To the Editor: Lackland et al1 reported an association between Stroke Belt mortality and birthplace such that those born outside the Southeast had lower stroke rates than those born within this region and still lower rates when compared to those born in South Carolina, a finding more striking for blacks than for whites. Similar results have been reported for stroke mortality among blacks in New York City: the highest rates were for immigrants from the South.2 Lackland et al1 suggest that place of birth may be a useful area of investigation to illuminate the perplexing question of why stroke rates are so high in the southeastern United States. It is suggested here that examining black-white admixture rates in terms of geography may be one approach to understanding this question for the black population. Reed3 showed that the presence of white-derived genes among black populations in the United States is not geographically uniform, with the lowest …