Diabetes in American Indians and other native populations of the New World.

Abstract

This is a review of previous and more recent observations on the prevalence and manifestations of diabetes in aboriginal populations of the New World. Rates of diabetes have now been measured or estimated in more than eighty of these groups in the Americas, Greenland, Polynesia, Micronesia and Melanesia. Diabetes was probably uncommon in all these native populations prior to 1940. It is now rife in many of these groups, but still rare in many. Among certain of these populations, rates of diabetes in adults still differ more than tenfold. Among groups of diabetics there are probably significant intertribal differences in the susceptibility to certain manifestations and complications such as retinopathy and coronary disease. There appear to be peculiarities in the insulin secretion patterns of certain of these tribes. The available evidence does not rule out the possibility that genetic factors play an important role in determining inter-tribal differences in prevalence and manifestations. But it is also clear that environmental factors exert powerful effects. Low rates of diabetes have been observed in Athapascan tribes and in some Shoshonean tribes. Diabetes was also rare prior to 1940 in Athapascan and Shoshonean Indians of Oklahoma. But diabetes has recently become common in these Oklahoma tribes. They were formerly lean and are now fat. The status of the many Oklahoma tribes is of particular interest because they represent seven of the eight major linguistic groups of North American Indians, having originated in very diverse parts of the Continent. Rates are now high in all Oklahoma tribes for which evidence is adequate to permit an estimate of prevalence. This includes fifteen tribes drawn from seven different linguistic groups. In seven additional Oklahoma tribes preliminary evidence, although less complete, suggests the probability that rates are also high. Studies of the dramatic emergence of diabetes and its manifestations in these aboriginal groups has considerable potential for gaining a better understanding of the genetic and environmental factors which influence risk and pathophysiology of diabetes and its complications.