Mortality and Morbidity Associated With Body Weight in People With IDDM: The WHO Multinational Study of Vascular Disease in Diabetes

OBJECTIVE: Strict glycemic control in people with insulin-dependent diabetes mellitus (IDDM) reduces the risk of microvascular complications, but improvements in control are also associated with weight gain. Fears about the mortality risks of obesity may limit the acceptability of tight control. Therefore, we examined morbidity and mortality risks associated with body weight in people with IDDM. RESEARCH DESIGN AND METHODS: This was a cohort study of 644 men and 576 women with IDDM from nine centers worldwide. Baseline examinations were performed in 1975-1977, and mortality follow-up continued until 1988. RESULTS: Body weight was positively associated with blood pressure and, in men, with cholesterol. Fasting blood glucose was higher in the most obese groups in women only. There were 204 deaths among the men and 148 among the women. There was a reverse J-shaped relationship between body weight and all-cause mortality, with the highest mortality rates occurring in the leanest body mass index (BMI) category. The age-, duration-, and center-adjusted mortality rate ratio (95% confidence interval) comparing BMI category < 20 kg/m2 with BMI category > or = 22 and < 24 kg/m2 was 2.64 (1.59-4.38) in men and 1.54 (0.77-3.06) in women. Additional adjustment for smoking, blood pressure, glucose, cholesterol, and proteinuria did not qualitatively alter these findings. CONCLUSIONS: We conclude that except in very lean people with IDDM, body weight is not significantly associated with mortality. Thus, efforts to improve glycemic control should not be restricted by concerns about the effects of weight gain on mortality.