LOW-LEVEL PRENATAL LEAD-EXPOSURE AND NEUROBEHAVIORAL DEVELOPMENT OF CHILDREN IN THE FIRST-YEAR OF LIFE - A PROSPECTIVE-STUDY IN SHANGHAI

We used a prospective study design to assess the effects of prenatal l ow-level lead exposure on the development of urban, inner-city childre n in Shanghai. Umbilical cord blood samples were consecutively collect ed from 605 live newborns. Two hundred and fifty-seven samples were ex cluded from the study due to clotting. Lead levels were determined on 348 cord blood samples, The geometric mean was 9.2 mu g/dl. Based on t heir cord blood lead levels, infants were classified into two exposure groups: 104 in a relatively low lead group (lead levels less than or equal to 30 percentile), and 104 in a relatively high lead group (lead levels greater than or equal to 70 percentile). Seventy-five subjects failed to complete the study, and 133 babies were included in the fin al cohort: 69 babies in the high lead group and 64 in the low lead gro up. At 3, 6, and 12 months, the Bayley Scales of Infant Development we re administered and capillary blood lead levels were measured, Detaile d information was obtained on a wide range of variables relevant to in fant development, At all three ages, the Mental Development Index (MDI ) scores, adjusted for confounders, were inversely related to the infa nts' cord blood lead levels. The difference of the mean adjusted NIDI scores between low and high lead groups was 3.4 at 3 months, 6.3 at 6 months, and 5.2 at 12 months of age. These differences were statistica lly significant at all time points. No significant association between cord blood lead levels and the Psychomotor Development Index (PDI) sc ores was detected at all three visits after adjustment for confounders . Postnatal lead levels were unrelated to concurrent developmental sta tus. We conclude that prenatal low-level lead exposure, which is relat ively common in Shanghai, is associated with an adverse developmental impact on children through the first year of life. (C) 1998 Academic P ress.