Longitudinal Changes in Bone Lead Levels The VA Normative Aging Study

Objective: Bone lead is a cumulative measure of lead exposure that can also be remobilized. We examined repeated measures of bone lead over 11 years to characterize long-term changes and identify predictors of tibia and patella lead stores in an elderly male population. Methods: Lead was measured every 3 to 5 years by k-x-ray fluorescence and mixed-effect models with random effects were used to evaluate change over time. Results: A total of 554 participants provided up to four bone lead measurements. Final models predicted a -1.4% annual decline (95% CI: -2.2 to -0.7) for tibia lead and piecewise linear model for patella with an initial decline of 5.1% per year (95% CI: -6.2 to -3.9) during the first 4.6 years but no significant change thereafter (-0.4% [95% CI: -2.4 to 1.7]). Conclusions: These results suggest that bone lead half-life may be longer than previously reported.