Dirk Taeger

A stand-alone windows application for computing exact person-years, standardized mortality ratios and confidence intervals in epidemiological studies

We introduce a stand-alone and user-friendly person-years and mortality computation program (PAMCOMP) for calculating exact person-years and standardized mortality and incidence ratios running under Windows 95/98 and NT. The calculation of person-years allows flexible stratification by self-defined and unrestricted categories of age and calendar years. Furthermore, it is possible to lag person-years to account for latency periods. The standardized mortality ratio computation includes calculation of 90%, 95%, and 99% confidence intervals. Import and export filters for standard personal computer file formats are available. The software is free of charge and can be downloaded from: http://medweb.uni-muenster.de/institute/epi/ pamcomp/pamcomp.html

Exposure to high concentrations of nitrosamines and cancer mortality among a cohort of rubber workers

OBJECTIVES To examine if the occurrence of different cancers was increased among rubber workers, as the highest known exposures of humans to nitrosamines have occurred in the rubber industry. METHODS A cohort of 8933 rubber workers (hired after 1 January 1950, still active or retired on 1 January 1981 and employed for at least 1 year in one of five study factories) was followed up for mortality from 1 January 1981 to 31 December 1991. Work histories were reconstructed with routinely documented cost centre codes, which allowed identification by employment in specific work areas. For each cost centre code time and factory specific, semi-quantitative exposures to nitrosamines (three levels: low, medium, high) and other compounds were estimated by industrial hygienists. Rate ratios for medium (RRm) and high (RRh) exposures and 95% confidence intervals (95% CIs) were calculated with Coxs proportional hazards models with the low exposure as reference. RESULTS Exposure to nitrosamines was significantly associated with an increased mortality from cancers of the oesophagus (13 deaths: RRm 1.7, 95% CI 0.3 to 10.3; RRh 7.3, 95% CI 1.9 to 27.8) and of the oral cavity and pharynx (17 deaths: RRm 0.8, 95% CI 0.2 to 4.1; RRh 3.9, 95% CI 1.4 to 11.1). A non-significant trend of increasing mortality with exposure to higher concentrations of nitrosamines was found for mortality from cancer of the prostate (26 deaths: RRm 1.4, 95% CI 0.5 to 3.8; RRh 2.2, 95% CI 0.9 to 5.6), and the brain (six deaths: RRm 3.9, 95% CI 0.3 to 42.6; RRh 6.0, 95% CI 0.6 to 57.6). No association was found between exposure to nitrosamines and cancer of the stomach (RRm 0.8, 95% CI 0.4 to 1.8; RRh1.2, 95% CI 0.5 to 2.5) or lung (RRm 1.0, 95% CI 0.6 to 1.5; RRh 1.0, 95% CI 0.7 to 1.6). CONCLUSIONS Exposure to high concentrations of nitrosamines is associated with increased mortality from cancers of the oesophagus, oral cavity, and pharynx, but not with increased mortality from cancers of the stomach or lung.

Self-reported traffic density and atopic disease in children. Results of the ISAAC Phase III survey in Muenster, Germany.

Positive associations between traffic exposure and atopic respiratory disorders in children have been described in several studies. We analyzed data related to self‐reported truck traffic density and several symptoms and diagnoses of asthma and hay fever (12‐month wheezing and rhinitis symptoms, diagnoses of asthma and hay fever) from the ISAAC Phase III survey in Muenster, Germany, using core written and video questionnaires. Data were collected from representative school‐based samples (nu2003=u20037345) of 6–7‐ and 13–14‐yr‐olds. In 13–14‐yr‐olds, according to exposure levels categorized into rare, frequent, and constant, with the ‘never’‐category used as reference, the sex‐adjusted prevalence ratios were 1.29 (95% CIu2003=u20031.08–1.53), 1.58 (1.29–1.94), and 1.57 (1.18–2.10) for wheeze in the past 12u2003months, and 1.20 (1.06–1.34), 1.35 (1.17–1.55), and 1.69 (1.42–2.0) for rhinitis symptoms in the past 12u2003months. Prevalence ratios in 6–7‐yr‐olds and results for a diagnosis of asthma were less consistent while no positive association was detected between hay fever and truck traffic in both age groups. When analyses were based on a more general traffic indicator (self‐reported traffic noise), no consistent associations were observed. Our data provide support for the hypothesis that residential exposure to truck traffic may adversely affect the health of children.

