Serum cholesterol levels in southwestern American Indians

Abstract

In an evaluation of 746 southwestern Indians, 70 non-southwestern Indians and 163 Caucasians, the mean serum cholesterol levels of both Indian groups were significantly lower than for the whites. The southwestern Indians were further characterized as a low serum cholesterol population by the lack of increasing blood cholesterol with aging. Some tribal differences were noted, with the Athapascan ethnic group (Apache and Navajo tribes) having higher mean circulating cholesterol values than the Hohokam (Pima and Papago tribes). Although the tribes in whom excessive body weight is most prevalent had lower mean serum cholesterol levels than those with less frequent occurrence of obesity, there was no significant correlation of the overweight status with blood cholesterol content in an individual evaluation of the two largest tribes studied—the Pima and Apache. The findings of this investigation suggest that some influence is operative among southwestern Indians, preventing progressive accumulation of cholesterol with aging, but this factor is unidentified. Perhaps an inherited mechanism exists, comparable to that which produces their partial lack of end-organ responsiveness to androgenic stimuli. A paucity of sustained, stressful, competitive, interpersonal activities may have relevance. Although most southwestern tribes apparently have a comparatively low fat diet, the fat they consume is predominantly of the saturated type. Evidence at present is insufficient to distinguish the role of heredity and environment, either in regard to the lower blood cholesterol levels of the Indians than for the Caucasians or in relation to the tribal variations in this serum lipid level.