide studies using the same methodology (2006-2008; ESPAD-Italia). Information on cannabis-related search engine query data was based on Google search volume indices (GSI). (1) Reliability analysis was conducted for GSI. (2) Latent measurement models of "true" cannabis prevalence were tested using perceived availability, web-based cannabis searches and self-reported prevalence as indicators. (3) Structure models were set up to test the influences of response tendencies and geographical position (latitude, longitude). In order to test the stability of the models, analyses were conducted on country level (Europe, US) and on provincial level in Italy. Cannabis-related GSI were found to be highly reliable and constant over time. The overall measurement model was highly significant in both data sets. On country level, no significant effects of response bias indicators and geographical position on perceived availability, web-based cannabis searches and self-reported prevalence were found. On provincial level, latitude had a significant positive effect on availability indicating that perceived availability of cannabis in northern Italy was higher than expected from the other indicators. Although GSI showed weaker associations with cannabis use than perceived availability, the findings underline the external validity and usefulness of search engine query data as external criteria. The findings suggest an acceptable relative comparability of national (provincial) prevalence
Joseph, B.; Ravikumar, R.; John, M.; Natarajan, K.; Steinhoff, M. C.; John, T. J.
Although reliable data on the prevalence and trends of paralytic poliomyelitis are necessary for health planning, they are often difficult to obtain in developing countries. Comparisons were made of the cost and the time taken to obtain prevalence rates of residual poliomyelitis paralysis in a single community by (1) a surveillance and reporting system using physicians and other practitioners, (2) a school survey covering grades 1 to 12, (3) annual surveys of grade 1 schoolchildren, and (4) a house-to-house questionnaire survey. These techniques gave poliomyelitis prevalence rates of 3-5 per 1000 school-age children, and poliomyelitis incidence rates of 12-29 per 100 000 population per year. The annual grade 1 school survey was the cheapest and easiest to carry out and appears reliable in areas with a high rate of school enrolment. PMID:6606499
Binbay, Tolga; Ulaş, Halis; Alptekin, Köksal; Elbi, Hayriye
To provide an overview of incidence and prevalence estimates, admission rates, and related features of psychotic disorders among immigrants from Turkey in Western Europe. Articles published in all languages between 1990 and 2010 were included. In order to detect relevant studies, a string ([schizo* OR psych*] AND [Turk*] AND [migra* OR immigra*]) was used in MEDLINE and PsychINFO. Turkish indexes and abstracts books of national congresses were also screened to locate additional papers. We included 21 studies which yielded 25 rates on psychotic disorders among immigrants from Turkey. Fifteen papers reported rates for the immigrants from Turkey in The Netherlands, four for Germany, one for Denmark and one for Switzerland. The incidence estimates of non-affective and affective psychosis among immigrants from Turkey were between 38.5 and 44.9 per 100,000 while incidence estimates of schizophrenia were between 12.4 and 63.8 per 100,000. The prevalence estimates of schizophrenia and other psychotic disorders were between 1.1 and 6.2 per 1,000. Rates and relative risks of psychotic disorders in immigrants from Turkey tended to be higher than the natives and lower than other immigrant groups with similar sociocultural background. In addition to other risk factors, social contextual factors including discrimination and neighbourhood characteristics were the key environmental factors that modulate rates of psychotic disorders among immigrants from Turkey. Males were under a higher risk of incidence, prevalence estimates, and admission rates. Variations in rates and relative risks indicate a possible etiological role of social experiences in immigrants. Studies with a focus on comparing the rates and the social factors of psychotic disorders between immigrants from Turkey in Western Europe and their family members residing in Turkey may provide additional insight into the epidemiology of psychotic disorders.
Chillag-Talmor, Orly; Giladi, Nir; Linn, Shai; Gurevich, Tanya; El-Ad, Baruch; Silverman, Barbara; Friedman, Nurit; Peretz, Chava
Estimating rates of Parkinson's disease (PD) is essential for health services planning and studies of disease determinants. However, few PD registries exist. We aimed to estimate annual prevalence and incidence of PD in a large Israeli population over the past decade using computerized drug purchase data. Based on profiles of anti-parkinsonian drugs, age at first purchase, purchase density, and follow-up time, we developed a refined algorithm for PD assessment (definite, probable or possible) and validated it against clinical diagnoses. We used the prescription database of the second largest Health Maintenance Organization in Israel (covers ~25% of population), for the years 1998-2008. PD rates by age, gender and year were calculated and compared using Poisson models. The algorithm was found to be highly sensitive (96%) for detecting PD cases. We identified 7,134 prevalent cases (67% definite/probable), and 5,288 incident cases (65% definite/probable), with mean age at first purchase 69 ± 13 years. Over the years 2000-2007, PD incidence rate of 33/100,000 was stable, and the prevalence rate increased from 170/100,000 to 256/100,000. For ages 50+, 60+, 70+, median prevalence rates were 1%, 2%, 3%, respectively. Incidence rates also increased with age (RR = 1.76, 95%CI 1.75-1.77, ages 50+, 5-year interval). For ages 50+, rates were higher among men for both prevalence (RR = 1.38, 95%CI 1.37-1.39) and incidence (RR = 1.45, 95%CI 1.42-1.48). In conclusion, our refined algorithm for PD assessment, based on computerized drug purchases data, may be a reliable tool for population-based studies. The findings indicate a burden of PD in Israel higher than previously assumed.
Balasubramaniam, Kirubakaran; Ravn, Pernille; Larsen, Pia V; Søndergaard, Jens; Jarbøl, Dorte E
To determine prevalence estimates of gynecological alarm symptoms in different age groups and to describe common patterns of gynecological symptoms. Web-based cross-sectional survey study. Nationwide in Denmark. A random sample of 51,090 women aged 20 years or above from the general population. An internet-based questionnaire study regarding the prevalence estimates of symptom experiences. A total of 18 symptoms of cervical, endometrial and ovarian cancer were selected through an extensive literature search, which included national and international guidelines. Prevalence estimates of self-reported experience of gynecological alarm symptoms within the preceding 4 weeks. A total of 26,466 women (54.5%) participated in the study. Some 80.3% had experienced at least one of the alarm symptoms within the preceding 4 weeks, and the median number of experienced symptoms was 2 (interquartile range 1-4). The most common symptoms were tiredness (53.0%) and abdominal bloating (36.7%); postmenopausal bleeding (2.3%) and involuntary weight loss (2.8%) were least frequent. Most of the symptoms were more prevalent among younger women, whereas only dyspnea and increased urgency of urination were more frequent among older women. Among younger women, multiple abdominal symptoms often occurred simultaneously and frequently in combination with pelvic pain, whereas older women were more likely to report single symptoms. Gynecological alarm symptoms are frequent in the general population, mostly among younger women. Older women reported fewer symptoms, and these often appeared as single symptoms. © 2014 Nordic Federation of Societies of Obstetrics and Gynecology.
Jull, Andrew; McCall, Elaine; Chappell, Matt; Tobin, Sam
To describe a surveillance approach for monitoring the effect of improvement initiatives on hospital-acquired pressure injuries and findings arising from that surveillance. Random sampling of patients on the same day of each successive month from a campus of child and adult hospitals using a standard audit tool to identify presence of hospital-acquired pressure injury. Where multiple pressure injuries were present, the most severe grade injury contributed to prevalence. Statistical process control charts were used to monitor monthly performance and Maximum Likelihood Estimation to determine timing of step change. 8274 patients were assessed over 3 years from an eligible population of 32,259 hospitalised patients. 517 patients had hospital-acquired pressure injuries giving an overall prevalence of 6.2% (95% CI 5.7-6.8%). Annual prevalence was 8.4% (95% CI 7.4-9.5%) in the first year, falling to 5.6% (95% CI 4.7-6.4%) in the second year and 4.8% (95% CI 4.0-5.6%) in the third year. A step change was signalled with mean prevalence up to July 2013 being 7.9% (95% CI 7.1-8.8%) and mean prevalence thereafter 4.8% (95% CI 4.2-5.4%). Hospital-acquired pressure injuries were found in all age ranges, but were more frequent in children up to 14 years (17.4%) and those aged 75 years or older (38.7%). Monthly random sampling of patients within clinical units can be used to monitor performance improvement. This approach represents a rational alternative to cross-sectional prevalence surveys especially if the focus is on performance improvement. Copyright © 2016 Elsevier Ltd. All rights reserved.
Fidell, Sanford; Mestre, Vincent; Schomer, Paul; Berry, Bernard; Gjestland, Truls; Vallet, Michel; Reid, Timothy
Numerous relationships between noise exposure and transportation noise-induced annoyance have been inferred by curve-fitting methods. The present paper develops a different approach. It derives a systematic relationship by applying an a priori, first-principles model to the findings of forty three studies of the annoyance of aviation noise. The rate of change of annoyance with day-night average sound level (DNL) due to aircraft noise exposure was found to closely resemble the rate of change of loudness with sound level. The agreement of model predictions with the findings of recent curve-fitting exercises (cf. Miedma and Vos, 1998) is noteworthy, considering that other analyses have relied on different analytic methods and disparate data sets. Even though annoyance prevalence rates within individual communities consistently grow in proportion to duration-adjusted loudness, variability in annoyance prevalence rates across communities remains great. The present analyses demonstrate that 1) community-specific differences in annoyance prevalence rates can be plausibly attributed to the joint effect of acoustic and non-DNL related factors and (2) a simple model can account for the aggregate influences of non-DNL related factors on annoyance prevalence rates in different communities in terms of a single parameter expressed in DNL units-a "community tolerance level."
Zahariadis, G; Plitt, S S; O'Brien, S; Yi, Q-L; Fan, W; Preiksaitis, J K
To determine the potential safety benefit of introducing nucleic acid testing (NAT) in tissue and organ donors, the risk of virus transmission was examined in a Canadian population. Anonymous data on Northern Alberta tissue and organ donors from 1998 to 2004 were used to determine the seroprevalence and estimate the seroincidence and residual risk of HIV, HBV, HCV and HTLV infection. Of the 3372 donors identified, 71.1% were surgical bone, 13.2% were living organ and 15.6% were deceased organ/tissue donors. Seroprevalence was: HIV 0.00%, HBV 0.09%, HCV 0.48% and HTLV 0.03%. Incidence (/100,000 p-yrs) and residual risks (/100,000 donors) could only be estimated for HBV (24.2 and 3.9) and HCV (11.2 and 2.2). Risk estimates were higher for deceased donors than surgical bone donors. HCV had the highest prevalence and HBV had the highest estimated incidence. HIV and HTLV risks were extremely low precluding accurate quantification. In this region of low overall viral prevalence, HCV NAT would be most effective in deceased organ donors. In surgical bone donors the cost of implementing NAT is high without significant added safety benefit.
Nankabirwa, Joaniter I; Yeka, Adoke; Arinaitwe, Emmanuel; Kigozi, Ruth; Drakeley, Chris; Kamya, Moses R; Greenhouse, Bryan; Rosenthal, Philip J; Dorsey, Grant; Staedke, Sarah G
Household surveys are important tools for monitoring the malaria disease burden and measuring impact of malaria control interventions with parasite prevalence as the primary metric. However, estimates of parasite prevalence are dependent on a number of factors including the method used to detect parasites, age of the population sampled, and level of immunity. To better understand the influence of diagnostics, age, and endemicity on estimates of parasite prevalence and how these change over time, community-based surveys were performed for two consecutive years in three settings and the sensitivities of microscopy and immunochromatographic rapid diagnostic tests (RDTs) were assessed, considering polymerase chain reaction (PCR) as the gold standard. Surveys were conducted over the same two-month period in 2012 and 2013 in each of three sub-counties in Uganda: Nagongera in Tororo District (January-February), Walukuba in Jinja District (March-April), and Kihihi in Kanungu District (May-June). In each sub-county, 200 households were randomly enrolled and a household questionnaire capturing information on demographics, use of malaria prevention methods, and proxy indicators of wealth was administered to the head of the household. Finger-prick blood samples were obtained for RDTs, measurement of hemoglobin, thick and thin blood smears, and to store samples on filter paper. A total of 1200 households were surveyed and 4433 participants were included in the analysis. Compared to PCR, the sensitivity of microscopy was low (65.3% in Nagongera, 49.6% in Walukuba and 40.9% in Kihihi) and decreased with increasing age. The specificity of microscopy was over 98% at all sites and did not vary with age or year. Relative differences in parasite prevalence across different age groups, study sites, and years were similar for microscopy and PCR. The sensitivity of RDTs was similar across the three sites (range 77.2-82.8%), was consistently higher than microscopy (p < 0.001 for all
Smith, Dianna M; Pearce, Jamie R; Harland, Kirk
Models created to estimate neighbourhood level health outcomes and behaviours can be difficult to validate as prevalence is often unknown at the local level. This paper tests the reliability of a spatial microsimulation model, using a deterministic reweighting method, to predict smoking prevalence in small areas across New Zealand. The difference in the prevalence of smoking between those estimated by the model and those calculated from census data is less than 20% in 1745 out of 1760 areas. The accuracy of these results provides users with greater confidence to utilize similar approaches in countries where local-level smoking prevalence is unknown.
Wang, Hui; Hai, Shan; Cao, Li; Zhou, Jianghua; Liu, Ping; Dong, Bi-Rong
The aim of the present study was to validate the usefulness of the new octapolar multifrequency bioelectrical impedance analysis (BIA) for assessment of appendicular skeletal muscle mass (ASM) by comparing it with that of dual-energy X-ray absorptiometry (DXA) and to investigate the prevalence of sarcopenia in Chinese community-dwelling elderly according to Asian Working Group for Sarcopenia (AWGS) definition. A cross-sectional study was conducted in communities of Chengdu, China. A total of 944 community-dwelling elderly adults aged ≥60 years were included. ASM was measured by using DXA as a criterion method to validate a standing eight-electrode multifrequency BIA (InBody 720), followed by a further estimation of the prevalence of sarcopenia according the AWGS definition. In the Bland-Altman analysis, no significant difference was found between DXA and BIA based on the ASM measurements. The prevalence of AWGS-defined sarcopenia was 12.5% in the elderly women and 8.2% in the elderly men. BIA is suitable for body composition monitoring (ASM) in elderly Chinese as a fast, noninvasive, and convenient method; therefore, it may be a better choice in large epidemiological studies in the Chinese population. The prevalence of AWGS-defined sarcopenia was approximately 10.4% and increased with age in the Chinese community-dwelling elderly in this study.
Smoking prevalence rates in Switzerland in the 1990s++ have been estimated from Perma data, which have been available quarterly since 1991, as well as from the data of the first and second Swiss Health Surveys, conducted in 1992/93 and 1997. Both sources--each providing data on more than 10,000 respondents--have been large-scale surveys that have used different but complementary survey designs. The probabilistic sampling design of the Health Surveys assures representative findings; the Perma data, although obtained through a non-probabilistic sampling design, permits trend analysis as Perma uses multiple measurement points and therefore time-series methodology can be applied. Both Perma and the Health Surveys yielded approximately the same prevalence of 37% male smokers in 1992/93 and 39% in 1997. For females Perma gave 4% higher prevalence rates than the Health Surveys (Surveys 1992/93: 24%; 1997: 31%). For both sexes the increase in total smoking prevalence was accounted for mainly by adolescents and young adults. Whereas the Surveys showed an increase from 29% to 41% (18% to 39%) in males (females) aged 15 to 19 years, the corresponding increase derived from Perma was 50% less. Except for this youngest age-group, differences between the methods remained within standard statistical norms. There is no doubt, however, that smoking in adolescents increased between 1992/93 and 1997.
Nord, Mark; Cafiero, Carlo; Viviani, Sara
Statistical methods based on item response theory are applied to experiential food insecurity survey data from 147 countries, areas, and territories to assess data quality and develop methods to estimate national prevalence rates of moderate and severe food insecurity at equal levels of severity across countries. Data were collected from nationally representative samples of 1,000 adults in each country. A Rasch-model-based scale was estimated for each country, and data were assessed for consistency with model assumptions. A global reference scale was calculated based on item parameters from all countries. Each country's scale was adjusted to the global standard, allowing for up to 3 of the 8 scale items to be considered unique in that country if their deviance from the global standard exceeded a set tolerance. With very few exceptions, data from all countries were sufficiently consistent with model assumptions to constitute reasonably reliable measures of food insecurity and were adjustable to the global standard with fair confidence. National prevalence rates of moderate-or-severe food insecurity assessed over a 12-month recall period ranged from 3 percent to 92 percent. The correlations of national prevalence rates with national income, health, and well-being indicators provide external validation of the food security measure.
Adel, Amel; Abatih, Emmanuel; Speybroeck, Niko; Soukehal, Abdelkrim; Bouguedour, Rachid; Boughalem, Karim; Bouhbal, Abdelmalek; Djerbal, Mouloud; Saegerman, Claude; Berkvens, Dirk
A large-scale study on canine Leishmania infection (CanL) was conducted in six localities along a west-east transect in the Algerian littoral zone (Tlemcen, Mostaganem, Tipaza, Boumerdes, Bejaia, Jijel) and covering two sampling periods. In total 2,184 dogs were tested with an indirect fluorescent antibody test (IFAT) and a direct agglutination test (DAT). Combined multiple-testing and several statistical methods were compared to estimate the CanL true prevalence and tests characteristics (sensitivity and specificity). The Bayesian full model showed the best fit and yielded prevalence estimates between 11% (Mostaganem, first period) and 38% (Bejaia, second period). Sensitivity of IFAT varied (in function of locality) between 86% and 88% while its specificity varied between 65% and 87%. DAT was less sensitive than IFAT but showed a higher specificity (between 80% and 95% in function of locality or/and season). A general increasing trend of the CanL prevalence was noted from west to east. A concordance between the present results and the incidence of human cases of visceral leishmaniasis was observed, where also a maximum was recorded for Bejaia. The results of the present study highlight the dangers when using IFAT as a gold standard. PMID:25793942
Adel, Amel; Abatih, Emmanuel; Speybroeck, Niko; Soukehal, Abdelkrim; Bouguedour, Rachid; Boughalem, Karim; Bouhbal, Abdelmalek; Djerbal, Mouloud; Saegerman, Claude; Berkvens, Dirk
A large-scale study on canine Leishmania infection (CanL) was conducted in six localities along a west-east transect in the Algerian littoral zone (Tlemcen, Mostaganem, Tipaza, Boumerdes, Bejaia, Jijel) and covering two sampling periods. In total 2,184 dogs were tested with an indirect fluorescent antibody test (IFAT) and a direct agglutination test (DAT). Combined multiple-testing and several statistical methods were compared to estimate the CanL true prevalence and tests characteristics (sensitivity and specificity). The Bayesian full model showed the best fit and yielded prevalence estimates between 11% (Mostaganem, first period) and 38% (Bejaia, second period). Sensitivity of IFAT varied (in function of locality) between 86% and 88% while its specificity varied between 65% and 87%. DAT was less sensitive than IFAT but showed a higher specificity (between 80% and 95% in function of locality or/and season). A general increasing trend of the CanL prevalence was noted from west to east. A concordance between the present results and the incidence of human cases of visceral leishmaniasis was observed, where also a maximum was recorded for Bejaia. The results of the present study highlight the dangers when using IFAT as a gold standard.
Crépet, Amélie; Albert, Isabelle; Dervin, Catherine; Carlin, Frédéric
A normal distribution and a mixture model of two normal distributions in a Bayesian approach using prevalence and concentration data were used to establish the distribution of contamination of the food-borne pathogenic bacteria Listeria monocytogenes in unprocessed and minimally processed fresh vegetables. A total of 165 prevalence studies, including 15 studies with concentration data, were taken from the scientific literature and from technical reports and used for statistical analysis. The predicted mean of the normal distribution of the logarithms of viable L. monocytogenes per gram of fresh vegetables was -2.63 log viable L. monocytogenes organisms/g, and its standard deviation was 1.48 log viable L. monocytogenes organisms/g. These values were determined by considering one contaminated sample in prevalence studies in which samples are in fact negative. This deliberate overestimation is necessary to complete calculations. With the mixture model, the predicted mean of the distribution of the logarithm of viable L. monocytogenes per gram of fresh vegetables was -3.38 log viable L. monocytogenes organisms/g and its standard deviation was 1.46 log viable L. monocytogenes organisms/g. The probabilities of fresh unprocessed and minimally processed vegetables being contaminated with concentrations higher than 1, 2, and 3 log viable L. monocytogenes organisms/g were 1.44, 0.63, and 0.17%, respectively. Introducing a sensitivity rate of 80 or 95% in the mixture model had a small effect on the estimation of the contamination. In contrast, introducing a low sensitivity rate (40%) resulted in marked differences, especially for high percentiles. There was a significantly lower estimation of contamination in the papers and reports of 2000 to 2005 than in those of 1988 to 1999 and a lower estimation of contamination of leafy salads than that of sprouts and other vegetables. The interest of the mixture model for the estimation of microbial contamination is discussed.
Howes, Rosalind E.; Piel, Frédéric B.; Patil, Anand P.; Nyangiri, Oscar A.; Gething, Peter W.; Dewi, Mewahyu; Hogg, Mariana M.; Battle, Katherine E.; Padilla, Carmencita D.; Baird, J. Kevin; Hay, Simon I.
Background Primaquine is a key drug for malaria elimination. In addition to being the only drug active against the dormant relapsing forms of Plasmodium vivax, primaquine is the sole effective treatment of infectious P. falciparum gametocytes, and may interrupt transmission and help contain the spread of artemisinin resistance. However, primaquine can trigger haemolysis in patients with a deficiency in glucose-6-phosphate dehydrogenase (G6PDd). Poor information is available about the distribution of individuals at risk of primaquine-induced haemolysis. We present a continuous evidence-based prevalence map of G6PDd and estimates of affected populations, together with a national index of relative haemolytic risk. Methods and Findings Representative community surveys of phenotypic G6PDd prevalence were identified for 1,734 spatially unique sites. These surveys formed the evidence-base for a Bayesian geostatistical model adapted to the gene's X-linked inheritance, which predicted a G6PDd allele frequency map across malaria endemic countries (MECs) and generated population-weighted estimates of affected populations. Highest median prevalence (peaking at 32.5%) was predicted across sub-Saharan Africa and the Arabian Peninsula. Although G6PDd prevalence was generally lower across central and southeast Asia, rarely exceeding 20%, the majority of G6PDd individuals (67.5% median estimate) were from Asian countries. We estimated a G6PDd allele frequency of 8.0% (interquartile range: 7.4–8.8) across MECs, and 5.3% (4.4–6.7) within malaria-eliminating countries. The reliability of the map is contingent on the underlying data informing the model; population heterogeneity can only be represented by the available surveys, and important weaknesses exist in the map across data-sparse regions. Uncertainty metrics are used to quantify some aspects of these limitations in the map. Finally, we assembled a database of G6PDd variant occurrences to inform a national-level index of
Adams, Jimi; Schaefer, David R
We use an empirically grounded simulation model to examine how initial smoking prevalence moderates the effectiveness of potential interventions designed to change adolescent smoking behavior. Our model investigates the differences that result when manipulating peer influence and smoker popularity as intervention levers. We demonstrate how a simulation-based approach allows us to estimate outcomes that arise (1) when intervention effects could plausibly alter peer influence and/or smoker popularity effects and (2) across a sample of schools that match the range of initial conditions of smoking prevalence in U.S. schools. We show how these different initial conditions combined with the exact same intervention effects can produce substantially different outcomes-for example, effects that produce smoking declines in some settings can actually increase smoking in others. We explore the form and magnitude of these differences. Our model also provides a template to evaluate the potential effects of alternative intervention scenarios. © American Sociological Association 2016.
Ondrusova, M; Mrozova, L; Ondrus, D; Mrinakova, B
Prostate cancer is the third most-common non-skin cancer and also the third leading cause of cancer death in the Slovak Republic in recent years. However, analysis of incidence and mortality long-term time-trends, on the basis of which the prevalence estimates could have been calculated, were not available. This paper analyses national trends in prostate cancer incidence and mortality from 1968 to 2007 by using the join-point regression to propose potential changes in health care. The authors noted a statistically significant increase in the values of incidence after 1999 and improvement in mortality after 1998. Using a mathematical modelation authors predicted the overall prostate cancer prevalence in the Slovak Republic to provide actual data for health management.
An experimental CATI-survey (N=2041), asking sensitive questions about xenophobia and anti-Semitism in Germany, was conducted to compare the randomized response technique (RRT) and the direct questioning technique. Unlike the vast majority of RRT surveys measuring the prevalence of socially undesirable behaviors, only few studies have explored the effectiveness of the RRT with respect to the disclosure of socially undesirable opinions. Results suggest that the RRT is an effective method eliciting more socially undesirable opinions and yielding more valid prevalence estimates of xenophobia and anti-Semitism than direct questioning ('more-is-better' assumption). Furthermore, the results indicate that with increasing topic sensitivity, the benefits of using the RRT also increase. Finally, adapted logistic regression analyses show that several covariates such as education and generalized trust are related to the likelihood of being prejudiced towards foreigners and Jews. Copyright © 2012 Elsevier Inc. All rights reserved.
Raj, Yujwal; Sahu, Damodar; Pandey, Arvind; Venkatesh, S; Reddy, Dcs; Bakkali, Taoufik; Das, Chinmoyee; Singh, Kh Jitenkumar; Kant, Shashi; Bhattacharya, M; Stover, John; Jha, Ugra Mohan; Kumar, Pradeep; Mishra, Ram Manohar; Chandra, Nalini; Gulati, B K; Mathur, Sharad; Joshi, Deepika; Chavan, L
This paper provides HIV estimation methodology used in India and key HIV estimates for 2010-2011. We used a modified version of the Spectrum tool that included an Estimation and Projection Package as part of its AIDS Impact Module. Inputs related to population size, age-specific pattern of fertility, gender-ratio at birth, age and gender-specific pattern of mortality, and volume and age-gender distribution of net migration were derived from census records, the Sample Registration System and large-scale demographic health surveys. Epidemiological and programmatic data were derived from HIV sentinel surveillance, large-scale epidemiological surveys and the programme management information system. Estimated adult HIV prevalence retained a declining trend in India, following its peak in 2002 at a level of 0.41% (within bounds 0.35-0.47%). By 2010 and 2011, it levelled at estimates of 0.28% (0.24-0.34%) and 0.27% (0.22-0.33%), respectively. The estimated number of people living with HIV (PLHIV) reduced by 8% between 2007 and 2011. While children accounted for approximately 6.3% of total HIV infections in 2007, this proportion increased to about 7% in 2011. With changing priorities and epidemic patterns, the programme has to customise its strategies to effectively address the emerging vulnerabilities and adapt them to suit the requirements of different geographical regions. © The Author(s) 2016.
Carey, Renee N; Driscoll, Timothy R; Peters, Susan; Glass, Deborah C; Reid, Alison; Benke, Geza; Fritschi, Lin
Although past studies of workplace exposures have contributed greatly to our understanding of carcinogens, significant knowledge gaps still exist with regard to the actual extent of exposure among current workers, with no routinely collected population-based data being available in most countries. This study, the Australian Work Exposures Study (AWES), aimed to investigate the current prevalence of occupational exposure to carcinogens. A random sample of men and women aged between 18 and 65, who were currently in paid employment, were invited to participate in a telephone interview collecting information about their current job and various demographic factors. Interviews were conducted using a web-based application (OccIDEAS). OccIDEAS uses the expert exposure method in which participants are asked about their job tasks and predefined algorithms are used to automatically assign exposures. Responses were obtained from 5023 eligible Australian residents, resulting in an overall response rate of 53%. 1879 respondents (37.6%) were assessed as being exposed to at least one occupational carcinogen in their current job. Extrapolation of these figures to the Australian working population suggested 3.6 million (40.3%) current workers could be exposed to carcinogens in their workplace. Exposure prevalence was highest among farmers, drivers, miners and transport workers, as well as men and those residing in regional areas. This study demonstrates a practical, web-based approach to collecting population information on occupational exposure to carcinogens and documents the high prevalence of current exposure to occupational carcinogens in the general population.
Maher, Senan; Cunningham, Aoife; O’Callaghan, Niamh; Byrne, Fintan; Mc Donald, Colm; McInerney, Shane; Hallahan, Brian
Objectives: The objective of this study was to evaluate the prevalence and severity of clozapine-induced hypersalivation, and assess the impact hypersalivation has on global functioning. Methods: Participants attending a dedicated clozapine clinic were invited to undertake a structured interview regarding their experiences of clozapine-induced hypersalivation. Two psychometric instruments to measure hypersalivation, the Nocturnal Hypersalivation Rating Scale and the Drooling Severity and Frequency Scale were used. Results: Clozapine-induced hypersalivation was experienced by 92% of participants, with nocturnal hypersalivation more prevalent compared to daytime hypersalivation (85% versus 48%). Daytime drooling was severe in 18% of cases and was present on a frequent or constant basis for 20% of individuals. Hypersalivation had at least a moderate impact on the quality of life of 15% of study participants. Conclusions: Clozapine-induced hypersalivation is the most prevalent adverse effect experienced by patients treated with clozapine and negatively impacts on quality of life, particularly if daytime drooling is present. The development of further strategies to ameliorate this adverse effect is required given the demonstrated lack of success to date in managing this condition. PMID:27354906
Laporte, Lise; Paris, Joel; Zelkowitz, Phyllis
Characteristics of borderline personality disorder (BPD) can undermine maternal capacity and in some cases lead to involvement with youth protection services (YPS). Yet, few studies exist on the prevalence of maternal BPD in this context and on the comparison of these families with families with other maternal psychiatric disorders or families with no mental illness within YPS. The current study surveyed 291 caseworkers working with mothers whose children and adolescents are followed by YPS. After reported prevalence was adjusted with validation procedures, the prevalence of maternal BPD in a sample of 1875 mothers was 34.3%. Comparison of three groups of families suggest that some risk factors, including substance abuse and severe conjugal conflicts, were more frequent in mothers with BPD than in mothers with other psychiatric illness or none. Furthermore, results revealed that 48.9% of mothers with BPD had a history of being followed by YPS in their childhood. Finally, children of mothers with BPD were placed at a younger age than the other children and were less often reported for conduct disorder. These results call for more attention to these highly vulnerable parents and children in both research and in adult and child mental health services. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.
Bezerra-de-Souza, D L; Bernal, M M; Gómez, F J; Gómez, G J
estimate colorectal cancer incidence and prevalence in, based on mortality and survival data from the period 1998-2007, and provide projections of incidence, prevalence and mortality until the year 2022. general and colorectal cancer mortality rates were obtained from the National Statistics Institute and survival data was obtained from the EUROCARE study. Estimations were carried out through the program MIAMOD. The joinpoint program was used to quantify the annual change expected in the projections. in men, an increase in prevalence is expected, from 237.2 (Crude Rate - CR = 303.5) to 237.7 (CR = 412.7) per 100.000 inhabitants/year in 2022. Incidence rates would increase from 48.2 (CR = 61.6) in 2007 to 55.2 (CR = 83.1), and mortality would increase from 22.7 (CR = 29.4) to 26.0 (CR = 39.6) when comparing 2007 and women, a reduction in prevalence is expected from 181.5 (CR = 268.3) to 167.9 (CR = 286.2) cases per 100,000 inhabitants/year. Incidence would change from 25.0 (CR = 38.0) in 2007 to 22.7 (CR = 39.2), and for mortality there is also an expected decrease, from 11.3 (CR =18.0) to 10.3 (CR = 18.5). the projections indicate that colorectal cancer in follows an increasing trend in incidence, mortality and prevalencein men, in opposition to corresponding decreasing trends in women.These projections must be considered in order to plan more effective prevention and treatment measures.
