PubMed Health⌕ Search

Biomedical subjects

W Ahrens

Publications and source records attributed to W Ahrens.

At least 19 recordsLinked to original sources
PubMed2006

Understanding and preventing childhood obesity and related disorders--IDEFICS: a European multilevel epidemiological approach.

The environment of children has drastically changed in Europe during the last decades as reflected in unhealthy dietary habits and sedentary lifestyle. Nutrition obviously plays a part in the development of overweight in childhood. However, dietary factors and physical activity are also involved in the development of metabolic syndrome, type II diabetes, cardiovascular diseases, osteoporosis, and postural deformities like scoliosis, effects related in part to excessive weight gain. To stop the resulting epidemic of diet- and lifestyle-induced morbidity, efficient evidence-based approaches are needed. These issues are the focus of IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants), a five-year project proposed under the sixth EU framework. The IDEFICS consortium comprises 25 research centres and SMEs across Europe. The planned prospective study will identify risk profile inventories for children susceptible to any of these disorders with emphasis on obesity and its co-morbid conditions. Genetic and non-genetic factors, psychosocial factors and social settings will be considered. The project will devise tailored prevention strategies that are effective, easy to implement and that account for the needs of different social groups. Population-based studies will investigate the impact of sensory perception and provide results concerning internal and external triggers of food choices and children's consumer behaviour. The ethical implications of a "right not to know" of genetic factors will be addressed. We will propose knowledge-based guidelines on dietary and lifestyle activities for health promotion and disease prevention in children for health professionals, stakeholders and consumers.

Adolescent↗
PubMed2006

[Epidemiological studies in the HTA evaluation process].

Results of epidemiological studies should be considered as part of the available evidence when evaluating drug treatment benefits in health technology assessment (HTA). Pharmaco-epidemiological databases can provide a broader understanding of the effectiveness of drugs in populations that are frequently underrepresented in clinical trials. Such databases are also useful to investigate drug safety with regard to socio-demographic and medical care-related indicators and hereby contribute to an optimal and targeted pharmacological therapy. Using examples from pharmaco-epidemiological asthma studies, the present article discusses associated difficulties in interpreting database results against the background of various sources of bias and proposes possibilities for integrating observational data into the HTA evaluation process. Researchers are challenged to engage in considerable efforts to develop a standardized inventory of epidemiological methods, e.g. for the pooled analysis of epidemiological data.

Biomedical Technology↗
PubMed2006

[Data sources in epidemiology].

The use of large databases has a high potential for future epidemiological research. Databases consisting of primary data as well as routine data that are mainly collected for administrative purposes will be of interest. This paper presents some large databases and some that are most relevant for epidemiological research, respectively, and shows how they might be exploited for research purposes. To make better use of large databases there are new requirements and challenges that we have to face regarding appropriate methods for their analysis. Some examples of such methods are given. An example of pharmaco-epidemiology illustrates linkage of several administrative databases and specific problems that have to be solved in this context. Finally, future challenges are discussed that have to be overcome on the way towards establishment, maintenance and analysis of large databases, especially regarding data protection, data quality and regular updates.

Computer Security↗
PubMed2006

[Calcinosis cutis in Albright hereditary osteodystrophy: pseudohypoparathyroidism type Ia].

Albright hereditary osteodystrophy (AHO) is characterized by a symptom complex including short stature, brachymetacarpia, obesity, round facies, cutaneous osteomas, and mental retardation. AHO is caused by mutations in the GNAS-gene localized on chromosome 20 encoding for Gsalpha protein, a signal transducer of endocrine pathways. Therefore, AHO is often associated with endocrinopathy such as pseudohypoparathyroidism or hypothyroidism. A nine-month-old boy presented with typical features of this syndrome. The diagnosis was confirmed by biochemical and molecular analyses. An unusual feature was calcinosis cutis at such an early age, which led to extensive differential diagnostic procedures.

Calcinosis↗
PubMed2005

[Smoking as potential confounder in german epidemiological studies: standardization of assessment, quantification, and analysis].

