Project Summary (1995-2000)

It is the objective of this project to pursue indirect lines of evidence suggesting that the resorption of bone that accompanies aging can entail the heightened release of lead into a circulating pool that may contribute to the adverse cognitive effects associated with aging. These in vivo studies of bone lead stores are being performed using the K-x-ray (K-XRF) fluorescence instrument located at the Clinical Research Center of the Brigham and Women's Hospital. Prospective measurements of bone lead levels in the men and women who participate in the Normative Aging and the Nurses Health Studies are made. For both men and women during the life of this project, researchers will be able to collect at least a second and third observation of data, including bone lead, blood lead, dietary assessments, and urinary measures of bone turnover. Researchers are also adding a one-hour battery of neuropsychological tests to the regular evaluations in order to assess cognitive functioning. Determinations of the relative contributions of bone lead vs. environmental lead exposure to blood lead, change in blood lead over time, the modifying effect of age-associated bone turnover, and bone lead as a predictor of performance on neuropsychological testing is being made. In addition, scientists are examining a secondary hypotheses regarding the modifying influences of dietary calcium and polymorphism of the ALAD gene on these relationships.