Two surprising risk factors - diminished lung function and low serum potassium levels - appear to have nearly the same impact as obesity in explaining why African-Americans are disproportionately prone to developing type 2 diabetes

The finding clarifies some of the large racial disparities associated with diabetes risk and provides potential new avenues for developing treatments. According to estimates from the National Health and Nutrition Exam Survey (NHANES), the prevalence of diabetes is 70% higher among African-Americans than non-Hispanic whites. Traditional risk factors such as obesity, socio-economic status, diet and behavioral factors account for some of the racial disparities, but not all. Researchers analyzed data from nearly 11,200 people with type 2 diabetes, including 8,840 whites and 2,322 African-Americans. Among the African-Americans, many well-known distinctions emerged: there were more women; they were heavier; they had higher blood pressure; and they were more likely to have lower incomes. Those and other known risk factors accounted for about 42% of the increased tendency for type 2 diabetes among African-Americans. Other, less well-known factors also surfaced, notably low lung function and lower serum potassium levels among the African-Americans who developed diabetes. Compared to obesity, which accounts for a 22% increased risk of developing diabetes, low lung function (measured as forced vital capacity) was nearly equally culpable, accounting for a 21.7% increased risk among the African-American diabetes patients. Low serum potassium levels accounted for 17.7% of the increased risk. It is unclear what role reduced lung function and low potassium levels might play in type 2 diabetes; whether they are markers, causes or consequences of the disease needs additional study. Both factors are typically different among African-Americans and whites.