Continued decline in blood lead levels among adults in the United States: the National Health and Nutrition Examination Surveys

Abstract

Background: Declines in blood lead levels between 1976 and 1991 among US adults have been previously reported. More recent trends in blood lead levels and the association of lower blood lead levels with chronic disease have not been reported.

Methods: Data from 2 nationally representative cross-sectional surveys, the Third National Health and Nutrition Examination Survey conducted in 1988-1994 (n = 16,609) and the National Health and Nutrition Examination Survey conducted in 1999-2002 (n = 9961) were analyzed.

Results: The geometric mean blood lead level declined 41% from 2.76 microg/dL (0.13 micromol/L) in 1988-1994 to 1.64 microg/dL (0.08 micromol/L) in 1999-2002. The percentage of adults with blood lead levels of 10 microg/dL (0.48 micromol/L) or higher declined from 3.3% in 1988-1994 to 0.7% in 1999-2002 (P<.001). In 1999-2002, the multivariable-adjusted odds ratio of having a blood lead level of 10 microg/dL (0.48 micromol/L) or higher was 2.91 (95% confidence interval [CI], 1.74-4.84) and 3.26 (1.83-5.81) for non-Hispanic blacks and Mexican Americans, respectively, compared with non-Hispanic whites. After multivariable adjustment, persons in the highest quartile (>or=2.47 microg/dL [>or=0.12 micromol/L]) compared with those in the lowest quartile (<1.06 microg/dL [<0.05 micromol/L]) of blood lead levels were 2.72 (95% CI, 1.47-5.04) and 1.92 (95% CI, 1.02-3.61) times more likely to have chronic kidney disease and peripheral arterial disease, respectively. In addition, higher blood lead levels were associated with a higher multivariable-adjusted odds ratio of hypertension among non-Hispanic blacks and Mexican Americans.

Conclusions: Blood lead levels continue to decline among US adults, but racial and ethnic disparities persist. Higher blood lead levels remain associated with a higher burden of chronic kidney and peripheral arterial diseases among the overall population and with hypertension among non-Hispanic blacks and Mexican Americans.