Johannes Wellmann

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Epidemiological studies of lung cancer among nonsmoking men are few. This case-control study was conducted among lifetime nonsmoking men between 1990 and 1996 in Germany to examine lung cancer risk in relation to occupation, environmental tobacco smoke, residential radon, family history of cancer and previous lung disease. A total of 58 male cases with(More)
In a 1990-1996 case-control study in western Germany, the authors investigated lung cancer risk due to exposure to residential radon. Confirmed lung cancer cases from hospitals and a random sample of community controls were interviewed by trained interviewers regarding different risk factors. For 1 year, alpha track detectors were placed in dwellings to(More)
The two-step clonal expansion (TSCE) model is applied to large case-control studies, frequency matched for age, which allow estimation of the RR of lung tumour risk caused by smoking. For estimating background hazard rates, mortality data from the study areas are used to supplement the case-control data. Two approaches are used to analyse the data, based on(More)
To examine the time-dependent effects of exposure histories on disease, we estimate a weight function within a generalized linear model. The shape of the weight function, which is modeled as a cubic B-spline, gives information about the impact of exposure increments at different times on disease risk. The method is evaluated in a simulation study and is(More)
It is well established that odds ratios estimated by logistic regression are subject to bias if exposure is measured with error. The dependence of this bias on exposure parameter values, particularly for multiplicative measurement error, and its implications in epidemiology are not, however, as fully acknowledged. We have been motivated by a German West(More)
To examine the time-dependent effects of exposure histories on disease we use sliding time windows as an exploratory alternative to the analysis of variables like time since last exposure and duration of exposure. The method fits a series of risk models which contain total cumulative exposure and an additional covariate for exposures received during fixed(More)
In epidemiologic studies on lung cancer risk due to indoor radon the quantification of individual radon exposure over a long time period is one of the main issues. Therefore, radon measurements in one or more dwellings, which in total have been inhabited by the participants for a sufficient time-period, are necessary as well as consideration of changes of(More)
The combination of concentrating solar power (CSP) plants with desalination units can be technically and economically competitive due to the fact that the solar irradiance occurs in regions with high water scarcity. CSP plants generate electricity and produce large amounts of waste heat at a low temperature level, which is usually rejected to the(More)
OBJECTIVE The relation of viral infections and allergic diseases is inconclusive. The objective of the analysis therefore was to examine the relation between immunoglobulin levels and sensitization to common allergens as measured by the skin prick test (SPT). METHODS In a population-based study of 2,470 children, 2,188 skin prick tests, and 2,042 blood(More)
The paper discusses a supply and demand scenario using renewable energy sources for the city El Gouna in Egypt as an example for a self-supplying community. All calculations are based on measured meteorological data and real power demand during the year 2013. The modeled energy system consists of a concentrating solar tower plant with thermal storage and(More)
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