Care guidelines for people with non-insulin-dependent diabetes mellitus (NIDDM) emphasize the importance of weight loss in reducing mortality risk. However, existing evidence regarding the relationship between weight and mortality and the effects of weight change is conflicting. We examined these relationships in the World Health Organization Multinational Study of Vascular Disease in Diabetes.
This was a cohort study of 1,416 men and 1,544 women. Baseline examinations were performed in 1975 through 1977, a morbidity follow-up was performed in 1983, and a mortality follow-up continued until 1988. Data were analyzed according to geographical groups: Europeans, East Asians, and Native Americans. The relationship between weight change and mortality was analyzed for Europeans only.
Generally, body mass index (BMI) was positively associated with age, blood pressure, and cholesterol but was negatively associated with duration of diabetes, prevalence of retinopathy, and use of insulin. There was no clear relationship between BMI and mortality across the geographical groups. In Europeans, weight loss in the leanest subjects at baseline (BMI < 26 kg/m2) was associated with a threefold increase in mortality risk compared with those who had maintained a steady weight (relative risk [RR] 3.05, 95% confidence interval [CI] 1.26–7.36). Only in the most obese group was weight loss associated with a reduction in mortality risk (BMI > 29 kg/m2, RR 0.84, 95% CI 0.40–1.74).
The positive association of BMI with age, blood pressure, and cholesterol and the negative association with duration of diabetes, retinopathy, and use of insulin may explain why there is no strong relationship between BMI and mortality in NIDDM. Weight loss, particularly in the relatively lean diabetic person, may be associated with an increased mortality risk.