Predictors and Variability of Repeat Measurements of Urinary Phenols and Parabens in a Cohort of Shanghai Women and Men

BACKGROUND Exposure to certain phenols is ubiquitous because of their use in many consumer and personal care products. However, predictors of exposure have not been well characterized in most populations. OBJECTIVES We sought to identify predictors of exposure and to assess the reproducibility of phenol concentrations across serial spot urine samples among Chinese adults. METHODS We measured 2,4-dichlorophenol, 2,5-dichlorophenol, butyl paraben, methyl paraben, propyl paraben, benzophenone-3, bisphenol A, and triclosan in urine collected during 1997-2006 from 50 participants of the Shanghai Women's Health Study cohort and during 2002-2006 from 50 participants of the Shanghai Men's Health Study cohort. We investigated predictors of concentrations using the Satterthwaite t-test, and assessed reproducibility among serial samples using intraclass correlation coefficients (ICCs) and Spearman correlation coefficients (SCCs). RESULTS Creatinine-corrected phenol concentrations were generally higher among women than men. Participants who had taken medicine within the previous 24 hr had higher concentrations of propyl paraben. Cigarette smoking was associated with lower concentrations of propyl and methyl parabens among men. Bottled water consumption was associated with higher bisphenol A, 2,4-dichlorophenol, and 2,5-dichlorophenol concentrations among women. Among men, reproducibility across serial samples was moderate for 2,4-dichlorophenol and 2,5-dichlorophenol (ICC = 0.54-0.60, SCC = 0.43-0.56), but lower for other analytes (ICC = 0.20-0.29). Reproducibility among women was low (ICC = 0.13-0.39), but increased when restricted to morning-only urine samples. CONCLUSIONS Among these 100 Shanghai residents, urinary phenol concentrations varied by sex, smoking, and consumption of bottled water. Our results suggest that a single urine sample may be adequate for ranking exposure to the precursors of 2,4-dichlorophenol and 2,5-dichlorophenol among men and, under certain circumstances, among women.