Identification of occupations susceptible to high exposure and risk associated with multiple toxicants in an observational study: National Health and Nutrition Examination Survey 1999-2014

Background: According to the World Health Organization, occupational exposures to hazardous chemicals are estimated to cause over 370,000 premature annual deaths. The risks due to multiple workplace chemical exposures, and those occupations most susceptible to the resulting health effects, remain poorly characterized. Objectives: The aim of this study is to identify occupations with elevated toxicant biomarker concentrations and increased health risk associated with toxicant exposures in a working US population from diverse categories of occupation. More specifically, we aim to 1) define differences in chemical exposures based on occupation description, 2) identify occupational groups with similar chemical exposure profiles, and 3) identify occupational groups with chemical biomarker levels exceeding acceptable health-based biomarker levels. Methods: For this observational study of 51,008 participants, we used data from the 1999-2014 National Health and Nutrition Examination Survey. We characterized differences in chemical exposures by occupational group for 129 chemicals by applying a series of generalized linear models with the outcome as biomarker concentrations and the main predictor as the occupational groups, adjusting for age, sex, race/ethnicity, poverty income ratio, study period, and biomarker of tobacco use. We identified groups of occupations with similar chemical exposure profiles via hierarchical clustering. For each occupational group, we calculated percentages of participants with chemical biomarker levels exceeding acceptable health-based guidelines. Results: Blue collar workers from "Construction", "Professional, Scientific, Technical Services", "Real Estate, Rental, Leasing", "Manufacturing", and "Wholesale Trade" have higher biomarker levels of toxic chemicals such as several heavy metals, acrylamide, glycideamide, and several volatile organic compounds compared to their white-collar counterparts. For these toxicants, 1-58% of blue-collar workers from these industries have toxicant concentrations exceeding acceptable levels. Discussion: Blue collar workers have toxicant levels higher relative to their white-collar counterparts, often exceeding acceptable levels associated with noncancer effects. Our findings identify multiple occupations to prioritize for targeted interventions and health policies to monitor and reduce high toxicant exposures.