Hypertension and low-level lead exposure: a scientific issue or a matter of faith?

Abstract

To the Editor: Vupputuri et al1 analyzed the NHANES III data. They reported that among blacks, a 3.3 μg/dL increment in the blood lead concentration was associated with an increase in systolic pressure averaging 0.82 mm Hg in men and 1.55 mm Hg in women. In contrast, blood pressure was not associated with the blood lead level among white men and women. We analyzed the same NHANES III database.2 In line with Vupputuri’s article, we also found a significant and positive relationship between systolic blood pressure and the blood lead concentration in blacks. On the other hand, our analyses revealed significant and negative associations between diastolic pressure and blood lead in whites. We concluded that, across the NHANES III race and sex strata, the relationship between blood pressure and lead exposure was not consistent and should probably be attributed to residual confounding rather than to causation. Vupputuri et al emphasized the …