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Motivation To provide an integrated software environment for model fitting and variable selection in regression models with a bounded outcome variable. Implementation The proposed modelling framework is implemented in the add-on package betaboost of the statistical software environment R. General features The betaboost methodology is based on beta-regression, which is a state-of-the-art method for modelling bounded outcome variables. By combining traditional model fitting techniques with recent advances in statistical learning and distributional regression, betaboost allows users to carry out data-driven variable and/or confounder selection in potentially high-dimensional epidemiological data. The software package implements a flexible routine to incorporate linear and non-linear predictor effects in both the mean and the precision parameter (relating inversely to the variance) of a beta-regression model. Availability The software is hosted publicly at [ http://github.com/boost-R/betaboost ] and has been published under General Public License (GPL) version 3 or newer. [ABSTRACT FROM AUTHOR]

The article presents an analysis of the Information Network of Departmernts of Dermatology (IVDK) data through machine-learning techniques in polysensitization-associated allergens' positive reactions. Topics discussed include an overview of IVDK data, the polysensitization of the positive reaction of allergens, and the unique view of polysensitization.

Abstract: Objective: To assess and to evaluate possible effects arising from Web-based data collection on the results of a study. Study Design and Setting: We analyzed participants of the German Weight Control Registry (GWCR) of whom 328 chose to use Web-based questionnaires and 139 preferred to participate via a traditional postal survey. Furthermore, we included data of 212 individuals sampled independently from the general population who fulfilled the study''s inclusion criteria—giving us the chance to differentiate between response bias (concerning Web-based data collection) and general selection bias (concerning participation in the GWCR). Results: In addition to selection bias (GWCR participants are overall better educated, more likely to live in a partnership, more often female, and older than the general population), we also found a substantial response bias: Participants using the Internet were younger, better educated, and more often male compared with participants preferring the paper-and-pencil version. However, after adjusting for these differences, we found no additional direct effect of Web-based data collection on any of the outcome variables. Conclusion: Web-based epidemiologic studies still do not attract the same participants as postal surveys, even in highly industrialized countries. However, after adjusting for this bias, the same results can be expected. [Copyright &y& Elsevier]

Background. Chronic kidney disease (CKD) is increasingly recognized as a global health problem. The conditions leading to CKD, the health impact of CKD and the prognosis differ markedly between affected individuals. In particular, renal failure and cardiovascular mortality are competing risks for CKD patients. Opportunities for targeted intervention are very limited so far and require an improved understanding of the natural course of CKD, of the risk factors associated with various clinical end points and co-morbidities as well as of the underlying pathogenic mechanisms. Methods. The German Chronic Kidney Disease (GCKD) study is a prospective observational national cohort study. It aims to enrol a total of 5000 patients with CKD of various aetiologies, who are under nephrological care, and to follow them for up to 10 years. At the time of enrolment, male and female patients have an estimated glomerular filtration rate (eGFR) of 30–60 mL/min × 1.73m2 or overt proteinuria in the presence of an eGFR >60 mL/min × 1.73m2. Standardized collection of biomaterials, including DNA, serum, plasma and urine will allow identification and validation of biomarkers associated with CKD, CKD progression and related complications using hypothesis-driven and hypothesis-free approaches. Patient recruitment and follow-up is organized through a network of academic nephrology centres collaborating with practising nephrologists throughout the country. Conclusions. The GCKD study will establish one of the largest cohorts to date of CKD patients not requiring renal replacement therapy. Similarities in its design with other observational CKD studies, including cohorts that have already been established in the USA and Japan, will allow comparative and joint analyses to identify important ethnic and geographic differences and to enhance opportunities for identification of relevant risk factors and markers. [ABSTRACT FROM PUBLISHER]

Background: Nickel, cobalt and chromium are some of the most common causes of type IV sensitizations and subsequent allergic contact dermatitis. Accurate diagnosis of contact sensitization to these metal salts is made possible through standardized patch testing; however, patch tests with metal allergens may be influenced by meteorological conditions at the time of testing. We aimed to investigate how patch test reactions to these metals relate to outdoor temperature and humidity at the time of testing. Methods: Clinical patch test results from 61,435 patients tested at Austrian and German dermatology departments participating in a contact sensitization surveillance network (www.ivdk.org) from 1993 through 2001 were evaluated with weather data measured near the testing location and at the time of testing. Test reactions and ambient temperature and humidity were examined with multinomial logistic regression models. Results: The odds of irritant and doubtful reactions to all 3 ionized metals increased during cold/arid conditions, and the odds of weak allergic (positive) reactions to nickel and cobalt also increased during cold/dry weather. Strong allergic reactions were essentially independent of weather conditions. Conclusions: The increase in irritant and doubtful reactions coinciding with decreasing temperature and humidity may be the result of an overall increase in skin irritation brought about by these ambient conditions. The observed increases in erythematous and infiltrated (‘weak allergic’) reactions may be due to doubtful reactions increasing in intensity and being (falsely) classified as positive during colder and drier conditions. Copyright © 2008 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Editorial. Comments on the evolution of the concept of attributable risk (AR) in epidemiology. Challenge of deriving a valid and reliable estimate of the proportion of cases of disease ascribed to exposure to environmental factors; Attribution of lung cancer cases to smoking; Danger of uncritical use of AR; Statistical foundation of AR; Developments in the field of AR estimation.

Various forms of immunotherapy utilizing bacille Calmette-Guérin vaccine or vaccinia vaccine have been evaluated in clinical trials on melanoma patients. The effect of the “natural” application of these vaccinations, administered to provide protection against tuberculosis and smallpox, has, however, never been studied in epidemiologic investigations on risk factors for melanoma. In a case–control study comprising 11 institutions in seven countries we recruited 603 incident melanoma cases and 627 population controls frequency matched to the cases with respect to sex, age, and ethnic origin within each center to assess this relationship to obtain insights into the prevention of melanoma. Exposure information, incorporating also detailed ascertainment of potential confounding variables, was obtained in standardized personal interviews at the study subject's home. We found an inverse association between melanoma risk and previous bacille Calmette-Guérin vaccine/vaccinia vaccination depicted by an adjusted odds ratio of 0.44 (95% confidence interval: 0.26–0.72) for those vaccinated against tuberculosis and smallpox compared with subjects without a positive history of either vaccination. A variety of subgroup analyses showing a consistent pattern of results make it unlikely that the observed inverse association is a spurious finding. We conclude that bacille Calmette-Guérin vaccination and vaccinia vaccination may lower melanoma risk. Current immunologic theory of melanoma development provides a sound basis for understanding the biologic plausibility of the findings that have to be confirmed in future studies. [ABSTRACT FROM AUTHOR]