Non-insulin-dependent diabetes and 11-year mortality in Asian Indian and Melanesian Fijians.

Abstract

This study reports 11-year all-cause and cause-specific mortality rates according to baseline glucose tolerance for a population-based sample of adult Melanesian and Indian Fijians (n = 2638), first surveyed in 1980. Risk factors for all-cause and cardiovascular disease (CVD) mortality in subjects with non-insulin-dependent diabetes (NIDDM) are also described. The baseline survey included 75 g oral glucose tolerance tests, measurements of blood pressure, body mass index, and triceps skinfold, assays of plasma cholesterol and triglycerides, electrocardiograms, and details of smoking habits and physical activity. Mortality status was ascertained for 2546 subjects through surveillance of death certificates, medical records and interview of subjects (or relatives). Mortality rates were increased in diabetic men and women of both ethnic groups: relative risks compared to subjects without diabetes at baseline were 1.7 (CI:0.9-3.1) and 2.0 (1.1-3.7) in Melanesian and 4.2 (2.7-6.5), 3.2 (1.9-5.7) in Indian men and women, respectively. A large proportion of mortality among diabetic subjects was attributed to CVD (62%, 66% in Melanesian and 54%, 58% in Indian men and women, respectively). Mortality rates tended to be higher in Melanesians than Indians, except for diabetic men where Indians had higher total and cardiovascular disease rates. In contrast to non-diabetic Fijians, diabetic women of both ethnic groups lost their relative protection from coronary heart disease (CHD). Cox regressions for diabetic subjects showed age and fasting plasma glucose to be independent predictors of all-cause mortality in men, and age, body mass index (inversely) and systolic blood pressure in women, but lipid concentrations, and cigarette smoking were not related. After accounting for conventional CVD risk factors, diabetes conferred significantly increased risk of total, CVD, and CHD mortality. The mortality experience of Melanesian and Indian Fijians with NIDDM is similar to that documented in developed populations, with excess mortality due to cardiovascular causes.