RETROSPECTIVE ASSESSMENT OF ASBESTOS EXPOSURE .2. AT THE JOB LEVEL - COMPLEMENTARITY OF JOB-SPECIFIC QUESTIONNAIRE AND JOB EXPOSURE MATRICES

The assessments of asbestos exposure by two a priori job exposure matr ices (JEM) and by a job-specific questionnaire (SQ) are compared at jo b level. The data used for the comparison were generated by an ongoing case-control study on lung cancer in a region of northern Germany wit h a relatively high past prevalence of asbestos exposure. Among jab pe riods assessed as unexposed by either JEM, 96% are recognized as such by the SQ. Discrepancies between the SQ and JEM were observed in jobs rated potentially exposed by the JEM. Despite varying estimates, the J EM and SQ were consistent as regards the relative classification of jo b periods by probability of exposure. The concordance of the methods, estimated by Kappa statistics, was stronger for the two JEM than for e ither of the JEM and the SQ. The identification of specific occupation /industry combinations in which discrepancies were most frequent and t he comparison with expert ratings in some jobs yield insights into the sources of the disagreement between the methods. The misclassificatio n of exposure by the JEM usually results in an overestimation of expos ure. This is essentially related to loss of information due to the use of job codes as surrogates for job task descriptions and to the insuf ficiency of published data on asbestos exposure in different industrie s. As regards the SQ, two main sources of potential loss of sensitivit y were identified: 1) possible omission of indirect sources of exposur e by this method, 2) possible incompleteness of the SQ. She present co mparison of methods of asbestos exposure assessment does not allow any one approach to be considered superior to another. Indeed, as propose d by Ahrens et al. in Part I of the study, both should be used to ensu re optimal epidemiological performance.