Objective: The objective of this study is to investigate the mobilization of lead from bone to blood (endogenous exposure) in a large epidemiologic population.
Methods: Study subjects were 776 participants in the Normative Aging Study. The subjects had their tibia lead, patella lead, blood lead, and urinary N-telopeptide (NTx) levels measured 1 to 4 times from 1991 to 2002. Regression models were estimated to quantify the association between tibia and patella lead and blood lead. We studied nonlinearity of the association, and explored possible factors that may modify it, including age and NTx levels.
Results and Conclusions: There is significant association between bone lead and blood lead, and the association is nonlinear. The nonlinear associations between blood lead and bone lead are not significantly modified by age and NTx.