Phthalate exposure in a Canadian birth cohort at three months of age: Exposure sources and the influence of socioeconomic status

Exposure to ubiquitous plasticizers known as phthalates may contribute to the development of an inflammatory response and be a factor in the development of allergic disease through direct or adjuvant mechanisms. Some of the important exposure pathways of phthalates include ingestion, injection, inhalation, and dermal absorption. The Canadian Healthy Infant Longitudinal Development (CHILD) Study is a multicentre, multidisciplinary, longitudinal, population-based birth cohort study of 5,000 children enrolled “pre-birth” and followed for five years. The purpose of this birth cohort is to identify and quantify determinants of asthma and allergy in early childhood. We examined associations between phthalate exposures in the indoor environment, including indoor furnishings, occupation, household care products and personal care products with seven phthalate metabolites (monobutyl phthalate (MBP), monobenzyl phthalate (MBzP), monoethyl phthalate (MEP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP), mono-2-ethylhexyl phthalate (MEHP), mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP) and monoethyl phthalate (MMP)) in urine from 578 CHILD subjects at three months of age. Additionally, we looked at their relationships with socio-economic status. We found higher levels of urinary phthalate metabolites associated with use of household product, such as bathroom tile cleaner; air fresheners, usage of plastic and personal baby care products such as baby wipes. Associations between household income and the levels of urinary phthalate metabolites concentrations were also found.