Effects of chronic lead exposure on neurobehavioral development of Chileanlactating children

Background: Lactating children are specially susceptible to lead toxicity d ue to their underdeveloped nervous system, lower body mass, higher intestin al absorption and lower elimination rates. Aim: To determine the effects of lead exposure, comparing Chilean lactating children residing in rural area s with low lead exposure, and in urban areas with high lead exposure. Mater ial and methods: Newborns from public maternity hospitals of the rural loca lity of San Felipe and from Metropolitan Santiago, were recruited for the s tudy. On admission to the study, umbilical cord and maternal blood samples were obtained and an inquiry about perinatal, sociohereditary and lead expo sure history was done. Children were followed every 6 months until 24 month s of age, measuring blood parameters and neurobehavioral development using Bayley scales. Results: Three hundred twelve children from Santiago and 113 from San Felipe were studied. Maternal and children blood lead levels were higher in Santiago, but lower than those reported in other international s tudies. At 24 months of age, 4.5% of children from Santiago and 0.7% of chi ldren from San Felipe had levels over 10 mu g/dl. No differences in neurobe havioral development were observed between children of both cities. At 24 m onths, scores of MDI scales were 91 in Santiago and 97 in San Felipe. The f igures for PDI scale were 93 in Santiago and 93 in San Felipe. Main risk fa ctors for a retarded neurobehavioral development were socioeconomic level w ith a mean Odds ratio of 3.5 (0.99-12.4), male sex with an Odds ratio of 2. 3 (1.09-5.07) and stimulation at home with an Odds ratio of 0.7 (0.53-0.82. Conclusions In this cohort of children, no effect of lead levels on neurob ehavioral development was found.