8282020 Occupational predictors of serum perfluoroalkyl substance concentrations in a national biomonitoring survey of adults in Canada

<h3>Objective</h3> Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) are two perfluoroalkyl substances (PFAS) widespread in industrial applications and consumer products. However, evidence substantiating occupations with elevated exposure is limited. The recent IARC classification of PFOA as carcinogenic has prompted concern about occupational exposure to PFAS for cancer prevention, particularly among women. We investigated the association of occupation and industry of employment with serum PFOA and PFOS biomarker concentrations in a national survey of Canadian adults, with a specific focus on exposure in female workers. <h3>Methods</h3> We conducted a cross-sectional study of 5,795 participants in four cycles of the Canadian Health Measures Survey between 2007-2011 and 2016-2019. Linear regression models adjusted for demographic, diet, and environmental factors were used to estimate predicted geometric means (GM) and geometric mean ratios (GMR) of PFOA and PFOS concentrations among workers in 137 occupation and industry groups, overall and stratified by sex. <h3>Results</h3> PFOA and PFOS concentrations were higher among participants who were older, male, East/Southeast Asian, urban residents or seafood consumers. Concentrations declined in successive CHMS cycles. By occupation, PFOA was elevated among workers in health services (GMR-PFOA 1.25; 95%CI: 1.10–1.43); labourers in processing and manufacturing; front-line protection services; and harvesting and landscaping labourers. Among women, predicted PFOA levels were also elevated in electrical and construction trades; and technical health occupations. For PFOS, aside from health-related occupations, results were similar. By industry, concentrations were elevated among workers in ambulatory care services (GMR-PFOA 1.12; 95%CI: 1.02–1.24) and clothing manufacturing (GMR-PFOS 2.22; 95%CI: 1.39–3.57). <h3>Conclusion</h3> Occupational and sex-based differences in PFOA and PFOS exposure are evident, with elevated exposure identified for workers in specific occupations, including health and manufacturing. Further research will examine exposure to other PFAS as well as associations with cancer risk. This research was supported by the Canadian Cancer Society.