RETROSPECTIVE ASSESSMENT OF OCCUPATIONAL EXPOSURE TO CHEMICALS IN COMMUNITY-EASED STUDIES - VALIDITY AND REPEATABILITY OF INDUSTRIAL-HYGIENE PANEL RATINGS

Background. Occupational hygiene panels are increasingly being used to rate retrospective occupational exposures to chemicals in community-b ased studies. This study aimed to assess the validity, reliability and feasibility of using such an expert panel in a brain tumour case-cont rol study. Methods. A panel of five experts was recruited to rate expo sure to 21 chemicals for 298 job descriptions to investigate the level of agreement. Validity was assessed by comparing the ratings of the e xperts for 49 of the jobs with objective quantitative exposure data wh ich existed for these jobs. Repeatability was assessed by comparing th e results for 50 resubmissions. Results. Specificity was high for repo rting that exposure occurred (all above 90%), but sensitivity was vari able with values between 48% and 79%. Weaker validity was found for ra ting exposure level and exposure frequency. The raters showed the grea test inter-rater agreement for exposure to three of the 21 chemicals c onsidered (kappa = 0.64 for cutting fluids, kappa = 0.57 for welding f umes and kappa = 0.42 for lubricating oils). Intra-rater reliability, based on the 50 resubmitted jobs, was fair to good (kappa = 0.46, 0.73 ). Conclusions. The potential effect of exposure misclassification fro m using expert panels was quantified and found to be a significant sou rce of bias. The optimum situation occurred where three of the five ra ters concurred, where an odds ratio of 2.2 was observed for a true odd s ratio of 4.0. Future studies which plan to use expert panels should screen the experts for their suitability by validating their performan ce against jobs with known exposure data.