Early Life Exposure to Phthalates in CHILD: A Multi-City Canadian Birth Cohort

Abstract

Phthalates, used as plasticizers and solvents, are ubiquitous in the environment. Phthalate exposure has been associated with adverse health effects including childhood asthma and allergic disease. Few studies have examined exposure to phthalates during early life particularly in infancy, a critical window for development. The Canadian Healthy Infant Longitudinal Development (CHILD) Study, a population-based birth cohort, has examined multiple environmental exposures during early life. The goal of this study was to characterize exposure to phthalates during infancy and early childhood in representative participants in the CHILD Study.Pregnant mothers were enrolled 2009-2012 across 4 cities and 1 rural area in Canada. Urine samples were collected at 3, 12 and 36 months of age and, in the first 1,578 children, analyzed for eight phthalate metabolites. Questionnaires were administered at each time point documenting the home environment and maternal and infant behaviours. Geometric mean (GM) metabolite concentrations were calculated at each age. Trends with age and factors that may influence urinary phthalate concentrations were examined using mixed models. Variability between all three measurements were assessed using intraclass correlation coefficients (ICC).Results indicated widespread exposure to phthalates. The highest urinary concentration was for the metabolite MBP at all time points (GM: 15-32 ng/mL). Concentrations of all phthalate metabolites significantly increased with age from 3 to 36 months. Low ICCs were observed for all metabolites (0 to 0.2), suggesting a high degree of variability between measurements from the same child at different ages. There were differences in urinary concentrations of MEP, MBP, MBzP, MCPP depending on study site and urinary MBzP concentrations decreased with mother's age. These data, which will be explored in detail in this presentation, describe widespread exposure to phthalates across a representative sample of the CHILD Study.