Gestational exposure to organophosphate ester flame retardants and child growth in weight, height, and body mass index at age 2-10 years: the Environmental influences on Child Health Outcomes Program.

BACKGROUND

Pregnant women are widely exposed to organophosphate esters (OPEs). Few studies have examined how gestational OPE exposures may influence child growth rates, which are important predictors of subsequent cardiometabolic health.

METHODS

Among 4566 mother-child dyads from 14 sites within the Environmental influences on Child Health Outcomes (ECHO) Cohort, we evaluated associations of gestational urinary concentrations of nine OPE metabolites with early and mid-childhood rates of change in age- and sex-standardized weight (WAZ), height (HAZ), and body mass index (BMIZ). Using linear mixed models, we estimated associations between each OPE metabolite and each growth measure separately in early childhood (2-5 years; n = 4321) and mid-childhood (6-10 years; n = 2504). We evaluated effect modification by child sex and maternal pre-pregnancy BMI.

RESULTS

Rates of change in WAZ and HAZ during early childhood were higher per doubling of gestational bis(1,3-dichloro-2-propyl) phosphate (BDCPP) (WAZ: 0.003 SD-units/year; 95% CI 0.001, 0.005; HAZ: 0.005 SD-units/year, 95% CI 0.002, 0.007). During mid-childhood, gestational diphenyl phosphate (DPHP) was positively associated with the rate of change in BMIZ (0.011 SD-units/year, 95% CI 0.004, 0.017) and WAZ (0.007 SD-units/year, 95% CI 0.002, 0.013). Bis(1-chloro-2-propyl) phosphate (BCPP) was associated with lower rates of growth in both periods. Some positive associations with rates of growth in early childhood were stronger among females, and children of mothers with BMI<25 kg/m2.

DISCUSSION: In this large, diverse sample of U.S. children, gestational exposure to OPEs was associated with child growth rates, but the direction and magnitude differed by OPE biomarker and developmental period (early- or mid-childhood).