Jaime, Alina; Mckensie, Martin; Auguste, Ava; Pérez, Enrique; Indar, Lisa
Saint Lucia was the first country to conduct a burden of illness study in the Caribbean to determine the community prevalence and underreporting of acute gastroenteritis (AGE). A retrospective cross-sectional population survey on AGE-related illness was administered to a random sample of residents of Saint Lucia in 20 April–16 May 2008 and 6-13 December 2009 to capture the high- and low-AGE season respectively. Of the selected 1,150 individuals, 1,006 were administered the survey through face-to-face interviews (response rate 87.4%). The overall monthly prevalence of AGE was 3.9%. The yearly incidence rate was 0.52 episodes/person-year. The age-adjusted monthly prevalence was 4.6%. The highest monthly prevalence of AGE was among children aged <5 years (7.5%) and the lowest in persons aged 45-64 years (2.6%). The average number of days an individual suffered from diarrhoea was 3.8 days [range 1-21 day(s)]. Of the reported AGE cases, only seven (18%) sought medical care; however, 83% stayed at home due to the illness [(range 1-16 day(s), mean 2.5]; and 26% required other individuals to take care of them. The estimated underreporting of syndromic AGE and laboratory-confirmed foodborne disease pathogens was 81% and 99% respectively during the study period. The economic cost for treating syndromic AGE was estimated at US$ 3,892.837 per annum. This was a pilot study on the burden of illness (BOI) in the Caribbean. The results of the study should be interpreted within the limitations and challenges of this study. Lessons learnt were used for improving the implementation procedures of other BOI studies in the Caribbean.
Imai, Natsuko; Dorigatti, Ilaria; Cauchemez, Simon; Ferguson, Neil M.
Background Estimates of dengue transmission intensity remain ambiguous. Since the majority of infections are asymptomatic, surveillance systems substantially underestimate true rates of infection. With advances in the development of novel control measures, obtaining robust estimates of average dengue transmission intensity is key for assessing both the burden of disease from dengue and the likely impact of interventions. Methodology/Principal Findings The force of infection (λ) and corresponding basic reproduction numbers (R0) for dengue were estimated from non-serotype (IgG) and serotype-specific (PRNT) age-stratified seroprevalence surveys identified from the literature. The majority of R0 estimates ranged from 1–4. Assuming that two heterologous infections result in complete immunity produced up to two-fold higher estimates of R0 than when tertiary and quaternary infections were included. λ estimated from IgG data were comparable to the sum of serotype-specific forces of infection derived from PRNT data, particularly when inter-serotype interactions were allowed for. Conclusions/Significance Our analysis highlights the highly heterogeneous nature of dengue transmission. How underlying assumptions about serotype interactions and immunity affect the relationship between the force of infection and R0 will have implications for control planning. While PRNT data provides the maximum information, our study shows that even the much cheaper ELISA-based assays would provide comparable baseline estimates of overall transmission intensity which will be an important consideration in resource-constrained settings. PMID:25881272
Kaufman, Zalman; Aharonowitz, Gali; Dichtiar, Rita; Green, Manfred S
Early clinical signs of influenza caused by a pandemic strain will presumably not differ significantly from those caused by other respiratory viruses. Similarly, early signs of diseases that may result from bioterrorism are frequently non-specific and resemble those of influenza-like illness. Since the time window for effective intervention is narrow, treatment may need to be initiated prior to a definitive diagnosis. Consequently, planning of medications, manpower and facilities should also account for those who would be treated for an unrelated acute illness. To estimate usual patterns of acute illness in the community as a baseline for integration into pandemic influenza and bioterrorism preparedness plans. Between 2000 and 2003 we conducted 13 telephone surveys to estimate the usual incidence and prevalence of symptoms of acute illness in the community. On average, 910 households were included in each of the surveys, representing about 3000 people. The compliance rates for full interviews ranged from 72.3% to 86.0%. In winter, on average, about 2% of the Israeli population (individuals) suffered each day from fever of > or = 38 degrees C, and about 0.8% during the other months. The prevalence of cough was higher, 9.2% in winter and 3% during summer. Daily incidence of fever ranged from about 0.4% per day in winter to about 0.2% in the fall. The prevalence and incidence of both fever and cough were highest for infants followed by children aged 1-5 years. These background morbidity estimates can be used for planning the overall treatment requirements, in addition to actual cases resulting from pandemic influenza or a bioterrorist incident.
Background Administrative databases are widely available and have been extensively used to provide estimates of chronic disease prevalence for the purpose of surveillance of both geographical and temporal trends. There are, however, other sources of data available, such as medical records from primary care and national surveys. In this paper we compare disease prevalence estimates obtained from these three different data sources. Methods Data from general practitioners (GP) and administrative transactions for health services were collected from five Italian regions (Veneto, Emilia Romagna, Tuscany, Marche and Sicily) belonging to all the three macroareas of the country (North, Center, South). Crude prevalence estimates were calculated by data source and region for diabetes, ischaemic heart disease, heart failure and chronic obstructive pulmonary disease (COPD). For diabetes and COPD, prevalence estimates were also obtained from a national health survey. When necessary, estimates were adjusted for completeness of data ascertainment. Results Crude prevalence estimates of diabetes in administrative databases (range: from 4.8% to 7.1%) were lower than corresponding GP (6.2%-8.5%) and survey-based estimates (5.1%-7.5%). Geographical trends were similar in the three sources and estimates based on treatment were the same, while estimates adjusted for completeness of ascertainment (6.1%-8.8%) were slightly higher. For ischaemic heart disease administrative and GP data sources were fairly consistent, with prevalence ranging from 3.7% to 4.7% and from 3.3% to 4.9%, respectively. In the case of heart failure administrative estimates were consistently higher than GPs’ estimates in all five regions, the highest difference being 1.4% vs 1.1%. For COPD the estimates from administrative data, ranging from 3.1% to 5.2%, fell into the confidence interval of the Survey estimates in four regions, but failed to detect the higher prevalence in the most Southern region (4.0% in
Dawkins, Rosie Claire Hewitt; Oliver, Genevieve Frances; Sharma, Manoj; Pinto, Basilio Martins; Jeronimo, Belmerio; Pereira, Bernadete; Magno, Julia; Motta, Lara Alexandra; Verma, Nitin; Shephard, Mark
Once considered an affliction of people in high-income countries, diabetes mellitus is increasingly seen as a global epidemic. However, for many countries very little is known about the prevalence of diabetes and its complications. This study aims to estimate the prevalence of diabetes, and diabetic retinopathy, in adults in Timor-Leste. From March 2013 to May 2014, adult patients being assessed for cataract surgery at the Sentru Matan Nasional (National Eye Centre) in Dili, Timor-Leste had a point-of-care HbA1c measurement performed on the DCA Vantage device (Siemens Ltd) under a quality framework. A diagnostic cut-off of 6.5% (48 mmol/mol) HbA1c was used for diagnosis of diabetes. Ocular examination, blood pressure, demographic and general health data were also collected. Diabetic retinopathy assessment was carried out by ophthalmologists. A total of 283 people [mean age 63.6 years (range 20-90 years)] were tested and examined during the study period. Forty-three people (15.2%) were found to have diabetes, with a mean HbA1c of 9.5% (77 mmol/mol). Of these, 27 (62.9%) were newly diagnosed, with a mean HbA1c of 9.7% (83 mmol/mol) and a range of 6.6-14% (49-130 mmol/mol). Nearly half (48.1%) of people newly diagnosed with diabetes had an HbA1c over 10.0% (86 mmol/mol). Of those with known diabetes, only 68.8% were receiving any treatment. Mean HbA1c for treated patients was 9.9% (85 mmol/mol). Diabetic retinopathy was identified in 18.6% of people with diabetes, of whom half had no previous diagnosis of diabetes. This study estimates the prevalence of diabetes at 15% in adults in Timor-Leste, a substantial proportion of whom have evidence of diabetic retinopathy. This is consistent with regional estimates. With the majority of patients undiagnosed, and management of people known to have diabetes largely inadequate, point-of-care testing is a valuable tool to assist with diabetes case detection and management. Whilst only a preliminary estimate, our data provides
Background The PROBIT methodology was presented in the 1995 World Health Organization Technical Report on Anthropometry as an alternative to the standard prevalence based method of measuring malnutrition in children. Theoretically the PROBIT method will always give a smaller standard error than the standard prevalence method in measuring malnutrition. A recent article by Dale et al. assessed the PROBIT method for measuring global acute malnutrition measure and found that the method was biased and the precision was superior only for sample sizes less than 150 when compared to the standard method. In a manner similar to Dale, our study further investigated the bias and precision of the PROBIT method for different sample sizes using simulated populations. Results The PROBIT method showed bias for each of the ten simulated populations, but the direction and magnitude of the average bias was changed depending on the simulated population. For a given simulated population, the average bias was relatively constant for all sample sizes drawn. The 95% half-width confidence interval was lower for the PROBIT method than the standard prevalence method regardless of the sample size or simulated population. The absolute difference in the confidence limits showed the most gains for the PROBIT method for the smaller samples sizes, but the ratio of confidence intervals was relatively constant across all sample sizes. Conclusions The PROBIT method will provide gains in precision regardless of the sample size, but the method may be biased. The direction and magnitude of the bias depends on the population it is drawn from. PMID:23981669
Obesity prevalence among inmates in the United States is unknown. Since incarceration disproportionately affects minorities, excluding inmates from surveys may bias national obesity estimates. Including inmates may also help explain racial obesity disparities among men. This descriptive study summarizes obesity prevalence among US male inmates and analyzes the effect of incarceration on national prevalence estimates. Data for male inmates came from the 2002 Survey of Inmates in Local Jails and the 2004 Survey of Inmates in State and Federal Correctional Facilities. Data for the non-incarcerated US adult male population came from the 2004 National Health Interview Survey. Self-reported weight and height data were analyzed from men aged 25-59 years for all surveys (obesity equaled BMI ≥ 30.0 kg/m(2)). Pooled inmate obesity prevalence was less than non-incarcerated estimates across all race/ethnic-education subgroups. However, unlike non-incarcerated estimates, inmates had obesity disparities between Hispanics and non-Hispanic Whites. Merging inmate and non-incarcerated estimates lowered obesity prevalence among men aged 25-39 with lower education levels. Merged estimates showed a positive obesity gradient within Whites by education. This study indicates that the exclusion of inmates from national obesity estimates leads to overestimates in obesity prevalence, particularly for low SES White and Black men.
Bennani, Aziza; El-Kettani, Amina; Hançali, Amina; El-Rhilani, Houssine; Alami, Kamal; Youbi, Mohamed; Rowley, Jane; Abu-Raddad, Laith; Smolak, Alex; Taylor, Melanie; Mahiané, Guy; Stover, John
Background Evolving health priorities and resource constraints mean that countries require data on trends in sexually transmitted infections (STI) burden, to inform program planning and resource allocation. We applied the Spectrum STI estimation tool to estimate the prevalence and incidence of active syphilis in adult women in Morocco over 1995 to 2016. The results from the analysis are being used to inform Morocco’s national HIV/STI strategy, target setting and program evaluation. Methods Syphilis prevalence levels and trends were fitted through logistic regression to data from surveys in antenatal clinics, women attending family planning clinics and other general adult populations, as available post-1995. Prevalence data were adjusted for diagnostic test performance, and for the contribution of higher-risk populations not sampled in surveys. Incidence was inferred from prevalence by adjusting for the average duration of infection with active syphilis. Results In 2016, active syphilis prevalence was estimated to be 0.56% in women 15 to 49 years of age (95% confidence interval, CI: 0.3%-1.0%), and around 21,675 (10,612–37,198) new syphilis infections have occurred. The analysis shows a steady decline in prevalence from 1995, when the prevalence was estimated to be 1.8% (1.0–3.5%). The decline was consistent with decreasing prevalences observed in TB patients, fishermen and prisoners followed over 2000–2012 through sentinel surveillance, and with a decline since 2003 in national HIV incidence estimated earlier through independent modelling. Conclusions Periodic population-based surveys allowed Morocco to estimate syphilis prevalence and incidence trends. This first-ever undertaking engaged and focused national stakeholders, and confirmed the still considerable syphilis burden. The latest survey was done in 2012 and so the trends are relatively uncertain after 2012. From 2017 Morocco plans to implement a system to record data from routine antenatal
Bennani, Aziza; El-Kettani, Amina; Hançali, Amina; El-Rhilani, Houssine; Alami, Kamal; Youbi, Mohamed; Rowley, Jane; Abu-Raddad, Laith; Smolak, Alex; Taylor, Melanie; Mahiané, Guy; Stover, John; Korenromp, Eline L
Evolving health priorities and resource constraints mean that countries require data on trends in sexually transmitted infections (STI) burden, to inform program planning and resource allocation. We applied the Spectrum STI estimation tool to estimate the prevalence and incidence of active syphilis in adult women in Morocco over 1995 to 2016. The results from the analysis are being used to inform Morocco's national HIV/STI strategy, target setting and program evaluation. Syphilis prevalence levels and trends were fitted through logistic regression to data from surveys in antenatal clinics, women attending family planning clinics and other general adult populations, as available post-1995. Prevalence data were adjusted for diagnostic test performance, and for the contribution of higher-risk populations not sampled in surveys. Incidence was inferred from prevalence by adjusting for the average duration of infection with active syphilis. In 2016, active syphilis prevalence was estimated to be 0.56% in women 15 to 49 years of age (95% confidence interval, CI: 0.3%-1.0%), and around 21,675 (10,612-37,198) new syphilis infections have occurred. The analysis shows a steady decline in prevalence from 1995, when the prevalence was estimated to be 1.8% (1.0-3.5%). The decline was consistent with decreasing prevalences observed in TB patients, fishermen and prisoners followed over 2000-2012 through sentinel surveillance, and with a decline since 2003 in national HIV incidence estimated earlier through independent modelling. Periodic population-based surveys allowed Morocco to estimate syphilis prevalence and incidence trends. This first-ever undertaking engaged and focused national stakeholders, and confirmed the still considerable syphilis burden. The latest survey was done in 2012 and so the trends are relatively uncertain after 2012. From 2017 Morocco plans to implement a system to record data from routine antenatal programmatic screening, which should help update and re
Hetsroni, Amir; Lowenstein, Hila
Religiosity may change the direction of the effect of TV viewing on assessment of the likelihood of personal victimization and estimates concerning crime prevalence. A content analysis of a representative sample of TV programming (56 hours of prime-time shows) was done to identify the most common crimes on television, followed by a survey of a representative sample of the adult public in a large urban district (778 respondents) who were asked to estimate the prevalence of these crimes and to assess the likelihood of themselves being victimized. People who defined themselves as non-religious increased their estimates of prevalence for crimes often depicted on TV, as they reported more time watching TV (ordinary cultivation effect), whereas estimates regarding the prevalence of crime and assessment of victimization likelihood among religious respondents were lower with reports of more time devoted to television viewing (counter-cultivation effect).
Ibrahim, Shimaa S; El-Matarawy, Olfat M; Ghieth, Marwa A; Abu Sarea, Enas Y; El-Badry, Ayman A
Amoebiasis diagnosis is usually based on microscopy that cannot differentiate pathogenic E. histolytica from morphologically identical non-pathogenic species. 194 fecal samples were collected from diarrheic &/or dysenteric patients and examined for Entamoeba complex microscopically, E. histolytica/E. dispar coproantigen using ICT and E. histolytica coproantigen using Tech lab E. histolytica II ELISA test. Entamoeba complex trophozoites/cysts, E. histolytica/E. dispar coproantigen and E. histolytica coproantigen were detected in 22.2, 14.4 and 3.6 % of samples, respectively. Microscopy and ICT method had limited sensitivity with poor PPV (9.3 and 7.1 %, respectively) and both slightly agree with ELISA test. The prevalence of E. histolytica was low (3.6 %) in studied individuals and was 14 times lower than non-pathogenic amoebae. E. histolytica detection studied individuals was positively associated with mucoid and bloody stool, which makes them disease predictors. E. histolytica fecal ELISA assay for E. histolytica detection surpassed microscopy and E. histolytica/E. dispar ICT assay. This has highlighted the need for practical non-microscopic detection methods that can differentiate between amoeba infections to avoid unnecessary and possibly harmful therapies and to determine the true prevalence and epidemiology of E. histolytica.
Mitchell, Kirstin R.; Jones, Kyle G.; Wellings, Kaye; Johnson, Anne M.; Graham, Cynthia A.; Datta, Jessica; Copas, Andrew J.; Bancroft, John; Sonnenberg, Pam; Macdowall, Wendy; Field, Nigel; Mercer, Catherine H.
Establishing the clinical significance of symptoms of sexual dysfunction is challenging. To address this, the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) introduced two new morbidity criteria (duration and symptom severity) to the existing criteria of distress. This study sought to establish the impact of these three criteria on the population prevalence of sexual function problems. The data come from a national probability survey (Natsal-3) and are based on 11,509 male and female participants aged 16–74, reporting at least one sexual partner in the past year. The key outcomes were: proportion of individuals reporting proxy measures of DSM-5 problems, and the proportion of those meeting morbidity criteria. We found that among sexually active men, the prevalence of reporting one or more of four specific sexual problems was 38.2%, but 4.2% after applying the three morbidity criteria; corresponding figures for women reporting one or more of three specific sexual problems, were 22.8% and 3.6%. Just over a third of men and women reporting a problem meeting all three morbidity criteria had sought help in the last year. We conclude that the DSM-5 morbidity criteria impose a focus on clinically significant symptoms. PMID:26605494
Monge, S; Díez, M; Alvarez, M; Guillot, V; Iribarren, J A; Palacios, R; Delgado, R; Jaén, A; Blanco, J R; Domingo, P; Portilla, J; Pérez Elías, M J; Garcia, F
Prevalence of transmitted drug resistance (pTDR) to antiretroviral drugs in Spain (2007-2012) was estimated using the CoRIS cohort, adjusting its territorial distribution and transmission route to the reference population from the Spanish Information System on New human immunodeficiency virus diagnoses. A total of 2702 patients from ten autonomous communities and with naive FASTA sequence within 6 months of human immunodeficiency virus diagnosis were selected. Weighted pTDR, estimated using the inverse probability of selection in the sample by autonomous communities and transmission group, was 8.12% (95% CI 6.44-9.80), not significantly different from unweighted pTDR. We illustrate how proportional weighting can maximize representativeness of cohort-based data, and its value to monitor pTDR at country level. Copyright © 2014 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.
Bajaj, Sarita; Purwar, Naincy; Gupta, Arvind; Gupta, Poonam; Srivastava, Anubha
Aims: To determine the prevalence of subclinical and overt hypothyroidism in diabetic kidney disease (DKD) and effect of thyroid hormone replacement on progression of DKD. Materials and Methods: A prospective cohort study on 41 adult DKD patients who were screened for hypothyroidism. Hypothyroid DKD patients were started on levothyroxine replacement and were reviewed after 3 and 6 months. Results: Of the total population, 14 (34.1%) cases were hypothyroid, among whom 12 (29.3%) cases were subclinical, and 2 (4.8%) were overt hypothyroidism. Prevalence of hypothyroidism and mean thyroid stimulating hormone levels increased with increasing severity of DKD. There were 2 (14.3%) hypothyroid cases in stage 3b, 4 (28.5%) cases in stage 4, and 8 (57.2%) in stage 5 DKD. The mean estimate glomerular filtration rate (ml/min/1.73 m2) at baseline was 13.6 ± 13.3 which increased to 16.4 ± 14.5 and 21.2 ± 15.3 after 3 and 6 months of thyroid hormone replacement therapy (THRT), respectively (P < 0.001). Conclusions: Hypothyroidism is commonly associated with DKD. Prevalence of hypothyroidism increased with declining renal function. THRT significantly improved renal function in DKD patients with hypothyroidism after 3 and 6 months of therapy. PMID:27867882
Clark, Samuel J; Houle, Brian
A recent study using Heckman-type selection models to adjust for non-response in the Zambia 2007 Demographic and Health Survey (DHS) found a large correction in HIV prevalence for males. We aim to validate this finding, replicate the adjustment approach in other DHSs, apply the adjustment approach in an external empirical context, and assess the robustness of the technique to different adjustment approaches. We used 6 DHSs, and an HIV prevalence study from rural South Africa to validate and replicate the adjustment approach. We also developed an alternative, systematic model of selection processes and applied it to all surveys. We decomposed corrections from both approaches into rate change and age-structure change components. We are able to reproduce the adjustment approach for the 2007 Zambia DHS and derive results comparable with the original findings. We are able to replicate applying the approach in several other DHSs. The approach also yields reasonable adjustments for a survey in rural South Africa. The technique is relatively robust to how the adjustment approach is specified. The Heckman selection model is a useful tool for assessing the possibility and extent of selection bias in HIV prevalence estimates from sample surveys.
Onufrak, Stephen; Holt, James B.; Croft, Janet B.
Introduction Traditional survey methods for obtaining nationwide small-area estimates (SAEs) of childhood obesity are costly. This study applied a geocoded national health survey in a multilevel modeling framework to estimate prevalence of childhood obesity at the census block-group level. Methods We constructed a multilevel logistic regression model to evaluate the influence of individual demographic characteristics, zip code, county, and state on the childhood obesity measures from the 2007 National Survey of Children’s Health. The obesity risk for a child in each census block group was then estimated on the basis of this multilevel model. We compared direct survey and model-based SAEs to evaluate the model specification. Results Multilevel models in this study explained about 60% of state-level variances associated with childhood obesity, 82.8% to 86.5% of county-level, and 93.1% of zip code-level. The 95% confidence intervals of block- group level SAEs have a wide range (0.795-20.0), a low median of 2.02, and a mean of 2.12. The model-based SAEs of childhood obesity prevalence ranged from 2.3% to 54.7% with a median of 16.0% at the block-group level. Conclusion The geographic variances among census block groups, counties, and states demonstrate that locale may be as significant as individual characteristics such as race/ethnicity in the development of the childhood obesity epidemic. Our estimates provide data to identify priority areas for local health programs and to establish feasible local intervention goals. Model-based SAEs of population health outcomes could be a tool of public health assessment and surveillance. PMID:23639763
Zhang, Xingyou; Onufrak, Stephen; Holt, James B; Croft, Janet B
Traditional survey methods for obtaining nationwide small-area estimates (SAEs) of childhood obesity are costly. This study applied a geocoded national health survey in a multilevel modeling framework to estimate prevalence of childhood obesity at the census block-group level. We constructed a multilevel logistic regression model to evaluate the influence of individual demographic characteristics, zip code, county, and state on the childhood obesity measures from the 2007 National Survey of Children's Health. The obesity risk for a child in each census block group was then estimated on the basis of this multilevel model. We compared direct survey and model-based SAEs to evaluate the model specification. Multilevel models in this study explained about 60% of state-level variances associated with childhood obesity, 82.8% to 86.5% of county-level, and 93.1% of zip code-level. The 95% confidence intervals of block- group level SAEs have a wide range (0.795-20.0), a low median of 2.02, and a mean of 2.12. The model-based SAEs of childhood obesity prevalence ranged from 2.3% to 54.7% with a median of 16.0% at the block-group level. The geographic variances among census block groups, counties, and states demonstrate that locale may be as significant as individual characteristics such as race/ethnicity in the development of the childhood obesity epidemic. Our estimates provide data to identify priority areas for local health programs and to establish feasible local intervention goals. Model-based SAEs of population health outcomes could be a tool of public health assessment and surveillance.
Miller, Ezer; Huppert, Amit; Novikov, Ilya; Warburg, Alon; Hailu, Asrat; Abbasi, Ibrahim; Freedman, Laurence S
In this work, we describe a two-stage sampling design to estimate the infection prevalence in a population. In the first stage, an imperfect diagnostic test was performed on a random sample of the population. In the second stage, a different imperfect test was performed in a stratified random sample of the first sample. To estimate infection prevalence, we assumed conditional independence between the diagnostic tests and develop method of moments estimators based on expectations of the proportions of people with positive and negative results on both tests that are functions of the tests' sensitivity, specificity, and the infection prevalence. A closed-form solution of the estimating equations was obtained assuming a specificity of 100% for both tests. We applied our method to estimate the infection prevalence of visceral leishmaniasis according to two quantitative polymerase chain reaction tests performed on blood samples taken from 4756 patients in northern Ethiopia. The sensitivities of the tests were also estimated, as well as the standard errors of all estimates, using a parametric bootstrap. We also examined the impact of departures from our assumptions of 100% specificity and conditional independence on the estimated prevalence. Copyright © 2015 John Wiley & Sons, Ltd.
Davison, Karen M; Kaplan, Bonnie J
Because little is known about food insecurity in people with mental health conditions, we investigated relationships among food insecurity, nutrient intakes, and psychological functioning in adults with mood disorders. Data from a study of adults randomly selected from the membership list of the Mood Disorder Association of British Columbia (n = 97), Canada, were analyzed. Food insecurity status was based on validated screening questions asking if in the past 12 months did the participant, due to a lack of money, worry about or not have enough food to eat. Nutrient intakes were derived from 3-day food records and compared to the Dietary Reference Intakes (DRIs). Psychological functioning measures included Global Assessment of Functioning, Hamilton Depression scale, and Young Mania Rating Scale. Using binomial tests of two proportions, Mann-Whitney U tests, and Poisson regression we examined: (1) food insecurity prevalence between the study respondents and a general population sample from the British Columbia Nutrition Survey (BCNS; n = 1,823); (2) differences in nutrient intakes based on food insecurity status; and (3) associations of food insecurity and psychological functioning using bivariate and Poisson regression statistics. In comparison to the general population (BCNS), food insecurity was significantly more prevalent in the adults with mood disorders (7.3% in BCNS vs 36.1%; p < 0.001). Respondents who were food-insecure had lower median intakes of carbohydrates and vitamin C (p < 0.05). In addition, a higher proportion of those reporting food insecurity had protein, folate, and zinc intakes below the DRI benchmark of potential inadequacy (p < 0.05). There was significant association between food insecurity and mania symptoms (adjusted prevalence ratio = 2.37, 95% CI 1.49-3.75, p < 0.05). Food insecurity is associated with both nutritional and psychological health in adults with mood disorders. Investigation of interventions aimed at food
Santana, Isabel; Farinha, Filipa; Freitas, Sandra; Rodrigues, Vítor; Carvalho, Ålvaro
Introdução: A incidência e prevalência de demência e de Doença de Alzheimer aumentam com a idade, duplicando a cada cinco anos após a sexta década de vida. Portugal é um país envelhecido, previsivelmente com um número crescente de casos de demência. No entanto, os dados epidemiológicos são escassos e os estudos sobre os custos da doença praticamente inexistentes. Propomo-nos apresentar uma estimativa actualizada da prevalência de demência/ Doença de Alzheimer em Portugal e inferir, a partir da prescrição específica para demência, o número de diagnósticos efectivos e os encargos financeiros com esses medicamentos.Material e Métodos: ÃÄ população residente em Portugal (2013), aplicámos os valores de prevalência de demência para a Europa Ocidental (estudo da AlzheimerâÄôs Disease International). A estimativa dos diagnósticos efectivos de Doença de Alzheimer e dos encargos financeiros com medicação específica baseou-se nas informações do Intercontinental Marketing Services Health (IMSH) âÄì 2013.Resultados: O número estimado de Portugueses com mais de 60 anos e com demência foi 160287, o que corresponde a 5,91% deste universo populacional. Sabendo que a Doença de Alzheimer representa 50-70% dos casos, inferimos que existirão entre 80144 e 112201 doentes. Por outro lado, os dados da IMSH indicam que estarão diagnosticados e a receceber anti-demenciais 76250 doentes, representando um encargo financeiro de 37 MâÇ¬/ano.Conclusão: O envelhecimento da população incrementa o número de casos de demência. Aparentemente, nem todos os doentes com Doença de Alzheimer recebem a medicação aconselhada, sugerindo que esta condição ainda está sub-diagnosticada. A evolução tem sido positiva, com incremento do número de doentes tratados e redução dos custos com fármacos específicos.
Li, Liang; Mao, Huzhang; Ishwaran, Hemant; Rajeswaran, Jeevanantham; Ehrlinger, John; Blackstone, Eugene H.
Atrial fibrillation (AF) is an abnormal heart rhythm characterized by rapid and irregular heart beat, with or without perceivable symptoms. In clinical practice, the electrocardiogram (ECG) is often used for diagnosis of AF. Since the AF often arrives as recurrent episodes of varying frequency and duration and only the episodes that occur at the time of ECG can be detected, the AF is often underdiagnosed when a limited number of repeated ECGs are used. In studies evaluating the efficacy of AF ablation surgery, each patient undergo multiple ECGs and the AF status at the time of ECG is recorded. The objective of this paper is to estimate the marginal proportions of patients with or without AF in a population, which are important measures of the efficacy of the treatment. The underdiagnosis problem is addressed by a three-class mixture regression model in which a patient’s probability of having no AF, paroxysmal AF, and permanent AF is modeled by auxiliary baseline covariates in a nested logistic regression. A binomial regression model is specified conditional on a subject being in the paroxysmal AF group. The model parameters are estimated by the EM algorithm. These parameters are themselves nuisance parameters for the purpose of this research, but the estimators of the marginal proportions of interest can be expressed as functions of the data and these nuisance parameters and their variances can be estimated by the sandwich method. We examine the performance of the proposed methodology in simulations and two real data applications. PMID:27983754
Yukich, Joshua; Briët, Olivier; Bretscher, Michael T; Bennett, Adam; Lemma, Seblewengel; Berhane, Yemane; Eisele, Thomas P; Keating, Joseph; Smith, Thomas
As some malaria control programs shift focus from disease control to transmission reduction, there is a need for transmission data to monitor progress. At lower levels of transmission, it becomes increasingly more difficult to measure precisely, for example through entomological studies. Many programs conduct regular cross sectional parasite prevalence surveys, and have access to malaria treatment data routinely collected by ministries of health, often in health management information systems. However, by themselves, these data are poor measures of transmission. In this paper, we propose an approach for combining annual parasite incidence and treatment data with cross-sectional parasite prevalence and treatment seeking survey data to estimate the incidence of new infections in the human population, also known as the force of infection. The approach is based on extension of a reversible catalytic model. The accuracy of the estimates from this model appears to be highly dependent on levels of detectability and treatment in the community, indicating the importance of information on private sector treatment seeking and access to effective and appropriate treatment.
Wakefield, Jerome C.; Schmitz, Mark F.
