A Longitudinal Study of Low-Level Lead Exposure and Impairment of Renal Function

OBJECTIVE: To determine whether low-level lead exposure is associated with impaired renal function. DESIGN: Retrospective cohort study. SETTING AND PARTICIPANTS: Subjects were 459 men randomly selected from the participants of the Normative Aging Study who were originally recruited from healthy veterans in the greater Boston area in 1961 and were periodically examined at the Department of Veterans Affairs Outpatient Clinic every 3 to 5 years. We reconstructed blood lead concentrations for the period between 1979 and 1994 using samples of either archived red blood cells or fresh whole blood. MAIN OUTCOME MEASURES: Serum creatinine concentration. RESULTS: After adjustment for age, body mass index, smoking, alcohol consumption, educational level, and hypertension, blood lead concentration was positively and significantly associated with concurrent concentration of serum creatinine (P=.005). A 10-fold increase in blood lead level predicted an increase of 7 micromol/L (0.08 micrograms/dL) in serum creatinine concentration, which is roughly equivalent to the increase predicted by 20 years of aging. The association was also significant among subjects whose blood lead concentrations had never exceeded 0.48 micromol/L (10 micrograms/L) throughout the study period. The age-related increase in serum creatinine level was earlier and faster in the group with the highest-quartile levels of long-term lead exposure than in the group with the lowest-quartile levels. CONCLUSIONS: Low-level exposure to lead may impair renal function in middle-aged and older men. Longitudinal data suggest an acceleration of age-related impairment of renal function in association with long-term low-level lead exposure.