Tobacco smoking is one of the most frequently examined risk factors in epidemiological studies due to the high frequency of smoking in the population and its high risk potential. This paper discusses the issue of standardization of the assessment of tobacco exposure in German epidemiological studies based on a suggestion of the working group "Epidemiological methods" of the German Society of Epidemiology (DGEpi), the German Society of Social Medicine and Prevention (DGSMP), and German Society of Medical Informatics, Biometry and Epidemiology (GMDS) together with the working group "Epidemiology in the workplace" of the DGEpi and the German Society of Occupational and Environmental Medicine (DGAUM). The main element is a short questionnaire for German adults for the assessment of tobacco smoking in epidemiological studies where smoking is a potential confounder. In addition, information on the consideration of intermittent periods of non-smoking, a very short questionnaire for medical examinations in the workplace or non-responder interviews as well as the quantification and statistical modelling of smoking are presented. A brief discussion of scientific problems and questionnaires related to the exposure to environmental tobacco smoke is given.

Bias↗
PubMed2004

Occupational exposure to chemical agents in the paper industry.

As part of an International Agency for Research on Cancer (IARC) international epidemiological study of workers in the pulp and paper industry, previously unpublished exposure measurements were assembled in a database. This article summarizes the results of 3,873 measurements carried out in the production departments of paper and paperboard mills and recycling plants in 12 countries. In the paper and paperboard mills, most of the agents were measured in the pulping and refining departments and in on-machine coating and winding of paper/paperboard. Exposures to asbestos, carbon monoxide, formaldehyde, fungal spores, bacteria, nitrogen dioxide, minerals dusts, paper dust, sulphuric acid and different solvents sometimes exceeded exposure limit values. In the re-pulping and de-inking departments of recycling plants high exposures to formaldehyde, fungal spores, bacteria and paper dust were observed. High exposures to asbestos, bioaerosols, carbon monoxide and paper dust were found in many departments; ammonia, formaldehyde, mineral and paper dust and solvents were found in coating machines; and diphenyl and polychlorobiphenyls (PCBs) were found in some special circumstances. Measurements in the newsprint and uncoated paper machine departments revealed only a few elevated exposures. In nearly all departments, measurements of epichlorohydrin, PCBs, sulphur dioxide, hydrogen sulphide and mercaptans tended to be low, often even below their detection limits. In spite of some uncertainties in the measurement data, the study provides new insights into the level and variation of occupational exposures of production workers in the paper and paperboard industry.

Europe↗
PubMed2004

[Databases as a source for monitoring systems of drug safety].

Clinical trials only allow for a limited assessment of adverse drug reactions (ADRs) due to their restricted number of patients, their short duration, and their narrow inclusion criteria. To assess potential ADRs in the population actually treated after drug approval, different systems for signal generation such as spontaneous reporting systems have been established and are required by drug laws in many countries. As of today epidemiological methods for signal confirmation for rare adverse events or events with long induction periods use record linkage databases such as the United Health Care (Ingenix) in the USA or the practice databases such as the General Practice Research Database in Great Britain. However, this approach also has its limitations. This type of database will be presented in this paper. In addition, databases operated by German public health insurance will be described. The topic of linking different data sources in Germany to support pharmaco-vigilance activities will be addressed.

Adverse Drug Reaction Reporting Systems↗
PubMed2004

Risk of fatal industrial accidents and death from other external causes among asphalt workers.

The hypothesis that asphalt workers are at increased risk of mortality from industrial accidents and other external causes was tested. Mortality rates for external and violent causes of death in a cohort of asphalt industry employees from seven European countries and Israel were compared to that of the general population. There was no evidence that mortality from external causes was increased among long term employees in asphalt application and mixing. There was an increased risk for mortality due to external causes among short term workers. However, none of the fatal accidents among short term workers appear to have occurred during employment in the studied asphalt companies. Overall, no evidence was found supporting the hypothesis that asphalt workers are at increased risk of fatal industrial or road accidents. Mortality from other external causes did not increase in this population as a whole, but increased risks among short term workers deserve further attention.

Accidents, Occupational↗
PubMed2003

Viral infection, atopy and mycosis fungoides: a European multicentre case-control study.

Mycosis fungoides (MF) is a rare disease with an unknown aetiology, although it has been suggested that infections may play a role. The present study investigates whether infections, atopic disorders and some other diseases are risk indicators for MF. A European multicentre case-control study involving seven rare cancers, including MF, was conducted from 1995 to 1998. Patients between 35 and 69 years of age diagnosed with MF (n = 140) were recruited, and the diagnoses were verified by a reference pathologist, who classified 83 cases as definitive and 35 cases as possible; 22 cases were not accepted. Of the 118 accepted cases, 104 patients were interviewed (including 76 definitive cases and 28 possible cases). These 76 definitive cases were used for this study. A common set of controls to serve all case groups were interviewed, representing a total of 4574 controls. The latter included 1008 colon cancer patients and 3566 subjects selected from population registers. Information on infections, skin pathology and clinical history 5 years before the diagnosis of MF was used to estimate odds ratios (ORs) derived from logistic regression-modelling, which included gender, age and country. The highest ORs for MF were found in patients who reported a history of psoriasis 5 years before MF was diagnosed (OR 7.2, 95% CI: 3.6-14.5). Urticaria had an OR of 1.4 (95% CI: 0.6-3.6). Infections and atopic diseases were not closely associated with MF. Some diseases correlated to MF. Whether this has a causal background or reflects early diagnostic uncertainty is not known.

