Racial differences in serum selenium concentration: analysis of US population data from the Third National Health and Nutrition Examination Survey.

Lower intake of the essential trace element selenium may be a risk factor for prostate cancer and other cancers. In the United States, many racial disparities in cancer incidence, such as the 61% higher incidence of prostate cancer among Blacks relative to Whites, remain unexplained. Using data from a large, nationally representative survey, the authors explored Black/White differences in serum selenium concentration. Mean serum selenium concentrations, both crude and adjusted for known predictors of serum selenium, were determined for 10,779 Black and White males and females aged >or=12 years who participated in the Third National Health and Nutrition Examination Survey (1988-1994). Crude mean serum selenium concentrations were 126.35 ng/ml for Whites and 118.76 ng/ml (approximately 6% lower) for Blacks. Adjustment for known serum selenium predictors, including a proxy for residence at the county level, reduced the racial disparity, although concentrations remained approximately 3% lower in Blacks than in Whites of both sexes (p<0.0001). The observation that Blacks had lower unadjusted and adjusted serum selenium concentrations relative to Whites is intriguing, given the racial disparity in incidence of prostate cancer and other cancers.