Community prevalence rates of alcohol use disorders (AUDs) provided by epidemiological studies using DSM-based diagnostic criteria pose several challenges: the rates appear implausibly high to many epidemiologists; they do not converge across similar studies; and, due to low service utilization by those diagnosed as disordered, they yield estimates of unmet need for services so high that credibility for planning purposes is jeopardized. For example, two early community studies using DSM diagnostic criteria, the Epidemiologic Catchment Area Study (ECA) and the National Comorbidity Survey (NCS), yielded lifetime AUD prevalence rates of 14 and 24%, respectively, with NCS unmet need for services 19% of the entire population. Attempts to address these challenges by adding clinical significance requirements to diagnostic criteria have proven unsuccessful. Hypothesizing that these challenges are due to high rates of false-positive diagnoses of problem drinking as AUDs, we test an alternative approach. We use the harmful dysfunction (HD) analysis of the concept of mental disorder as a guide to construct more valid criteria within the framework of the standard out-of-control model of AUD. The proposed HD criteria require harm and dysfunction, where harm can be any negative social, personal, or physical outcome, and dysfunction requires either withdrawal symptoms or inability to stop drinking. Using HD criteria, ECA and NCS lifetime prevalences converge to much-reduced rates of 6 and 6.8%, respectively. Due to higher service utilization rates, NCS lifetime unmet need is reduced to 3.4%. Service use and duration comparisons suggest that HD criteria possess increased diagnostic validity. Moreover, HD criteria eliminate 90% of transient teenage drinking from disorder status. The HD version of the out-of-control model thus potentially resolves the three classic prevalence challenges while offering a more rigorous approach to distinguishing AUDs from problematic drinking. PMID
Baujat, Geneviève; Choquet, Rémy; Bouée, Stéphane; Jeanbat, Viviane; Courouve, Laurène; Ruel, Amélie; Michot, Caroline; Le Quan Sang, Kim-Hanh; Lapidus, David; Messiaen, Claude; Landais, Paul; Cormier-Daire, Valérie
Fibrodysplasia ossificans progressiva (FOP) is a rare, severely disabling, and life-shortening genetic disorder that causes the formation of heterotopic bone within soft connective tissue. Previous studies found that the FOP prevalence was about one in every two million lives. The aim of this study is to estimate the FOP prevalence in France by probabilistic record-linkage of 2 national databases: 1) the PMSI (Programme de médicalisation des systèmes d'information), an administrative database that records all hospitalization activities in France and 2) CEMARA, a registry database developed by the French Centres of Reference for Rare Diseases. Using a capture-recapture methodology to adjust the crude number of patients identified in both data sources, 89 FOP patients were identified, which results in a prevalence of 1.36 per million inhabitants (CI95% = [1.10; 1.68]). FOP patients' mean age was 25 years, only 14.9% were above 40 years, and 53% of them were males. The first symptoms - beside toe malformations- occurred after birth for 97.3% of them. Mean age at identified symptoms was 7 years and above 18 years for only 6.9% of patients. Mean age at diagnosis was 10 years, and above 18 years for 14.9% of the patients. FOP patients were distributed across France. Despite the challenge of ascertaining patients with rare diseases, we report a much higher prevalence of FOP in France than in previous studies elsewhere. We suggest that efforts to identify patients and confirm the diagnosis of FOP should be reinforced and extended at both national and European level.
Hartsfield, Cynthia L; Korner, Eli J; Ellis, Jennifer L; Raebel, Marsha A; Merenich, John; Brandenburg, Nancy
The objectives of this study were to validate an algorithm for identifying patients with painful diabetic peripheral neuropathy (pDPN) and demonstrate its practical applications. Using the Kaiser Permanente Colorado Diabetes Registry, an algorithm was developed with selected ICD-9 diagnosis codes combined with automated pharmacy data for medications prescribed for pDPN symptoms. Medical records were reviewed to confirm pDPN presence and to inform algorithm refinement. Prevalence was estimated with a numerator of members with diabetes who had inclusion but no exclusion codes in 2003 (Method 1) and with a numerator of diabetes patients with inclusion codes between 1998 and 2003 who had no subsequent exclusion codes and who remained members in 2003 (Method 2); the denominator was all members with diabetes in 2003. Medication utilization was compared between patients with and without pDPN. A total of 19,577 members with diabetes were identified; 2612 met initial inclusion criteria. Medical record review (n = 298) demonstrated sensitivity of 94%, specificity of 55%, and positive predictive value (PPV) of 64%. Inclusion criteria were modified and pharmacy data eliminated. The revised algorithm identified 1754 additional patients meeting inclusion criteria. Medical record review (n = 190) demonstrated sensitivity of 99%, specificity of 49%, and PPV of 79%. Using the validated algorithm, pDPN prevalence was 113 (Method 1) and 208 (Method 2) per 1000 persons with diabetes. Significant differences were observed in medication prescriptions between patients with and without pDPN. Estimated pDPN prevalence among persons with diabetes was 11%-21% and pDPN patients had greater utilization of selected medications than those without pDPN. Identifying patients with pDPN is a fundamental step for improving disease management and understanding the economic impact of pDPN.
O'Donnell, S; Vanderloo, S; McRae, L; Onysko, J; Patten, S B; Pelletier, L
To compare trends in the estimated prevalence of mood and/or anxiety disorders identified from two data sources (self-report and administrative). Reviewing, synthesising and interpreting data from these two sources will help identify potential factors that underlie the observed estimates and inform public health action. We used self-reported, diagnosed mood and/or anxiety disorder cases from the Canadian Community Health Survey (CCHS) across a 5-year span (from 2003 to 2009) to estimate the prevalence among the Canadian population aged ≥15 years. We also estimated the prevalence of mood and/or anxiety disorders using the Canadian Chronic Disease Surveillance System (CCDSS), which identified cases using ICD-9/-10-CA codes from physician billing claims and hospital discharge records during the same time period. The prevalence rates for mood and/or anxiety disorders were compared across the CCHS and CCDSS by age and sex for all available years of data from 2003 to 2009. Summary rates were age-standardised to the Canadian population as of 1 October 1991. In 2009, the prevalence of mood and/or anxiety disorders was 9.4% using self-reported data v. 11.3% using administrative data. Prevalence rates obtained from administrative data were consistently higher than those from self-report for both men and women. However, due to an increase in the prevalence of self-reported cases, these differences decreased over time (rate ratios for both sexes: 1.6-1.2). Prevalence estimates were consistently higher among females compared with males irrespective of data source. While differences in the prevalence estimates between the two data sources were evident across all age groups, the reduction of these differences was greater among adolescent, young and middle-aged adults compared with those 70 years and older. The overall narrowing of differences over time reflects a convergence of information regarding the prevalence of mood and/or anxiety disorders trends between self-report and
Hübschle, O J; Yang, C
A method for the purification of the precipitating antigen of bluetongue virus (BTV) is described. The results obtained indicate that the precipitating antigen is identical with a core protein of BTV having a molecular weight of 39,000 (P7). So far all bluetongue virus serotypes have been shown to possess this protein. It is evident therefore that a group-specific reaction could be based on the presence of antibodies against this core protein. The purification of this protein by chromatofocusing proved relatively easy to perform and immunodiffusion tests revealed a group-specific reaction.
Gjerde, Hallvard; Normann, Per T; Christophersen, Asbjørg S; Mørland, Jørg
To estimate the prevalence of driving with blood drug concentrations above the recently proposed Norwegian legal limits for drugged driving in random traffic. The results from a roadside survey of 10,816 drivers was used as basis for the estimation, and the most prevalent drugs were included. Three approaches were used to estimate the prevalence of drug concentrations above the proposed legal limits in blood based on drug concentrations in oral fluid: comparison with drug concentrations observed in oral fluid and blood in pharmacokinetic studies, estimating the prevalence of drug concentrations in blood by calculating the prevalence of drug concentrations in oral fluid that were larger than the limit in blood multiplied with mean oral fluid/blood ratios, and a mathematical simulation mimicking the relationship between drug concentration distributions in blood and oral fluid for populations of drug users. In total, alcohol or drugs were detected in 5.7% of the samples of oral fluid from drivers in normal traffic; 3.8% (n=410) were positive for the drugs that we included in the assessment. The estimation of drug concentrations in blood suggested that about 1.5% had concentrations above the proposed legal limits in blood for the studied drugs, which is about 40% of those who were positive for the drugs in oral fluid. The estimated prevalence of driving with concentrations of psychoactive drugs in blood above the proposed legal limits was for illegal drugs 0.4% and for medicinal drugs 1.1%. These may be regarded as minimum estimates as some drugs were not included in the assessment. These prevalences are higher than the prevalence of driving with blood alcohol concentrations above the legal limit of 0.2g/kg in Norway. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.
Stroke is increasingly becoming a challenging public health issue in Africa, and the non-availability of data has limited research output and consequently the response to this burden. This study aimed to estimate the incidence and prevalence of stroke in Africa in 2009 towards improved policy response and management of the disease in the region. A systematic search of Medline, EMBASE and Global Health for original population-based or hospital-based studies on stroke was conducted. A random effect meta-analysis was conducted on crude stroke incidence and prevalence rates, and a meta-regression-like epidemiological model was applied on all data points. The fitted curve generated from the model was used to estimate incident cases of stroke and number of stroke survivors in Africa at midpoints of the United Nation population 5-year age groups for the year 2009. The literature search yielded a total of 1227 studies. 19 studies from 10 African countries were selected. 483 thousand new stroke cases among people aged 15 years or more were estimated in Africa in 2009, equivalent to 81.2 (13.2-94.9)/100,000 person years. A total of 1.89 million stroke survivors among people aged 15 years or more were estimated in Africa in 2009, with a prevalence of 317.3 (314.0-748.2)/100,000 population. Comparable figures for the year 2013 based on the same rates would amount to 535 thousand (87.0-625.3) new stroke cases and 2.09 million (2.06-4.93) stroke survivors, suggesting an increase of 10.8% and 9.6% of incident stroke cases and stroke survivors respectively, attributable to population growth and ageing between 2009 and 2013. The findings of this review suggest the burden of stroke in Africa is high and still increasing. There is need for more research on stroke and other vascular risk factors towards instituting appropriate policy, and effective preventive and management measures.
Background Stroke is increasingly becoming a challenging public health issue in Africa, and the non-availability of data has limited research output and consequently the response to this burden. This study aimed to estimate the incidence and prevalence of stroke in Africa in 2009 towards improved policy response and management of the disease in the region. Methods A systematic search of Medline, EMBASE and Global Health for original population-based or hospital-based studies on stroke was conducted. A random effect meta-analysis was conducted on crude stroke incidence and prevalence rates, and a meta-regression-like epidemiological model was applied on all data points. The fitted curve generated from the model was used to estimate incident cases of stroke and number of stroke survivors in Africa at midpoints of the United Nation population 5-year age groups for the year 2009. Results The literature search yielded a total of 1227 studies. 19 studies from 10 African countries were selected. 483 thousand new stroke cases among people aged 15 years or more were estimated in Africa in 2009, equivalent to 81.2 (13.2–94.9)/100,000 person years. A total of 1.89 million stroke survivors among people aged 15 years or more were estimated in Africa in 2009, with a prevalence of 317.3 (314.0–748.2)/100000 population. Comparable figures for the year 2013 based on the same rates would amount to 535 thousand (87.0–625.3) new stroke cases and 2.09 million (2.06–4.93) stroke survivors, suggesting an increase of 10.8% and 9.6% of incident stroke cases and stroke survivors respectively, attributable to population growth and ageing between 2009 and 2013. Conclusion The findings of this review suggest the burden of stroke in Africa is high and still increasing. There is need for more research on stroke and other vascular risk factors towards instituting appropriate policy, and effective preventive and management measures. PMID:24967899
Carrascal, Alvaro; DiRienzo, A. Gregory; Flanigan, Colleen; McClamroch, Kristi; Smith, Lou
The degree to which case surveillance captures persons ever infected with HCV is unknown. We determined the discrepancy between HCV seroprevalence, estimated from national survey data, among adults in New York State in 2008 (n = 286 262, or 1.95%) and the number of infected persons reported to the state’s surveillance hepatitis registries (n = 144 015). Findings suggest the need to strengthen the existing surveillance system. PMID:23763407
Agostinelli, Gina; Grube, Joel
Correcting normative information about the prevalence of heavy drinking is a key element in many prevention programs. To isolate the influence of normative information on older high school students' (n = 230) alcohol-related judgments, the effects of delivering normative information in different contexts (no normative information, normative information only, normative information plus a self-focusing comparison to one's drinking) and under different measurement conditions (public, private) were examined. First, relative to presenting no norms, presenting norms both with and without a self-focus reduced the underestimation of the percent of high school students who never drink heavily. Second, effects on both positive and negative evaluations of heavy drinking were examined independently. Heavy drinking students more strongly endorsed positive evaluations of heavy drinking than did non-heavy drinking students, but this self-serving bias was limited to the normative information only condition. Normative information failed to impact negative evaluations of heavy drinking for students at all drinking levels. Third, in judging the acceptable number of heavy drinking days approved by others, presenting the normative information in both contexts (relative to presenting no norms) led to more conservative judgments. Yet, only the normative context that added a self-focus to the norm led students to adopt more conservative personal standards for the acceptable number of heavy drinking days. Finally, public versus private measurement did not affect any of the dependent variables. The findings are discussed as they relate to confrontational versus empathic styles in delivering interventions.
Vilar, M J; Ranta, J; Virtanen, S; Korkeala, H
Bayesian analysis was used to estimate the pig's and herd's true prevalence of enteropathogenic Yersinia in serum samples collected from Finnish pig farms. The sensitivity and specificity of the diagnostic test were also estimated for the commercially available ELISA which is used for antibody detection against enteropathogenic Yersinia. The Bayesian analysis was performed in two steps; the first step estimated the prior true prevalence of enteropathogenic Yersinia with data obtained from a systematic review of the literature. In the second step, data of the apparent prevalence (cross-sectional study data), prior true prevalence (first step), and estimated sensitivity and specificity of the diagnostic methods were used for building the Bayesian model. The true prevalence of Yersinia in slaughter-age pigs was 67.5% (95% PI 63.2-70.9). The true prevalence of Yersinia in sows was 74.0% (95% PI 57.3-82.4). The estimates of sensitivity and specificity values of the ELISA were 79.5% and 96.9%.
Vilar, M. J.; Ranta, J.; Virtanen, S.; Korkeala, H.
Bayesian analysis was used to estimate the pig's and herd's true prevalence of enteropathogenic Yersinia in serum samples collected from Finnish pig farms. The sensitivity and specificity of the diagnostic test were also estimated for the commercially available ELISA which is used for antibody detection against enteropathogenic Yersinia. The Bayesian analysis was performed in two steps; the first step estimated the prior true prevalence of enteropathogenic Yersinia with data obtained from a systematic review of the literature. In the second step, data of the apparent prevalence (cross-sectional study data), prior true prevalence (first step), and estimated sensitivity and specificity of the diagnostic methods were used for building the Bayesian model. The true prevalence of Yersinia in slaughter-age pigs was 67.5% (95% PI 63.2–70.9). The true prevalence of Yersinia in sows was 74.0% (95% PI 57.3–82.4). The estimates of sensitivity and specificity values of the ELISA were 79.5% and 96.9%. PMID:26539540
Roberto, Anna; Deandrea, Silvia; Greco, Maria Teresa; Corli, Oscar; Negri, Eva; Pizzuto, Massimo; Ruggeri, Fabrizio
Because of the increasing body of literature on neuropathic cancer pain (NCP), an accurate estimate of its prevalence requires recurring updates. To provide this estimate using information from a systematic review and a survey. Using MEDLINE, Embase, and a previous review, we searched for studies published up to 2014 reporting data on NCP prevalence in adult cancer populations. Pooled prevalence rates from observational prospective studies were computed. The association between NCP prevalence and possible predictors was investigated for oncology and palliative settings. Prevalence rates were extracted from a questionnaire answered by 137 physicians working in 50 Italian centers of palliative care. Estimates from studies conducted in palliative settings and from the experts were analyzed separately and eventually pooled with an informative Bayesian random-effect model. Twenty-nine observational studies were identified. The overall pooled prevalence was 31.2%, with high heterogeneity; similar figures were observed when oncology and palliative settings were individually considered. A slightly higher prevalence of NCP was detected for hospice/inpatients as compared to outpatients, in both settings. The mean NCP prevalence reported by the survey experts was 44.2%; the pooled Bayesian estimate for the palliative setting corresponded to 43.0% (95% CI: 40.0-46.0). The subgroup with the lowest heterogeneity and where the literature and experts' estimates were closest is hospice/inpatients, with a pooled Bayesian prevalence rate of 34.9% (95% CI: 29.9-41.0). The systematic review and the survey suggest that more than one in three patients with cancer pain also experiences NCP. Copyright © 2016 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.
Ige, Janet O; Aderemi, Adewale V; Adeleye, Ngozi; Amoo, Emmanuel O; Auta, Asa; Oni, Gbolahan
Background There is not yet a comprehensive evidence-based epidemiological report on type 2 diabetes mellitus (T2DM) in Nigeria. We aimed to estimate country-wide and zonal prevalence, hospitalisation and mortality rates of T2DM in Nigeria. Methods We searched MEDLINE, EMBASE, Global Health, Africa Journals Online (AJOL) and Google Scholar for population and hospital-based studies on T2DM in Nigeria. We conducted a random-effects meta-analysis on extracted crude estimates, and applied a meta-regression epidemiological model, using the United Nations demographics for Nigeria in 1990 and 2015 to determine estimates of diabetes in Nigeria for the two years. Results 42 studies, with a total population of 91 320, met our selection criteria. Most of the studies selected were of medium quality (90.5%). The age-adjusted prevalence rates of T2DM in Nigeria among persons aged 20–79 years increased from 2.0% (95% CI 1.9% to 2.1%) in 1990 to 5.7% (95% CI 5.5% to 5.8%) in 2015, accounting for over 874 000 and 4.7 million cases, respectively. The pooled prevalence rate of impaired glucose tolerance was 10.0% (95% CI 4.5% to 15.6%), while impaired fasting glucose was 5.8% (95% CI 3.8% to 7.8%). Hospital admission rate for T2DM was 222.6 (95% CI 133.1 to 312.1) per 100 000 population with hyperglycaemic emergencies, diabetic foot and cardiovascular diseases being most common complications. The overall mortality rate was 30.2 (95% CI 14.6 to 45.8) per 100 000 population, with a case fatality rate of 22.0% (95% CI 8.0% to 36.0%). Conclusion Our findings suggest an increasing burden of T2DM in Nigeria with many persons currently undiagnosed, and few known cases on treatment. PMID:28495817
Barreto, Rafael E; Narváez, Javier; Sepúlveda, Natalia A; Velásquez, Fabián C; Díaz, Sandra C; López, Myriam Consuelo; Reyes, Patricia; Moncada, Ligia I
Public health programs for the control of soil-transmitted helminthiases require valid diagnostic tests for surveillance and parasitic control evaluation. However, there is currently no agreement about what test should be used as a gold standard for the diagnosis of hookworm infection. Still, in presence of concurrent data for multiple tests it is possible to use statistical models to estimate measures of test performance and prevalence. The aim of this study was to estimate the diagnostic accuracy of five parallel tests (direct microscopic examination, Kato-Katz, Harada-Mori, modified Ritchie-Frick, and culture in agar plate) to detect hookworm infections in a sample of school-aged children from a rural area in Colombia. We used both, a frequentist approach, and Bayesian latent class models to estimate the sensitivity and specificity of five tests for hookworm detection, and to estimate the prevalence of hookworm infection in absence of a Gold Standard. The Kato-Katz and agar plate methods had an overall agreement of 95% and kappa coefficient of 0.76. Different models estimated a sensitivity between 76% and 92% for the agar plate technique, and 52% to 87% for the Kato-Katz technique. The other tests had lower sensitivity. All tests had specificity between 95% and 98%. The prevalence estimated by the Kato-Katz and Agar plate methods for different subpopulations varied between 10% and 14%, and was consistent with the prevalence estimated from the combination of all tests. The Harada-Mori, Ritchie-Frick and direct examination techniques resulted in lower and disparate prevalence estimates. Bayesian approaches assuming imperfect specificity resulted in lower prevalence estimates than the frequentist approach. Copyright © 2017 Elsevier B.V. All rights reserved.
Newman, Lori; Rowley, Jane; Vander Hoorn, Stephen; Wijesooriya, Nalinka Saman; Unemo, Magnus; Low, Nicola; Stevens, Gretchen; Gottlieb, Sami; Kiarie, James; Temmerman, Marleen
Background Quantifying sexually transmitted infection (STI) prevalence and incidence is important for planning interventions and advocating for resources. The World Health Organization (WHO) periodically estimates global and regional prevalence and incidence of four curable STIs: chlamydia, gonorrhoea, trichomoniasis and syphilis. Methods and Findings WHO’s 2012 estimates were based upon literature reviews of prevalence data from 2005 through 2012 among general populations for genitourinary infection with chlamydia, gonorrhoea, and trichomoniasis, and nationally reported data on syphilis seroprevalence among antenatal care attendees. Data were standardized for laboratory test type, geography, age, and high risk subpopulations, and combined using a Bayesian meta-analytic approach. Regional incidence estimates were generated from prevalence estimates by adjusting for average duration of infection. In 2012, among women aged 15–49 years, the estimated global prevalence of chlamydia was 4.2% (95% uncertainty interval (UI): 3.7–4.7%), gonorrhoea 0.8% (0.6–1.0%), trichomoniasis 5.0% (4.0–6.4%), and syphilis 0.5% (0.4–0.6%); among men, estimated chlamydia prevalence was 2.7% (2.0–3.6%), gonorrhoea 0.6% (0.4–0.9%), trichomoniasis 0.6% (0.4–0.8%), and syphilis 0.48% (0.3–0.7%). These figures correspond to an estimated 131 million new cases of chlamydia (100–166 million), 78 million of gonorrhoea (53–110 million), 143 million of trichomoniasis (98–202 million), and 6 million of syphilis (4–8 million). Prevalence and incidence estimates varied by region and sex. Conclusions Estimates of the global prevalence and incidence of chlamydia, gonorrhoea, trichomoniasis, and syphilis in adult women and men remain high, with nearly one million new infections with curable STI each day. The estimates highlight the urgent need for the public health community to ensure that well-recognized effective interventions for STI prevention, screening, diagnosis, and
Yang, Kun; Pagaling, Eulyn
Presently, the understanding of bacterial enteric diseases in the community and their virulence factors relies almost exclusively on clinical disease reporting and examination of clinical pathogen isolates. This study aimed to investigate the feasibility of an alternative approach that monitors potential enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) prevalence and intimin gene (eae) diversity in a community by directly quantifying and characterizing target virulence genes in the sanitary sewage. The quantitative PCR (qPCR) quantification of the eae, stx1, and stx2 genes in sanitary sewage samples collected over a 13-month period detected eae in all 13 monthly sewage samples at significantly higher abundance (93 to 7,240 calibrator cell equivalents [CCE]/100 ml) than stx1 and stx2, which were detected sporadically. The prevalence level of potential EPEC in the sanitary sewage was estimated by calculating the ratio of eae to uidA, which averaged 1.0% (σ = 0.4%) over the 13-month period. Cloning and sequencing of the eae gene directly from the sewage samples covered the majority of the eae diversity in the sewage and detected 17 unique eae alleles belonging to 14 subtypes. Among them, eae-β2 was identified to be the most prevalent subtype in the sewage, with the highest detection frequency in the clone libraries (41.2%) and within the different sampling months (85.7%). Additionally, sewage and environmental E. coli isolates were also obtained and used to determine the detection frequencies of the virulence genes as well as eae genetic diversity for comparison. PMID:24141131
Hoffmann, Karolina; Bryl, Wiesław; Marcinkowski, Jerzy T; Strażyńska, Agata; Pupek-Musialik, Danuta
Excessive body mass and sedentary lifestyle are well-known factors for cardiovascular risk, which when present in the young population may have significant health consequences, both in the short- and long-term. The aim of the study was to evaluate the prevalence of overweight, obesity, and sedentary lifestyle in two teenage populations living in an urban or rural area. An additional aim was to compare their physical activity. The study was designed and conducted in 2009. The study population consisted of 116 students aged 15-17 years - 61 males (52.7%) and 55 females (47.3%), randomly selected from public junior grammar schools and secondary schools in the Poznań Region. There were 61 respondents from a rural area - 32 males (52.5%) and 29 females (47.5%), whereas 55 teenagers lived in an urban area - 29 males (47.5%) and 26 females (47.3%). Students were asked to complete a questionnaire, which was especially prepared for the study and contained questions concerning health and lifestyle. A basic physical examination was carried out in all 116 students, including measurements of the anthropometric features. Calculations were performed using the statistical package STATISTICA (data analysis software system), Version. 8.0. When comparing these two populations, no statistically significant differences were detected in the ratio of weight-growth, with the exception of the fact that the urban youths had a larger hip circumference (97.1 v. 94.3 cm, p<0.05). In the group of urban students there were also significantly more subjects with excessive body weight (27.3% v. 24.6%, p<0.05), with a predominant proportion of obese students (60%). There were significantly more male obese individuals (66.7%). In the population of rural teenagers, obesity rate did not differ statistically significantly from the percentage of overweight (11.5% v. 13.1%, p>0.05), the problem of excessive weight affected both sexes in a similar proportion (25% boys and 24.1% girls, p>0.05). In this
McCoy, Dana Charles; Danaei, Goodarz; Black, Maureen M.; Sudfeld, Christopher R.; Fawzi, Wafaie; Fink, Günther
Background The development of cognitive and socioemotional skills early in life influences later health and well-being. Existing estimates of unmet developmental potential in low- and middle-income countries (LMICs) are based on either measures of physical growth or proxy measures such as poverty. In this paper we aim to directly estimate the number of children in LMICs who would be reported by their caregivers to show low cognitive and/or socioemotional development. Methods and Findings The present paper uses Early Childhood Development Index (ECDI) data collected between 2005 and 2015 from 99,222 3- and 4-y-old children living in 35 LMICs as part of the Multiple Indicator Cluster Survey (MICS) and Demographic and Health Surveys (DHS) programs. First, we estimate the prevalence of low cognitive and/or socioemotional ECDI scores within our MICS/DHS sample. Next, we test a series of ordinary least squares regression models predicting low ECDI scores across our MICS/DHS sample countries based on country-level data from the Human Development Index (HDI) and the Nutrition Impact Model Study. We use cross-validation to select the model with the best predictive validity. We then apply this model to all LMICs to generate country-level estimates of the prevalence of low ECDI scores globally, as well as confidence intervals around these estimates. In the pooled MICS and DHS sample, 14.6% of children had low ECDI scores in the cognitive domain, 26.2% had low socioemotional scores, and 36.8% performed poorly in either or both domains. Country-level prevalence of low cognitive and/or socioemotional scores on the ECDI was best represented by a model using the HDI as a predictor. Applying this model to all LMICs, we estimate that 80.8 million children ages 3 and 4 y (95% CI 48.1 million, 113.6 million) in LMICs experienced low cognitive and/or socioemotional development in 2010, with the largest number of affected children in sub-Saharan Africa (29.4.1 million; 43.8% of children
Wilking, Hendrik; Thamm, Michael; Stark, Klaus; Aebischer, Toni; Seeber, Frank
Representative data on the extent of endemicity, burden, and risk of human toxoplasmosis are scarce. We assessed the prevalence and determinants of seropositivity of Toxoplasma gondii among adult participants of a nationwide representative cross-sectional survey in Germany. Sera collected from a representative cohort of adults (age 18–79; n = 6,663) in Germany were tested for anti-T. gondii IgG antibodies. Interview-derived data were used to evaluate associated factors. Multivariable logistic regression was applied using sampling weights and accounting for survey design cluster effects. Seroprevalence increased from 20% (95%-CI:17–23%) in the 18–29 age group to 77% (95%-CI:73–81%) in the 70–79 age group. Male gender, keeping cats and BMI ≥30 were independent risk factors for seropositivity, while being vegetarian and high socio-economic status were negatively associated. Based on these data, we estimate 1.1% of adults and 1.3% of women aged 18–49 to seroconvert each year. This implies 6,393 seroconversions annually during pregnancies. We conclude that T. gondii infection in Germany is highly prevalent and that eating habits (consuming raw meat) appear to be of high epidemiological relevance. High numbers of seroconversions during pregnancies pose substantial risks for unborn children. Efforts to raise awareness of toxoplasmosis in public health programs targeting to T. gondii transmission control are therefore strongly advocated. PMID:26936108
Bajaj, S.; Purwar, N.; Gupta, A.; Gupta, P.; Srivastava, A.
Reduced T3 and free T4, elevated thyroid stimulating hormone, and hyporesponsiveness to thyrotropin releasing hormone raise questions about the presence of hypothyroidism in chronic kidney disease (CKD) and raise the possibility of benefit from thyroxine supplementation. A prospective cohort study was conducted on 73 nondiabetic CKD cases. Hypothyroid patients were started on levothyroxine and were reviewed after 3 and 6 months. The mean age of study population was 42.3 ± 16.8 years. Of the total population, 32 (43.8%) cases had hypothyroidism, among whom 2 (2.7%) had overt hypothyroidism and 30 (41.1%) had subclinical hypothyroidism. Prevalence of hypothyroidism increased with increasing severity of CKD. There were 1 (3.1%) case with hypothyroidism in stage 3b, 8 (25%) cases in stage 4, and 23 (71.9%) cases in stage 5. The mean estimated glomerular filtration rate (ml/min/1.73 m2) at baseline was 13.7 ± 8.9 which increased to 17.5 ± 6.8 and 22.4 ± 9.3 after 3 and 6 months of thyroid hormone replacement therapy (THRT), respectively (P < 0.001). Hypothyroidism is commonly associated with nondiabetic CKD and its prevalence increases with declining renal function. THRT significantly improves renal function in nondiabetic CKD with hypothyroidism. PMID:28356660
Forde, David R; Baron, Stephen W; Scher, Christine D; Stein, Murray B
This study examines the psychometric properties of the Childhood Trauma Questionnaire short form (CTQ-SF) with street youth who have run away or been expelled from their homes (N = 397). Internal reliability coefficients for the five clinical scales ranged from .65 to .95. Confirmatory Factor Analysis (CFA) was used to test the five-factor structure of the scales yielding acceptable fit for the total sample. Additional multigroup analyses were performed to consider items by gender. Results provided only evidence of weak factorial invariance. Constrained models showed invariance in configuration, factor loadings, and factor covariances but failed for equality of intercepts. Mean trauma scores for street youth tended to fall in the moderate to severe range on all abuse/neglect clinical scales. Females reported higher levels of abuse and neglect. Prevalence of child maltreatment of individual forms was very high with 98% of street youth reporting one or more forms; 27.4% of males and 48.9% of females reported all five forms. Results of this study support the viability of the CTQ-SF for screening maltreatment in a highly vulnerable street population. Caution is recommended when comparing prevalence estimates for male and female street youth given the failure of the strong factorial multigroup model.
Bhatnagar, Tarun; Dutta, Tapati; Stover, John; Godbole, Sheela; Sahu, Damodar; Boopathi, Kangusamy; Bembalkar, Shilpa; Singh, Kh. Jitenkumar; Goyal, Rajat; Pandey, Arvind; Mehendale, Sanjay M.
