Phthalate metabolites and bisphenol A in urines from German school-aged children: results of the Duisburg birth cohort and Bochum cohort studies.

Some phthalates and also bisphenol A (BPA) interfere with the human endocrine system and are labelled as reproductive toxicants. Children's exposure to these contaminants is suspected to be associated with developmental disorders and other health impairments. We provide biomonitoring data on 21 urinary phthalate metabolite and BPA levels in first morning urine of 8-10 year old children. Participants were children born between 1999 and 2002 of the Duisburg birth cohort (8-9 years, N=113) and of the Bochum cohort study (8-10 years, N=352). Additionally, for the Duisburg birth cohort we compare current data of children from Duisburg (8-9 years) with data from 2 years earlier when the children were 6-7 years old. We analyzed influences of important covariates on exposure levels by multiple regression analysis and those from two sampling time points by generalized equation estimation models adjusted for important covariates. Compared to recently published studies the phthalate metabolite and BPA concentrations were within the range of background levels. There were no significant differences between children from Bochum and Duisburg. Comparison between the two Duisburg birth cohort data sets (2007-2008 and 2009-2010) showed significant correlations for most of the phthalate metabolites (r Spearman between 0.25 and 0.51; p ≤ 0.05) but not for BPA (r Spearman=0.162; p=0.143). Most of the phthalate metabolites in the groups of the 6-7 and 8-9 years old Duisburg children were negatively associated with higher age, except for BPA concentrations with nearly constant levels. Exposure levels may be influenced by changes in child specific exposure patterns with age but also by the rapidly changing phthalate market.