Black-white differences in blood pressure among participants in NHANES II: the contribution of blood lead.

Separate studies using data from the second National Health and Nutrition Examination Survey, 1976-1980 (NHANES II) have shown that blacks in the United States have higher blood lead levels than whites and that blood lead is positively related to blood pressure. Based on these reports, we examined data from NHANES II to determine the extent to which race differences in blood pressure were explained by elevated blood lead levels in blacks. Regression analyses, with race as an indicator variable, were used to estimate the contribution of blood lead to black-white differences in blood pressure. The overall effect of blood lead on race differences in blood pressure was small, reflecting, in part, the magnitude of race differences in blood lead and in the association of blood lead and blood pressure. Nevertheless, a pronounced and consistent effect of lead on race differences in blood pressure was found among the poor, particularly women.