Models are designed to provide evidence for strategic program planning by examining the impact of different interventions on projected HIV incidence. We employed the Goals Model to fit the HIV epidemic curves in Andhra Pradesh, Maharashtra and Tamil Nadu states of India where HIV epidemic is considered to have matured and in a declining phase. Input data in the Goals Model consisted of demographic, epidemiological, transmission-related and risk group wise behavioral parameters. The HIV prevalence curves generated in the Goals Model for each risk group in the three states were compared with the epidemic curves generated by the Estimation and Projection Package (EPP) that the national program is routinely using. In all the three states, the HIV prevalence trends for high-risk populations simulated by the Goals Model matched well with those derived using state-level HIV surveillance data in the EPP. However, trends for the low- and medium-risk populations differed between the two models. This highlights the need to generate more representative and robust data in these sub-populations and consider some structural changes in the modeling equation and parameters in the Goals Model to effectively use it to assess the impact of future strategies of HIV control in various sub-populations in India at the sub-national level. PMID:27711212
Salas, M M S; Nascimento, G G; Huysmans, M C; Demarco, F F
The main purpose of this systematic review was to estimate the prevalence of dental erosion in permanent teeth of children and adolescents. An electronic search was performed up to and including March 2014. Eligibility criteria included population-based studies in permanent teeth of children and adolescents aged 8-19-year-old reporting the prevalence or data that allowed the calculation of prevalence rates of tooth erosion. Data collection assessed information regarding geographic location, type of index used for clinical examination, sample size, year of publication, age, examined teeth and tissue exposure. The estimated prevalence of erosive wear was determined, followed by a meta-regression analysis. Twenty-two papers were included in the systematic review. The overall estimated prevalence of tooth erosion was 30.4% (95%IC 23.8-37.0). In the multivariate meta-regression model use of the Tooth Wear Index for clinical examination, studies with sample smaller than 1000 subjects and those conducted in the Middle East and Africa remained associated with higher dental erosion prevalence rates. Our results demonstrated that the estimated prevalence of erosive wear in permanent teeth of children and adolescents is 30.4% with high heterogeneity between studies. Additionally, the correct choice of a clinical index for dental erosion detection and the geographic location play an important role for the large variability of erosive tooth wear in permanent teeth of children and adolescents. The prevalence of tooth erosion observed in permanent teeth of children and adolescents was considerable high. Our results demonstrated that prevalence rate of erosive wear was influenced by methodological and diagnosis factors. When tooth erosion is assessed, the clinical index should be considered. Copyright © 2014 Elsevier Ltd. All rights reserved.
Gill, Geoffrey V; Ismail, Aziz A; Beeching, Nicholas J; Macfarlane, Sarah B J; Bellis, Mark A
An early requirement of the UK's Diabetes National Service Framework is enumeration of the total affected population. Existing estimates tend to be based on incomplete lists. In a study conducted over one year in North Liverpool, we compared crude prevalence rates for type 1 and type 2 diabetes with estimates obtained by capture-recapture (CR) analysis of multiple incomplete patient lists, to assess the extent of unascertained but diagnosed cases. Patient databases were constructed from six sources-a hospital diabetes centre; general practitioner registers; hospital admissions with a diagnosis of diabetes; a hospital diabetic retinal clinic; a research list of patients with diabetes admitted with stroke; and a local children's hospital. Log linear modelling was used to estimate missing cases, hence total prevalence. The crude prevalence of diabetes was 1.5% (95% confidence interval [CI] 1.41, 1.52), compared with a CR-adjusted rate of 3.1% (CI 3.03, 3.19). Age-banded CR-adjusted prevalence was always higher in males than in females and the difference became more pronounced with increasing age. Among males, CR-adjusted prevalence rose from 0.4% at age 10-19 years to 18.3% at 80+ years; in females the corresponding figures were 0.4% and 9.3%. The gap between crude and CR-estimated prevalence points to a rate of 'hidden diabetes' that has substantial implications for future diabetes care.
Johnell, O; Kanis, J A
The aim of this study was to quantify the global burden of osteoporotic fracture worldwide. The incidence of hip fractures was identified by systematic review and the incidence of osteoporotic fractures was imputed from the incidence of hip fractures in different regions of the world. Excess mortality and disability weights used age- and sex-specific data from Sweden to calculate the Disability Adjusted Life Years (DALYs) lost due to osteoporotic fracture. In the year 2000 there were an estimated 9.0 million osteoporotic fractures of which 1.6 million were at the hip, 1.7 million at the forearm and 1.4 million were clinical vertebral fractures. The greatest number of osteoporotic fractures occurred in Europe (34.8%). The total DALYs lost was 5.8 million of which 51% were accounted for by fractures that occurred in Europe and the Americas. World-wide, osteoporotic fractures accounted for 0.83% of the global burden of non-communicable disease and was 1.75% of the global burden in Europe. In Europe, osteoporotic fractures accounted for more DALYs lost than common cancers with the exception of lung cancer. For chronic musculo-skeletal disorders the DALYs lost in Europe due to osteoporosis (2.0 million) were less than for osteoarthrosis (3.1 million) but greater than for rheumatoid arthritis (1.0 million). We conclude that osteoporotic fractures are a significant cause of morbidity and mortality, particularly in the developed countries.
Laumann, Edward O; Leitsch, Sara A; Waite, Linda J
The National Social Life, Health and Aging Project is the first population-based, nationally representative study to ask older adults about their recent experience of mistreatment. This article provides estimates of mistreatment by family members and examines the association of mistreatment with demographic and health characteristics. We selected community-residing participants aged 57 to 85 using a multistage area probability design. Of those eligible, 3,005 participated in the study, for a weighted response rate of 75.5%. We asked respondents if in the past year they had experienced mistreatment in the following domains: verbal, financial, and physical. We asked those who reported mistreatment about their relationship to the person responsible. In all, 9% of older adults reported verbal mistreatment, 3.5% financial mistreatment, and 0.2% physical mistreatment by a family member. Odds of verbal mistreatment were higher for women and those with physical vulnerabilities and were lower for Latinos than for Whites. Odds of financial mistreatment were higher for African Americans and lower for Latinos than for Whites and were lower for those with a spouse or romantic partner than for those without partners. Few older adults report mistreatment by family members, with older adults quite insulated from physical mistreatment.
Beauvais, W; Orynbayev, M; Guitian, J
Estimation of farm prevalence is common in veterinary research. Typically, not all animals within the farm are sampled, and imperfect tests are used. Often, assumptions about herd sizes and sampling proportions are made, which may be invalid in smallholder settings. We propose an alternative method for estimating farm prevalence in the context of Brucella seroprevalence estimation in an endemic region of Kazakhstan. We collected 210 milk samples from Otar district, with a population of about 1000 cattle and 16 000 small ruminants, and tested them using an indirect ELISA. Individual-level prevalence and 95% confidence intervals were estimated using Taylor series linearization. A model was developed to estimate the smallholding prevalence, taking into account variable sampling proportions and uncertainty in the test accuracy. We estimate that 73% of households that we sampled had at least one Brucella-seropositive animal (95% credible interval 68-82). We estimate that 58% (95% confidence interval 40-76) of lactating small ruminants and 14% (95% confidence interval 1-28) of lactating cows were seropositive. Our results suggest that brucellosis is highly endemic in the area and conflict with those of the official brucellosis-testing programme, which found that in 2013 0% of cows and 1·7% of small ruminants were seropositive.
Kurth, Bärbel-Maria; Ellert, Ute
This study examines the degree of divergence between BMI calculated from subjective assessments and BMI calculated from measured height and weight as a function of gender and body image. In the German National Health Interview and Examination Survey for Children and Adolescents (KiGGS) the height and weight of 17,641 children and adolescents aged 0-18 years were measured. Participants were also questioned about their subjective body image (whether they considered themselves much too thin, a bit too thin, exactly the right weight, too fat or much too fat). A representative subsample of adolescents between 11 and 17 years old (N = 3,436: 1,663 boys and 1,773 girls) was asked additionally to self-report their body weight and height before being measured. The bias in the self-reported BMI yielded an underestimation of overweight and obesity prevalence. Girls who considered themselves much too fat or too fat and boys who considered themselves as much too fat underestimated their BMI. This was taken into account using a correction procedure for prevalence estimates of overweight and obesity based on the concept of conditional probabilities. The proposed correction formula using data from the KiGGS study can be applied to other German studies of adolescents in which weight, height and body image are only determined by self-report. Furthermore the correction procedure in principle can be transferred to other studies in other countries as long as a parallel validation study has been conducted to assess both subjective and objective BMI and body image. Copyright (c) 2010 S. Karger AG, Basel.
Yoon, Uicheul; Lee, Jong-Min; Koo, B B; Shin, Yong-Wook; Lee, Kyung Jin; Kim, In Young; Kwon, Jun Soo; Kim, Sun I
We developed group-specific tissue probability map (TPM) for gray matter (GM), white matter (WM) and cerebrospinal fluid (CSF) on the common spatial coordinates of an averaged brain atlas derived from normal controls (NC) and from schizophrenic patients (SZ). To identify differences in group-specific TPMs, we used quantitative evaluation methods based on differences in probabilistic distribution as a global criterion, and the mean probability and the similarity index (SI) by lobe as regional criteria. The SZ group showed more spatial variation with a lower mean probability than NC subjects. And, for the right temporal and left parietal lobes, the SI between each group was lower than the other lobes. It can be said that there were significant differences in spatial distribution between controls and schizophrenic patients at those areas. In case of female group, although group differences in the volumes of GM and WM were not significant, global difference in the probabilistic distribution of GM was more prominent and the SI was lower and its descent rate was greater in all lobes, compared with the male group. If these morphological differences caused by disease or group-specific features were not considered in TPM, the accuracy and certainty of specific group studies would be greatly reduced. Therefore, suitable TPM is required as a common framework for functional neuroimaging studies and an a priori knowledge of tissue classification.
Mark, Henry E; Houghton, Lisa A; Gibson, Rosalind S; Monterrosa, Eva; Kraemer, Klaus
Micronutrient deficiencies continue to be a major public health concern worldwide with many South Asian countries suffering a significant proportion of the global burden. A lack of nationally representative data on micronutrient deficiencies hampers sustained action to address the problem. Using data on the national food supply produced by the Food and Agriculture Organisation of the United Nations, and international food composition tables, the present study estimated the prevalence of inadequacy of seven micronutrients (vitamin A, thiamine, riboflavin, folate, vitamin B-12, zinc and calcium) in seven South Asian countries--Bangladesh, India, Iran, Maldives, Nepal, Pakistan and Sri Lanka. The estimated average requirement cut-point method was employed to determine the likelihood of inadequate micronutrient intakes. We report multiple micronutrient inadequacies in the food supply in the region, especially in the low and lower-middle income countries. Of the seven micronutrients investigated, calcium had the highest risk levels of inadequacy. Folate, riboflavin, vitamin B-12 and zinc were also deemed to be at high risk of inadequacy, although results differed markedly between countries. Various strategies to combat micronutrient deficiencies are currently underway in these countries. In order to facilitate the implementation of these efforts, the collection of nationally representative nutritional assessment survey data are urgently required to ascertain the true burden of micronutrient malnutrition.
Bourdon, K H; Rae, D S; Locke, B Z; Narrow, W E; Regier, D A
The National Institute of Mental Health Epidemiologic Catchment Area Survey is a comprehensive, community-based survey of mental disorders and use of services by adults, ages 18 and older. Diagnoses are based on the criteria in the "Diagnostic and Statistical Manual of Mental Disorders," third edition, and were obtained in five communities in the United States through lay-interviewer administration of the National Institute of Mental Health Diagnostic Interview Schedule. Results from the survey provide the public health field with data on the prevalence and incidence of specific mental disorders in the community, unbiased by the treatment status of the sample. The population with disorders is estimated, and the survey findings that respond to some of the most common requests for information about the epidemiology of mental disorders in the United States are highlighted briefly. Based on the survey, it is estimated that one of every five persons in the United States suffers from a mental disorder in any 6-month period, and that one of every three persons suffers a disorder in his or her lifetime. Fewer than 20 percent of those with a recent mental disorder seek help for their problem, according to the survey. High rates of comorbid substance abuse and mental disorders were found, particularly among those who had sought treatment for their disorders. PMID:1454978
Bourdon, K H; Rae, D S; Locke, B Z; Narrow, W E; Regier, D A
The National Institute of Mental Health Epidemiologic Catchment Area Survey is a comprehensive, community-based survey of mental disorders and use of services by adults, ages 18 and older. Diagnoses are based on the criteria in the "Diagnostic and Statistical Manual of Mental Disorders," third edition, and were obtained in five communities in the United States through lay-interviewer administration of the National Institute of Mental Health Diagnostic Interview Schedule. Results from the survey provide the public health field with data on the prevalence and incidence of specific mental disorders in the community, unbiased by the treatment status of the sample. The population with disorders is estimated, and the survey findings that respond to some of the most common requests for information about the epidemiology of mental disorders in the United States are highlighted briefly. Based on the survey, it is estimated that one of every five persons in the United States suffers from a mental disorder in any 6-month period, and that one of every three persons suffers a disorder in his or her lifetime. Fewer than 20 percent of those with a recent mental disorder seek help for their problem, according to the survey. High rates of comorbid substance abuse and mental disorders were found, particularly among those who had sought treatment for their disorders.
Horness, B.H.; Lomax, D.P.; Johnson, L.L.; Myers, M.S.; Pierce, S.M.; Collier, T.K.
Comprehensive, integrative assessments of coastal sediment quality are best effected by using large, diverse data sets that include measures of biological dysfunction observed in association with chronic exposure to sediment contaminants. Under the auspices of the National Oceanic and Atmospheric Administration`s National Status and Trends Program, the National Benthic Surveillance Project accumulated a database of synoptic sediment contaminant concentrations and indices of biological effects that were measured in indigenous animals collected during field surveys conducted from 1984 to 1994. This compilation of data provided the opportunity to develop a new approach for determining sediment quality criteria to add to the current repertoire of environmental assessment tools. Using a two-segment hockey stick regression, statistically significant chemical thresholds of biological effects were estimated for hepatic lesion prevalences in English sole (Pleuronectes vetulus, formerly Parophrys vetulus) in relation to sediment concentrations of polycyclic aromatic hydrocarbons. These threshold estimates are notably lower than many of those reported for other techniques. Application of this relatively simple dose-response model to subacute, chronic effects that are involved in pepatocarcinogenesis and associated with sediment toxicant content (1) reflects the link between toxicopathic disease progression and conditions observed in benthic fish exposed to contaminants and (2) provides endpoints for assessing sediment quality contaminant concentrations that are not necessarily acutely fatal but may have long-term health implications for populations that are chronically exposed.
Scher, Howard I.; Solo, Kirk; Valant, Jason; Todd, Mary B.; Mehra, Maneesha
Objective To identify patient populations most in need of treatment across the prostate cancer disease continuum, we developed a novel dynamic transition model based on risk of disease progression and mortality. Design and Outcome Measurements We modeled the flow of patient populations through eight prostate cancer clinical states (PCCS) that are characterized by the status of the primary tumor, presence of metastases, prior and current treatment, and testosterone levels. Simulations used published US incidence rates for each year from 1990. Progression and mortality rates were derived from published clinical trials, meta-analyses, and observational studies. Model outputs included the incidence, prevalence, and mortality for each PCCS. The impact of novel treatments was modeled in three distinct scenarios: metastatic castration-resistant prostate cancer (mCRPC), non-metastatic CRPC (nmCRPC), or both. Results and Limitations The model estimated the prevalence of prostate cancer as 2,219,280 in the US in 2009 and 3,072,480 in 2020, and incidence of mCRPC as 36,100 and 42,970, respectively. All-cause mortality in prostate cancer was estimated at 168,290 in 2009 and 219,360 in 2020, with 20.5% and 19.5% of these deaths, respectively, occurring in men with mCRPC. The majority (86%) of incidence flow into mCRPC states was from the nmCRPC clinical state. In the scenario with novel interventions for nmCRPC states, the progression to mCRPC is reduced, thus decreasing mCRPC incidence by 12% in 2020, with a sustained decline in mCRPC mortality. A limitation of the model is that it does not estimate prostate cancer—specific mortality. Conclusion The model informs clinical trial design for prostate cancer by quantifying outcomes in PCCS, and demonstrates the impact of an effective therapy applied in an earlier clinical state of nmCRPC on the incidence of mCRPC morbidity and subsequent mortality. PMID:26460686
Mumtaz, Ghina R.; Weiss, Helen A.; Vickerman, Peter; Larke, Natasha; Abu-Raddad, Laith J.
Objectives: The objective of this study is to understand the association between HIV and hepatitis C virus (HCV) among people who inject drugs (PWIDs) in the Middle East and North Africa (MENA), and to estimate HIV epidemic potential among PWIDs using HCV prevalence. Design/methods: Using data from a systematic review of HIV and HCV among PWID in MENA, we conducted two analyses, stratified by HIV epidemic state: a meta-analysis of the risk ratio of HCV to HIV prevalence (RRHCV/HIV) using DerSimonian-Laird random-effects models, and multivariable linear regression predicting log HIV prevalence. The HCV-HIV association from both analyses was used to estimate HIV prevalence at endemic equilibrium. We compared predicted with current HIV prevalence to classify HIV epidemic potential at country-level as low, medium or high, using predefined criteria. Results: The review identified 88 HCV prevalence measures among PWID in MENA, of which 54 had a paired HIV prevalence measure. The pooled RRHCV/HIV were 16, 4 and 3 in low-level, emerging and established HIV epidemics, respectively. There was a significant linear relationship between HCV and HIV at endemic equilibrium (P = 0.002). The predicted endemic HIV prevalence ranged between 8% (Tunisia) and 22% (Pakistan). Of the nine countries with data, five have high and three medium HIV epidemic potential. Only one country, Pakistan, appears to have reached saturation. Conclusion: HCV prevalence could be a predictor of future endemic HIV prevalence. In MENA, we predict that there will be further HIV epidemic growth among PWID. The proposed methodology can identify PWID populations that should be prioritized for HIV prevention interventions. PMID:26372281
Bui, Tan Van; Blizzard, Christopher Leigh; Luong, Khue Ngoc; Truong, Ngoc Le Van; Tran, Bao Quoc; Otahal, Petr; Gall, Seana; Nelson, Mark R; Au, Thuy Bich; Ha, Son Thai; Phung, Hai Ngoc; Tran, Mai Hoang; Callisaya, Michele; Srikanth, Velandai
To estimate the prevalence of non-communicable disease (NCD) risk factors at a provincial level in Vietnam, and to assess whether the summary estimates allow reliable inferences to be drawn regarding regional differences in risk factors and associations between them. Participants (n = 14706, 53.5 % females) aged 25-64 years were selected by multi-stage stratified cluster sampling from eight provinces each representing one of the eight geographical regions of Vietnam. Measurements were made using the World Health Organization STEPS protocols. Data were analysed using complex survey methods. Differences by sex in mean years of schooling (males 8.26 ± 0.20, females 7.00 ± 0.18), proportions of current smokers (males 57.70 %, females 1.73 %), and binge-drinkers (males 25.11 %, females 0.63 %), and regional differences in diet, reflected the geographical and socio-cultural characteristics of the country. Provinces with a higher proportion of urban population had greater mean levels of BMI (r = 0.82), and lesser proportions of active people (r = -0.89). The associations between the summary estimates were generally plausible (e.g. physical activity and BMI, r = -0.80) but overstated, and with some anomalous findings due to characterisation of smoking and hypertension by STEPS protocols. This report provides an extensive description of the sex-specific and regional distribution of NCD risk factors in Vietnam and an account of some health-related consequences of industrialisation in its early stages. The STEPS protocols can be utilized to provide aggregate data for valid between-population comparisons, but with important caveats identified.
Eng, C.; Brody, L.; Wagner, T.; Devilee, P.; Vijg, J.; Szabo, C.; Tavtigian, S.; Nathanson, K.; Ostrander, E.; Frank, T.
While sequence analysis is considered by many to be the most sensitive method of detecting unknown mutations in large genes such as BRCA1, most published estimates of the prevalence of mutations in this gene have been derived from studies that have used other methods of gene analysis. In order to determine the relative sensitivity of techniques that are widely used in research on BRCA1, a set of blinded samples containing 58 distinct mutations were analysed by four separate laboratories. Each used one of the following methods: single strand conformational polymorphism analysis (SSCP), conformation sensitive gel electrophoresis (CSGE), two dimensional gene scanning (TDGS), and denaturing high performance liquid chromatography (DHPLC). Only the laboratory using DHPLC correctly identified each of the mutations. The laboratory using TDGS correctly identified 91% of the mutations but produced three apparent false positive results. The laboratories using SSCP and CSGE detected abnormal migration for 72% and 76% of the mutations, respectively, but subsequently confirmed and reported only 65% and 60% of mutations, respectively. False negatives therefore resulted not only from failure of the techniques to distinguish wild type from mutant, but also from failure to confirm the mutation by sequence analysis as well as from human errors leading to misreporting of results. These findings characterise sources of error in commonly used methods of mutation detection that should be addressed by laboratories using these methods. Based upon sources of error identified in this comparison, it is likely that mutations in BRCA1 and BRCA2 are more prevalent than some studies have previously reported. The findings of this comparison provide a basis for interpreting studies of mutations in susceptibility genes across many inherited cancer syndromes. Keywords: BRCA1; mutation detection; cancer genetics PMID:11748305
Okumura, Masao; Satoh, Atsuko; Yoshiyama, Takashi; Yanai, Hideki; Rhi, Rina; Kudoh, Shoji; Ogata, Hideo
The QuantiFERON-TB (QFT) blood test is the major tool for the diagnosis of Mycobacterium tuberculosis (TB) infection among healthcare workers (HCWs). We used QFT tests to estimate the prevalence of TB infection among HCWs in our hospital. Between 2003 and 2010, a total of 733 HCWs were enrolled in this study, and the prevalence of TB infection was analyzed according to the HCWs' jobs and work place. Among the 152 men and 581 women who were evaluated, 3 female HCWs had a history of TB. Fifty-eight HCWs (8 men and 50 women with a mean age of 56.3 years and 48.4 years, respectively) demonstrated positive QFT tests. The positive rate was 7.9% for all staff members throughout the study period. The QFT test was positive for 1 HCW who was treated for TB in 1998, and negative and inconclusive for 2 other HCWs treated for TB in 2002. The positive rate for QFT was 16.0% in the TB ward (12/75, 95% confidence interval [CI]: 7.7-24.3%), 9.9% in the other wards (22/222, 95% CI: 7.9-11.9), and 1.1% in the outpatient department (1/91, 95% CI: 0-2.2). According to the job category, the QFT positive rates were as follows: doctors, 4.3% (3/70, 95% CI: 1.9-6.7); nurses, 10.3 (4/35, 95% CI: 6.0-16.8). The positive rate among doctors working in the TB ward was 10.0%, and that for nurses was 24.3%. This indicates that the prevalence of infection among HCWs in the TB ward was significantly higher than that in other work places. A comparison of the results from 2003 through 2007 revealed that for a total of 307 workers, 90.6% and 5.2% remained negative and positive, respectively, while 1.6% converted from negative to positive, and 2.6% from positive to negative. The positive rate among HCWs in the TB ward was higher than that in other wards. This is especially remarkable for doctors and nurses working in the TB ward.
Bovet, Pascal; Shamlaye, Conrad; Gabriel, Anne; Riesen, Walter; Paccaud, Fred
We assessed the prevalence of risk factors for cardiovascular disease (CVD) in a middle-income country in rapid epidemiological transition and estimated direct costs for treating all individuals at increased cardiovascular risk, i.e. following the so-called "high risk strategy". Survey of risk factors using an age- and sex-stratified random sample of the population of Seychelles aged 25-64 in 2004. Assessment of CVD risk and treatment modalities were in line with international guidelines. Costs are expressed as USD per capita per year. 1255 persons took part in the survey (participation rate of 80.2%). Prevalence of main risk factors was: 39.6% for high blood pressure (> or =140/90 mmHg or treatment) of which 59% were under treatment; 24.2% for high cholesterol (> or =6.2 mmol/l); 20.8% for low HDL-cholesterol (<1.0 mmol/l); 9.3% for diabetes (fasting glucose > or =7.0 mmol/l); 17.5% for smoking; 25.1% for obesity (body mass index > or =30 kg/m2) and 22.1% for the metabolic syndrome. Overall, 43% had HBP, high cholesterol or diabetes and substantially increased CVD risk. The cost for medications needed to treat all high-risk individuals amounted to USD 45.6, i.e. 11.2 dollars for high blood pressure, 3.8 dollars for diabetes, and 30.6 dollars for dyslipidemia (using generic drugs except for hypercholesterolemia). Cost for minimal follow-up medical care and laboratory tests amounted to 22.6 dollars. High prevalence of major risk factors was found in a rapidly developing country and costs for treatment needed to reduce risk factors in all high-risk individuals exceeded resources generally available in low or middle income countries. Our findings emphasize the need for affordable cost-effective treatment strategies and the critical importance of population strategies aimed at reducing risk factors in the entire population.
Hansen, N; Hay, G; Cowan, S; Jepsen, P; Bygum Krarup, H; Obel, N; Weis, N; Brehm Christensen, P
The prevalence of chronic hepatitis B virus (HBV) infection in Denmark is not clear. The primary aim of this study was to estimate the prevalence of chronic HBV infection in Denmark. The capture–recapture method was used to estimate the total population diagnosed with chronic HBV infection in Denmark using four nationwide registers. The population with undiagnosed chronic HBV infection was estimated by incorporating data from a two-year nationwide HBsAg screening programme in pregnant women. We identified 4,466 individuals with chronic HBV infection in the four registers until the end of 2007, and the capture–recapture estimate of the total population diagnosed with chronic hepatitis B was 7,112 (95% confidence interval (CI): 6,953–10,747). Only 17% of the identified patients attended recommended clinical care according to national guidelines. Including undiagnosed patients, the current population alive with HBV infection was 10,668 (95% CI: 10,224–16,164), corresponding to a prevalence of 0.24% (95% CI: 0.23–0.37%) in the Danish population older than 15 years. The estimated prevalence of chronic HBV infection among adults in Denmark was lower than reported from other northern European countries. Only half of the infected population had been diagnosed, and a minority attended specialised clinical care.
Sint, Daniela; Niederklapfer, Bettina; Kaufmann, Ruediger; Traugott, Michael
The applicability of species-specific primers to study feeding interactions is restricted to those ecosystems where the targeted prey species occur. Therefore, group-specific primer pairs, targeting higher taxonomic levels, are often desired to investigate interactions in a range of habitats that do not share the same species but the same groups of prey. Such primers are also valuable to study the diet of generalist predators when next generation sequencing approaches cannot be applied beneficially. Moreover, due to the large range of prey consumed by generalists, it is impossible to investigate the breadth of their diet with species-specific primers, even if multiplexing them. However, only few group-specific primers are available to date and important groups of prey such as flying insects have rarely been targeted. Our aim was to fill this gap and develop group-specific primers suitable to detect and identify the DNA of common taxa of flying insects. The primers were combined in two multiplex PCR systems, which allow a time- and cost-effective screening of samples for DNA of the dipteran subsection Calyptratae (including Anthomyiidae, Calliphoridae, Muscidae), other common dipteran families (Phoridae, Syrphidae, Bibionidae, Chironomidae, Sciaridae, Tipulidae), three orders of flying insects (Hymenoptera, Lepidoptera, Plecoptera) and coniferous aphids within the genus Cinara. The two PCR assays were highly specific and sensitive and their suitability to detect prey was confirmed by testing field-collected dietary samples from arthropods and vertebrates. The PCR assays presented here allow targeting prey at higher taxonomic levels such as family or order and therefore improve our ability to assess (trophic) interactions with flying insects in terrestrial and aquatic habitats. PMID:25525799
Williams, Geoffrey S; Mweya, Clement; Stewart, Laveta; Mtove, George; Reyburn, Hugh; Cook, Jackie; Corran, Patrick H; Riley, Eleanor M; Drakeley, Chris J
Sero-epidemiological methods are being developed as a tool for rapid assessment of malaria transmission intensity. Simple blood collection methods for use in field settings will make this more feasible. This paper describes validation of such a method, by analysing immunoglobulins from blood retained within immunophoretic rapid diagnostic tests (RDTs) for Plasmodium falciparum. RDTs are now widely used for the diagnosis of malaria and estimation of parasite rates, and this method represents a further use for these devices in malaria control. Immunoglobulins eluted from RDTs, designed to detect parasite histidine rich protein-2 (HRP-2), were analysed by indirect ELISA for IgG recognizing the P. falciparum blood stage antigens merozoite surface protein-1(19) (MSP-1(19)) and apical membrane antigen-1 (AMA-1). Optimal storage conditions for RDTs were evaluated by comparing antibody responses from RDTs stored in dry or humid conditions at 4 degrees C or at ambient temperature (with or without air-conditioning) for 7, 31 or 70 days. Antibody levels estimated using 3,700 RDT samples from attendees at health facilities in North-eastern Tanzania were compared with contemporaneously collected filter paper blood spots (FPBS) and used to estimate seroconversion rates. Storage of RDTs at 4 degrees C was optimal for immunoglobulin recovery but short-term storage at ambient temperatures did not substantially affect anti-malarial IgG levels. Results from RDTs were comparable with those from FPBSs, for both antigens. RDT-generated titres tended to be slightly higher than those generated from FPBSs, possibly due to greater recovery of immunoglobulins from RDTs compared to filter paper. Importantly, however, RDT-based seroconversion rates, and hence serological estimates of malaria transmission intensity, agreed closely with those from FPBSs. RDTs represent a practical option for collecting blood for sero-epidemiological surveys, with potential cost and logistical advantages over
Williams, Geoffrey S; Mweya, Clement; Stewart, Laveta; Mtove, George; Reyburn, Hugh; Cook, Jackie; Corran, Patrick H; Riley, Eleanor M; Drakeley, Chris J
Background Sero-epidemiological methods are being developed as a tool for rapid assessment of malaria transmission intensity. Simple blood collection methods for use in field settings will make this more feasible. This paper describes validation of such a method, by analysing immunoglobulins from blood retained within immunophoretic rapid diagnostic tests (RDTs) for Plasmodium falciparum. RDTs are now widely used for the diagnosis of malaria and estimation of parasite rates, and this method represents a further use for these devices in malaria control. Methods Immunoglobulins eluted from RDTs, designed to detect parasite histidine rich protein-2 (HRP-2), were analysed by indirect ELISA for IgG recognizing the P. falciparum blood stage antigens merozoite surface protein-119 (MSP-119) and apical membrane antigen-1 (AMA-1). Optimal storage conditions for RDTs were evaluated by comparing antibody responses from RDTs stored in dry or humid conditions at 4°C or at ambient temperature (with or without air-conditioning) for 7, 31 or 70 days. Antibody levels estimated using 3,700 RDT samples from attendees at health facilities in North-eastern Tanzania were compared with contemporaneously collected filter paper blood spots (FPBS) and used to estimate seroconversion rates. Results Storage of RDTs at 4°C was optimal for immunoglobulin recovery but short-term storage at ambient temperatures did not substantially affect anti-malarial IgG levels. Results from RDTs were comparable with those from FPBSs, for both antigens. RDT-generated titres tended to be slightly higher than those generated from FPBSs, possibly due to greater recovery of immunoglobulins from RDTs compared to filter paper. Importantly, however, RDT-based seroconversion rates, and hence serological estimates of malaria transmission intensity, agreed closely with those from FPBSs. Conclusion RDTs represent a practical option for collecting blood for sero-epidemiological surveys, with potential cost and logistical
van Griensven, Frits; Varangrat, Anchalee; Wimonsate, Wipas; Tanpradech, Suvimon; Kladsawad, Keratikarn; Chemnasiri, Tareerat; Suksripanich, Orapin; Phanuphak, Praphan; Mock, Philip; Kanggarnrua, Kamolset; McNicholl, Janet; Plipat, Tanarak
Men who have sex with men (MSM) continue to be at high risk for HIV infection. Here we evaluate trends in HIV prevalence, estimated HIV incidence, and risk behavior among MSM in Bangkok, Thailand. Between 2003 and 2007, 3 biennial cross-sectional HIV prevalence assessments were conducted among MSM in Bangkok,Thailand, using venue-day-time sampling. Oral fluid was tested for HIV infection; demographic and behavioral data were self-collected using hand-held computers. Estimates of annual HIV incidence in young MSM were derived as follows: (number of HIV infections/sum of [current age–age at start of anal intercourse]) 3 100). Logistic and Poisson regression was used to evaluate trends in HIV prevalence,estimated HIV incidence, and risk behavior. The overall HIV prevalence increased from 17.3% in 2003 to 28.3% in 2005 to 30.8% in 2007 (P , 0.001 for trend). The estimated HIV incidence among young MSM increased from 4.1%in 2003 to 6.4% in 2005, to 7.7% in 2007 (P , 0.02 for trend). The increase in HIV prevalence from 2005 to 2007 was not statistically significant. The proportion of men reporting anal sex and casual or steady male sex partners in the past 3 months significantly decreased,whereas the proportion reporting drug use and drug use during sex significantly increased. No increase was observed in the proportion of men reporting consistent condom use. Our data suggest that after a strong increase from 2003 to 2005, the HIV prevalence among MSM in Bangkok may have begun to stabilize. Given the continuing high levels of risk behavior and the estimated high HIV incidence in young MSM,additional HIV preventive interventions are necessary.
