WEIGHT HISTORY, GLUCOSE-INTOLERANCE, AND INSULIN LEVELS IN MIDDLE-AGED SWEDISH MEN

The association between weight history and glucose intolerance was exa mined in a cross-sectional study consisting of 3,128 Swedish men aged 35-56 years, 52 percent of whom had a family background of diabetes me llitus. Oral glucose tolerance testing detected 55 cases of type 2 (no n-insulin-dependent) diabetes and 172 cases of impaired glucose tolera nce. Among men with no family history of diabetes, the estimated odds ratios for impaired glucose tolerance associated with short (<5 years) and long (greater than or equal to 10 years) durations of obesity (bo dy mass index (weight (kg)/height(2) (m(2)) greater than or equal to 2 5.0) were 1.3 (95% confidence interval (Cl) 0.2-7.7) and 11.8 (95% CI 3.3-41.9), respectively. Among men with a family history of diabetes, the odds ratios were 2.0 (95% CI 0.8-4.7) and 4.0 (95% CI 1.8-9.1), re spectively. Corresponding estimates of the odds of type 2 diabetes, ad justed for family history of diabetes, were 1.9 (95% CI 0.5-7.1) and 7 .3 (95% CI 2.2-23.7), respectively. The odds of high (greater than or equal to 30.0 mU/liter) fasting insulin levels in subjects with impair ed glucose tolerance were 6.9 (95% CI 0.6-74.2) and 21.0 (95% CI 2.1-2 06.4) for short and long durations of obesity, respectively. Correspon ding estimated odds of low 2-hour insulin response (less than or equal to 71.9 mU/liter) were 0.7 (95% CI 0.2-2.9) and 3.3 (95% CI 1.2-8.9). Homeostasis model assessment of insulin resistance yielded an odds ra tio of 6.7 (95% CI 0.6-73.4) for a short duration of obesity and 20.0 (95% CI 2.0-200.6) for a long duration. Examination of beta-cell funct ion with homeostasis model assessment resulted in odds ratios of 0.2 ( 95% CI 0.0-1.6) and 2.0 (95% CI 0.7-5.4) for short and long durations of obesity, respectively. These data indicate that obesity decreases g lucose tolerance by way of progressively increased insulin resistance and, in the case of prolonged duration, by decreased insulin secretion as well.