Lead chelation, Blood lead levels & mortality
METHODS: To evaluate the association of lead exposure and mortality in the United States, we used the recently released mortality follow-up data for participants of the Second National Health and Nutrition Examination Survey, a national cross-sectional survey of the general population conducted from 1976 to 1980.
RESULTS: After adjustment for potential confounders, individuals with baselineblood lead levels of 20 to 29 microg/dL (1.0-1.4 micromol/L) had 46% increased all-cause mortality (rate ratio [RR], 1.46; 95% confidence interval [CI], 1.14-1.86), 39% increased circulatory mortality (RR, 1.39; 95% CI, 1.01-1.91), and 68% increased cancer mortality (RR, 1.68; 95% CI, 1.02-2.78) compared with those with blood lead levels of less than 10 microg/dL (<0.5micromol/L). All-cause mortality for those with blood lead levels of 10 to 19 microg/dL (0.5-0.9 micromol/L) was intermediately increased and not statistically significant (RR, 1.17; 95% CI, 0.90-1.52).
CONCLUSIONS: Individuals with blood lead levels of 20 to 29 micro g/dL in 1976 to 1980 (15% of the US population at that time) experienced significantly increased all-cause, circulatory, and cardiovascular mortality from 1976 through 1992. Thus, we strongly encourage efforts to reduce lead exposure for occupationally exposed workers and the 1.7 million Americans with blood lead levels of at least 20 micro g/dL (> or = 1.0 micromol/L).