Schneider, L. G.; Dietzschold, B.; Dierks, R. E.; Matthaeus, W.; Enzmann, P.-J.; Strohmaier, K.
Cell-associated ribonucleoprotein (RNP) was isolated from BHK-21 cells infected with several strains of rabies and rabies-related viruses. The RNP-antigen from rabies and related viruses induced the formation of complement-fixing, precipitating, and immunofluorescent antibodies, and proved to be the group-specific antigen common to all rabies viruses. Antigens of the envelope which induce virus-neutralizing antibodies are apparently determinative for the serotype of a virus as evidenced by two-way neutralization tests. A combination of these methods seems to be a useful approach to the serological grouping and typing of rhabdoviruses. Images PMID:4196634
Elhai, Jon D; Miller, Megan E; Ford, Julian D; Biehn, Tracey L; Palmieri, Patrick A; Frueh, B Christopher
We empirically investigated recent proposed changes to the posttraumatic stress disorder (PTSD) diagnosis for DSM-5 using a non-clinical sample. A web survey was administered to 585 college students using the Stressful Life Events Screening Questionnaire to assess for trauma exposure but with additions for the proposed traumatic stressor changes in DSM-5 PTSD. For the 216 subjects endorsing previous trauma exposure and nominating a worst traumatic event, we administered the original PTSD Symptom Scale based on DSM-IV PTSD symptom criteria and an adapted version for DSM-5 symptoms, and the Center for Epidemiological Studies-Depression Scale. While 67% of participants endorsed at least one traumatic event based on DSM-IV PTSD's trauma classification, 59% of participants would meet DSM-5 PTSD's proposed trauma classification. Estimates of current PTSD prevalence were .4-1.8% points higher for the DSM-5 (vs. the DSM-IV) diagnostic algorithm. The DSM-5 symptom set fit the data very well based on confirmatory factor analysis, and neither symptom set's factors were more correlated with depression.
Jenness, Samuel M; Neaigus, Alan; Murrill, Christopher S; Gelpi-Acosta, Camila; Wendel, Travis; Hagan, Holly
We investigated the impact of recruitment bias within the venue-based sampling (VBS) method, which is widely used to estimate disease prevalence and risk factors among groups, such as men who have sex with men (MSM), that congregate at social venues. In a 2008 VBS study of 479 MSM in New York City, we calculated venue-specific approach rates (MSM approached/MSM counted) and response rates (MSM interviewed/MSM approached), and then compared crude estimates of HIV risk factors and seroprevalence with estimates weighted to address the lower selection probabilities of MSM who attend social venues infrequently or were recruited at high-volume venues. Our approach rates were lowest at dance clubs, gay pride events, and public sex strolls, where venue volumes were highest; response rates ranged from 39% at gay pride events to 95% at community-based organizations. Sixty-seven percent of respondents attended MSM-oriented social venues at least weekly, and 21% attended such events once a month or less often in the past year. In estimates adjusted for these variations, the prevalence of several past-year risk factors (e.g., unprotected anal intercourse with casual/exchange partners, ≥5 total partners, group sex encounters, at least weekly binge drinking, and hard-drug use) was significantly lower compared with crude estimates. Adjusted HIV prevalence was lower than unadjusted prevalence (15% vs. 18%), but not significantly. Not adjusting VBS data for recruitment biases could overestimate HIV risk and prevalence when the selection probability is greater for higher-risk MSM. While further examination of recruitment-adjustment methods for VBS data is needed, presentation of both unadjusted and adjusted estimates is currently indicated.
Jenness, Samuel M.; Neaigus, Alan; Murrill, Christopher S.; Gelpi-Acosta, Camila; Wendel, Travis; Hagan, Holly
Objectives We investigated the impact of recruitment bias within the venue-based sampling (VBS) method, which is widely used to estimate disease prevalence and risk factors among groups, such as men who have sex with men (MSM), that congregate at social venues. Methods In a 2008 VBS study of 479 MSM in New York City, we calculated venue-specific approach rates (MSM approached/MSM counted) and response rates (MSM interviewed/MSM approached), and then compared crude estimates of HIV risk factors and seroprevalence with estimates weighted to address the lower selection probabilities of MSM who attend social venues infrequently or were recruited at high-volume venues. Results Our approach rates were lowest at dance clubs, gay pride events, and public sex strolls, where venue volumes were highest; response rates ranged from 39% at gay pride events to 95% at community-based organizations. Sixty-seven percent of respondents attended MSM-oriented social venues at least weekly, and 21% attended such events once a month or less often in the past year. In estimates adjusted for these variations, the prevalence of several past-year risk factors (e.g., unprotected anal intercourse with casual/exchange partners, ≥5 total partners, group sex encounters, at least weekly binge drinking, and hard-drug use) was significantly lower compared with crude estimates. Adjusted HIV prevalence was lower than unadjusted prevalence (15% vs. 18%), but not significantly. Conclusions Not adjusting VBS data for recruitment biases could overestimate HIV risk and prevalence when the selection probability is greater for higher-risk MSM. While further examination of recruitment-adjustment methods for VBS data is needed, presentation of both unadjusted and adjusted estimates is currently indicated. PMID:21886323
Shay, Christina M.; Ning, Hongyan; Allen, Norrina B.; Carnethon, Mercedes R.; Chiuve, Stephanie E.; Greenlund, Kurt J.; Daviglus, Martha L.; Lloyd-Jones, Donald M.
Background The American Heart Association's 2020 Strategic Impact Goals define a new concept, “cardiovascular (CV) health”; however, current prevalence estimates of the status of CV health in U.S. adults according to age, sex and race/ethnicity have not been published. Methods and Results We included 14,515 adults (≥20 years) from the 2003-2008 National Health and Nutrition Examination Surveys. Participants were stratified by young (20-39 years), middle (40-64 years), and older ages (65+ years). CV health behaviors (diet, physical activity, body mass index, smoking) and CV health factors (blood pressure, total cholesterol, fasting blood glucose, smoking) were defined as poor, intermediate, or ideal. Less than 1% of adults exhibited ideal CV health for all 7 metrics. For CV health behaviors, non-smoking was most prevalent (range:60.2-90.4%) while ideal Healthy Diet Score was least prevalent (range:0.2-2.6%) across groups. Prevalence of ideal BMI (range:36.5-45.3%) and ideal physical activity levels (range:50.2-58.8%) were higher in young adults compared to middle or older ages. Ideal total cholesterol (range:23.7-36.2%), blood pressure (range:11.9-16.3%) and fasting blood glucose (range:31.2-42.9%) were lower in older adults compared with young and middle age adults.Prevalence of poor CV health factors was lowest in young age but higher at middle and older ages. Prevalence estimates by age and sex were consistent across race/ethnic groups. Conclusions These prevalence estimates of CV health represent a starting point from which effectiveness of efforts to promote CV health and prevent CV disease can be monitored and compared in U.S. adult populations. PMID:22095826
Herek, Gregory M.
Using survey responses collected via the Internet from a U.S. national probability sample of gay, lesbian, and bisexual adults (N = 662), this article reports prevalence estimates of criminal victimization and related experiences based on the target's sexual orientation. Approximately 20% of respondents reported having experienced a person or…
Herek, Gregory M.
Using survey responses collected via the Internet from a U.S. national probability sample of gay, lesbian, and bisexual adults (N = 662), this article reports prevalence estimates of criminal victimization and related experiences based on the target's sexual orientation. Approximately 20% of respondents reported having experienced a person or…
Rosinska, M; Gwiazda, P; De Angelis, D; Presanis, A M
HIV spread in men who have sex with men (MSM) is an increasing problem in Poland. Despite the existence of a surveillance system, there is no direct evidence to allow estimation of HIV prevalence and the proportion undiagnosed in MSM. We extracted data on HIV and the MSM population in Poland, including case-based surveillance data, diagnostic testing prevalence data and behavioural data relating to self-reported prior diagnosis, stratified by age (⩽35, >35 years) and region (Mazowieckie including the capital city of Warsaw; other regions). They were integrated into one model based on a Bayesian evidence synthesis approach. The posterior distributions for HIV prevalence and the undiagnosed fraction were estimated by Markov Chain Monte Carlo methods. To improve the model fit we repeated the analysis, introducing bias parameters to account for potential lack of representativeness in data. By placing additional constraints on bias parameters we obtained precisely identified estimates. This family of models indicates a high undiagnosed fraction [68·3%, 95% credibility interval (CrI) 53·9-76·1] and overall low prevalence (2·3%, 95% CrI 1·4-4·1) of HIV in MSM. Additional data are necessary in order to produce more robust epidemiological estimates. More effort is urgently needed to ensure timely diagnosis of HIV in Poland.
Town, K; Furegato, M; Field, N; Hughes, G
In England, dual tests detecting chlamydia and gonorrhoea are used in specialist and community-based sexual health services (SHSs). Test performance is poor when prevalence is low, therefore UK national guidelines recommend against opportunistic gonorrhoea screening unless there is a clear local public health need. While surveillance data on gonorrhoea prevalence is comprehensive in specialist SHSs, it is sparse in community SHSs. We aimed to estimate gonorrhoea prevalence in heterosexual men and women aged 15-24 attending community SHSs to inform testing care pathways. We used linear and quadratic regression to model the relationship between prevalence in community and specialist SHSs in local authorities (LAs) with available surveillance data. We applied best-fitting models to predict prevalence in community SHSs in remaining LAs. Data from community SHSs were available for 102/326 LAs. There was a weak positive association between gonorrhoea prevalence in community and specialist SHSs in corresponding LAs within (R 2 = 0·13, P = 0·058) and outside (R 2 = 0·07, P = 0·02) London. Applying best-fitting models, we estimated a median gonorrhoea prevalence of 0·5% (mean 0·6%; range 0·2%-2·7%) in heterosexuals attending community SHSs. Despite some unexplained variation, our analyses suggest gonorrhoea prevalence in young heterosexuals attending community SHSs is below 1% in most English LAs. Our findings re-inforce the current national guidelines that recommend care pathways for gonorrhoea testing in community SHSs include confirmatory testing to reduce the risk of misdiagnosis and inappropriate management.
Carroll, Rebecca I; Forbes, Andrew; Graham, David A; Messam, Locksley L McV
Abattoir surveys and findings from post-mortem meat inspection are commonly used to estimate infection or disease prevalence in farm animal populations. However, the function of an abattoir is to slaughter animals for human consumption, and the collection of information on animal health for research purposes is a secondary objective. This can result in methodological shortcomings leading to biased prevalence estimates. Selection bias can occur when the study population as obtained from the abattoir is not an accurate representation of the target population. Virtually all of the tests used in abattoir surveys to detect infections or diseases that impact animal health are imperfect, leading to errors in identifying the outcome of interest and consequently, information bias. Examination of abattoir surveys estimating prevalence in the literature reveals shortcomings in the methods used in these studies. While the STROBE-Vet statement provides clear guidance on the reporting of observational research, we have not found any guidelines in the literature advising researchers on how to conduct abattoir surveys. This paper presents a protocol in two flowcharts to help researchers (regardless of their background in epidemiology) to first identify, and, where possible, minimise biases in abattoir surveys estimating prevalence. Flowchart 1 examines the identification of the target population and the appropriate study population while Flowchart 2 guides the researcher in identifying, and, where possible, correcting potential sources of outcome misclassification. Examples of simple sensitivity analyses are also presented which approximate the likely uncertainty in prevalence estimates due to systematic errors. Finally, the researcher is directed to outline any limitations of the study in the discussion section of the paper. This protocol makes it easier to conduct an abattoir survey using sound methods, identifying and, where possible, minimizing biases. Copyright © 2017
Skinner, Asheley Cockrell; Miles, Donna; Perrin, Eliana M; Coyne-Beasley, Tamera; Ford, Carol
We compared parental reports of children's height and weight when the values were estimated vs. parent-measured to determine how these reports influence the estimated prevalence of childhood obesity. In the 2007 and 2008 North Carolina Child Health Assessment and Monitoring Program surveys, parents reported height and weight for children aged 3-17 years. When parents reported the values were not measured (by doctor, school, or home), they were asked to measure their child and were later called back. We categorized body mass index status using standard CDC definitions, and we used Chi-square tests and the Stuart-Maxwell test of marginal homogeneity to examine reporting differences. About 80% (n=509) of the 638 parents who reported an unmeasured height and/or weight participated in a callback and provided updated measures. Children originally classified as obese were subsequently classified as obese (67%), overweight (13%), and healthy weight (19%). An estimated 28% of younger children (<10 years of age) vs. 6% of older children (aged ≥10 years) were reclassified on callback. Having parents who guessed the height and weight of their children and then reported updated values did not significantly change the overall population estimates of obesity. Our findings demonstrate that using parent-reported height and weight values may be sufficient to provide reasonable estimates of obesity prevalence. Systematically asking the source of height and weight information may help improve how it is applied to research of the prevalence of childhood obesity when gold-standard measurements are not available.
Vanrolleghem, Ann M.; Isken, Leslie D.; van Deuren, Marcel; Sturkenboom, Miriam C. J. M.; Timen, Aura
Background In 2011, a unique Q fever vaccination campaign targeted people at risk for chronic Q fever in the southeast of the Netherlands. General practitioners referred patients with defined cardiovascular risk-conditions (age >15 years). Prevalence rates of those risk-conditions were lacking, standing in the way of adequate planning and coverage estimation. We aimed to obtain prevalence rates retrospectively in order to estimate coverage of the Q fever vaccination campaign. Methods With broad search terms for these predefined risk-conditions, we extracted patient-records from a large longitudinal general-practice research-database in the Netherlands (IPCI-database). After validation of these records, obtained prevalence rates (stratified for age and sex) extrapolated to the Q fever high-incidence area population, gave an approximation of the size of the targeted patient-group. Coverage calculation addressed people actually screened by a pre-vaccination Q fever skin test and serology (coverage) and patients referred by their general practitioners (adjusted-coverage) in the 2011 campaign. Results Our prevalence estimate of any risk-condition was 3.1% (lower-upper limits 2.9-3.3%). For heart valve defects, aorta aneurysm/prosthesis, congenital anomalies and endocarditis, prevalence was 2.4%, 0.6%, 0.4% and 0.1%, respectively. Estimated number of eligible people in the Q fever high-incidence area was 11,724 (10,965-12,532). With 1330 people screened for vaccination, coverage of the vaccination campaign was 11%. For referred people, the adjusted coverage was 18%. Coverage was lowest among the very-old and highest for people aged 50–70 years. Conclusion The estimated coverage of the vaccination campaign was limited. This should be interpreted in the light of the complexity of this target-group with much co-morbidity, and of the vaccine that required invasive pre-vaccination screening. Calculation of prevalence rates of risk-conditions based on the IPCI-database was
Vermeer-de Bondt, Patricia E; Schoffelen, Teske; Vanrolleghem, Ann M; Isken, Leslie D; van Deuren, Marcel; Sturkenboom, Miriam C J M; Timen, Aura
In 2011, a unique Q fever vaccination campaign targeted people at risk for chronic Q fever in the southeast of the Netherlands. General practitioners referred patients with defined cardiovascular risk-conditions (age >15 years). Prevalence rates of those risk-conditions were lacking, standing in the way of adequate planning and coverage estimation. We aimed to obtain prevalence rates retrospectively in order to estimate coverage of the Q fever vaccination campaign. With broad search terms for these predefined risk-conditions, we extracted patient-records from a large longitudinal general-practice research-database in the Netherlands (IPCI-database). After validation of these records, obtained prevalence rates (stratified for age and sex) extrapolated to the Q fever high-incidence area population, gave an approximation of the size of the targeted patient-group. Coverage calculation addressed people actually screened by a pre-vaccination Q fever skin test and serology (coverage) and patients referred by their general practitioners (adjusted-coverage) in the 2011 campaign. Our prevalence estimate of any risk-condition was 3.1% (lower-upper limits 2.9-3.3%). For heart valve defects, aorta aneurysm/prosthesis, congenital anomalies and endocarditis, prevalence was 2.4%, 0.6%, 0.4% and 0.1%, respectively. Estimated number of eligible people in the Q fever high-incidence area was 11,724 (10,965-12,532). With 1330 people screened for vaccination, coverage of the vaccination campaign was 11%. For referred people, the adjusted coverage was 18%. Coverage was lowest among the very-old and highest for people aged 50-70 years. The estimated coverage of the vaccination campaign was limited. This should be interpreted in the light of the complexity of this target-group with much co-morbidity, and of the vaccine that required invasive pre-vaccination screening. Calculation of prevalence rates of risk-conditions based on the IPCI-database was feasible. This procedure proved an
Rapaport, F. T.; Dausset, J.; Legrand, L.; Barge, A.; Lawrence, H. S.; Converse, J. M.
Erythrocyte group antigens A and B can act as potent and group-specific transplantation antigens in man. ABO group-incompatible recipients pretreated with such antigens have rejected skin allografts obtained from donors incompatible for the same antigens in an accelerated (4-5 days) or white graft manner. Skin grafts applied to the same recipients from ABO-compatible donors were accorded first-set survival times. Intact erythrocyte suspensions and antigens isolated from hog (A substance) and horse (B substance) stomachs, were equally capable of inducing this type of allograft sensitivity. The latter observation broadens the spectrum of heterologous antigens capable of inducing allograft sensitivity in the mammalian host and provides a readily available, heat-stable, and water-soluble source of antigens for further studies of allograft rejection mechanisms in man. PMID:4877681
Theis, Kevin R; Schmidt, Thomas M; Holekamp, Kay E
Symbiotic microbes can benefit their animal hosts by enhancing the diversity of communication signals available to them. The fermentation hypothesis for chemical recognition posits that 1) fermentative bacteria in specialized mammalian scent glands generate odorants that mammals co-opt to communicate with one another, and 2) that variation in scent gland odors is due to underlying variation in the structure of bacterial communities within scent glands. For example, group-specific social odors are suggested to be due to members of the same social group harboring more similar bacterial communities in their scent glands than do members of different social groups. We used 16S rRNA gene surveys to show that 1) the scent secretions of spotted hyenas are densely populated by fermentative bacteria whose closest relatives are well-documented odor producers, and that 2) these bacterial communities are more similar among hyenas from the same social group than among those from different groups.
Porphyre, V; Betson, M; Rabezanahary, H; Mboussou, Y; Zafindraibe, N J; Rasamoelina-Andriamanivo, H; Costard, S; Pfeiffer, D U; Michault, A
Taenia solium cysticercosis was reported in official veterinary and medical statistics to be highly prevalent in pigs and humans in Madagascar, but few estimates are available for pigs. This study aimed to estimate the seroprevalence of porcine cysticercosis among pigs slaughtered in Antananarivo abattoirs. Firstly, the diagnostic performance of two antigen-ELISA techniques (B158B60 Ag-ELISA and HP10 Ag-ELISA) and an immunoblotting method were compared with meat inspection procedures on a sample of pigs suspected to be infected with (group 1; n=250) or free of (group 2; n=250) T. solium based on direct veterinary inspection in Madagascar. Sensitivity and specificity of the antigen ELISAs were then estimated using a Bayesian approach for detection of porcine cysticercosis in the absence of a gold standard. Then, a third set of pig sera (group 3, n=250) was randomly collected in Antananarivo slaughterhouses and tested to estimate the overall prevalence of T. solium contamination in pork meat traded in Antananarivo. The antigen ELISAs showed a high sensitivity (>84%), but the B158B60 Ag-ELISA appeared to be more specific than the HP10 Ag-ELISA (model 1: 95% vs 74%; model 2: 87% vs 71%). The overall prevalence of porcine cysticercosis in Antananarivo slaughterhouses was estimated at 2.3% (95% credibility interval [95%CrI]: 0.09-9.1%) to 2.6% (95%CrI: 0.1-10.3%) depending on the model and priors used. Since the sample used in this study is not representative of the national pig population, village-based surveys and longitudinal monitoring at slaughter are needed to better estimate the overall prevalence, geographical patterns and main risk factors for T. solium contamination, in order to improve control policies.
Booth, Helen P; Prevost, A Toby; Gulliford, Martin C
Primary care electronic health records (EHRs) are increasingly used as a resource for epidemiological research. Cigarette smoking is an important variable in many epidemiological studies. We evaluated the validity of smoking records in primary care EHRs by comparing estimates for smoking prevalence from primary care EHRs with national health survey data. Data were analysed for adults over 30 years of age from the Clinical Practice Research Datalink (CPRD) in comparison with data from the Health Survey for England between 2007 and 2011. Electronic health records in the CPRD were searched for records of smoking status and smoking cessation treatment. Annual age- and sex-standardised prevalence of current-, non- and former smoking were calculated, and compared with equivalent data from the Health Survey for England (HSE). The difference between estimates of current smoking in CPRD and HSE was generally <1% from 2007 to 2011. In 2011, the prevalence of current smoking in men was: CPRD 24.3%, HSE 24.2%. The mean difference was 0.1% (95% confidence interval −1.5 to 1.7%). In women, current smoking prevalence was CPRD 20.3%, HSE 19.0%; mean difference 1.3% (0.0 to 2.6%). Estimates for former smoking were lower in CPRD than HSE for men (CPRD 26.7%, HSE 31.3%) and women (CPRD 22.9%, HSE 25.0%). Prevalence estimates for current smoking, and non-smoking, from primary care EHRs are similar to those from nationally representative surveys, but former smoking may be under-recorded. © 2013 The Authors. Pharmacoepidemiology and Drug Safety published by John Wiley & Sons, Ltd.
Lakhan, Ram; Ekúndayò, Olúgbémiga T.; Shahbazi, Mohammad
Background: Intellectual disability (ID) is a global public health concern. Prevalence of ID and its association with age and other demographic factors is required for planning purposes in India. Objective: This study analyzed the age-adjusted prevalence of ID in rural and urban populations and its correlation with age in children and adults. Materials and Methods: Disability data published in the report (2002) of National Sample Survey Organization were analyzed, using Z-test to measure differences in age-adjusted prevalence. Spearman rho was calculated to determine strength and direction of the association, and regression analysis was used to predict prevalence rate, based on age in rural and urban population settings. Results: Overall, India has a prevalence of 10.5/1000 in ID. Urban population has slightly higher rate (11/1000) than rural (10.08/1000; P = 0.044). Age was found to be highly correlated with prevalence of ID in rural children (ϱ =0.981, P = 0.019) as well as in children (ϱ = −0.954, P = 0.000) and adults (ϱ = −0.957, P = 0.000) in urban population. The possibility of confounding or the existence of covariates for children in urban settings was noted. Conclusion: Results of this study match findings in other epidemiological studies. However, multistage, large-scale studies are recommended for investigating prevalence rates with different severity levels of ID. PMID:26752897
Dusek, L; Pavlík, T; Májek, O; Büchler, T; Muzik, J; Maluskova, D; Koptíková, J; Bortlicek, Z; Abrahámová, J
Cancer burden in the Czech population ranks among the highest worldwide, which introduces a strong need for a prospective modelling of cancer incidence and prevalence rates. Moreover, a prediction of number of cancer patients requiring active antitumor therapy is also an important issue. This paper presents the stage-specific predictions of cancer incidence and prevalence, and the stage- and region-specific patients requiring active antitumor therapy for the most common cancer diagnoses in the Czech Republic for years 2015 and 2020. The stage-specific estimates are also presented with regard to the treatment phase as newly diagnosed patients, patients treated for non-terminal recurrence, and patients treated for terminal recurrence. Data of the Czech National Cancer Registry from 1977 to 2011 has been used for the analysis, omitting the records of patients diagnosed as death certificate only or at autopsy. In total, 1,777,775 incidences have been considered for the estimation using a statistical model utilizing solely the population-based cancer registry data. All estimates have been calculated with respect to the changing demographic structure of the Czech population and the clinical stage at diagnosis. Considering year 2011 as the baseline, we predict 89%, 15%, 31% and 32% increase in prostate, colorectal, female breast and lung cancer incidence, respectively, in 2020 resulting in 13,153, 9,368, 8,695, and 8,604 newly dia-g--nosed cancer patients in that year, respectively. Regarding cancer prevalence in 2020, the estimated increase is 140%, 40%, 51%, and 17% for prostate, colorectal, female breast and lung cancer, respectively, meaning that more than 100,000 prevalent female breast cancer patients as well as more than 100,000 prevalent prostate cancer patients are expected in the Czech Republic. The estimated numbers of patients requiring active antitumor therapy for prostate, colorectal, female breast and lung cancer in the Czech Republic in 2020 are 23,652, 14
Cossrow, Nicole; Pawaskar, Manjiri; Witt, Edward A; Ming, Eileen E; Victor, Timothy W; Herman, Barry K; Wadden, Thomas A; Erder, M Haim
To estimate binge eating disorder (BED) prevalence according to DSM-5 and DSM-IV-TR criteria in US adults and to estimate the proportion of individuals meeting DSM-5 BED criteria who reported being formally diagnosed. A representative sample of US adults who participated in the National Health and Wellness Survey were asked to respond to an Internet survey (conducted in October 2013). Assessments included 3-month, 12-month, and lifetime BED prevalence based on DSM-5 and DSM-IV-TR criteria and demographics, psychiatric comorbidities, and self-esteem (Rosenberg Self-Esteem Scale). Descriptive statistics are provided. Prevalence estimates were calculated using poststratification sampling weights. Of 22,397 respondents, 344 (women, n = 242; men, n = 102) self-reported symptoms consistent with DSM-5 BED symptom criteria. The 3-month, 12-month, and lifetime DSM-5 prevalence estimates (95% CIs) projected to the US population were 1.19% (1.04%-1.37%), 1.64% (1.45%-1.85%), and 2.03% (1.83%-2.26%), respectively. The 12-month and lifetime projected DSM-IV-TR prevalence estimates were 1.15% (1.00%-1.32%) and 1.52% (1.35%-1.70%), respectively. Of respondents meeting DSM-5 BED criteria in the past 12 months, 3.2% (11/344) reported receiving a formal diagnosis. Compared with non-BED respondents, respondents meeting DSM-5 BED criteria in the past 12 months were younger (mean ± SD age = 46.01 ± 14.32 vs 51.59 ± 15.80 years; P < .001), had a higher body mass index (mean ± SD = 33.71 ± 9.36 vs 27.96 ± 6.68 kg/m²; P < .001), and had lower self-esteem (mean ± SD score = 16.47 ± 6.99 vs 23.33 ± 6.06; P < .001). DSM-5 BED criteria resulted in higher BED prevalence estimates than with DSM-IV-TR criteria. Most BED respondents did not report being formally diagnosed, indicating an unmet need in BED recognition and diagnosis. © Copyright 2016 Physicians Postgraduate Press, Inc.
Alexander, Harriet; Rouco, Mónica; Haley, Sheean T.; Wilson, Samuel T.; Karl, David M.; Dyhrman, Sonya T.
A diverse microbial assemblage in the ocean is responsible for nearly half of global primary production. It has been hypothesized and experimentally demonstrated that nutrient loading can stimulate blooms of large eukaryotic phytoplankton in oligotrophic systems. Although central to balancing biogeochemical models, knowledge of the metabolic traits that govern the dynamics of these bloom-forming phytoplankton is limited. We used eukaryotic metatranscriptomic techniques to identify the metabolic basis of functional group-specific traits that may drive the shift between net heterotrophy and autotrophy in the oligotrophic ocean. Replicated blooms were simulated by deep seawater (DSW) addition to mimic nutrient loading in the North Pacific Subtropical Gyre, and the transcriptional responses of phytoplankton functional groups were assayed. Responses of the diatom, haptophyte, and dinoflagellate functional groups in simulated blooms were unique, with diatoms and haptophytes significantly (95% confidence) shifting their quantitative metabolic fingerprint from the in situ condition, whereas dinoflagellates showed little response. Significantly differentially abundant genes identified the importance of colimitation by nutrients, metals, and vitamins in eukaryotic phytoplankton metabolism and bloom formation in this system. The variable transcript allocation ratio, used to quantify transcript reallocation following DSW amendment, differed for diatoms and haptophytes, reflecting the long-standing paradigm of phytoplankton r- and K-type growth strategies. Although the underlying metabolic potential of the large eukaryotic phytoplankton was consistently present, the lack of a bloom during the study period suggests a crucial dependence on physical and biogeochemical forcing, which are susceptible to alteration with changing climate. PMID:26460011
McCarty, Maclyn; Lancefield, Rebecca C.
