A birth cohort study to investigate the association between prenatal phthalate and bisphenol A exposures and fetal markers of metabolic dysfunction
- DOI
- Language of the publication
- English
- Date
- 2014-10-22
- Type
- Article
- Author(s)
- Ashley-Martin, Jillian
- Dodds, Linda
- Arbuckle, Tye E.
- Ettinger, Adrienne S.
- Shapiro, Gabriel D.
- Fisher, Mandy
- Morisset, Anne-Sophie
- Taback, Shayne
- Bouchard, Maryse F.
- Monnier, Patricia
- Dallaire, Renee
- Fraser, William D.
- Publisher
- BMC
Abstract
Background: Obesity and type-2 diabetes are on the rise and in utero exposure to environmental contaminants is a suspected contributing factor. Our objective was to examine associations between prenatal exposure to potential endocrine disrupting chemicals and markers of fetal metabolic dysfunction. Methods: The Maternal-Infant Research on Environmental Chemicals Study (MIREC) recruited 2001 women during the first trimester of pregnancy from 10 Canadian sites. First trimester maternal urine was measured for 11 phthalate metabolites and bisphenol A (BPA). Leptin and adioponectin measured in 1,363 available umbilical cord blood samples served as markers of metabolic function. Restricted cubic spline curves were used to assess the relationship between continuous measures of phthalate and BPA levels and cord blood adipokines. Polytomous logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) for the association between phthalates and BPA and both high (≥90th percentile) and low (≤10th percentile) fetal adiponectin and leptin, adjusting for confounding factors. Analyses were conducted for all subjects, overall, and separately by fetal sex. Results: Leptin was significantly higher in female than male infants. We observed an inverse, non-linear relationship between BPA and adiponectin among males in the restricted cubic spline and linear regression analysis. Mono-(3-carboxypropyl) (MCPP) was associated with increased odds of high leptin among males in the polytomous logistic regression models (4th quartile OR = 3.5 95% CI: 1.1-11.6). Conclusion: Our findings contribute to the growing body of evidence examining the influence of early life exposure on metabolic regulation and function. Associations between maternal exposure to chemicals and markers of metabolic function appear to be potentially sex specific. However, further investigation is required to determine whether in utero and childhood exposure to BPA and phthalates are associated with metabolic dysfunctions later in life.
Plain language summary
Phthalates and bisphenol A (BPA) are chemicals that are used in a variety of plastic consumer products. Because these chemicals are structurally similar to the hormones that our bodies produce, these chemicals may have harmful effects on the endocrine and reproductive systems. This is of particular concern for pregnant women and their developing babies because gestation is a time of enhanced susceptibility to the potential adverse effects of environmental contaminants. Scientific research has recently been examining the role of common environmental contaminants that impact metabolism, through effects on the endocrine system, as possible contributing factors in the rise in the number of individuals that exceed a healthy weight and that have type-2 diabetes. In particular, this study examined the relationship between pregnant mother’s exposure to phthalates and bisphenol A, as measured through levels in their urine, and biomarkers of metabolic function in umbilical cord blood obtained through the Maternal-Infant Research on Environmental Chemicals (MIREC) biobank. The two biomarkers, leptin and adiponectin, are hormones that may provide an indication of childhood growth patterns. The results showed that leptin levels were higher among female infants than male infants, while adiponectin levels were approximately the same among males and females. When compared to women with low exposure levels, women with moderate levels of exposure to one phthalate metabolite, monobenzyl phthalate, were slightly more likely to have high cord blood leptin levels. As well, women with high exposure to the phthalate metabolite, monoethyl phthalate, were slightly more likely to have high cord blood adiponectin levels. This research suggests that exposures to common environmental contaminants during pregnancy may have an impact on fetal hormone levels associated with metabolic function. Further research needs to be done to examine whether these changes in hormone levels are associated with changes in childhood growth trajectories leading to obesity and/or type-2 diabetes. This work was led by researchers at Dalhousie University and funded by the Canadian Diabetes Association (CDA). Health Canada scientists are the lead on the MIREC study, assisted with the interpretation of these results, provided editorial advice and are co-investigators on the grant to Dalhousie University scientists from the CDA.
Subject
- Health,
- Health and safety