Prenatal Exposure to Organophosphorous Pesticides and Fetal Growth: Pooled Results from Four Longitudinal Birth Cohort Studies

BACKGROUND: Organophosphorous (OP) pesticides are associated with reduced fetal growth in animals, but human studies are inconsistent. OBJECTIVES: We pooled data from four cohorts to examine associations of prenatal OP exposure with birth weight (n = 1,169), length (n = 1,152), and head circumference (n = 1,143). METHODS: Data were from the CHAMACOS, HOME, Columbia, and Mount Sinai birth cohorts. Concentrations of three diethyl phosphate (Sigma DEP) and three dimethyl phosphate (Sigma DMP) metabolites of OP pesticides [summed to six dialkyl phosphates (Sigma DAPs)] were measured in maternal urine. Linear regression and mixed-effects models were used to examine associations with birth outcomes. RESULTS: We found no significant associations of Sigma DEP, Sigma DMP, or Sigma DAPs with birth weight, length, or head circumference overall. However, among non-Hispanic black women, increasing urinary Sigma DAP and Sigma DMP concentrations were associated with decreased birth length (beta = -0.4 cm; 95% CI: -0.9, 0.0 and beta = -0.4 cm; 95% CI: -0.8, 0.0, respectively, for each 10-fold increase in metabolite concentration). Among infants with the PON1(192RR) genotype, Sigma DAP and Sigma DMP were negatively associated with length (beta = -0.4cm; 95% CI: -0.9, 0.0 and beta = -0.5cm; 95% CI: -0.9, -0.1). CONCLUSIONS: This study confirms previously reported associations of prenatal OP exposure among black women with decreased infant size at birth, but finds no evidence of smaller birth weight, length, or head circumference among whites or Hispanics. Contrary to our hypothesis, we found stronger inverse associations of DAPs and birth outcome in infants with the less susceptible PON1192RR genotype. The large pooled data set facilitated exploration of interactions by race/ethnicity and PON1 genotype, but was limited by differences in study populations.