The phenomenon of apparent loss of group-specific carbohydrate in the course of mouse passage of group A streptococci has been subjected to further study, and several additional variants showing this property have been described. The loss of group reactivity is shown to be due to an alteration in the chemical structure and serological specificity of the cell wall carbohydrate. This alteration appears to be essentially the same in each of the variants available for study. The carbohydrate of the variant strains (V) contains the same two monosaccharide components as the group A carbohydrate (A), but they are present in different proportions. Precipitating sera reactive with V carbohydrate have been prepared, and the A and V carbohydrates have been compared by qualitative and quantitative precipitin analysis. A second type of variation has been encountered during mouse passage. This variation is characterized by the occurrence of a cell wall carbohydrate (I) intermediate in chemical and serological properties between the A and V carbohydrates. The I carbohydrate reacts with both A and V antisera and does not appear to be a simple mixture of A and V carbohydrate. Similarly, antisera against the intermediate strain contain antibodies reactive with both A and V carbohydrates, and evidence is presented indicating that in part this represents antibody with double specificity. PMID:14392237
van Kuppeveld, F J; Johansson, K E; Galama, J M; Kissing, J; Bölske, G; van der Logt, J T; Melchers, W J
The suitability of a 16S rRNA-based mycoplasma group-specific PCR for the detection of mycoplasma contamination in cell cultures was investigated. A total of 104 cell cultures were tested by using microbiological culture, DNA fluorochrome staining, DNA-rRNA hybridization, and PCR techniques. A comparison of the results obtained with these techniques revealed agreement for 95 cell cultures. Discrepant results, which were interpreted as false negative or false positive on the basis of a comparison with the results obtained with other methods, were observed with nine cell cultures. The microbiological culture technique produced false-negative results for four cell cultures. The hybridization technique produced false-negative results for two cell cultures, and for one of these cell cultures the DNA staining technique also produced a false-negative result. The PCR may have produced false-positive results for one cell culture. Ambiguous results were obtained with the remaining two cell cultures. Furthermore, the presence of contaminating bacteria interfered with the interpretation of the DNA staining results for 16 cell cultures. For the same reason the hybridization signals of nine cell cultures could not be interpreted. Our results demonstrate the drawbacks of each of the detection methods and the suitability of the PCR for the detection of mycoplasmas in cell cultures. PMID:7509584
Dillner, L; Moreno-Lopez, J; Dillner, J
Certain types of human papillomaviruses have been linked to the development of carcinoma of the cervix uteri. We have analyzed 114 serum specimens from women with cervical intraepithelial neoplasia (CIN) or carcinoma of the cervix uteri for the presence of serum antibodies against purified, disrupted bovine papillomavirus (BPV). The titers of immunoglobulin A (IgA) antibodies against BPV were slightly elevated (P less than 0.025) in the sera from CIN or cervical carcinoma patients compared with the titers of 139 serum specimens from sex- and age-matched healthy controls. In contrast, both the IgG and IgM serum antibody titers against BPV were significantly decreased for CIN and cervical carcinoma patients compared with those of healthy controls (P less than 0.001 and P less than 0.005, respectively). These results suggest that the difference between IgA and IgG or IgM antibodies to papillomavirus group-specific antigens may represent interesting serological parameters that could possibly be used in the epidemiologic study of women at risk for CIN. PMID:2157738
Alexander, Harriet; Rouco, Mónica; Haley, Sheean T; Wilson, Samuel T; Karl, David M; Dyhrman, Sonya T
A diverse microbial assemblage in the ocean is responsible for nearly half of global primary production. It has been hypothesized and experimentally demonstrated that nutrient loading can stimulate blooms of large eukaryotic phytoplankton in oligotrophic systems. Although central to balancing biogeochemical models, knowledge of the metabolic traits that govern the dynamics of these bloom-forming phytoplankton is limited. We used eukaryotic metatranscriptomic techniques to identify the metabolic basis of functional group-specific traits that may drive the shift between net heterotrophy and autotrophy in the oligotrophic ocean. Replicated blooms were simulated by deep seawater (DSW) addition to mimic nutrient loading in the North Pacific Subtropical Gyre, and the transcriptional responses of phytoplankton functional groups were assayed. Responses of the diatom, haptophyte, and dinoflagellate functional groups in simulated blooms were unique, with diatoms and haptophytes significantly (95% confidence) shifting their quantitative metabolic fingerprint from the in situ condition, whereas dinoflagellates showed little response. Significantly differentially abundant genes identified the importance of colimitation by nutrients, metals, and vitamins in eukaryotic phytoplankton metabolism and bloom formation in this system. The variable transcript allocation ratio, used to quantify transcript reallocation following DSW amendment, differed for diatoms and haptophytes, reflecting the long-standing paradigm of phytoplankton r- and K-type growth strategies. Although the underlying metabolic potential of the large eukaryotic phytoplankton was consistently present, the lack of a bloom during the study period suggests a crucial dependence on physical and biogeochemical forcing, which are susceptible to alteration with changing climate.
Ayoub, Elia M.; Dudding, Burton A.
A temperature-dependent alteration in the synthesis of the group-specific polysaccharide was found to occur in two "variant" streptococcal strains, A-486-Var and C 121/46/4. These strains synthesize a polysaccharide with variant immunochemical characteristics when grown at 37°C. However, when these organisms are grown at lower temperatures, 22°C, an enhanced synthesis of Group A carbohydrate occurs. Other variant strains show no appreciable alteration of the cell wall carbohydrate composition when grown at lower temperatures. Studies on an intermediate strain show that this organism has a propensity for the synthesis of a polysaccharide with higher glucosamine content and enhanced Group A serological reactivity when grown at 22°C. Immunochemical studies performed on the carbohydrates produced by the A-486-Var at various temperatures revealed that the appearance of Group A serological reactivity at lower temperatures is due to the additional synthesis of a polysaccharide with Group A specificity along with the continued synthesis of a variant carbohydrate. This finding contrasts with data obtained on the carbohydrate produced by the intermediate organisms that appears to consist predominently of one molecule bearing dual A and variant antigenic determinants. PMID:4123827
Brouwer, Kimberly C.; Firestone Cruz, Michelle A.; Ramos, Rebeca; Ramos, Maria Elena; Lozada, Remedios M.; Magis-Rodriguez, Carlos; Strathdee, Steffanie A.
Respondent-driven sampling (RDS), a chain referral sampling approach, is increasingly used to recruit participants from hard-to-reach populations, such as injection drug users (IDUs). Using RDS, we recruited IDUs in Tijuana and Ciudad (Cd.) Juárez, two Mexican cities bordering San Diego, CA and El Paso, TX, respectively, and compared recruitment dynamics, reported network size, and estimates of HIV and syphilis prevalence. Between February and April 2005, we used RDS to recruit IDUs in Tijuana (15 seeds, 207 recruits) and Cd. Juárez (9 seeds, 197 recruits), Mexico for a cross-sectional study of behavioral and contextual factors associated with HIV, HCV and syphilis infections. All subjects provided informed consent, an anonymous interview, and a venous blood sample for serologic testing of HIV, HCV, HBV (Cd. Juárez only) and syphilis antibody. Log-linear models were used to analyze the association between the state of the recruiter and that of the recruitee in the referral chains, and population estimates of the presence of syphilis antibody were obtained, correcting for biased sampling using RDS-based estimators. Sampling of the targeted 200 recruits per city was achieved rapidly (2 months in Tijuana, 2 weeks in Cd. Juárez). After excluding seeds and missing data, the sample prevalence of HCV, HIV and syphilis were 96.6, 1.9 and 13.5% respectively in Tijuana, and 95.3, 4.1, and 2.7% respectively in Cd. Juárez (where HBV prevalence was 84.7%). Syphilis cases were clustered in recruitment trees. RDS-corrected estimates of syphilis antibody prevalence ranged from 12.8 to 26.8% in Tijuana and from 2.9 to 15.6% in Ciudad Juárez, depending on how recruitment patterns were modeled, and assumptions about how network size affected an individual’s probability of being included in the sample. RDS was an effective method to rapidly recruit IDUs in these cities. Although the frequency of HIV was low, syphilis prevalence was high, particularly in Tijuana. RDS
Frost, Simon D W; Brouwer, Kimberly C; Firestone Cruz, Michelle A; Ramos, Rebeca; Ramos, Maria Elena; Lozada, Remedios M; Magis-Rodriguez, Carlos; Strathdee, Steffanie A
Respondent-driven sampling (RDS), a chain referral sampling approach, is increasingly used to recruit participants from hard-to-reach populations, such as injection drug users (IDUs). Using RDS, we recruited IDUs in Tijuana and Ciudad (Cd.) Juárez, two Mexican cities bordering San Diego, CA and El Paso, TX, respectively, and compared recruitment dynamics, reported network size, and estimates of HIV and syphilis prevalence. Between February and April 2005, we used RDS to recruit IDUs in Tijuana (15 seeds, 207 recruits) and Cd. Juárez (9 seeds, 197 recruits), Mexico for a cross-sectional study of behavioral and contextual factors associated with HIV, HCV and syphilis infections. All subjects provided informed consent, an anonymous interview, and a venous blood sample for serologic testing of HIV, HCV, HBV (Cd. Juárez only) and syphilis antibody. Log-linear models were used to analyze the association between the state of the recruiter and that of the recruitee in the referral chains, and population estimates of the presence of syphilis antibody were obtained, correcting for biased sampling using RDS-based estimators. Sampling of the targeted 200 recruits per city was achieved rapidly (2 months in Tijuana, 2 weeks in Cd. Juárez). After excluding seeds and missing data, the sample prevalence of HCV, HIV and syphilis were 96.6, 1.9 and 13.5% respectively in Tijuana, and 95.3, 4.1, and 2.7% respectively in Cd. Juárez (where HBV prevalence was 84.7%). Syphilis cases were clustered in recruitment trees. RDS-corrected estimates of syphilis antibody prevalence ranged from 12.8 to 26.8% in Tijuana and from 2.9 to 15.6% in Ciudad Juárez, depending on how recruitment patterns were modeled, and assumptions about how network size affected an individual's probability of being included in the sample. RDS was an effective method to rapidly recruit IDUs in these cities. Although the frequency of HIV was low, syphilis prevalence was high, particularly in Tijuana. RDS
Wang, Chao; Cui, Yazhou; Li, Yan; Liu, Xiao; Han, Jinxiang
Summary Epidemiological information of hereditary spherocytosis in China is slight. This systematic review summarizes the number of cases of hereditary spherocytosis reported in China Biology Medicine disc from 1978 to 2013. In total, 2,043 cases were reported in the past 36 years. We describe its distribution from time and space. We also estimate the literature reported prevalence of hereditary spherocytosis by DisMod-II software, overall prevalence in China was estimated to be: 1.27 cases per 100,000 people in males and 1.49 cases per 100,000 people in females. All results suggest a stronger network of diagnosis and treatment including all levels of hospitals should be created to improve healthcare for hereditary spherocytosis and even other rare diseases in the future, meanwhile we can obtain more useful information for orphan drug designation purposes and make public health decisions regarding such diseases through the use of the burden of disease models. PMID:25984425
Wang, Chao; Cui, Yazhou; Li, Yan; Liu, Xiao; Han, Jinxiang
Epidemiological information of hereditary spherocytosis in China is slight. This systematic review summarizes the number of cases of hereditary spherocytosis reported in China Biology Medicine disc from 1978 to 2013. In total, 2,043 cases were reported in the past 36 years. We describe its distribution from time and space. We also estimate the literature reported prevalence of hereditary spherocytosis by DisMod-II software, overall prevalence in China was estimated to be: 1.27 cases per 100,000 people in males and 1.49 cases per 100,000 people in females. All results suggest a stronger network of diagnosis and treatment including all levels of hospitals should be created to improve healthcare for hereditary spherocytosis and even other rare diseases in the future, meanwhile we can obtain more useful information for orphan drug designation purposes and make public health decisions regarding such diseases through the use of the burden of disease models.
Merchant, Roland C.; Liu, Tao; Baird, Janette R.
Introduction Among adult emergency department (ED) patients, we sought to examine how estimates of substance use prevalence and the need for interventions can differ, based on the type of screening and assessment strategies employed. Methods We estimated the prevalence of substance use and the need for interventions using the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) in a secondary analysis of data from two cross-sectional studies using random samples of English- or Spanish-speaking 18–64-year-old ED patients. In addition, the test performance characteristics of three simplified screening strategies consisting of selected questions from the ASSIST (lifetime use, past three-month use, and past three-month frequency of use) to identify patients in need of a possible intervention were compared against using the full ASSIST. Results Of 6,432 adult ED patients, the median age was 37 years-old, 56.6% were female, and 61.6% were white. Estimated substance use prevalence among this population differed by how it was measured (lifetime use, past three-month use, past three-month frequency of use, or need for interventions). As compared to using the full ASSIST, the predictive value and accuracy to identify patients in need of any intervention was best for a simplified strategy asking about past three-month substance use. A strategy asking about daily/near-daily use was better in identifying patients needing intensive interventions. However, some patients needing interventions were missed when using these simplified strategies. Conclusion Substance use prevalence estimates and identification of ED patients needing interventions differ by screening strategies used. EDs should carefully select strategies to identify patients in need of substance use interventions. PMID:27330663
Wapenaar, Wendela; Barkema, Herman W.; O’Handley, Ryan M.; Bartels, Chris J.M.
This study evaluated the use of bulk milk as a diagnostic tool for estimation of herd-level Neospora caninum exposure in Atlantic Canada; it was used to estimate the prevalence of dairy farms with a within-herd N. caninum-seroprevalence ≥ 15% in Prince Edward Island (PEI). The variation over time of N. caninum antibodies in bulk milk is also reported. Skimmed bulk milk and individual serum samples were analyzed for N. caninum antibodies by using an enzyme-linked immunosorbent assay (ELISA). Bulk milk samples were collected in May 2004 (n = 235), May 2005 (n = 189), and June 2005 (n = 235). The prevalence of dairy farms with a within-herd seroprevalence ≥ 15% on PEI was 6.4% in May 2004. In May and June 2005, respectively, 10.1% and 10.2% of farms had a ≥ 15% within-herd seroprevalence. In 11 farms that were considered positive based on bulk milk samples, blood samples were collected from all adult cows in September 2005, in conjunction with a 4th bulk milk sample on the same day. The correlation coefficient between serology and bulk milk ELISA was 0.87. The results of this study demonstrate that the prevalence of N. caninum in dairy farms can be estimated by using a bulk milk ELISA. PMID:17542367
Makumbi, Boniface; Purfield, Anne; Ndjavera, Christophine; Mutandi, Gram; Maher, Andrew; Kaindjee-Tjituka, Francina; Kaplan, Jonathan E.; Park, Benjamin J.; Lowrance, David W.
Background Cryptococcal meningitis is common and associated with high mortality among HIV infected persons. The World Health Organization recommends that routine Cryptococcal antigen (CrAg) screening in ART-naïve adults with a CD4+ count <100 cells/μL followed by pre-emptive antifungal therapy for CrAg-positive patients be considered where CrAg prevalence is ≥3%. The prevalence of CrAg among HIV adults in Namibia is unknown. We estimated CrAg prevalence among HIV-infected adults receiving care in Namibia for the purpose of informing routine screening strategies. Methods The study design was cross-sectional. De-identified plasma specimens collected for routine CD4+ testing from HIV-infected adults enrolled in HIV care at 181 public health facilities from November 2013 to January 2014 were identified at the national reference laboratory. Remnant plasma from specimens with CD4+ counts <200 cells/μL were sampled and tested for CrAg using the IMMY® Lateral Flow Assay. CrAg prevalence was estimated and assessed for associations with age, sex, and CD4+ count. Results A total of 825 specimens were tested for CrAg. The median (IQR) age of patients from whom specimens were collected was 38 (32–46) years, 45.9% were female and 62.9% of the specimens had CD4 <100 cells/μL. CrAg prevalence was 3.3% overall and 3.9% and 2.3% among samples with CD4+ counts of CD4+<100 cells/μL and 100–200 cells/μL, respectively. CrAg positivity was significantly higher among patients with CD4+ cells/μL < 50 (7.2%, P = 0.001) relative to those with CD4 cells/μL 50–200 (2.2%). Conclusion This is the first study to estimate CrAg prevalence among HIV-infected patients in Namibia. CrAg prevalence of ≥3.0% among patients with CD4+<100 cells/μL justifies routine CrAg screening and preemptive treatment among HIV-infected in Namibia in line with WHO recommendations. Patients with CD4+<100 cells/μL have a significantly greater risk for CrAg positivity. Revised guidelines for ART in
Sawadogo, Souleymane; Makumbi, Boniface; Purfield, Anne; Ndjavera, Christophine; Mutandi, Gram; Maher, Andrew; Kaindjee-Tjituka, Francina; Kaplan, Jonathan E; Park, Benjamin J; Lowrance, David W
Cryptococcal meningitis is common and associated with high mortality among HIV infected persons. The World Health Organization recommends that routine Cryptococcal antigen (CrAg) screening in ART-naïve adults with a CD4+ count <100 cells/μL followed by pre-emptive antifungal therapy for CrAg-positive patients be considered where CrAg prevalence is ≥3%. The prevalence of CrAg among HIV adults in Namibia is unknown. We estimated CrAg prevalence among HIV-infected adults receiving care in Namibia for the purpose of informing routine screening strategies. The study design was cross-sectional. De-identified plasma specimens collected for routine CD4+ testing from HIV-infected adults enrolled in HIV care at 181 public health facilities from November 2013 to January 2014 were identified at the national reference laboratory. Remnant plasma from specimens with CD4+ counts <200 cells/μL were sampled and tested for CrAg using the IMMY® Lateral Flow Assay. CrAg prevalence was estimated and assessed for associations with age, sex, and CD4+ count. A total of 825 specimens were tested for CrAg. The median (IQR) age of patients from whom specimens were collected was 38 (32-46) years, 45.9% were female and 62.9% of the specimens had CD4 <100 cells/μL. CrAg prevalence was 3.3% overall and 3.9% and 2.3% among samples with CD4+ counts of CD4+<100 cells/μL and 100-200 cells/μL, respectively. CrAg positivity was significantly higher among patients with CD4+ cells/μL < 50 (7.2%, P = 0.001) relative to those with CD4 cells/μL 50-200 (2.2%). This is the first study to estimate CrAg prevalence among HIV-infected patients in Namibia. CrAg prevalence of ≥3.0% among patients with CD4+<100 cells/μL justifies routine CrAg screening and preemptive treatment among HIV-infected in Namibia in line with WHO recommendations. Patients with CD4+<100 cells/μL have a significantly greater risk for CrAg positivity. Revised guidelines for ART in Namibia now recommend routine screening for CrAg.
Garvey, Sean M; Dugle, Janis E; Kennedy, Adam D; McDunn, Jonathan E; Kline, William; Guo, Lining; Guttridge, Denis C; Pereira, Suzette L; Edens, Neile K
Mammalian skeletal muscles exhibit age-related adaptive and pathological remodeling. Several muscles in particular undergo progressive atrophy and degeneration beyond median lifespan. To better understand myocellular responses to aging, we used semi-quantitative global metabolomic profiling to characterize trends in metabolic changes between 15-month-old adult and 32-month-old aged Fischer 344 × Brown Norway (FBN) male rats. The FBN rat gastrocnemius muscle exhibits age-dependent atrophy, whereas the soleus muscle, up until 32 months, exhibits markedly fewer signs of atrophy. Both gastrocnemius and soleus muscles were analyzed, as well as plasma and urine. Compared to adult gastrocnemius, aged gastrocnemius showed evidence of reduced glycolytic metabolism, including accumulation of glycolytic, glycogenolytic, and pentose phosphate pathway intermediates. Pyruvate was elevated with age, yet levels of citrate and nicotinamide adenine dinucleotide were reduced, consistent with mitochondrial abnormalities. Indicative of muscle atrophy, 3-methylhistidine and free amino acids were elevated in aged gastrocnemius. The monounsaturated fatty acids oleate, cis-vaccenate, and palmitoleate also increased in aged gastrocnemius, suggesting altered lipid metabolism. Compared to gastrocnemius, aged soleus exhibited far fewer changes in carbohydrate metabolism, but did show reductions in several glycolytic intermediates, fumarate, malate, and flavin adenine dinucleotide. Plasma biochemicals showing the largest age-related increases included glycocholate, heme, 1,5-anhydroglucitol, 1-palmitoleoyl-glycerophosphocholine, palmitoleate, and creatine. These changes suggest reduced insulin sensitivity in aged FBN rats. Altogether, these data highlight skeletal muscle group-specific perturbations of glucose and lipid metabolism consistent with mitochondrial dysfunction in aged FBN rats.
Lakhan, Ram; Ekúndayò, Olúgbémiga T
The Indian population suffers with significant burden of mental illness. The prevalence rate and its association with age and other demographic indicators are needed for planning purpose. This study attempted to calculate age-wise prevalence of mental illness for rural and urban settings, and its association with age. Data published in National Sample Survey Organization (2002) report on disability is used for the analysis. Spearman correlation for strength of association, z-test for difference in prevalence, and regression statistics for predicting the prevalence rate of mental illness are used. Overall population have 14.9/1000 prevalence of mental illness. It is higher in rural setting 17.1/1000 than urban 12.7/1000 (P < 0.001). There is a strong correlation found with age in rural (ϱ = 0.910, P = 0.001) and urban (ϱ = 0.940, P = 0.001). Results of this study confirm other epidemiological research in India. Large-population epidemiological studies are recommended.
Hadjilouka, Agni; Mantzourani, Kyriaki-Sofia; Katsarou, Anastasia; Cavaiuolo, Marina; Ferrante, Antonio; Paramithiotis, Spiros; Mataragas, Marios; Drosinos, Eleftherios H
The aims of the present study were to determine the prevalence and levels of Listeria monocytogenes and Escherichia coli O157:H7 in rocket and cucumber samples by deterministic (estimation of a single value) and stochastic (estimation of a range of values) approaches. In parallel, the chromogenic media commonly used for the recovery of these microorganisms were evaluated and compared, and the efficiency of an enzyme-linked immunosorbent assay (ELISA)-based protocol was validated. L. monocytogenes and E. coli O157:H7 were detected and enumerated using agar Listeria according to Ottaviani and Agosti plus RAPID' L. mono medium and Fluorocult plus sorbitol MacConkey medium with cefixime and tellurite in parallel, respectively. Identity was confirmed with biochemical and molecular tests and the ELISA. Performance indices of the media and the prevalence of both pathogens were estimated using Bayesian inference. In rocket, prevalence of both L. monocytogenes and E. coli O157:H7 was estimated at 7% (7 of 100 samples). In cucumber, prevalence was 6% (6 of 100 samples) and 3% (3 of 100 samples) for L. monocytogenes and E. coli O157:H7, respectively. The levels derived from the presence-absence data using Bayesian modeling were estimated at 0.12 CFU/25 g (0.06 to 0.20) and 0.09 CFU/25 g (0.04 to 0.170) for L. monocytogenes in rocket and cucumber samples, respectively. The corresponding values for E. coli O157:H7 were 0.59 CFU/25 g (0.43 to 0.78) and 1.78 CFU/25 g (1.38 to 2.24), respectively. The sensitivity and specificity of the culture media differed for rocket and cucumber samples. The ELISA technique had a high level of cross-reactivity. Parallel testing with at least two culture media was required to achieve a reliable result for L. monocytogenes or E. coli O157:H7 prevalence in rocket and cucumber samples.
Sanchez, Emelyn Y.; Velarde, Silvia; Britton, Gabrielle B.
The present study investigated the prevalence of ADHD in a school sample of children ages 6-11 years in the city of Panama. The assessment battery included the Conners' Parent and Teacher Rating Scales, the Structured Developmental History of the Behavioral Assessment System for Children (BASC-2), and the Wechsler Intelligence Scale for Children…
Abraham, Alison G.; Lau, Bryan; Deeks, Steven; Moore, Richard D.; Zhang, Jinbing; Eron, Joseph; Harrigan, Richard; Gill, M. John; Kitahata, Mari; Klein, Marina; Napravnik, Sonia; Rachlis, Anita; Rodriguez, Benigno; Rourke, Sean; Benson, Constance; Bosch, Ron; Collier, Ann; Gebo, Kelly; Goedert, James; Hogg, Robert; Horberg, Michael; Jacobson, Lisa; Justice, Amy; Kirk, Greg; Martin, Jeff; McKaig, Rosemary; Silverberg, Michael; Sterling, Timothy; Thorne, Jennifer; Willig, James; Gange, Stephen J.
Determination of the prevalence of accumulated antiretroviral drug resistance among persons infected with human immunodeficiency virus (HIV) is complicated by the lack of routine measurement in clinical care. By using data from 8 clinic-based cohorts from the North American AIDS Cohort Collaboration on Research and Design, drug-resistance mutations from those with genotype tests were determined and scored using the Genotypic Resistance Interpretation Algorithm developed at Stanford University. For each year from 2000 through 2005, the prevalence was calculated using data from the tested subset, assumptions that incorporated clinical knowledge, and multiple imputation methods to yield a complete data set. A total of 9,289 patients contributed data to the analysis; 3,959 had at least 1 viral load above 1,000 copies/mL, of whom 2,962 (75%) had undergone at least 1 genotype test. Using these methods, the authors estimated that the prevalence of accumulated resistance to 2 or more antiretroviral drug classes had increased from 14% in 2000 to 17% in 2005 (P < 0.001). In contrast, the prevalence of resistance in the tested subset declined from 57% to 36% for 2 or more classes. The authors’ use of clinical knowledge and multiple imputation methods revealed trends in HIV drug resistance among patients in care that were markedly different from those observed using only data from patients who had undergone genotype tests. PMID:21813792
Coward, Amy; Kenna, Dervla T D; Perry, Claire; Martin, Kate; Doumith, Michel; Turton, Jane F
We aimed to estimate the prevalence of different Achromobacter species among UK Cystic Fibrosis (CF) patients. nrdA sequence clustering was used to identify 147 Achromobacter isolates from 96 patients from 27 hospitals to species level. Potential cross-infection was investigated by MLST, pulsed-field gel electrophoresis and whole genome sequencing (WGS). Achromobacter xylosoxidans was the most prevalent species affecting 59 of 96 (61%) patients, followed by Achromobacter insuavis and Achromobacter dolens (12.4% and 8%, respectively). Three novel nrdA clusters were identified. One was further characterised by sequencing the intrinsic blaOXA gene, revealing novel variants. WGS of A. insuavis 2a isolates from four patients attending the same paediatric unit revealed that three were ST144, but differed from one another by a minimum of 385 SNPs, suggesting cross-infection was unlikely. nrdA sequence clustering permitted an estimation of UK Achromobacter species prevalence, highlighted additional novel species, and aided cross-infection investigations. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.
Johnston, Lisa; Saumtally, Ahmed; Corceal, Sewraz; Mahadoo, Indrasen; Oodally, Farida
Mauritius, an Indian Ocean Island nation of approximately 1,000,000 people, has a large number of injecting drug users (IDUs), many of whom are infected with HIV and HCV. Mauritius has been expanding harm reduction and HIV services based in the belief that HIV prevalence amongst IDUs is somewhere between 30 and 60% and the IDU population size is around 20,000. In 2009, the government of Mauritius conducted a survey to estimate the infection prevalence and risk factors and to estimate the population size of IDUs in order to more effectively expand programmes. Men and women aged >15 years living in Mauritius and injecting illicit drugs in the past three months were recruited using respondent driven sampling (RDS). Consenting participants were interviewed about HIV-risk behaviours and tested for HIV, syphilis, HCV and HBV. Six multipliers were collected from service data and by the 'unique identifier' method in conjunction with the RDS survey. Proportions were calculated using the RDS analysis tool. 511 IDUs enrolled in the survey; 61.2% reported injecting 2-3 times/day and 29.3% reported past month injection with a previously used needle. Amongst the 60% of IDUs who reported having sexual intercourse in the past three months, 39.5% did so with ≥2 partners. Almost all IDUs (98.1%) reported inconsistent condom use in the past 12 months. HIV prevalence was 47.4%, HCV 97.3%, HBV 9.0%, and syphilis 2.7%; 99.7% of those infected with HIV were also infected with HCV. Our population size estimates put the number of IDUs in Mauritius at around 9500, lower than previous estimates. We observed high rates of HCV and HIV infection amongst IDUs in Mauritius. The scale-up of targeted HCV and HIV prevention, care and treatment services for IDUs should be a high priority. Copyright © 2011 Elsevier B.V. All rights reserved.
Szwarcwald, Célia Landmann; de Souza Júnior, Paulo Roberto Borges; Damacena, Giseli Nogueira; Junior, Aristides Barbosa; Kendall, Carl
Respondent-driven sampling (RDS) is a chain-referral method that is being widely used to recruit most at-risk populations. Because the method is respondent driven, observations are dependent. However, few publications have focused on methodological challenges in the analysis of data collected by RDS. In this article, we propose a method for estimating the variance of the HIV prevalence rate, based on the Markov transition probabilities and within recruitment cluster variation. The method was applied to a female commercial sex workers study carried out in 10 Brazilian cities in 2008. Both the inverse of network size and the size of the city were considered in the estimation of overall sampling weights. The study included a behavior questionnaire and rapid tests for HIV and syphilis. About 2523 interviews were conducted successfully, excluding the seeds. Results show a positive homophily between recruits for those HIV+; HIV- recruiters selected HIV+ recruits 4% of the time; HIV+ recruiters selected other HIV+ recruits 19.6% of the time, about 5 times higher. The prevalence rate was estimated at 4.8% (95% confidence interval: 3.4 to 6.1), and a design effect of 2.63. Using statistical methods for complex sample designs, it was possible to estimate HIV prevalence, standard error, and the design effect analytically. Additionally, the proposed analysis lends itself to logistic regression, permitting multivariate models. The stratification in cities has proved suitable for reducing the effect of design and can be adopted in other RDS studies, provided the weights of the strata are known.
Polis, Chelsea B; Cox, Carie M; Tunçalp, Özge; McLain, Alexander C; Thoma, Marie E
Can infertility prevalence be estimated using a current duration (CD) approach when applied to nationally representative Demographic and Health Survey (DHS) data collected routinely in low- or middle-income countries? Our analysis suggests that a CD approach applied to DHS data from Nigeria provides infertility prevalence estimates comparable to other smaller studies in the same region. Despite associations with serious negative health, social and economic outcomes, infertility in developing countries is a marginalized issue in sexual and reproductive health. Obtaining reliable, nationally representative prevalence estimates is critical to address the issue, but methodological and resource challenges have impeded this goal. This cross-sectional study was based on standard information available in the DHS core questionnaire and data sets, which are collected routinely among participating low-to-middle-income countries. Our research question was examined among women participating in the 2013 Nigeria DHS (n = 38 948). Among women eligible for the study, 98% were interviewed. We applied a CD approach (i.e. current length of time-at-risk of pregnancy) to estimate time-to-pregnancy (TTP) and 12-month infertility prevalence among women 'at risk' of pregnancy at the time of interview (n = 7063). Women who were 18-44 years old, married or cohabitating, sexually active within the past 4 weeks and not currently using contraception (and had not been sterilized) were included in the analysis. Estimates were based on parametric survival methods using bootstrap methods (500 bootstrap replicates) to obtain 95% CIs. The estimated median TTP among couples at risk of pregnancy was 5.1 months (95% CI: 4.2-6.3). The estimated percentage of infertile couples was 31.1% (95% CI: 27.9-34.7%)-consistent with other smaller studies from Nigeria. Primary infertility (17.4%, 95% CI: 12.9-23.8%) was substantially lower than secondary infertility (34.1%, 95% CI: 30.3-39.3%) in this population
Cox, Carie M.; Tunçalp, Özge; McLain, Alexander C.; Thoma, Marie E.
Abstract STUDY QUESTION Can infertility prevalence be estimated using a current duration (CD) approach when applied to nationally representative Demographic and Health Survey (DHS) data collected routinely in low- or middle-income countries? SUMMARY ANSWER Our analysis suggests that a CD approach applied to DHS data from Nigeria provides infertility prevalence estimates comparable to other smaller studies in the same region. WHAT IS KNOWN ALREADY Despite associations with serious negative health, social and economic outcomes, infertility in developing countries is a marginalized issue in sexual and reproductive health. Obtaining reliable, nationally representative prevalence estimates is critical to address the issue, but methodological and resource challenges have impeded this goal. STUDY DESIGN, SIZE, DURATION This cross-sectional study was based on standard information available in the DHS core questionnaire and data sets, which are collected routinely among participating low-to-middle-income countries. Our research question was examined among women participating in the 2013 Nigeria DHS (n = 38 948). Among women eligible for the study, 98% were interviewed. PARTICIPANTS/MATERIALS, SETTING, METHODS We applied a CD approach (i.e. current length of time-at-risk of pregnancy) to estimate time-to-pregnancy (TTP) and 12-month infertility prevalence among women ‘at risk’ of pregnancy at the time of interview (n = 7063). Women who were 18–44 years old, married or cohabitating, sexually active within the past 4 weeks and not currently using contraception (and had not been sterilized) were included in the analysis. Estimates were based on parametric survival methods using bootstrap methods (500 bootstrap replicates) to obtain 95% CIs. MAIN RESULTS AND THE ROLE OF CHANCE The estimated median TTP among couples at risk of pregnancy was 5.1 months (95% CI: 4.2–6.3). The estimated percentage of infertile couples was 31.1% (95% CI: 27.9–34.7%)—consistent with other
Zimmermann, Michael B; Hussein, Izzeldin; Al Ghannami, Samia; El Badawi, Salah; Al Hamad, Nawal M; Abbas Hajj, Basima; Al-Thani, Mohamed; Al-Thani, Al Anoud; Winichagoon, Pattanee; Pongcharoen, Tippawan; van der Haar, Frits; Qing-Zhen, Jia; Dold, Susanne; Andersson, Maria; Carriquiry, Alicia L
The urinary iodine concentration (UIC), a biomarker of iodine intake, is used to assess population iodine status by deriving the median UIC, but this does not quantify the percentage of individuals with habitually deficient or excess iodine intakes. Individuals with a UIC <100 μg/L or ≥300 μg/L are often incorrectly classified as having deficient or excess intakes, but this likely overestimates the true prevalence. Our aim was to estimate the prevalence of inadequate and excess iodine intake in children (aged 4-14 y) with the distribution of spot UIC from iodine surveys. With the use of data from national iodine studies (Kuwait, Oman, Thailand, and Qatar) and a regional study (China) in children (n = 6117) in which a repeat UIC was obtained in a subsample (n = 1060), we calculated daily iodine intake from spot UICs from the relation between body weight and 24-h urine volume and within-person variation by using the repeat UIC. We also estimated pooled external within-person proportion of total variances by region. We used within-person variance proportions to obtain the prevalence of inadequate or excess usual iodine intake by using the Estimated Average Requirement (EAR)/Tolerable Upper Intake Level (UL) cutoff method. Median UICs in Kuwait, Oman, China, Thailand, and Qatar were 132, 192, 199, 262, and 333 μg/L, respectively. Internal within-person variance proportions ranged from 25.0% to 80.0%, and pooled regional external estimates ranged from 40.4% to 77.5%. The prevalence of inadequate and excess intakes as defined by the adjusted EAR/UL cutoff method was ∼45-99% lower than those defined by a spot UIC <100 μg/L or ≥300 μg/L (P < 0.01). Applying the EAR/UL cutoff method to iodine intakes from adjusted UIC distributions is a promising approach to estimate the number of individuals with deficient or excess iodine intakes. © 2016 American Society for Nutrition.
