Age-related adiposity and beta-cell function: impact on prediabetes and diabetes prevalence in middle-aged and older Han Chinese adults.

PURPOSE: To investigate the effect of aging on the prevalence of prediabetes and diabetes, and the influence of aging on the associations among adipose mass, redistribution, ß cell function, and the prevalence of hyperglycaemia. METHOD: This urban-based cross-sectional study included 1033 Chinese Han people, aged 40-65 years. The abdominal subcutaneous fat area (SFA) and visceral fat area (VFA) were determined by magnetic resonance imaging. The prevalence rates of prediabetes and diabetes were analyzed according to age group (40-49, 50-59, and 60-65 years). The effects of aging on abdominal fat mass, adipose distribution, insulin action indexes were also assessed. RESULTS: Prediabetes and diabetes prevalence gradually increased with age. Both SFA and VFA increased, while SFA/VFA decreased, in the 50-59 and 60-65 years age groups compared to the 40-49 years group. Homeostatic model assessment of insulin resistance (HOMA-IR) increased with fat mass. Homeostatic model assessment of beta-cell function (HOMA-ß) and early-phase insulin secretion (∆I30/∆G30) were decreased in the 60-65 years group compared to the younger age groups. Increased age, VFA, and HOMA-IR, as well as decreased HOMA-ß, were risk factors for the development of prediabetes and diabetes. The associations between central obesity and the development of prediabetes and diabetes, but not the associations of SFA/VFA, HOMA-IR, and HOMA-ß with hyperglycaemia prevalence, weakened with age. CONCLUSIONS: The prevalence of prediabetes and diabetes increased with age. Central obesity may be related stronger to the development of hyperglycaemia in younger people.