Exposure to Endocrine-Disrupting Chemicals during Pregnancy and Weight at 7 Years of Age: A Multi-pollutant Approach

Abstract

Background: Prenatal exposure to endocrine-disrupting chemicals (EDCs) may induce weight gain and obesity in children, but the obesogenic effects of mixtures have not been studied.

Objective: We evaluated the associations between pre- and perinatal biomarker concentrations of 27 EDCs and child weight status at 7 years of age.

Methods: In pregnant women enrolled in a Spanish birth cohort study between 2004 and 2006, we measured the concentrations of 10 phthalate metabolites, bisphenol A, cadmium, arsenic, and lead in two maternal pregnancy urine samples; 6 organochlorine compounds in maternal pregnancy serum; mercury in cord blood; and 6 polybrominated diphenyl ether congeners in colostrum. Among 470 children at 7 years, body mass index (BMI) z-scores were calculated, and overweight was defined as BMI > 85th percentile. We estimated associations with EDCs in single-pollutant models and applied principal-component analysis (PCA) on the 27 pollutant concentrations.

Results: In single-pollutant models, HCB (hexachlorobenzene), βHCH (β-hexachlorocyclohexane), and polychlorinated biphenyl (PCB) congeners 138 and 180 were associated with increased child BMI z-scores; and HCB, βHCH, PCB-138, and DDE (dichlorodiphenyldichloroethylene) with overweight risk. PCA generated four factors that accounted for 43.4% of the total variance. The organochlorine factor was positively associated with BMI z-scores and with overweight (adjusted RR, tertile 3 vs. 1: 2.59; 95% CI: 1.19, 5.63), and these associations were robust to adjustment for other EDCs. Exposure in the second tertile of the phthalate factor was inversely associated with overweight.

Conclusions: Prenatal exposure to organochlorines was positively associated with overweight at age 7 years in our study population. Other EDCs exposures did not confound this association.

Figure 1

Crude and adjusted associations [β coefficient (95% CI)] between maternal exposure to tertiles of 27 EDCs and child zBMI at age 7 years, single- pollutant models, for complete case and imputed data (n = 470). Abbreviations: As, arsenic; BDE, polybrominated diphenyl ethers congeners; βHCH, β-hexachlorocyclohexane; BPA, bisphenol A; Cd, cadmium; CI, confidence interval; DDE, dichlorodiphenyldichloroethylene; EDCs, endocrine-disrupting chemicals; HCB, hexachlorobenzene; Hg, Mercury; MBzP, monobenzyl phthalate; MEHHP, mono(2-ethyl-5-hydroxyhexyl) phthalate; MEHP, mono(2-ethylhexyl) phthalate; MEOHP, mono(2-ethyl-5-oxohexyl) phthalate; MEP, mono-ethyl phthalate; MiBP, monoisobutyl phthalate; MnBP, mono-n-butyl phthalate; Pb, lead; MCMHP, mono(2-carboxyhexyl) phthalate; MECPP, mono(2-ethyl-5-carboxypentyl) phthalate; 7OHMMeOP, mono(4-methyl-7-hydroxyoctyl) phthalate; PCBs, polychlorinated biphenyl congeners; zBMI, body mass index z-score.