In vivo bone lead measurement in suburban teenagers

Objective. Bone represents a biologically active long-term storage site for lead, and bone lead data on teenagers are limited. Therefore, this study was designed to identify the distribution of bone lead in a teenage population and to explore the environmental and demographic factors associated with bone lead concentrations in young, nonoccupationally exposed subjects. Design. A cross-sectional study of bone lead levels in high school students. Participants. A total of 168 students at a suburban Boston high school. Subjects (90 boys, 78 girls) ranged in age from 13.5 to 19 years and included 40% nonwhite minorities. Of the 168 subjects, 45 lived in homes constructed before 1960. None of the participants reported a history of lead poisoning. Outcome Measures. Tibial bone lead concentrations were measured in vivo for 60 minutes using K x-ray fluorescence. Lead exposure information was obtained by self-administered questionnaire. Results. Point estimates of bone lead levels ranged from -7.15 to 14.23 mu g lead/g bone mineral (mu g/g), (mean, 4.0 mu g/g; standard deviation, 4.4 mu g/g). The reported measurement uncertainties accompanying each of the point estimates ranged from 2.56 to 9.01 mu g/g (mean, 3.9 mu g/g; standard deviation, 1.0 mu g/g). Bone lead levels were not associated with the demographic factors of age, sex, or race. Additionally, current home conditions (housing age, traffic level) were not predictive of bone lead levels, even though these factors were predictive of in-home lead concentrations. Conclusions. These results demonstrate that although bone lead levels are measurable in this age group, the common predictors of blood and bone lead concentrations are not explanatory for bone lead levels.