Urinary biomarkers of polycyclic aromatic hydrocarbons in pre- and peri-pubertal girls in Northern California: Predictors of exposure and temporal variability

2018 
Abstract Background Polycyclic aromatic hydrocarbons (PAHs), a class of chemicals produced as combustion by-products, have been associated with endocrine disruption. To understand exposure in children, who have been less studied than adults, we examined PAH metabolite concentrations by demographic characteristics, potential sources of exposure, and variability over time, in a cohort study of pre- and peri-pubertal girls in Northern California. Methods Urinary concentrations of ten PAH metabolites and cotinine were quantified in 431 girls age 6–8 years at baseline. Characteristics obtained from parental interview, physical exam, and linked traffic data were examined as predictors of PAH metabolite concentrations using multivariable linear regression. A subset of girls (n = 100) had repeat measures of PAH metabolites in the second and fourth years of the study. We calculated the intraclass correlation coefficient (ICC), Spearman correlation coefficients, and how well the quartile ranking by a single measurement represented the four-year average PAH biomarker concentration. Results Eight PAH metabolites were detected in ≥ 95% of the girls. The most consistent predictors of PAH biomarker concentrations were cotinine concentration, grilled food consumption, and region of residence, with some variation by demographics and season. After adjustment, select PAH metabolite concentrations were higher for Hispanic and Asian girls, and lower among black girls; 2-naphthol concentrations were higher in girls from lower income households. Other than 1-naphthol, there was modest reproducibility over time (ICCs between 0.18 and 0.49) and the concentration from a single spot sample was able to reliably rank exposure into quartiles consistent with the multi-year average. Conclusions These results confirm diet and environmental tobacco smoke exposure as the main sources of PAHs. Controlling for these sources, differences in concentrations still existed by race for specific PAH metabolites and by income for 2-naphthol. The modest temporal variability implies adequate exposure assignment using concentrations from a single sample to define a multi-year exposure timeframe for epidemiologic exposure-response studies.
    • Correction
    • Source
    • Cite
    • Save
    • Machine Reading By IdeaReader
    60
    References
    17
    Citations
    NaN
    KQI
    []