The Impact of the Day of the Week and Month of Admission on the Length of Hospital Stay in Stroke Patients

Background: Length of hospital stay (LOS) in many diseases is determined by patient-related sociodemographic and clinical factors but also by the management of treatment and care. We examined the influence of the day of the week (DW) and month of admission on LOS in stroke patients. Methods: We used data from a large regional stroke registry in the northwest of Germany for the years 2000 and 2001. The registry is based on a standardised data assessment in participating hospitals, including patient-related sociodemographic and clinical items, diagnostic and treatment procedures, stroke classification, as well as admission and discharge dates. Data management and analysis were done centrally. Results: A total of 11,942 patients from 42 hospital departments were included. Median LOS was 13 days for ischemic stroke and 8 days for TIA. Patients with ischaemic stroke admitted on Tuesdays or Wednesdays had the longest LOS. We observed a significantly shorter LOS in patients discharged towards the weekend, both for ischaemic stroke and TIA, independent of age, gender and symptom severity. Discharges were predominantly done on Fridays (25%), transferrals to rehabilitation centres most often on Thursdays (28%) in neurologic departments but on Tuesdays in departments of internal medicine. LOS according to the month of admission revealed a biphasic curve for both ischaemic stroke and TIA, with shortest LOS in July and December. Conclusions: Discharge patterns on weekends contribute to differences in LOS for the various DWs of admission. Changes in discharge organisation and improved co-operation with rehabilitation centres may shorten LOS. Differences in LOS between the months show considerable seasonal variability.

Job titles and work areas as surrogate indicators of occupational exposure.

Background. Job titles or work areas are often used as surrogate indicators of exposure in occupational epidemiological studies. In this article, we assess the validity and comparability of commonly used surrogate indicators. Methods. We analyzed lung cancer mortality among a hypothetical and an actual cohort of rubber workers. Surrogate indicators of exposure were defined according to jobs in which workers were “only,” “ever,” “longest” or “last” employed, or in which they were employed at the “census” of the study. Occupational risks were estimated using standardized mortality ratios. Validity of surrogate indicators was assessed in the simulated data by comparison between estimated effects and the known underlying associations. Comparisons of surrogate indicators were conducted in both simulated and empirical data. Results. Use of the definition “only” as the surrogate indicator gave valid but imprecise results. For all other definitions, we observed a moderate overestimation of risks in no-risk or low-risk jobs and attenuation of underlying dose-response relationships, without substantial differences among the applied definitions. Conclusions. Our results demonstrate a limitation of using surrogate indicators of exposure in occupational epidemiological studies. However, they suggest that the inconsistencies of published study findings in the rubber industry are unlikely to be attributable to the use of different surrogate indicators.

Prevalence of and relationship between rhinoconjunctivitis and lower airway diseases in compost workers with current or former exposure to organic dust.

INTRODUCTION AND OBJECTIVEnThe relationship between allergic rhinitis and allergic asthma is well characterized. However, it remains unknown whether an association exists between symptoms of upper and lower airway diseases and occupational bioaerosol exposure beyond the scope of allergy.nnnMATERIALS AND METHODSnThe current cross-sectional study focuses on 190 current and 59 former compost workers exposed to bioaerosols. Work-related symptoms indicative of conjunctivitis, rhinitis and lower airway irritation were assessed and compared with 38 non-exposed control subjects. Allergic asthma was diagnosed using a calculated score, and chronic obstructive pulmonary disease (COPD) was spirometrically determined.nnnRESULTSn12 current, 8 former and 5 non-exposed subjects were diagnosed with allergic asthma and excluded from further analysis. Multivariate logistic regression models suggested that cough and chronic bronchitis in current compost workers were associated with eye irritation (OR 2.75 (0.93-8.07); OR 7.22 (1.12-46.5)). Chronic bronchitis in former workers was strongly associated with work-related eye irritation (OR 38.6 (1.33->1000) and nose irritation (OR 25.0 (1.21-513)).nnnCONCLUSIONSnAfter excluding allergic asthmatics, there was no evidence that eye or nose irritation was due to an underlying atopic disease, but rather to non-allergic mucous membrane irritation syndrome. Therefore, the higher incidence of chronic bronchitis in former compost workers may reflect a chronic irritative process triggered by exposure to bioaerosols.

