Metabolic Rate in Individuals with a Predisposition to Type 2 Diabetes

Type 2 diabetes is a metabolic disease that is associated with an increased risk of cardiovascular disease. Studies have found that a decrease in metabolic rate may be a causative factor for the development of type 2 diabetes and may be present years before the development of the disease. PURPOSE: To determine if healthy, young individuals with a family history of type 2 diabetes (FH+) have lower resting energy expenditure (REE) compared to individuals who have no family history of type 2 diabetes (FH-). The FH+ group was denned as individuals who had a parent diagnosed with type 2 diabetes after the age of 35 years (n = 12). Individuals who did not have a grandparent or parent with type 2 diabetes were placed in the control group (n = 13). METHODS: Men and women between the ages of 18–30 years, who did not exercise, smoke and were not obese (BMI <32), were recruited to participate in this study. REE was determined using open circuit spirometry. REE was divided by body weight (BW) to control for differences in mass between individuals. Blood flow was measured in response to 4 and 10 minutes of cuff ischemia using quantitative Doppler Ultrasound. RESULTS: Comparisons between the experimental (FH+ and FH-) groups indicated that there was a significant difference on age (p = 0.003); thus, an ANCOVA was used for all between group measures. Comparisons between genders indicated that there were significant differences on 10 minute half time to recovery (p = 0.005) and REE (p <0.001). REE for women and men was not significantly different between the experimental groups. REE/BW was significantly lower in men with a family history of type 2 diabetes (21.3 ± 1.1 vs. 23.6 ± 2.4 for FH+ vs. FH-, respectively; p = 0.05), however, there was no difference between groups in women. There were no significant differences in blood flow between groups. Half time to recovery after a 10 minute cuff occlusion was prolonged in men and women with a family history of type 2 diabetes (8.4 and 43.4%, respectively; p = 0.057) but was not significantly different after a 4 minute cuff occlusion. CONCLUSIONS: Metabolic rate was reduced in young, healthy men with a family history of type 2 diabetes as evidenced by a reduced REE/BW. Half time to recovery after a 10 minute cuff was prolonged in men and women in the FH+ group. This prolonged half time to recovery could be due to a slower metabolic recovery or reduced vascular reactivity. Increased blood flow after 10 minutes of cuff occlusion, unlike the 4 minute cuff occlusion, is due in part to restoring phosphocreatine after ischemia. Thus, the prolonged recovery after 10 minutes of cuff occlusion in the FH+ group may indicate a slower metabolic recovery.