Adult↗
PubMed2003

Glutathione S-transferase genotype and p53 mutations in adenocarcinoma of the small intestine.

Adenocarcinoma of the small intestine (ASI) is a rare disease of unknown aetiology. The glutathione S-transferase M1 (GSTM1) enzyme catalyses the detoxification of compounds involved in carcinogenesis of adenocarcinoma of the stomach, colon and lung, including constituents of tobacco smoke. We investigated a possible interaction between the lack of GSTM1 enzyme activity and the carcinogenic compounds of tobacco smoke. Based on the theory that certain carcinogens cause specific point mutations in the p53 gene we analysed by single strand conformation polymorphism (SSCP) and sequencing, p53 exon 5-8 of 52 samples of ASI collected in Sweden, Germany, France, Italy and Denmark between 1995 and 1997. The GSTM1 gene status was investigated by multiplex PCR. The prevalence of GSTM1 negative genotype among cases with ASI was 69% and higher than previous reports of 50% suggesting a higher risk of ASI among GSTM1 negative compared with GSTM1 positive subjects. A 'case-only' approach was used to address the combined association between the GSTM1 negative genotype and lifestyle exposures in patients with ASI. Using this method, heavy smokers (> 20 pack-years) with the GSTM1 negative genotype had an odds ratio of 4.8; 95% confidence interval (CI) (0.6-38.7) for ASI as compared to smokers who expressed GSTM1. No similar association between alcohol consumption and ASI was found. No p53 mutations in exon 5-8 were found in these samples, but the method may not be sensitive enough to identify smaller differences. Thus p53 does not seem to be the target of carcinogens acting in the small intestine.

Adenocarcinoma↗
PubMed2002

[Biological markers in epidemiology: concepts, applications, perspectives (part I)].

The inclusion of biomarkers in epidemiological research provides new possibilities for exposure assessment and the study of early structural or functional changes and pre-clinical stages of diseases. At the same time issues of validity, reliability, and quality control as well as logistics require special attention. Usually epidemiological studies become more expensive with regard to time and cost. Interdisciplinary collaboration between epidemiology, basic research, and laboratory research is crucial. A prerequisite for this collaboration are agreements on definitions, methods and procedures. The definition of "biomarker" and a description of previous uses of biomarkers in epidemiological studies are presented in the first part of this paper. The second part addresses genetic markers and markers of individual sensitivity and susceptibility. We will end with a discussion about the possible future of biomarkers in epidemiology.

Biomarkers↗
PubMed2002

[Biological Markers in Epidemiology: Concepts, applications, Perspectives (Part II)].

The first part of this paper outlined terms and definitions in the context of the application of biological markers in epidemiological studies. Cardiovascular epidemiology served as an example for their historical development. The second part focusses on DNA-based biomarkers, practical and methodological dimensions of the use of biomarkers in analytic epidemiological studies as well as requirements in respect of validity and quality assurance. Most genetic polymorphisms have no impact on health. However, some can be used as biomarkers for individual sensitvity to exposures and susceptibility for specific diseases. The Human Genome Project has brought about a quantum leap in the development of genetic markers. The practical implications cannot presently be assessed with certainty. However, present and future research programmes of gene-environment interactions depend on "traditional" epidemiological study designs, methods, and concepts. Ethical principles and data protection requirements apply equally to genetic and molecular epidemiology as do the "Guidelines for Good Epidemiological Practice".

Biomarkers↗
PubMed2002

Asbestos fibreyears and lung cancer: a two phase case-control study with expert exposure assessment.

