Prenatal Phthalate Exposure and Childhood Growth and Blood Pressure: Evidence from the Spanish INMA-Sabadell Birth Cohort Study

BACKGROUND: Human evidence on the effects of early life phthalate exposure on obesity and cardiovascular disease risks, reported by experimental studies, is limited to a few cross-sectional studies. OBJECTIVES: We evaluated the associations between prenatal phthalate exposure and childhood growth and blood pressure in a Spanish birth cohort study. METHODS: We assessed exposure using the average of two phthalate metabolite spot-urine concentrations collected from the mothers in the first and third pregnancy trimesters (creatinine-adjusted, n = 391). Study outcomes were the difference in age- and sex-specific z-scores for weight between birth and 6 months of age; and repeated age- and sex-specific z-scores for body mass index (BMI) at 1, 4, and 7 years; waist-to-height ratio at 4 and 7 years; and age- and height-specific z-scores for systolic and diastolic blood pressure at 4 and 7 years. RESULTS: The sum of five high-molecular-weight phthalate metabolites (ΣHMWPm) was associated with lower weight z-score difference between birth and 6 months (β per doubling of exposure = -0.41; 95% CI: -0.75, -0.06) and BMI z-scores at later ages in boys (β = -0.28; 95% CI: -0.60, 0.03) and with higher weight z-score difference (β = 0.24; 95% CI: -0.16, 0.65) and BMI z-scores in girls (β = 0.30; 95% CI: -0.04, 0.64) (p for sex interaction = 0.01 and 0.05, respectively). The sum of three low-molecular-weight phthalates (ΣLMWPm) was not significantly associated with any of the growth outcomes. ΣHMWPm and ΣLMWPm were associated with lower systolic blood pressure z-scores in girls but not in boys. CONCLUSIONS: This study suggests that prenatal phthalate exposure may be associated with postnatal growth and blood pressure in a sex-specific manner. Inconsistencies with previous cross-sectional findings highlight the necessity for evaluating phthalate health effects in prospective studies.This study was funded by grants from the RecerCaixa (Register no. 2010ACUP00349), the “Instituto Carlos III” (Red INMA G03/176, CB06/02/0041 and predoctoral grant PFIS 2010, Register no. FI10/00399), the Spanish Ministry of Health (FIS-PI041436, FIS-PI081151), the Generalitat de Catalunya-CIRIT (1999SGR 00241), and the Fundació Roger Torn