Diabetes in a northern Minnesota Chippewa Tribe. Prevalence and incidence of diabetes and incidence of major complications, 1986-1988.

The purpose of this study was to determine the prevalence and incidence of diabetes and the incidence of major diabetic complications, in a Chippewa Indian population. The format was a longitudinal population study that used active community and health center-based surveillance. The setting was an American Indian reservation community of 4,075 residents, served by an IHS clinic from 1986 to 1988. Patients were American Indians of Chippewa descent living on or near the Red Lake Reservation. Midway through the study, 346 people had been diagnosed with diabetes, which yielded an age- and sex-adjusted point prevalence of 148/1,000 population. The adjusted rate for individuals > or = 25 years of age was 252/1,000 population, 3.82 times the U.S. rate (Confidence Interval 2.95-4.93). Some 97 new cases of diabetes were identified for an age-and sex-adjusted average annual incidence of 17/1,000 population. The incidence of hospitalization for LEA was 26/1,000 diabetic person years, 4.3 times the 1978 U.S. rate (95%, CI 2.8-6.8). Twelve individuals developed proliferative retinopathy, for an incidence of 12/1,000 diabetic person years. Newly diagnosed ESRD incidence was 6/1,000 diabetic person years. Twenty-three acute myocardial infarctions were observed, yielding an incidence of 22/1,000 diabetic person years. Diabetes and its complications are prevalent in this Chippewa population, and further surveillance is needed to evaluate the effectiveness of prevention efforts.