Editorial Geographic Determinants of Stroke Mortality Role of Ambient Air Pollution

Where survivors of stroke live may make a difference intheir clinical outcomes, including long-term mortality. A large body of supportive evidence from epidemiological studies has demonstrated that a geographic difference in stroke mortality is nonartifactual, although both its presence and magnitude are likely scale dependent at different popu-lation levels.1 For instance, since at least the 1940s, there has been a consistent pattern of marked geographic variation in stroke mortality within the United States, with very high rates reported in the southeast Atlantic coastal plain and very low rates in the mountain census division.2 By the mid 1990s, despite minor geographic shifts, such regional differences in stroke mortality had persisted for more than half a century, yet the underlying causes of geographic disparities remained elusive.3 In 2001, the REasons for Geographic And Racial Differences in Stroke study was launched.4 This landmar