Environmental exposure to metals and children's growth to age 5 years: a prospective cohort study.

In this prospective cohort study, based on 1,505 mother-infant pairs in rural Bangladesh, we evaluated the associations between early-life exposure to arsenic, cadmium, and lead, assessed via concentrations in maternal and child urine, and childrens weights and heights up to age 5 years, during the period 20012009. Concurrent and prenatal exposures were evaluated using linear regression analysis, while longitudinal exposure was assessed using mixed-effects linear regression. An inverse association was found between childrens weight and height, age-adjusted z scores, and growth velocity at age 5 years and concurrent exposure to cadmium and arsenic. In the longitudinal analysis, multivariable-adjusted attributable differences in childrens weight at age 5 years were 0.33 kg (95 confidence interval (CI): 0.60, 0.06) for high (95th percentile) arsenic exposure and 0.57 kg (95 CI: 0.88, 0.26) for high cadmium exposure, in comparison with children with the lowest exposure (5th percentile). Multivariable-adjusted attributable differences in height were 0.50 cm (95 CI: 1.20, 0.21) for high arsenic exposure and 1.6 cm (95 CI: 2.4, 0.77) for high cadmium exposure. The associations were apparent primarily among girls. The negative effects on childrens growth at age 5 years attributable to arsenic and cadmium were of similar magnitude to the difference between girls and boys in terms of weight (0.67 kg, 95% CI: 0.82, 0.53) and height (1.3 cm, 95% CI: 1.7, 0.89).