Impact of NIDDM on Mortality and Causes of Death in Pima Indians

Abstract

OBJECTIVE To compare overall and cause-specific death rates for diabetic and nondiabetic Pima Indians. RESEARCH DESIGN AND METHODS This community-based study determined overall and cause-specific death rates in persons with and without NIDDM in the Pima population. Underlying causes of death for the 10-yr period from 1975 to 1984 were derived from review of death certificates and medical records. Diabetes diagnoses were based on an ongoing diabetes study initiated by the National Institutes of Health in 1965. RESULTS Of the 512 deaths, 241 were in Pima Indians with NIDDM; 203 (84%) of the deaths in diabetic subjects were attributed to natural causes (46 diabetic nephropathy, 35 IHD, 29 infections, 20 malignant neoplasms, 20 alcoholic liver disease, 18 stroke, 35 other causes). For natural causes, the overall age-sex-adjusted death rate in diabetic subjects was 1.7 times (95% CI 1.4–2.2) that in nondiabetic subjects. Longer duration of diabetes was significantly related to mortality, an association that was stronger in women than in men. Rates of death from diabetic nephropathy, IHD, and infections (but not stroke) were each significantly related to longer diabetes duration. Together, diabetic nephropathy and IHD accounted for 90% of the excess death rate among diabetic, compared with nondiabetic, Pimas. CONCLUSIONS In Pima Indians, NIDDM has a significant adverse effect on death rates that is directly related to diabetes duration, especially for deaths from diabetic nephropathy, IHD, or infections. Among the Pima, diabetic nephropathy is the leading cause of death, and IHD ranks second—a variation from other populations (in which IHD ranks first), probably partly attributable to a much younger age of onset of diabetes among the Pima than in the U.S. white population.