McCue, M E; Anderson, S M; Valberg, S J; Piercy, R J; Barakzai, S Z; Binns, M M; Distl, O; Penedo, M C T; Wagner, M L; Mickelson, J R
The GYS1 gene mutation that is causative of Type 1 Polysaccharide Storage Myopathy (PSSM) has been identified in more than 20 breeds of horses. However, the GYS1 mutation frequency or Type 1 PSSM prevalence within any given breed is unknown. The purpose of this study was to determine the frequency of the GYS1 mutation and prevalence of genetic susceptibility to Type 1 PSSM in selected breeds from Europe and North America. The GYS1 mutation was detected in 11 breeds, including, in order of increasing allele frequency, Shires, Morgans, Appaloosas, Quarter Horses, Paints, Exmoor Ponies, Saxon-Thuringian Coldbloods, South German Coldbloods, Belgians, Rhenish German Coldbloods and Percherons. The prevalence of genetic susceptibility to Type 1 PSSM in these breeds varied from 0.5% to 62.4%. The GYS1 mutation was not found in the sampled Thoroughbreds, Akhal-Tekes, Connemaras, Clydesdales, Norwegian Fjords, Welsh Ponies, Icelandics, Schleswig Coldbloods or Hanoverians, but failure to detect the mutation does not guarantee its absence. This knowledge will help breed associations determine whether they should screen for the GYS1 mutation and will alert veterinarians to a possible differential diagnosis for muscle pain, rhabdomyolysis or gait abnormalities.
Guyatt, Helen L; Fèvre, Eric M
To assess the association between the prevalence of tongue cyst-positive and antigen-positive pigs across different settings in Africa, to evaluate whether examining pigs for cysts could be used as a rapid surveillance tool for identifying geographical areas with a higher probability of high transmission of cysticercosis. Published data were collated from 26 study sites across Africa that reported the prevalence of porcine cysticercosis by both lingual and serological examinations. The study sites were located in 10 countries across Africa. Seroprevalence rates ranged from 4% to 41%. Despite the varied study sites, the relationship between the two variables was highly consistent and suggests identification of tongue cysts may be useful for cysticercosis surveillance. We found that all areas with more than 10% of pigs having cysts in their tongues had at least 30% seroprevalence (PPV of 100%), although this cut-off is less reliable at predicting that an area is of low transmission (NPV of 84%). Assessing the prevalence of tongue cyst-positive pigs is a potential rapid epidemiological tool for identifying areas at high risk of cysticercosis, although further refinement and validation is required using standardised data sets. © 2016 The Authors. Tropical Medicine & International Health Published by John Wiley & Sons Ltd.
Dal Maso, L.; Guzzinati, S.; Buzzoni, C.; Capocaccia, R.; Serraino, D.; Caldarella, A.; Dei Tos, A. P.; Falcini, F.; Autelitano, M.; Masanotti, G.; Ferretti, S.; Tisano, F.; Tirelli, U.; Crocetti, E.; De Angelis, R.; Virdone, S.; Zucchetto, A.; Gigli, A.; Francisci, S.; Baili, P.; Gatta, G.; Castaing, M.; Zanetti, R.; Contiero, P.; Bidoli, E.; Vercelli, M.; Michiara, M.; Federico, M.; Senatore, G.; Pannozzo, F.; Vicentini, M.; Bulatko, A.; Pirino, D. R.; Gentilini, M.; Fusco, M.; Giacomin, A.; Fanetti, A. C.; Cusimano, R.
Background Persons living after a cancer diagnosis represent 4% of the whole population in high-income countries. The aim of the study was to provide estimates of indicators of long-term survival and cure for 26 cancer types, presently lacking. Patients and methods Data on 818 902 Italian cancer patients diagnosed at age 15–74 years in 1985–2005 were included. Proportions of patients with the same death rates of the general population (cure fractions) and those of prevalent patients who were not at risk of dying as a result of cancer (cure prevalence) were calculated, using validated mixture cure models, by cancer type, sex, and age group. We also estimated complete prevalence, conditional relative survival (CRS), time to reach 5- and 10-year CRS >95%, and proportion of patients living longer than those thresholds. Results The cure fractions ranged from >90% for patients aged <45 years with thyroid and testis cancers to <10% for liver and pancreatic cancers of all ages. Five- or 10-year CRS >95% were both reached in <10 years by patients with cancers of the stomach, colon–rectum, pancreas, corpus and cervix uteri, brain, and Hodgkin lymphoma. For breast cancer patients, 5- and 10-year CRSs reached >95% after 19 and 25 years, respectively, and in 15 and 18 years for prostate cancer patients. Five-year CRS remained <95% for >25 years after cancer diagnosis in patients with liver and larynx cancers, non-Hodgkin lymphoma, myeloma, and leukaemia. Overall, the cure prevalence was 67% for men and 77% for women. Therefore, 21% of male and 31% of female patients had already reached 5-year CRS >95%, whereas 18% and 25% had reached 10-year CRS >95%. Conclusions A quarter of Italian cancer patients can be considered cured. This observation has a high potential impact on health planning, clinical practice, and patients' perspective. PMID:25149707
Raimondo, Mariangela; Dorrucci, Maria; Regine, Vincenza; Salfa, Maria Cristina; Suligoi, Barbara
Abstract In 2012, we conducted a retrospective cross-sectional study to assess the number of people living with HIV linked to care and, among these, the number of people on antiretroviral therapy. The health authority in each of the 20 Italian Regions provided the list of Public Infectious Diseases Clinics providing antiretroviral therapy and monitoring people with HIV infection. We asked every Public Infectious Diseases Clinic to report the number of HIV-positive people diagnosed and linked to care and the number of those on antiretroviral therapy during 2012. In 2012, 94,146 people diagnosed with HIV and linked to care were reported. The majority were males (70.1%), Italians (84.4%), and aged between 25 and 49 years (63.4%); the probable route of transmission was heterosexual contact in 37.5% of cases, injecting drug use in 28.1%, and male-to-male contact in 27.9%. Among people in care, 20.1% had less than 350 CD4 cells/μl, 87.6% received antiretroviral therapy, and among these, 62.4% had a CD4 cell count higher than 350 cells/μl. The overall estimated prevalence of individuals diagnosed and linked to care in 2012 in Italy was 0.16 per 100 residents (all ages). Adding the estimated proportion of undiagnosed people, the estimated HIV prevalence would range between 0.19 and 0.26 per 100 residents. In Italy, the majority of people diagnosed and linked to care receive antiretroviral therapy. A higher prevalence of individuals diagnosed and linked to care was observed in Northern Italy and among males. More information for developing the HIV care continuum is necessary to improve the entire engagement in care, focusing on test-and-treat strategies to substantially reduce the proportion of people still undiagnosed or with a detectable viral load. PMID:25432098
Camoni, Laura; Raimondo, Mariangela; Dorrucci, Maria; Regine, Vincenza; Salfa, Maria Cristina; Suligoi, Barbara
In 2012, we conducted a retrospective cross-sectional study to assess the number of people living with HIV linked to care and, among these, the number of people on antiretroviral therapy. The health authority in each of the 20 Italian Regions provided the list of Public Infectious Diseases Clinics providing antiretroviral therapy and monitoring people with HIV infection. We asked every Public Infectious Diseases Clinic to report the number of HIV-positive people diagnosed and linked to care and the number of those on antiretroviral therapy during 2012. In 2012, 94,146 people diagnosed with HIV and linked to care were reported. The majority were males (70.1%), Italians (84.4%), and aged between 25 and 49 years (63.4%); the probable route of transmission was heterosexual contact in 37.5% of cases, injecting drug use in 28.1%, and male-to-male contact in 27.9%. Among people in care, 20.1% had less than 350 CD4 cells/μl, 87.6% received antiretroviral therapy, and among these, 62.4% had a CD4 cell count higher than 350 cells/μl. The overall estimated prevalence of individuals diagnosed and linked to care in 2012 in Italy was 0.16 per 100 residents (all ages). Adding the estimated proportion of undiagnosed people, the estimated HIV prevalence would range between 0.19 and 0.26 per 100 residents. In Italy, the majority of people diagnosed and linked to care receive antiretroviral therapy. A higher prevalence of individuals diagnosed and linked to care was observed in Northern Italy and among males. More information for developing the HIV care continuum is necessary to improve the entire engagement in care, focusing on test-and-treat strategies to substantially reduce the proportion of people still undiagnosed or with a detectable viral load.
Williams, Valerie S L; Baldwin, David S; Hogue, Susan L; Fehnel, Sheri E; Hollis, Kelly A; Edin, Heather M
Sexual dysfunction is a common side effect of antidepressant treatment, but recognition of the problem is variable. The aim of this study was to estimate the prevalence and impact of sexual dysfunction during antidepressant treatment in 2 European countries. A cross-sectional survey of 502 adults in France and the United Kingdom. All participants were diagnosed with depression and taking a selective serotonin reuptake inhibitor (SSRI) or serotonin-norepinephrine reuptake inhibitor (SNRI), starting within the previous 3 months. Information was gathered about other medications and conditions known to impair sexual functioning, recent changes in sexual functioning, and the impact of any changes. The Medical Outcomes Study 12-Item Short-Form Health Survey and the Arizona Sexual Experience Scale were administered to measure health status and sexual functioning. Data were collected from June to July of 2002. Applying a prevalence estimate algorithm, 26.6% of the French sample and 39.2% of the U.K. sample were classified as having antidepressant-induced sexual dysfunction; 34.2% of men and 32.5% of women were classified with antidepressant-induced sexual dysfunction. There was no clear pattern of antidepressant-induced sexual dysfunction related to specific antidepressants. Patients with antidepressant-induced sexual dysfunction reported that changes in sexual functioning negatively affected their self-esteem, mood, and relationships with sexual partners. 23.8% of the French sample and 25.2% of the U.K. sample reported that they perceived that their partner was dissatisfied with their sex life. The prevalence of antidepressant-induced sexual dysfunction in this study is similar to previous estimates reported in the literature. The impact of antidepressant-induced sexual dysfunction is substantial and negatively affects quality of life, self-esteem, mood, and relationships with sexual partners.
Suárez-Pérez, E; Oliver-Vázquez, M; De Andino, R; Vega, R; Conde, J; García, M; Rosario, R; Vélez, H
In order to plan the health services for the elderly population, it is necessary to quantify their health status and their functional capacity. In Puerto Rico, few epidemiological studies have been conducted regarding functional capacity and chronic diseases in the elderly population. One of the difficulties to undertake these studies is the high cost and risks to move this population for clinical exams, in addition to the methodology limitation of self-report in the elderly population. This study shows the use of logistic regression to estimate the prevalence of chronic diseases and functional capacity, when the observed data are not consisted with the planed sampling scheme. Four hundred and eighty-seven elderly persons (65 yr. and over) were interviewed in the municipalities of Canóvanas, Carolina, Loíza and Trujillo Alto in Puerto Rico, using a cross-sectional design. More than half of the elderly had visual problems (IC 95%: 54.8%, 63.8%), arthritis (IC 95%: 52.7%, 61.5%) and hypertension (IC 95%: 47.3%, 56.3%). In the case of hypertension, significant differences (p < 0.05) by sex were observed, where women reported a higher prevalence than men. One of the higher prevalences in the functional capacity status was with urine accidents. More than one-third of the population is estimated to have this problem (IC 95%: 34.7%, 43.4%). One-fourth of the population had limitations with going out for shopping (IC 95%: 23.9%, 31.9%) and using public and private transportation (IC 95%: 19.5%, 26.9%). We conclude that the applied methodology was consistent with the estimation presented in the literature and statistics from the Puerto Rico Health Department. However, it is necessary to continue assessing the design and analytical methodology, in order to undertake consistent and periodic evaluations of the elderly population.
Wang, Haidong; Wolock, Tim M; Carter, Austin; Nguyen, Grant; Kyu, Hmwe Hmwe; Gakidou, Emmanuela; Hay, Simon I; Mills, Edward J; Trickey, Adam; Msemburi, William; Coates, Matthew M; Mooney, Meghan D; Fraser, Maya S; Sligar, Amber; Salomon, Joshua; Larson, Heidi J; Friedman, Joseph; Abajobir, Amanuel Alemu; Abate, Kalkidan Hassen; Abbas, Kaja M; Razek, Mohamed Magdy Abd El; Abd-Allah, Foad; Abdulle, Abdishakur M; Abera, Semaw Ferede; Abubakar, Ibrahim; Abu-Raddad, Laith J; Abu-Rmeileh, Niveen M E; Abyu, Gebre Yitayih; Adebiyi, Akindele Olupelumi; Adedeji, Isaac Akinkunmi; Adelekan, Ademola Lukman; Adofo, Koranteng; Adou, Arsène Kouablan; Ajala, Oluremi N; Akinyemiju, Tomi F; Akseer, Nadia; Lami, Faris Hasan Al; Al-Aly, Ziyad; Alam, Khurshid; Alam, Noore K M; Alasfoor, Deena; Aldhahri, Saleh Fahed S; Aldridge, Robert William; Alegretti, Miguel Angel; Aleman, Alicia V; Alemu, Zewdie Aderaw; Alfonso-Cristancho, Rafael; Ali, Raghib; Alkerwi, Ala'a; Alla, François; Mohammad, Rajaa; Al-Raddadi, Salem; Alsharif, Ubai; Alvarez, Elena; Alvis-Guzman, Nelson; Amare, Azmeraw T; Amberbir, Alemayehu; Amegah, Adeladza Kofi; Ammar, Walid; Amrock, Stephen Marc; Antonio, Carl Abelardo T; Anwari, Palwasha; Ärnlöv, Johan; Artaman, Al; Asayesh, Hamid; Asghar, Rana Jawad; Assadi, Reza; Atique, Suleman; Atkins, Lydia S; Avokpaho, Euripide Frinel G Arthur; Awasthi, Ashish; Quintanilla, Beatriz Paulina Ayala; Bacha, Umar; Badawi, Alaa; Barac, Aleksandra; Bärnighausen, Till; Basu, Arindam; Bayou, Tigist Assefa; Bayou, Yibeltal Tebekaw; Bazargan-Hejazi, Shahrzad; Beardsley, Justin; Bedi, Neeraj; Bennett, Derrick A; Bensenor, Isabela M; Betsu, Balem Demtsu; Beyene, Addisu Shunu; Bhatia, Eesh; Bhutta, Zulfiqar A; Biadgilign, Sibhatu; Bikbov, Boris; Birlik, Sait Mentes; Bisanzio, Donal; Brainin, Michael; Brazinova, Alexandra; Breitborde, Nicholas J K; Brown, Alexandria; Burch, Michael; Butt, Zahid A; Campuzano, Julio Cesar; Cárdenas, Rosario; Carrero, Juan Jesus; Castañeda-Orjuela, Carlos A; Rivas, Jacqueline Castillo; Catalá-López, Ferrán; Chang, Hsing-Yi; Chang, Jung-Chen; Chavan, Laxmikant; Chen, Wanqing; Chiang, Peggy Pei-Chia; Chibalabala, Mirriam; Chisumpa, Vesper Hichilombwe; Choi, Jee-Young Jasmine; Christopher, Devasahayam Jesudas; Ciobanu, Liliana G; Cooper, Cyrus; Dahiru, Tukur; Damtew, Solomon Abreha; Dandona, Lalit; Dandona, Rakhi; das Neves, José; de Jager, Pieter; De Leo, Diego; Degenhardt, Louisa; Dellavalle, Robert P; Deribe, Kebede; Deribew, Amare; Des Jarlais, Don C; Dharmaratne, Samath D; Ding, Eric L; Doshi, Pratik Pinal; Driscoll, Tim R; Dubey, Manisha; Elshrek, Yousef Mohamed; Elyazar, Iqbal; Endries, Aman Yesuf; Ermakov, Sergey Petrovich; Eshrati, Babak; Esteghamati, Alireza; Faghmous, Imad D A; Farinha, Carla Sofia E Sa; Faro, Andre; Farvid, Maryam S; Farzadfar, Farshad; Fereshtehnejad, Seyed-Mohammad; Fernandes, Joao C; Fischer, Florian; Fitchett, Joseph Robert Ander; Foigt, Nataliya; Fullman, Nancy; Fürst, Thomas; Gankpé, Fortuné Gbètoho; Gebre, Teshome; Gebremedhin, Amanuel Tesfay; Gebru, Alemseged Aregay; Geleijnse, Johanna M; Gessner, Bradford D; Gething, Peter W; Ghiwot, Tsegaye Tewelde; Giroud, Maurice; Gishu, Melkamu Dedefo; Glaser, Elizabeth; Goenka, Shifalika; Goodridge, Amador; Gopalani, Sameer Vali; Goto, Atsushi; Gugnani, Harish Chander; Guimaraes, Mark D C; Gupta, Rahul; Gupta, Rajeev; Gupta, Vipin; Haagsma, Juanita; Hafezi-Nejad, Nima; Hagan, Holly; Hailu, Gessessew Bugssa; Hamadeh, Randah Ribhi; Hamidi, Samer; Hammami, Mouhanad; Hankey, Graeme J; Hao, Yuantao; Harb, Hilda L; Harikrishnan, Sivadasanpillai; Haro, Josep Maria; Harun, Kimani M; Havmoeller, Rasmus; Hedayati, Mohammad T; Heredia-Pi, Ileana Beatriz; Hoek, Hans W; Horino, Masako; Horita, Nobuyuki; Hosgood, H Dean; Hoy, Damian G; Hsairi, Mohamed; Hu, Guoqing; Huang, Hsiang; Huang, John J; Iburg, Kim Moesgaard; Idrisov, Bulat T; Innos, Kaire; Iyer, Veena J; Jacobsen, Kathryn H; Jahanmehr, Nader; Jakovljevic, Mihajlo B; Javanbakht, Mehdi; Jayatilleke, Achala Upendra; Jeemon, Panniyammakal; Jha, Vivekanand; Jiang, Guohong; Jiang, Ying; Jibat, Tariku; Jonas, Jost B; Kabir, Zubair; Kamal, Ritul; Kan, Haidong; Karch, André; Karema, Corine Kakizi; Karletsos, Dimitris; Kasaeian, Amir; Kaul, Anil; Kawakami, Norito; Kayibanda, Jeanne Françoise; Keiyoro, Peter Njenga; Kemp, Andrew Haddon; Kengne, Andre Pascal; Kesavachandran, Chandrasekharan Nair; Khader, Yousef Saleh; Khalil, Ibrahim; Khan, Abdur Rahman; Khan, Ejaz Ahmad; Khang, Young-Ho; Khubchandani, Jagdish; Kim, Yun Jin; Kinfu, Yohannes; Kivipelto, Miia; Kokubo, Yoshihiro; Kosen, Soewarta; Koul, Parvaiz A; Koyanagi, Ai; Defo, Barthelemy Kuate; Bicer, Burcu Kucuk; Kulkarni, Veena S; Kumar, G Anil; Lal, Dharmesh Kumar; Lam, Hilton; Lam, Jennifer O; Langan, Sinead M; Lansingh, Van C; Larsson, Anders; Leigh, James; Leung, Ricky; Li, Yongmei; Lim, Stephen S; Lipshultz, Steven E; Liu, Shiwei; Lloyd, Belinda K; Logroscino, Giancarlo; Lotufo, Paulo A; Lunevicius, Raimundas; Razek, Hassan Magdy Abd El; Mahdavi, Mahdi; Majdan, Marek; Majeed, Azeem; Makhlouf, Carla; Malekzadeh, Reza; Mapoma, Chabila C; Marcenes, Wagner; Martinez-Raga, Jose; Marzan, Melvin Barrientos; Masiye, Felix; Mason-Jones, Amanda J; Mayosi, Bongani M; McKee, Martin; Meaney, Peter A; Mehndiratta, Man Mohan; Mekonnen, Alemayehu B; Melaku, Yohannes Adama; Memiah, Peter; Memish, Ziad A; Mendoza, Walter; Meretoja, Atte; Meretoja, Tuomo J; Mhimbira, Francis Apolinary; Miller, Ted R; Mikesell, Joseph; Mirarefin, Mojde; Mohammad, Karzan Abdulmuhsin; Mohammed, Shafiu; Mokdad, Ali H; Monasta, Lorenzo; Moradi-Lakeh, Maziar; Mori, Rintaro; Mueller, Ulrich O; Murimira, Brighton; Murthy, Gudlavalleti Venkata Satyanarayana; Naheed, Aliya; Naldi, Luigi; Nangia, Vinay; Nash, Denis; Nawaz, Haseeb; Nejjari, Chakib; Ngalesoni, Frida Namnyak; de Dieu Ngirabega, Jean; Nguyen, Quyen Le; Nisar, Muhammad Imran; Norheim, Ole F; Norman, Rosana E; Nyakarahuka, Luke; Ogbo, Felix Akpojene; Oh, In-Hwan; Ojelabi, Foluke Adetola; Olusanya, Bolajoko Olubukunola; Olusanya, Jacob Olusegun; Opio, John Nelson; Oren, Eyal; Ota, Erika; Padukudru, Mahesh Anand; Park, Hye-Youn; Park, Jae-Hyun; Patil, Snehal T; Patten, Scott B; Paul, Vinod K; Pearson, Katherine; Peprah, Emmanuel Kwame; Pereira, Claudia C; Perico, Norberto; Pesudovs, Konrad; Petzold, Max; Phillips, Michael Robert; Pillay, Julian David; Plass, Dietrich; Polinder, Suzanne; Pourmalek, Farshad; Prokop, David M; Qorbani, Mostafa; Rafay, Anwar; Rahimi, Kazem; Rahimi-Movaghar, Vafa; Rahman, Mahfuzar; Rahman, Mohammad Hifz Ur; Rahman, Sajjad Ur; Rai, Rajesh Kumar; Rajsic, Sasa; Ram, Usha; Rana, Saleem M; Rao, Paturi Vishnupriya; Remuzzi, Giuseppe; Rojas-Rueda, David; Ronfani, Luca; Roshandel, Gholamreza; Roy, Ambuj; Ruhago, George Mugambage; Saeedi, Mohammad Yahya; Sagar, Rajesh; Saleh, Muhammad Muhammad; Sanabria, Juan R; Santos, Itamar S; Sarmiento-Suarez, Rodrigo; Sartorius, Benn; Sawhney, Monika; Schutte, Aletta E; Schwebel, David C; Seedat, Soraya; Sepanlou, Sadaf G; Servan-Mori, Edson E; Shaikh, Masood Ali; Sharma, Rajesh; She, Jun; Sheikhbahaei, Sara; Shen, Jiabin; Shibuya, Kenji; Shin, Hwashin Hyun; Sigfusdottir, Inga Dora; Silpakit, Naris; Silva, Diego Augusto Santos; Silveira, Dayane Gabriele Alves; Simard, Edgar P; Sindi, Shireen; Singh, Jasvinder A; Singh, Om Prakash; Singh, Prashant Kumar; Skirbekk, Vegard; Sliwa, Karen; Soneji, Samir; Sorensen, Reed J D; Soriano, Joan B; Soti, David O; Sreeramareddy, Chandrashekhar T; Stathopoulou, Vasiliki; Steel, Nicholas; Sunguya, Bruno F; Swaminathan, Soumya; Sykes, Bryan L; Tabarés-Seisdedos, Rafael; Talongwa, Roberto Tchio; Tavakkoli, Mohammad; Taye, Bineyam; Tedla, Bemnet Amare; Tekle, Tesfaye; Shifa, Girma Temam; Temesgen, Awoke Misganaw; Terkawi, Abdullah Sulieman; Tesfay, Fisaha Haile; Tessema, Gizachew Assefa; Thapa, Kiran; Thomson, Alan J; Thorne-Lyman, Andrew L; Tobe-Gai, Ruoyan; Topor-Madry, Roman; Towbin, Jeffrey Allen; Tran, Bach Xuan; Dimbuene, Zacharie Tsala; Tsilimparis, Nikolaos; Tura, Abera Kenay; Ukwaja, Kingsley Nnanna; Uneke, Chigozie Jesse; Uthman, Olalekan A; Venketasubramanian, N; Vladimirov, Sergey K; Vlassov, Vasiliy Victorovich; Vollset, Stein Emil; Wang, Linhong; Weiderpass, Elisabete; Weintraub, Robert G; Werdecker, Andrea; Westerman, Ronny; Wijeratne, Tissa; Wilkinson, James D; Wiysonge, Charles Shey; Wolfe, Charles D A; Won, Sungho; Wong, John Q; Xu, Gelin; Yadav, Ajit Kumar; Yakob, Bereket; Yalew, Ayalnesh Zemene; Yano, Yuichiro; Yaseri, Mehdi; Yebyo, Henock Gebremedhin; Yip, Paul; Yonemoto, Naohiro; Yoon, Seok-Jun; Younis, Mustafa Z; Yu, Chuanhua; Yu, Shicheng; Zaidi, Zoubida; Zaki, Maysaa El Sayed; Zeeb, Hajo; Zhang, Hao; Zhao, Yong; Zodpey, Sanjay; Zoeckler, Leo; Zuhlke, Liesl Joanna; Lopez, Alan D; Murray, Christopher J L
Timely assessment of the burden of HIV/AIDS is essential for policy setting and programme evaluation. In this report from the Global Burden of Disease Study 2015 (GBD 2015), we provide national estimates of levels and trends of HIV/AIDS incidence, prevalence, coverage of antiretroviral therapy (ART), and mortality for 195 countries and territories from 1980 to 2015. For countries without high-quality vital registration data, we estimated prevalence and incidence with data from antenatal care clinics and population-based seroprevalence surveys, and with assumptions by age and sex on initial CD4 distribution at infection, CD4 progression rates (probability of progression from higher to lower CD4 cell-count category), on and off antiretroviral therapy (ART) mortality, and mortality from all other causes. Our estimation strategy links the GBD 2015 assessment of all-cause mortality and estimation of incidence and prevalence so that for each draw from the uncertainty distribution all assumptions used in each step are internally consistent. We estimated incidence, prevalence, and death with GBD versions of the Estimation and Projection Package (EPP) and Spectrum software originally developed by the Joint United Nations Programme on HIV/AIDS (UNAIDS). We used an open-source version of EPP and recoded Spectrum for speed, and used updated assumptions from systematic reviews of the literature and GBD demographic data. For countries with high-quality vital registration data, we developed the cohort incidence bias adjustment model to estimate HIV incidence and prevalence largely from the number of deaths caused by HIV recorded in cause-of-death statistics. We corrected these statistics for garbage coding and HIV misclassification. Global HIV incidence reached its peak in 1997, at 3·3 million new infections (95% uncertainty interval [UI] 3·1-3·4 million). Annual incidence has stayed relatively constant at about 2·6 million per year (range 2·5-2·8 million) since 2005, after
Kuusk, A K; Agustí, N
Group-specific, degenerate polymerase chain reaction primers for DNA-based detection of springtails (Hexapoda: Collembola) within predator gut contents have been developed for the first time. Primers were designed from 18S rDNA and amplified fragments of 272 bp and 177 bp from 17 springtail species collected in agricultural habitats. Specificity tests against 41 nontarget species revealed no cross-reactivity. Group-specific polymerase chain reaction is advantageous when working in species-rich habitats and these primers could facilitate studies of trophic links between springtails and generalist arthropod predators worldwide.
Ben Jazia, R; Ben Salem, H; Gargouri, I; Aissa, S; Garrouche, A; Hayouni, A; Benzarti, M; Boussarsar, M; Abdelghani, A
Obstructive sleep apnea syndrome (OSAS) is a highly prevalent clinical condition and frequently associated with obesity. Recent literature has suggested the independent contribution of OSAS in the pathogenesis of metabolic disturbances. Metabolic syndrome (MS), a cardiovascular risk factor, was frequently associated with OSAS. This is a prospective study without intervention. Will be included, all consecutive patients referred to the Department of Pulmonology for suspected OSAS confirmed by respiratory polygraphy. Anthropometric, clinical and biological parameters needed to define the MS will be collected. MS was defined according to the IDF 2005. Assessment of cardiovascular risk related to MS will be performed by appropriate scores. To determine the prevalence of MS in a sample of OSAS patients recruited in the Department of Pulmonology of Farhat Hached Hospital (Sousse, Tunisia). To identify risk factors independently associated with the presence of MS in patients with OSAS among the following parameters (age, gender, degree of obesity and the various parameters of OSAS severity). To assess compared cardiovascular risks according to the presence of MS by validated scales to demonstrate the impact of MS in patients with OSAS. Copyright © 2015 Elsevier Masson SAS. All rights reserved.
Hatefi, Armin; Jafari Jozani, Mohammad
Rank-based sampling designs are widely used in situations where measuring the variable of interest is costly but a small number of sampling units (set) can be easily ranked prior to taking the final measurements on them and this can be done at little cost. When the variable of interest is binary, a common approach for ranking the sampling units is to estimate the probabilities of success through a logistic regression model. However, this requires training samples for model fitting. Also, in this approach once a sampling unit has been measured, the extra rank information obtained in the ranking process is not used further in the estimation process. To address these issues, in this paper, we propose to use the partially rank-ordered set sampling design with multiple concomitants. In this approach, instead of fitting a logistic regression model, a soft ranking technique is employed to obtain a vector of weights for each measured unit that represents the probability or the degree of belief associated with its rank among a small set of sampling units. We construct an estimator which combines the rank information and the observed partially rank-ordered set measurements themselves. The proposed methodology is applied to a breast cancer study to estimate the proportion of patients with malignant (cancerous) breast tumours in a given population. Through extensive numerical studies, the performance of the estimator is evaluated under various concomitants with different ranking potentials (i.e. good, intermediate and bad) and tie structures among the ranks. We show that the precision of the partially rank-ordered set estimator is better than its counterparts under simple random sampling and ranked set sampling designs and, hence, the sample size required to achieve a desired precision is reduced.