Extended cancer mortality follow-up of a German rubber industry cohort.

Objective: We extended follow-up of a cohort of German rubber industry workers (active or retired in 1981) by 9 years (1992 to 2000) to reassess previously observed cancer mortality risks. Methods: We calculated standardized mortality ratios and stratified results by work area, duration of employment, and year of hire. Results: The cohort includes 11,632 men and 1863 women from five tire or general rubber goods producing factories. Among men we observed significantly elevated standardized mortality ratios for cancers of the lung and the pleura in the full cohort and in specific strata. Among women we observed a significantly elevated standardized mortality ratio for cancer of the lung. Conclusions: We observed excess risk for several cancer sites among men and women. Further cancer risk analysis of workers in the rubber industry should focus on differences in work areas and associated exposures.

Circulating miR-132-3p as a Candidate Diagnostic Biomarker for Malignant Mesothelioma

The use of circulating microRNAs as biomarkers has opened new opportunities for diagnosis of cancer because microRNAs exhibit tumor-specific expression profiles. The aim of this study was the identification of circulating microRNAs in human plasma as potential biomarkers for the diagnosis of malignant mesothelioma. For discovery, TaqMan Low Density Array Human MicroRNA Cards were used to analyze 377 microRNAs in plasma samples from 21 mesothelioma patients and 21 asbestos-exposed controls. For verification, individual TaqMan microRNA assays were used for quantitative real-time PCR in plasma samples from 22 mesothelioma patients and 44 asbestos-exposed controls. The circulating miR-132-3p showed different expression levels between mesothelioma patients and asbestos-exposed controls. For discrimination, sensitivity of 86% and specificity of 61% were calculated. Circulating miR-132-3p in plasma was not affected by hemolysis and no impact of age or smoking status on miR-132-3p levels could be observed. For the combination of miR-132-3p with the previously described miR-126, sensitivity of 77% and specificity of 86% were calculated. The results of this study indicate that miR-132-3p might be a new promising diagnostic biomarker for malignant mesothelioma. It is indicated that the combination of miR-132-3p with other individual biomarkers improves the biomarker performance.

Cancer and non-cancer mortality in a cohort of recent entrants (1981–2000) to the German rubber industry

Working in the rubber industry is associated with increased cancer risks, particularly for cancers of the lung, larynx, urinary bladder and leukaemia.1 Most epidemiological studies, however, still reflect working conditions back to the 1940s. As occupational exposures were lowered considerably since the late 1970s, prospective health surveillance is warranted to assess the effectiveness of exposure control.nnThe cohort included all blue-collar workers of 13 participating rubber manufacturing companies in western Germany who were hired after 1 January 1981 and worked for at least 1 year until the end of follow-up. Follow-up started on 1 January 1982 and ended on 31 December 2000, but was censored at the age of 85 years.nnThe vital status was ascertained via population registries. Death certificates were requested from community health departments and underlying causes of death were coded by professional nosologists according to the ninth revision of the International Classification of Diseases (ICD-9).nnThe mortality experience of the cohort was compared with the mortality of the corresponding population of western Germany. Standardised mortality ratios (SMRs) and exact 95% confidence …

Exposure assessment in epidemiological studies: what has to be considered when comparing job-exposure matrices?

In a recent article, Offermans et al studied the agreement of three job-exposure matrices (JEM) in the Netherlands Cohort (NLCS) with respect to asbestos, polycyclic aromatic hydrocarbons (PAH) and welding fume exposure.1 The studied JEMs were quite different in their approach to assess exposure: one was based on prevalent mesothelioma cases in jobs highly exposed to asbestos (Asbestos-JEM), the second one (FINJEM) used time-dependent continuous values based on expert assessment and measurement data, and the third (DOMJEM) was a semi-quantitative expert-based JEM that assigned exposure scores (0, 1, 2) to job titles without consideration of change of exposure levels over time. Thus time-dependent exposure levels are not available for the DOMJEM.nnUsing …