Determinants of bone and blood lead levels among teenagers living in urbanareas with high lead exposure

Although lead has been extensively studied in children, its sources and eff ects remain unclear in adolescents. This study examined the relation of blo od and tibia bone lead levels to lead determinants. One hundred adolescents living in Mexico City and surrounding suburbs were studied. Blood lead was measured by atomic absorption spectroscopy, and tibia lead was measured by a K X-ray Fluorescence (KXRF) instrument. Blood lead ranged from 1.8 to 29 .2 mu g/dl, with a mean of 7.4 mu g/dl. Bone lead ranged from <1 to 44.82 p g Pb/g bone mineral, with a mean of 4.8 mu g Pb/g. Predictors of bone lead included higher traffic density near the home, mother's smoking history, an d time spent outdoors. Predictors of log-transformed blood lead included bo ne lead levels, male sex, use of lead-glazed ceramics, and living in Mexico City. Bone lead remained a significant predictor of blood lead after adjus ting for covariates in a final multivariate regression model. In our final model, a rise in bone lead from the middle of the lowest quintile to the mi ddle of the highest quintile (a difference of 21.6 mu g Pb/g) was associate d with an increase in blood lead of 1.2 mu g/dl. Our data suggest that in a ddition to current sources of environmental lead exposure, bone lead accumu lated over time constitutes a moderate source of circulating lead during ad olescence and may account for some of the adverse health effects documented in recent studies.