The Impact of a Family History of Type 2 Diabetes on Insulin Secretion and Insulin Sensitivity in Individuals With Varying Glucose Tolerance

IntroductionThis study was performed to investigate the impact of a family history of type 2 diabetes (T2DM) on insulin resistance and beta-cell dysfunction in populations with varying glucose tolerance.MethodsAmong the total of 142 participants, 73 subjects with no family history of T2DM (FH?) included 42 with normal glucose tolerance (NGT/FH?) and 31 with impaired glucose tolerance (IGT/FH?); and 69 first-degree relatives of patients with T2DM (FH+) included 36 with NGT (NGT/FH+) and 33 with IGT (IGT/FH+). Insulin resistance was evaluated by Insulin Sensitivity Index (ISI) based on the euglycemic hyperinsulinemic clamp. Islet beta-cell function was assessed by disposition index (DI) for the acute insulin response to glucose (AIRg) using intravenous glucose tolerance test. Metabolic data were compared between groups after adjustment for age, sex, body mass index and waist-to-hip ratio.ResultsThe NGT/FH+ group showed lower level of ISI (P = 0.023) than the NGT/FH? group, whereas no difference was found in AIRg or DI between these 2 subgroups. In the FH? individuals, both ISI and DI of the IGT/FH? group decreased compared with the NGT/FH? group (both P < 0.05). In the FH+ individuals, no difference was found in ISI between the IGT/FH+ and NGT/FH+ groups, whereas the IGT/FH+ group had a lower level of AIRg and DI than the NGT/FH+ group (both P < 0.0001).ConclusionsThis study showed that the pathophysiological changes were different between individuals with and without a family history of T2DM during the glucose tolerance aggravation.