Sex- and age-related differences of metabolic parameters in impaired glucose metabolism and type 2 diabetes compared to normal glucose tolerance

Aims: This study analysed potential sex differences in glucose metabolism of European subjects with different degrees of glucose tolerance impairment. Methods: Subjects with impaired glucose metabolism, IGM (n = 735), or type 2 diabetes, T2DM (n = 415), were compared to subjects with normal glucose tolerance, NGT (n = 422), with similar BMI. For both males (M) and females (F), 50 years threshold was used for estimation of menopausal/andropausal state. Subjects underwent 75-g OGTT for measurements of insulin sensitivity (OGIS), beta-cell function (insulinogenic index, IGIC), and overall metabolic condition, disposition index (DI). Results: In IGM, OGIS did not change with age in both sexes, whereas marked reduction of IGIC was seen in F (p = 0.0003). In T2DM, again OGIS did not change with age, but M 50 yrs had reduced IGIC and DI (p < 0.002) compared to M < 50 yrs. Conclusions: IGM did not reveal relevant changes of insulin resistance with age, but early phase insulin release deteriorated, with higher change in women. T2DM men featured age-related deterioration of glucose metabolism. In women, sex advantage seen in NGT vanished in T2DM, since glucose metabolism was overall not different than in men, both young and elderly.