8292432 Urinary phthalate metabolite concentrations by occupation and industry: evidence from the Canadian Health measures survey

<h3>Objective</h3> Phthalates are ubiquitous endocrine-disrupting compounds linked to numerous adverse health outcomes, including hormone-sensitive cancers. Previous studies of phthalates, such as the widely used plasticizer di-2-ethylhexylphthalate (DEHP), have identified important environmental determinants, but few have examined their association with occupational factors. We sought to identify occupations with elevated urinary phthalate biomarker concentrations in a nationally-representative biomonitoring study of adults in Canada. <h3>Methods</h3> We conducted a cross-sectional study of 4,180 individuals aged 20-80 years from the Canadian Health Measures Survey (CHMS) between 2007-2011 (cycles 1-2) and 2016-2019 (cycles 5-6). Spot urine samples were analyzed for concentrations of 11 phthalate metabolites quantified using chromatography and spectrometry. Creatinine-corrected molar sum groups were constructed to describe DEHP and high- and low- molecular weight phthalate (HMWP &amp; LMWP, respectively) exposures. Linear regression models estimated predicted least-squares adjusted geometric means (GMs) and geometric mean ratios by occupation and industry groups. Models were adjusted for dietary, sociodemographic, and anthropometric factors. <h3>Results</h3> Phthalate concentrations (nmol/g creatinine) were elevated among women, older adults, individuals of Asian ethnicities, smokers, urban residents, frequent consumers of grain products, and those in the earliest CHMS cycles. By occupation, LMWP concentrations were highest among labourers in processing, manufacturing, and utilities (GM[LMWP] = 559.92; 95% CI: 333.03-941.40). Workers in these occupations were commonly employed in clothing, electrical, and machinery manufacturing industries. HMWP and DEHP concentrations were highest in trades helpers, construction labourers, and related occupations (GM[HMWP] = 124.94; 95% CI: 88.10-177.18) as well as workers in natural resources, agriculture, and related production (GM[DEHP] = 64.10; 95% CI: 46.39-88.56), respectively. Among women, elevated LMWP and DEHP concentrations were observed in installers, repairers, servicers, and material handlers. <h3>Conclusion</h3> Results suggest heterogeneity in phthalate exposure by occupation and sex. Findings will be used to inform subsequent investigations of breast and prostate cancer risk.