AIMS: To assess the cumulative effect of asbestos on lung cancer risk where the exposure is assessed by an expert rating. METHODS: 1678 male cases and controls were enrolled in a population based matched case-control study, focused on occupational risk factors, carried out in West Germany. The exposure to asbestos was computed as lifelong working hours. For a validation subsample of 164 matched pairs from this study the intensity of asbestos exposure was further assessed by a panel of experts in order to obtain an estimate of the cumulative exposure on a time by intensity scale (fibreyears). The information on duration of asbestos exposure in the original study was combined with the fibreyears following the two phase case control study paradigm. RESULTS: The number of exposed subjects in the validation subsample was 75 cases and 71 controls. The percentage of subjects with a cumulative exposure < or =1, 1 to < or =10, and >10 fibreyears was 16%, 15%, and 15% for the cases and 18%, 16%, and 9% respectively for the controls. The smoking adjusted odds ratios for the fibreyears based on an unconditional logistic regression were 0.81, 1.02, and 1.60 respectively with increasing exposure categories (not significant). The coefficient (beta) for a log transformed trend was 1.156. Applying the two phase paradigm, these odds ratios became 0.86, 1.33, and 1.94; the latter reached significance and the beta coefficient was 1.178. CONCLUSIONS: The two phase paradigm allowed us to obtain a more precise estimate of the effect of asbestos on lung cancer. Results are consistent with a doubling of the lung cancer risk with 25 fibreyears asbestos exposure.

Adult↗
PubMed2001

Lung cancer and cigarette smoking in Europe: an update of risk estimates and an assessment of inter-country heterogeneity.

Ten case-control studies have been carried out in 6 European countries to investigate the major risk factors for lung cancer. Carcinogenic effect from cigarette smoke was the most relevant interest in our study, which has included 7,609 cases of lung cancer and 10,431 controls, mainly population based. The results indicate elevated odds ratios (ORs; 23.9 among men and 8.7 among women) with attributable risks exceeding 90% for men and close to 60% for women. A large, and statistically significant, variability of the results across countries was detected after adjusting for the most common confounding variables, and after controlling, at least in part, for the instability of the ORs due to the small number of non-smokers in some of the study subsets. This pattern of lung cancer risk associated with cigarettes smoke, across different European regions, reflects inherent characteristics of the studies as well as differences in smoking habits, particularly calendar periods of starting, and it is likely to have been influenced by effect modifiers like indoor radon exposure, occupation, air pollution and dietary habits.

Aged↗
PubMed2001

Nitrated and oxidized plasma proteins in smokers and lung cancer patients.

Cigarette smoking is a cause of lung cancer and other respiratory diseases. Oxidants either present in cigarette smoke and/or formed in the lung of smokers may trigger oxidative and nitrative damage to DNA and cellular components, contributing to carcinogenesis. We have used immunodot and Western blot analyses to measure nitrated (nitrotyrosine-containing) and oxidized (carbonyl-containing) proteins in plasma samples collected from 52 lung cancer patients and 43 control subjects (heavy and light smokers, nonsmokers with or without exposure to environmental tobacco smoke). The levels of nitrated proteins were significantly higher in lung cancer patients than in controls (P = 0.003). On the other hand, the levels of oxidized proteins were significantly higher in smokers than in nonsmokers (P < 0.001). Western-blot analyses showed the presence of two to five nitrated proteins and one oxidized protein. Using immunoprecipitation and Western-blot analyses with eight different antibodies against human plasma proteins, we identified fibrinogen, transferrin, plasminogen, and ceruloplasmin as nitrated proteins and fibrinogen as the only oxidized protein present in human plasma of lung cancer patients and smokers. Our results indicate that cigarette smoking increases oxidative stress and that during lung cancer development, formation of reactive nitrogen species results in nitration and oxidation of plasma proteins.

Aged↗
PubMed2001

Are alcohol intake and smoking associated with mycosis fungoides? A European multicentre case-control study.

The incidence of mycosis fungoides (MF) is low, and the aetiology of the disease is unknown. The aim of this study was to investigate whether wine consumption protects against the disease and whether smoking constitutes a risk factor. This paper is part of the European Rare Cancers Study that tries to determine the risk factors for seven selective rare cancers, including mycosis fungoides, involved in the development of cancer. A multicentre case-control study was conducted in six European countries. Only incident cases with confirmed histology were included in the analysis which include a total of 76 cases of MF and 2899 controls. Wine intake had no protective effect; on the contrary the consumption of more than 24 g of alcohol per day was associated with a high risk of MF (odds ratio (OR)=3.02, 95% confidence interval (CI), 1.34-6.79), after adjusting for centre, country, age, sex and education. There was a dose-dependent increase in the risk of MF with increased smoking habits, albeit the observed trend was not statistically significant. A combined exposure to high tobacco and alcohol use yielded a significantly increased risk factor for MF (P=0.0073). Alcohol intake was associated with MF.

Adult↗