Occupation and urinary phthalate metabolite concentrations in a national survey of adults in Canada.

backgroundPhthalates are synthetic chemicals with widespread exposure linked to adverse health effects. Occupational determinants remain understudied despite the potential for substantially elevated workplace exposure levels. This study aimed to investigate the associations between occupation and urinary phthalate metabolite concentrations in a national sample of Canadian adults.

methodsWe analyzed data from 4,259 adults, aged 20–79 years, from four cycles (2007–2019) of the cross-sectional Canadian Health Measures Survey, which quantified 11 urinary phthalate metabolites. We compared creatinine-corrected concentrations of individual metabolites and four summary measures of phthalates across occupation (10 broad- and 40 major-level groups) and industry (19 sectors). Multivariable linear regression models estimated geometric mean ratios (GMRs) and 95% confidence intervals (CIs). For four metabolites with low detection frequencies, multivariable logistic regression estimated odds ratios of detection. Models were adjusted for sociodemographic, lifestyle, and dietary confounders. Sensitivity analyses compared results using specific gravity-corrected concentrations.

resultsNon-occupational factors, including female sex, Asian and Black ethnicity, and higher fruit and vegetable consumption, were associated with elevated phthalate concentrations. Workers in natural resources, agriculture, and related production had elevated concentrations of most metabolites, including mono(3-carboxypropyl) phthalate (MCPP) (GMR = 1.64, 95% CI: 1.15, 2.33) and monobenzyl phthalate (MBzP) (GMR = 1.41, 95% CI: 0.97, 2.03). Workers in trades, transport, and equipment operation also exhibited modestly increased exposures, particularly trades helpers and construction labourers for mono-n-butyl phthalate (MBP) (GMR = 1.41, 95% CI: 1.05, 1.89) and MCPP (GMR = 1.80, 95% CI: 1.22, 2.67). Elevated concentrations were also observed among workers in service support and other service occupations, with precise increases across several metabolites. Elevated concentrations in construction and industrial trades were largely driven by males, while females were the primary drivers of elevated di(2-ethylhexyl) phthalate (DEHP) metabolites in natural resources and agriculture, and of increases more broadly in service support occupations.

conclusionThis study identifies significantly elevated phthalate exposures among Canadian workers in agriculture, construction, and trades, as well as in service support roles. These findings highlight novel at-risk occupational groups beyond traditional manufacturing settings providing critical evidence for targeting exposure reduction and disease prevention strategies.