Calibrating a population-based job-exposure matrix using inspection measurements to estimate historical occupational exposure to lead for a population-based cohort in Shanghai, China

Abstract

The epidemiologic evidence for the carcinogenicity of lead is inconsistent and requires improved exposure assessment to estimate risk. We evaluated historical occupational lead exposure for a population-based cohort of women (n=74,942) by calibrating a job-exposure matrix (JEM) with lead fume (n=20,084) and lead dust (n=5,383) measurements collected over four decades in Shanghai, China. Using mixed-effect models, we calibrated intensity JEM ratings to the measurements using fixed-effects terms for year and JEM rating. We developed job/industry-specific estimates from the random-effects terms for job and industry. The model estimates were applied to subjects’ jobs when the JEM probability rating was high for either job or industry; remaining jobs were considered unexposed. The models predicted that exposure increased monotonically with JEM intensity rating and decreased 20–50-fold over time. The cumulative calibrated JEM estimates and job/industry-specific estimates were highly correlated (Pearson correlation=0.79–0.84). Overall, 5% of the person-years and 8% of the women were exposed to lead fume; 2% of the person-years and 4% of the women were exposed to lead dust. The most common lead-exposed jobs were manufacturing electronic equipment. These historical lead estimates should enhance our ability to detect associations between lead exposure and cancer risk in future epidemiologic analyses.

Reliability and validity of expert assessment based on airborne and urinary measures of nickel and chromium exposure in the electroplating industry

“…The poor validity on both the four and two-category scales suggests that even a limited, a priori, characterization of exposure may help determine appropriate semi-quantitative categories for the exposure range and the number of exposure categories to use for expert assessment in a workplace or study before requesting experts to provide their exposure estimates. For example, syntheses of the data in the published literature 37-39 or from inspection measurements 40-44 and other exposure databases 45 can provide useful information on exposure variability and help anchor the experts’ ratings to a concentration scale.…”

Development of a source-exposure matrix for occupational exposure assessment of electromagnetic fields in the INTEROCC study

“…Previous efforts to reduce exposure misclassification included the development of task-exposure matrices for other agents 34–37 . However, earlier advocates of a source-based approach for EMF exposure assessment 38–41 recommended the use of combined estimates from a JEM together with information such as duration and location related to specific sources of exposure. To our knowledge, this is the first time that a full source-based approach, independent of the occupation, has been attempted.…”

Occupational Determinants of Cumulative Lead Exposure

“…Bone lead measurements can be used as a supplement to job exposure matrix methodology, such as professional judgments of industrial hygienists(23–25) and area exposure samplings. (26)…”