Relation of in utero lead exposure with insulin-like growth factor-I levels and neonatal anthropometric parameters

Our aim was to establish whether independent relationships exist between either anthropometric parameters or insulin-like growth factor-I (IGF-I) and cord blood lead levels in newborns. Umbilical cord blood samples and anthropometric data were obtained at delivery. Cord blood lead levels were analyzed by atomic absorption spectrophotometer. IGF-I levels were measured using RIA. Blood lead levels >or=100 microg/l were considered elevated in accordance with CDC guidelines. Data on all variables of interest were obtained for 54 term neonates. The mean cord blood lead level was 144+/-89 microg/l with a range of 51-355 microg/l. Twenty-nine (53.7%) neonates had blood lead levels >or=100 microg/l. However, only 5 (9.2%) of the neonates had blood lead levels of >or=250 microg/l. No statistically significant difference was found in case of anthropometric parameters and IGF-I levels between neonates with high lead levels (>or=100 microg/l) and with low lead levels (<100mug/l) in cord blood (p>0.05). There was a significant correlation between lead and birth weight in neonates with high lead levels (r: -0.49, p=0.01) but not other anthropometric data and IGF-I levels. A multivariate regression analysis using the full range of lead values adjusted for the relevant confounders such as gestational age and socioeconomic status was performed. In the model birth weight (p: 0.01, beta: -0.81), birth length (p: 0.05, beta: 0.41) and midarm circumferences (p: 0.05, beta: 0.30) were the best predictors of lead levels, with the total variance explained being 36%. Significant relationship was found between birth weight and lead burden in newborns. Whether serum lead level predicts the development of failure to thrive in these children remains to be determined in follow-up studies.