Predictors of urinary biomarker concentrations of legacy phthalates and some of their replacements in children in the Project Viva cohort

Abstract

Background: Some phthalates are still widely used in food packaging, toys, and personal care products, and links to adverse health have motivated substitution with replacement chemicals. Identifying predictors of exposure to legacy phthalates and their replacements in childhood can inform preventive interventions.

Objective: To examine associations of sociodemographic, dietary, and urine collection characteristics with urinary concentrations of biomarkers of legacy phthalates and their replacements in mid-childhood.

Methods: We studied 830 children ages 6-10 years in 2007-2010 in a Boston-area cohort. We quantified urinary metabolites and summed their concentrations to calculate biomarkers of the concentrations of ten parent phthalates/replacements. We used linear regression to examine mutually adjusted associations of each predictor with each phthalate biomarker. We used logistic regression to examine predictors of 1,2-cyclohexane dicarboxylic acid, diisononyl ester (DINCH) biomarker detectability.

Results: Predictor characteristics explained 25%-48% of urinary biomarker variability. Di-2-ethylhexyl terephthalate (DEHTP) biomarker was higher in girls (18.7% [95% CI: 0.7, 39.9]), children who consumed more meat and dairy, and samples collected from later years. DINCH biomarker was more detectable in girls (odds ratio [OR] 2.1 [95% CI: 1.5, 3.0]) and samples from later years.

Significance: These findings can inform interventions to reduce exposure in children.

Impact Statement: Our study uses data from a large cohort that is one of the first to measure DINCH, DEHTP, and metabolites of di-isononyl phthalate (DiNP) and di-isodecyl phthalate (DiDP). Additionally, we evaluate predictors during mid-childhood when phthalate biomarkers might be highest. As the use of replacement phthalates increases, our study is one of the first to examine