PRENATAL MOLYBDENUM EXPOSURE AND INFANT NEURODEVELOPMENT IN MEXICO

Abstract

Background: Molybdenum (Mo) is an essential dietary nutrient in humans and animals. Possible adverse health effects on human beings are not well studied. Objectives: To evaluate the association between prenatal Mo exposure and neurodevelopment in Mexican children, during the first postnatal 30 months. Methods: In 2000-2009 we performed a cohort study in Mexico to evaluate prenatal organochlorine exposure and child neurodevelopment. Each mother was monitored throughout pregnancy and interviewed about diet and health aspects of her pregnancy evolution; from each we obtained a spot urine sample in at least one trimester. We evaluated Mental (MI) and Psychomotor indexes (PMI) of the Bayley Scales for Infant Development of children from 1 to 30 months of age without perinatal complications. For this report, maternal Mo urine concentrations were determined by electrothermal atomic absorption spectrometry in a random subset (n=147) and were adjusted by creatinine concentration. Separate generalized mixed effects models by each trimester estimated the effect of Mo exposure on MI and PMI , adjusting for quality of the home environment, maternal IQ, birth weight, sex, and maternal lead levels. Results: Throughout pregnancy Mo geometric means ranged from 45.6 a 54.0 (mu)g/g and 15% of women had Mo concentrations higher than P95 reported by NHANES for women. Doubling of Mo concentration ((mu)g/g) during the 3rd trimester was associated with a reduction (Beta=-0.57; p=0.03) of PMI and no effect on MI (Beta=0.07; p=0.66). Conclusions: This is the first report suggesting a negative association between prenatal Mo exposure and infant neurodevelopment. Mo levels observed are similar to those reported by CDC and a recent study with Mexican children. Larger studies are needed to confirm these findings.