http://repub.eur.nl/res/aut/6379/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/33233/ 2011-11-01T00:00:00Z Background: Asbestos is a well-recognized cause of lung cancer, but there is considerable between-study heterogeneity in the slope of the exposure-response relationship. Objective: We considered the role of quality of the exposure assessment to potentially explain heterogeneity in exposure-response slope estimates. Data sources: We searched PubMed MEDLINE (1950-2009) for studies with quantitative estimates of cumulative asbestos exposure and lung cancer mortality and identified 19 original epidemiological studies. One was a population-based case-control study, and the others were industry-based cohort studies. Data extraction: Cumulative exposure categories and corresponding risks were abstracted. Exposure-response slopes [KL(lung cancer potency factor of asbestos)] were calculated using linear relative risk regression models. Data synthesis: We assessed the quality of five exposure assessment aspects of each study and conducted random effects univariate and multivariate meta-regressions. Heterogeneity in exposure-response relationships was greater than expected by chance (I2= 64%). Stratification by exposure assessment characteristics revealed that studies with well-documented exposure assessment, larger contrast in exposure, greater coverage of the exposure history by exposure measurement data, and more complete job histories had higher meta-KLvalues than did studies without these characteristics. The latter two covariates were most strongly associated with the KLvalue. Meta-KL values increased when we incrementally restricted analyses to higher-quality studies. Conclusions: This meta-analysis indicates that studies with higher-quality asbestos exposure assessment yield higher meta-estimates of the lung cancer risk per unit of exposure. Potency differences for predominantly chrysotile versus amphibole asbestos-exposed cohorts become difficult to ascertain when meta-analyses are restricted to studies with fewer exposure assessment limitations. http://repub.eur.nl/res/pub/33390/ 2011-07-01T00:00:00Z Mesothelioma deaths due to environmental exposure to asbestos in The Netherlands led to parliamentary concern that exposure guidelines were not strict enough. The Health Council of the Netherlands was asked for advice. Its report has recently been published. The question of quality of the exposure estimates was studied more systematically than in previous asbestos meta-analyses. Five criteria of quality of exposure information were applied, and cohort studies that failed to meet these were excluded. For lung cancer, this decreased the number of cohorts included from 19 to 3 and increased the risk estimate 3- to 6-fold, with the requirements for good historical data on exposure and job history having the largest effects. It also suggested that the apparent differences in lung cancer potency between amphiboles and chrysotile may be produced by lower quality studies. A similar pattern was seen for mesothelioma. As a result, the Health Council has proposed that the occupational exposure limit be reduced from 10 000 fibres m-3(all types) to 250 f m-3(amphiboles), 1300 f m-3(mixed fibres), and 2000 f m-3(chrysotile). The process illustrates the importance of evaluating quality of exposure in epidemiology since poor quality of exposure data will lead to underestimated risk. http://repub.eur.nl/res/pub/14255/ 2008-12-01T00:00:00Z The Health Council of the Netherlands published a report in which the best procedure and method for recommending health-based occupational exposure limits (OELs) for inhaled allergens were identified by evaluating the scientific state of the art. Many respiratory disorders in the workplace arise from inhalation of substances which can cause allergy. To protect workers against respiratory allergy, various preventive measures are taken, one of them being reduction of exposure by setting legally binding standards. These are based on health-based OELs that specify a level of exposure to an airborne substance, a threshold level, below which it may reasonably be expected that there is no risk of adverse health effects. The Council is of the opinion that an OEL should prevent against allergic sensitization, as sensitization plays a crucial biological role and is a prerequisite for the development of allergy. Furthermore, the Council considers it most likely that the exposure level below which no allergic sensitization develops for most allergens is so low, that OELs are difficult to set with the current knowledge and technical feasibilities. An alternative approach is to accept exposure, which carries a small predefined risk in developing allergic sensitization. In addition, it is worth considering periodic screening of exposed workers on allergic sensitization, because timely intervention can prevent worse. The feasibility of periodic screening and what else is needed to comply with the most important criteria, should however be judged case-by-case. http://repub.eur.nl/res/pub/8832/ 1998-01-01T00:00:00Z OBJECTIVES: Questionnaires, lung function tests, and peak flow measurements are widely used in occupational health care to screen for subjects with respiratory disease. However, the diagnostic performance of these tests is often poor. Application of these tests in a stepwise manner would presumably result in a better characterisation of subjects with respiratory disease. METHODS: Cross sectional data from workers exposed to acid anhydrides, to laboratory animals, and to flour dusts were used. Sensitivity and specificity were calculated from cross tables of different (combinations of) tests for bronchial hyperresponsiveness and bronchial irritability in the past four weeks (BIS). From sensitivity and specificity likelihood ratios were computed and change in probability of BIS was calculated. RESULTS: The prevalence of BIS was 7%, 7%, and 5%, respectively. In all groups questionnaire data provided excellent sensitivity but poor specificity, which was inherent on the broad definition of symptoms. Adding the forced expiratory volume in one second/forced vital capacity (FEV1/FVC) ratio yields almost perfect specificity, and peak expiratory flow (PEF) variability is intermediate in populations in which smoking induced or non-allergic respiratory diseases predominates. In occupational groups in which asthma is a problem, adding PEF measurements will optimise sensitivity and specificity in detection of BIS. The probability of BIS for subjects with a negative combined test outcome was lower than the probability before testing. Subjects with a positive combined test outcome had a probability of BIS after the tests at least three times the probability before. CONCLUSIONS: Combined testing yields better sensitivity and specificity. An advantage of combined testing is an economy in the effort to screen for subjects with BIS. Combined testing resulted in more detailed estimation of the probability of BIS.