Trautmann, Freya; Schuler, Markus; Schmitt, Jochen
Sarcomas constitute a rare group of malignant tumors which can originate from any organ, tissue, bone or cartilage. Due to their heterogeneity, estimates of sarcoma incidence, prevalence and survival are rare. We estimated the burden of sarcoma in Germany from a large unselected cohort of patients from routine healthcare. We utilized the AOK PLUS health services research database covering complete medical information on 2,615,865 individuals from the German federal state of Saxony from 2005 to 2012. Persons were defined as sarcoma cases if they had ≥4 medical accounts with respective ICD-10 code C49 (soft-tissue sarcoma) or C40/C41 (bone sarcoma). We assessed sarcoma burden by calculating five-year prevalences, cumulative incidences, and one- and five-year relative survival rates. Overall 1,468 persons with soft-tissue sarcoma and 671 persons with bone sarcoma were identified. Age-standardized cumulative incidence was 4.5/100,000 persons for soft-tissue and 2.1/100,000 persons for bone sarcoma (European Standard). One- and five-year relative survival was 87.8% and 66.4% for soft-tissue and 91.8% and 52.9% for bone sarcoma, respectively. This is the first estimation of the burden of sarcoma based on an unselected sample of routine care data and the first estimation of the burden of sarcoma in Germany. We believe that the proposed methods offer a valuable approach for further outcomes research on cancer. Copyright © 2015 Elsevier Ltd. All rights reserved.
Eckmanns, Tim; Abu Sin, Muna; Ducomble, Tanja; Harder, Thomas; Sixtensson, Madlen; Velasco, Edward; Weiß, Bettina; Kramarz, Piotr; Monnet, Dominique L.; Kretzschmar, Mirjam E.; Suetens, Carl
Background Estimating the burden of healthcare-associated infections (HAIs) compared to other communicable diseases is an ongoing challenge given the need for good quality data on the incidence of these infections and the involved comorbidities. Based on the methodology of the Burden of Communicable Diseases in Europe (BCoDE) project and 2011–2012 data from the European Centre for Disease Prevention and Control (ECDC) point prevalence survey (PPS) of HAIs and antimicrobial use in European acute care hospitals, we estimated the burden of six common HAIs. Methods and Findings The included HAIs were healthcare-associated pneumonia (HAP), healthcare-associated urinary tract infection (HA UTI), surgical site infection (SSI), healthcare-associated Clostridium difficile infection (HA CDI), healthcare-associated neonatal sepsis, and healthcare-associated primary bloodstream infection (HA primary BSI). The burden of these HAIs was measured in disability-adjusted life years (DALYs). Evidence relating to the disease progression pathway of each type of HAI was collected through systematic literature reviews, in order to estimate the risks attributable to HAIs. For each of the six HAIs, gender and age group prevalence from the ECDC PPS was converted into incidence rates by applying the Rhame and Sudderth formula. We adjusted for reduced life expectancy within the hospital population using three severity groups based on McCabe score data from the ECDC PPS. We estimated that 2,609,911 new cases of HAI occur every year in the European Union and European Economic Area (EU/EEA). The cumulative burden of the six HAIs was estimated at 501 DALYs per 100,000 general population each year in EU/EEA. HAP and HA primary BSI were associated with the highest burden and represented more than 60% of the total burden, with 169 and 145 DALYs per 100,000 total population, respectively. HA UTI, SSI, HA CDI, and HA primary BSI ranked as the third to sixth syndromes in terms of burden of disease
Cassini, Alessandro; Plachouras, Diamantis; Eckmanns, Tim; Abu Sin, Muna; Blank, Hans-Peter; Ducomble, Tanja; Haller, Sebastian; Harder, Thomas; Klingeberg, Anja; Sixtensson, Madlen; Velasco, Edward; Weiß, Bettina; Kramarz, Piotr; Monnet, Dominique L; Kretzschmar, Mirjam E; Suetens, Carl
Estimating the burden of healthcare-associated infections (HAIs) compared to other communicable diseases is an ongoing challenge given the need for good quality data on the incidence of these infections and the involved comorbidities. Based on the methodology of the Burden of Communicable Diseases in Europe (BCoDE) project and 2011-2012 data from the European Centre for Disease Prevention and Control (ECDC) point prevalence survey (PPS) of HAIs and antimicrobial use in European acute care hospitals, we estimated the burden of six common HAIs. The included HAIs were healthcare-associated pneumonia (HAP), healthcare-associated urinary tract infection (HA UTI), surgical site infection (SSI), healthcare-associated Clostridium difficile infection (HA CDI), healthcare-associated neonatal sepsis, and healthcare-associated primary bloodstream infection (HA primary BSI). The burden of these HAIs was measured in disability-adjusted life years (DALYs). Evidence relating to the disease progression pathway of each type of HAI was collected through systematic literature reviews, in order to estimate the risks attributable to HAIs. For each of the six HAIs, gender and age group prevalence from the ECDC PPS was converted into incidence rates by applying the Rhame and Sudderth formula. We adjusted for reduced life expectancy within the hospital population using three severity groups based on McCabe score data from the ECDC PPS. We estimated that 2,609,911 new cases of HAI occur every year in the European Union and European Economic Area (EU/EEA). The cumulative burden of the six HAIs was estimated at 501 DALYs per 100,000 general population each year in EU/EEA. HAP and HA primary BSI were associated with the highest burden and represented more than 60% of the total burden, with 169 and 145 DALYs per 100,000 total population, respectively. HA UTI, SSI, HA CDI, and HA primary BSI ranked as the third to sixth syndromes in terms of burden of disease. HAP and HA primary BSI were
Johnson, Andrew O.; Mink, Michael D.; Harun, Nusrat; Moore, Charity G.; Martin, Amy B.; Bennett, Kevin J.
Objectives: The purpose of this study was to compare national estimates of drug use and exposure to violence between rural and urban teens. Methods: Twenty-eight dependent variables from the 2003 Youth Risk Behavior Survey were used to compare violent activities, victimization, suicidal behavior, tobacco use, alcohol use, and illegal drug use…
Johnson, Andrew O.; Mink, Michael D.; Harun, Nusrat; Moore, Charity G.; Martin, Amy B.; Bennett, Kevin J.
Objectives: The purpose of this study was to compare national estimates of drug use and exposure to violence between rural and urban teens. Methods: Twenty-eight dependent variables from the 2003 Youth Risk Behavior Survey were used to compare violent activities, victimization, suicidal behavior, tobacco use, alcohol use, and illegal drug use…
Estrella, Michelle M.; Astor, Brad C.; Köttgen, Anna; Selvin, Elizabeth; Coresh, Josef; Parekh, Rulan S.
Background. Anaemia worsens as kidney function declines. Both conditions are associated with increased mortality. Serum cystatin C is purportedly a more sensitive marker of kidney disease and a better predictor of mortality than serum creatinine. However, studies suggest that extrarenal factors also influence cystatin C levels. Methods. We determined whether estimates of glomerular filtration rate [estimated glomerular filtration rate (eGFR)] based on serum cystatin C alone or in combination with serum creatinine were superior to those based on serum creatinine in recognizing impaired kidney function in the setting of anaemia in a sub-sample of the Third National Health and Nutrition Examination Survey of the USA consisting of 6734 participants, 20 years or older. Results. The prevalence of moderate to severe kidney disease (eGFR 15–59 mL/min/1.73 m2) among anaemic persons was 15–16% when based on serum creatinine alone (eGFRSCR) or combined with cystatin C (eGFRSCR + CYSC); this estimate increased to nearly 25% when kidney function was estimated by cystatin C (eGFRCYSC). The adjusted odds ratios of kidney disease in anaemic versus non-anaemic persons were slightly higher with eGFRCYSC than eGFRSCR and eGFRSCR + CYSC in younger adults [odds ratio (OR) = 5.22, 95% confidence interval (CI): 2.23, 12.17], women (OR = 5.34, 95% CI: 2.36, 12.06) and those with elevated C-reactive protein (CRP) (OR = 7.36, 95% CI: 1.98–27.36). Conclusions. Impaired kidney function was common in individuals with anaemia. Among anaemic individuals, the prevalence estimate for kidney disease was notably higher when kidney function was estimated by cystatin C alone compared with the estimations by serum creatinine alone or in combination with serum cystatin C. eGFRCYSC may be particularly helpful in identifying kidney disease in the setting of anaemia among younger persons, women and those with elevated CRP. Regardless of which renal biomarker is used, our study suggests that an
Gjerde, Hallvard; Verstraete, Alain
To study several methods for estimating the prevalence of high blood concentrations of tetrahydrocannabinol and amphetamine in a population of drug users by analysing oral fluid (saliva). Five methods were compared, including simple calculation procedures dividing the drug concentrations in oral fluid by average or median oral fluid/blood (OF/B) drug concentration ratios or linear regression coefficients, and more complex Monte Carlo simulations. Populations of 311 cannabis users and 197 amphetamine users from the Rosita-2 Project were studied. The results of a feasibility study suggested that the Monte Carlo simulations might give better accuracies than simple calculations if good data on OF/B ratios is available. If using only 20 randomly selected OF/B ratios, a Monte Carlo simulation gave the best accuracy but not the best precision. Dividing by the OF/B regression coefficient gave acceptable accuracy and precision, and was therefore the best method. None of the methods gave acceptable accuracy if the prevalence of high blood drug concentrations was less than 15%. Dividing the drug concentration in oral fluid by the OF/B regression coefficient gave an acceptable estimation of high blood drug concentrations in a population, and may therefore give valuable additional information on possible drug impairment, e.g. in roadside surveys of drugs and driving. If good data on the distribution of OF/B ratios are available, a Monte Carlo simulation may give better accuracy. 2009 Elsevier Ireland Ltd. All rights reserved.
Pearce, Dora C; Cadilhac, Dominique A; Pierce, Robert J; Thrift, Amanda G; David, Stephen; Donnan, Geoffrey A
Assessing sleep-disordered breathing (SDB) in aged or disabled populations is difficult. To validate a multivariable apnea risk prediction index (MAPI) in stroke survivors and estimate SDB prevalence (apnea-hypopnea index >or=10) in a community-based stroke cohort. Self-reported sleep apnea symptoms, demographic and anthropometric data were obtained from a hospital-based (SCOPES II, n = 152) and a community-based (NEMESIS, n = 431) cohort at about 3 years after stroke. Logistic regression models for prediction of SDB using the MAPI were validated with home-based nocturnal polygraphic data recordings obtained in 74 SCOPES II participants. NEMESIS subjects (median age 76, females 45%) were older than SCOPES II subjects (median age 70, females 42%). SDB prevalence was 44.9% in the nocturnal polygraphy subset, and estimated as 44.1% (SCOPES II) and 50.6% (NEMESIS) using a modified MAPI. The MAPI can be reliably used in stroke cohorts and SDB affects about half of chronic stroke survivors. Copyright 2008 S. Karger AG, Basel.
Background Recently, the Kidney Disease: Improving Global Outcomes (KDIGO) group recommended that patients with CKD should be assigned to stages and composite relative risk groups according to GFR (G) and proteinuria (A) criteria. Asians have among the highest rates of ESRD in the world, but establishing the prevalence and prognosis CKD is a problem for Asian populations since there is no consensus on the best GFR estimating (eGFR) equation. We studied the effects of the choice of new Asian and Caucasian eGFR equations on CKD prevalence, stage distribution, and risk categorization using the new KDIGO classification. Methods The prevalence of CKD and composite relative risk groups defined by eGFR from with Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI); standard (S) or Chinese(C) MDRD; Japanese CKD-EPI (J-EPI), Thai GFR (T-GFR) equations were compared in a Thai cohort (n = 5526) Results There was a 7 fold difference in CKD3-5 prevalence between J-EPI and the other Asian eGFR formulae. CKD3-5 prevalence with S-MDRD and CKD-EPI were 2 - 3 folds higher than T-GFR or C-MDRD. The concordance with CKD-EPI to diagnose CKD3-5 was over 90% for T-GFR or C-MDRD, but they only assigned the same CKD stage in 50% of the time. The choice of equation also caused large variations in each composite risk groups especially those with mildly increased risks. Different equations can lead to a reversal of male: female ratios. The variability of different equations is most apparent in older subjects. Stage G3aA1 increased with age and accounted for a large proportion of the differences in CKD3-5 between CKD-EPI, S-MDRD and C-MDRD. Conclusions CKD prevalence, sex ratios, and KDIGO composite risk groupings varied widely depending on the equation used. More studies are needed to define the best equation for Asian populations. PMID:22226403
Parks, Kathleen A; Frone, Michael R; Muraven, Mark; Boyd, Carol
The present study of college students investigated (a) the prevalence of nonmedical use of three classes of prescription drugs (stimulants, anxiolytics/sedatives, analgesics), (b) the prevalence of negative sexual events (NSE) associated with any nonmedical use of prescription drugs (NMUPD), and (c) a set of correlates of NSE. The specific NSE were sexual aggression victimization and perpetration, and regretted sex. The correlates of the NSE were sex, race/ethnicity, year in school, psychological symptoms, alcohol use, illegal drug use, and NMUPD. Participants were 509 (254 females, 255 males) randomly-selected college students who reported any NMUPD. The majority (76.2%) of the sample reported ever using stimulants, 38.9% reported ever using anxiolytics/sedatives, and 40.9% reported using analgesics. During NMUPD, 14.3% of the students reported regretted sex, 7.1% of female students reported sexual victimization, and 6.3% of male students reported perpetrating sexual aggression. Multiple logistic regression analyses indicated that anxiolytic/sedative use (Adj. OR=1.99; 95% CI=1.51-2.62) was positively associated with regretted sex, whereas anxiolytic/sedative use (Adj. OR=1.79; 95% CI=1.01-3.16) and psychological symptoms (Adj. OR=1.06; 95% CI=1.02-1.10) were positively associated with sexual victimization. Illegal drug use was positively associated with perpetrating sexual aggression (Adj. OR=4.10; 95% CI=1.21-13.86). These findings suggest that among these college students, NMUPD-associated NSE were not uncommon, and primarily associated with anxiolytic/sedative use. Given the academic, physical, and psychological implications associated with NSE, research needs to further explore the causal nature of these relations.
Soukarieh, Omar; Gaildrat, Pascaline; Hamieh, Mohamad; Drouet, Aurélie; Baert-Desurmont, Stéphanie; Frébourg, Thierry; Tosi, Mario; Martins, Alexandra
The identification of a causal mutation is essential for molecular diagnosis and clinical management of many genetic disorders. However, even if next-generation exome sequencing has greatly improved the detection of nucleotide changes, the biological interpretation of most exonic variants remains challenging. Moreover, particular attention is typically given to protein-coding changes often neglecting the potential impact of exonic variants on RNA splicing. Here, we used the exon 10 of MLH1, a gene implicated in hereditary cancer, as a model system to assess the prevalence of RNA splicing mutations among all single-nucleotide variants identified in a given exon. We performed comprehensive minigene assays and analyzed patient’s RNA when available. Our study revealed a staggering number of splicing mutations in MLH1 exon 10 (77% of the 22 analyzed variants), including mutations directly affecting splice sites and, particularly, mutations altering potential splicing regulatory elements (ESRs). We then used this thoroughly characterized dataset, together with experimental data derived from previous studies on BRCA1, BRCA2, CFTR and NF1, to evaluate the predictive power of 3 in silico approaches recently described as promising tools for pinpointing ESR-mutations. Our results indicate that ΔtESRseq and ΔHZEI-based approaches not only discriminate which variants affect splicing, but also predict the direction and severity of the induced splicing defects. In contrast, the ΔΨ-based approach did not show a compelling predictive power. Our data indicates that exonic splicing mutations are more prevalent than currently appreciated and that they can now be predicted by using bioinformatics methods. These findings have implications for all genetically-caused diseases. PMID:26761715
Steinbach, G; Blaha, T; Methner, U
Information about the proportion of truly Salmonella-free herds is required for an evaluation of the epidemiological situation, the development of control strategies and their implementation. Findings regarding the presence of salmonellas in faeces and intestinal lymph nodes as well as the presence of Salmonella antibodies in meat juice from slaughtered pigs were obtained in the context of a study conducted by a number of institutes. These data were used for an analysis of the validity of data on the prevalence of infected animals within herds and on the prevalence of infected herds. The proportion of batches or herds with exclusively negative individual findings was found to depend not only on the true proportion of truly Salmonella-free animals within herds but quite essentially also on the distribution of the proportion of infected animals within herds, the sensitivity of the methods of examination and sample sizes. When taking into account the existing dependencies, it was found that among the swine, the real numbers of Salmonella carriers were much higher than shown by bacteriological and serological examination. Regarding salmonellosis in swine, also a number of contaminated herds must be expected which is far higher than that shown by the number of herds with positive findings in at least one animal. Even a low contamination of all or almost all herds would result in the numbers of 'negative' batches observed, i.e. batches with exclusively negative individual findings. A rating of the salmonella exposure of herds as high, low, or very low is possible and may, and should be, used for measures of consumer protection, irrespective of the proportion of truly Salmonella-free herds.
Unisa, Sayeed; Jagannath, Palepu; Dhir, Vinay; Khandelwal, Chiranjeeva; Sarangi, Lalatendu; Roy, Tarun Kumar
Background A high prevalence of gallbladder diseases (GBD) in Northern India warranted a population survey into environmental risk factors. Methods In 60 villages of Uttar Pradesh and Bihar from 13 334 households, 22 861 persons aged >30 years were interviewed for symptoms of GBD, diet and environmental factors. Subsequently ultrasonography (US) was performed in 5100 and 1448 people with and without symptoms, respectively. Heavy metal and pesticide content in soil and water were estimated. Results US revealed a prevalence of GBD of 6.20%. GBD was more common in 5100 persons with symptoms (7.12%) compared with 1448 without (2.99%) (P < 0.05). Adjusted odds ratio (ORs) [95% confidence interval (CI)] revealed a significantly increased risk of GBD in females >50, 1.703 (CI 1.292–2.245); multiparity 1.862 (CI 1.306–2.655) and a genetic history 1.564 (CI 1.049–2.334). An increased risk noted in males with diabetes was 4.271 (CI 2.130–8.566), chickpea consumption 2.546 (CI 1.563–4.146) and drinking unsafe water 3.835 (CI 2.368–6.209). Prevalence of gallstones was 4.15%; more in females 5.59% than males 1.99% (P < 0.05). Cluster analysis identified a positive correlation of nickel, cadmium and chromium in water with a high prevalence of GBD in adjacent villages in Vaishali district, Bihar. Conclusion A high risk of GBD was observed in older, multiparous women and men with diabetes, intake of chickpeas, unsafe water and villages with heavy metal water pollution. PMID:21241429
van Leth, Frank; Evenblij, Kirsten; Wit, Ferdinand; Kiers, Albert; Sprenger, Herman; Verhagen, Maurits; Hillebregt, Mariska; Kalisvaart, Nico; Schimmel, Henrieke; Verbon, Annelies
Knowledge of the HIV status in patients with tuberculosis (TB) and vice versa is crucial for proper individual patient management, while knowledge of the prevalence of co-infection guides preventive and therapeutic strategies. The aim of the study was to assess if national disease databases on TB and HIV are adequate sources to provide this information. A two way capture-recapture analysis to assess the completeness of the registers, and to obtain the prevalence of TB-HIV co-infection in the Netherlands in the years 2002-2012. HIV testing was performed in less than 50% of the patients with TB. Of the 932 TB-HIV infected patients, just 293 (31.4%) were registered in both registers. Under-reporting of TB-HIV co-infection ranged from 50% to 70% in the national TB register, and from 31% to 37% in the HIV database. Prevalence of TB-HIV co-infection in the Netherlands in 2012 was 7.1% (95% CI 6.0% to 8.3%), which was more than double of the prevalence estimated from the national TB database. TB-HIV co-infection is markedly under-reported in national disease databases. There is an urgent need for improved registration and preferably a routine data exchange between the two surveillance systems. 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/
Background In South and Southeast Asian countries, tobacco is consumed in diverse forms, and smoking among women is very low. We aimed to provide national estimates of prevalence and social determinants of smoking and smokeless tobacco use among men and women separately. Methods Data from Demographic and Health Surveys completed in nine countries (India, Pakistan, Nepal, Bangladesh, Maldives, Philippines, Cambodia, Indonesia, and Timor Leste) were analyzed. Current smoking or smokeless tobacco use was assessed as response “yes” to one or more of three questions, such as “Do you currently smoke cigarettes?” Weighted country-level prevalence rates for socio-economic subgroups were calculated for smoking and smokeless tobacco use. Binary logistic regression analyses were done on STATA/IC (version 10) by ‘svy’ command. Results Prevalence and type of tobacco use among men and women varied across the countries and among socio-economic sub groups. Smoking prevalence was much lower in women than men in all countries. Smoking among men was very high in Indonesia, Maldives, and Bangladesh. Smokeless tobacco (mainly chewable) was used in diverse forms, particularly in India, among both men and women. Chewing tobacco was common in Nepal, Bangladesh, Maldives, and Cambodia. Both smoking and smokeless tobacco use were associated with higher age, lower education, and poverty, but their association with place of residence and marital status was not uniform between men and women across the countries. Conclusion Policymakers should consider type of tobacco consumption and their differentials among various population subgroups to implement country-specific tobacco control policies and target the vulnerable groups. Smokeless tobacco use should also be prioritized in tobacco control efforts. PMID:25183954
Miguel-Carrera, Jonatan; García-Porrua, Carlos; de Toro Santos, Francisco Javier; Picallo-Sánchez, Jose Antonio
To study the prevalence of osteoporosis and fracture probability in patients diagnosed with prostate cancer. Observational descriptive transversal study. SITE: Study performed from Primary Care of Lugo in collaboration with Rheumatology and Urology Services of our referral hospital. Patients diagnosed with prostate cancer without bone metastatic disease from January to December 2012. Epidemiologic, clinical, laboratory and densitometric variables involved in osteoporosis were collected. The likelihood of fracture was estimated by FRAX(®) Tool. Eighty-three patients met the inclusion criteria. None was excluded. The average age was 67 years. The Body Mass Index was 28.28. Twenty-five patients (30.1%) had previous osteoporotic fractures. Other prevalent risk factors were alcohol (26.5%) and smoking (22.9%). Eighty-two subjects had vitamin D below normal level (98.80%). Femoral Neck densitometry showed that 8.9% had osteoporosis and 54% osteopenia. The average fracture risk in this population, estimated by FRAX(®), was 2.63% for hip fracture and 5.28% for major fracture. Cut level for FRAX(®) major fracture value without DXA >5% and ≥7.5% proposed by Azagra et al. showed 24 patients (28.92%) and 8 patients (9.64%) respectively. The prevalence of osteoporosis in this population was very high. The more frequent risk factors associated with osteoporosis were: previous osteoporotic fracture, alcohol consumption, smoking and family history of previous fracture. The probability of fracture using femoral neck FRAX(®) tool was low. Vitamin D deficiency was very common (98.8%). Copyright © 2017 Elsevier España, S.L.U. All rights reserved.
Fix, Brian V; Hyland, Andrew; O’Connor, Richard J; Cummings, K Michael; Fong, Geoffrey T; Chaloupka, Frank J; Licht, Andrea S
Background Increases in tobacco taxes are effective in reducing tobacco consumption, but because of the addictive nature of cigarettes, smokers often seek out less expensive sources of cigarettes. The objective of this study is to estimate the prevalence of cigarette packs that are untaxed by the state in which the participant resides in a sample of US smokers at two time points. Methods Data for this study were taken from the 2009 and 2010 waves of the International Tobacco Control United States Survey. Members of this nationally representative cohort of smokers were invited to send us an unopened pack of their usual brand of cigarettes. Results In 2009, 318 packs were received from 401 eligible participants (79%). In 2010, 366 packs were received from 491 eligible participants (75%). In total, 20% of the packs in 2009 and 21% in 2010 were classified as untaxed by the participant’s state of residence. The prevalence of untaxed cigarettes was higher in states with higher-excise taxes. Smokers who do not have a plan to quit were significantly more likely to have sent back a pack that was classified as untaxed by the participant’s state of residence. Conclusions One in five packs were untaxed with rates higher in states with higher-excise taxes. It is unclear whether these estimates differ from the actual prevalence of cigarettes that are untaxed by a smoker’s state of residence. Harmonisation of excise tax rates across all 50 US states might be one method of reducing or eliminating the incentive to avoid or evade these taxes. PMID:23970794
May, Philip A.; Fiorentino, Daniela; Coriale, Giovanna; Kalberg, Wendy O.; Hoyme, H. Eugene; Aragón, Alfredo S.; Buckley, David; Stellavato, Chandra; Gossage, J. Phillip; Robinson, Luther K.; Jones, Kenneth Lyons; Manning, Melanie; Ceccanti, Mauro
Objective: To determine the population-based epidemiology of fetal alcohol syndrome (FAS) and other fetal alcohol spectrum disorders (FASD) in towns representative of the general population of central Italy. Methods: Slightly revised U.S. Institute of Medicine diagnostic methods were used among children in randomly-selected schools near Rome. Consented first grade children (n = 976) were screened in Tier I for height, weight, or head circumference and all children ≤10th centile on one of these measurements were included in the study. Also, teachers referred children for learning or behavioral problems. Children meeting either of these two criteria, along with randomly-selected controls, advanced to Tier II which began with a dysmorphology examination. Children with a possible FASD, and controls, advanced to Tier III for neurobehavioral testing, and their mothers were interviewed for maternal risks. Final diagnoses using indicators of dysmorphology, neurobehavior, and maternal risk were made in formally-structured, interdisciplinary case conferences. Results: Case control comparisons of physical, neurobehavioral, and maternal risk variables are presented for 46 children with an FASD and 116 randomly-selected controls without a diagnosis on the FASD continuum. Rates of diagnoses within the FASD continuum are then estimated from these in-school data via three different methods. The range of rates of FAS produced by these methods is between 4.0 to 12.0 per 1,000; Partial FAS ranges from 18.1 to 46.3 per 1,000; and an FASD was found in 2.3% to 6.3% of the children. Conclusions: These rates are substantially higher than previous estimates of FAS and overall FASD for the general populations of Western Europe and the U. S., and raise questions as to the total impact of FASD on mental deficit in mainstream populations of Western Europe and the United States where the majority are middle class and are not believed to be characterized by heavy episodic drinking. PMID
May, Philip A; Fiorentino, Daniela; Coriale, Giovanna; Kalberg, Wendy O; Hoyme, H Eugene; Aragón, Alfredo S; Buckley, David; Stellavato, Chandra; Gossage, J Phillip; Robinson, Luther K; Jones, Kenneth Lyons; Manning, Melanie; Ceccanti, Mauro
To determine the population-based epidemiology of fetal alcohol syndrome (FAS) and other fetal alcohol spectrum disorders (FASD) in towns representative of the general population of central Italy. Slightly revised U.S. Institute of Medicine diagnostic methods were used among children in randomly-selected schools near Rome. Consented first grade children (n=976) were screened in Tier I for height, weight, or head circumference and all children≤10th centile on one of these measurements were included in the study. Also, teachers referred children for learning or behavioral problems. Children meeting either of these two criteria, along with randomly-selected controls, advanced to Tier II which began with a dysmorphology examination. Children with a possible FASD, and controls, advanced to Tier III for neurobehavioral testing, and their mothers were interviewed for maternal risks. Final diagnoses using indicators of dysmorphology, neurobehavior, and maternal risk were made in formally-structured, interdisciplinary case conferences. Case control comparisons of physical, neurobehavioral, and maternal risk variables are presented for 46 children with an FASD and 116 randomly-selected controls without a diagnosis on the FASD continuum. Rates of diagnoses within the FASD continuum are then estimated from these in-school data via three different methods. The range of rates of FAS produced by these methods is between 4.0 to 12.0 per 1,000; Partial FAS ranges from 18.1 to 46.3 per 1,000; and an FASD was found in 2.3% to 6.3% of the children. These rates are substantially higher than previous estimates of FAS and overall FASD for the general populations of Western Europe and the U. S., and raise questions as to the total impact of FASD on mental deficit in mainstream populations of Western Europe and the United States where the majority are middle class and are not believed to be characterized by heavy episodic drinking.
Beaton, G H; Calloway, D H; Murphy, S P
This paper presents a probability assessment of the adequacy of protein intakes of toddlers (aged 18-30 mo) in study communities in Egypt, Kenya, and Mexico judged in relation to FAO/WHO/UNU estimates of requirements. Effects of supplementing amino acid intakes, or of assuming lower bioavailability for lysine are also considered. In Egypt and Mexico existing protein intakes of toddlers were adequate. In Kenya existing intakes were marginal. Total protein intake was low and often lysine or tryptophan concentration was low. If Kenyan intakes met estimated energy requirements, protein intakes would be adequate. We conclude that protein intake is unlikely to be a primary limiting factor for toddler growth and development, and the benefit to be expected from increasing the intake of limiting amino acids is marginal. Reported associations of animal-source protein and energy with growth, size, and psychologic function of these toddlers are unlikely to be causally attributable to inadequacy of protein intakes.
McIver, David J.; Brownstein, John S.
Circulating levels of both seasonal and pandemic influenza require constant surveillance to ensure the health and safety of the population. While up-to-date information is critical, traditional surveillance systems can have data availability lags of up to two weeks. We introduce a novel method of estimating, in near-real time, the level of influenza-like illness (ILI) in the United States (US) by monitoring the rate of particular Wikipedia article views on a daily basis. We calculated the number of times certain influenza- or health-related Wikipedia articles were accessed each day between December 2007 and August 2013 and compared these data to official ILI activity levels provided by the Centers for Disease Control and Prevention (CDC). We developed a Poisson model that accurately estimates the level of ILI activity in the American population, up to two weeks ahead of the CDC, with an absolute average difference between the two estimates of just 0.27% over 294 weeks of data. Wikipedia-derived ILI models performed well through both abnormally high media coverage events (such as during the 2009 H1N1 pandemic) as well as unusually severe influenza seasons (such as the 2012–2013 influenza season). Wikipedia usage accurately estimated the week of peak ILI activity 17% more often than Google Flu Trends data and was often more accurate in its measure of ILI intensity. With further study, this method could potentially be implemented for continuous monitoring of ILI activity in the US and to provide support for traditional influenza surveillance tools. PMID:24743682
McIver, David J; Brownstein, John S
Circulating levels of both seasonal and pandemic influenza require constant surveillance to ensure the health and safety of the population. While up-to-date information is critical, traditional surveillance systems can have data availability lags of up to two weeks. We introduce a novel method of estimating, in near-real time, the level of influenza-like illness (ILI) in the United States (US) by monitoring the rate of particular Wikipedia article views on a daily basis. We calculated the number of times certain influenza- or health-related Wikipedia articles were accessed each day between December 2007 and August 2013 and compared these data to official ILI activity levels provided by the Centers for Disease Control and Prevention (CDC). We developed a Poisson model that accurately estimates the level of ILI activity in the American population, up to two weeks ahead of the CDC, with an absolute average difference between the two estimates of just 0.27% over 294 weeks of data. Wikipedia-derived ILI models performed well through both abnormally high media coverage events (such as during the 2009 H1N1 pandemic) as well as unusually severe influenza seasons (such as the 2012-2013 influenza season). Wikipedia usage accurately estimated the week of peak ILI activity 17% more often than Google Flu Trends data and was often more accurate in its measure of ILI intensity. With further study, this method could potentially be implemented for continuous monitoring of ILI activity in the US and to provide support for traditional influenza surveillance tools.