Recently, integrated network analysis has revealed dysregulation in the metabolism of mannose, an epimer of glucose, in individuals with severe obesity who do not have significant diabetes. It was also found that fasting plasma mannose levels (M0) are associated with insulin resistance independent of BMI. Since the association between mannose and insulin sensitivity (IS) in those with impaired glucose tolerance remains unknown, we aimed to investigate the association in individuals with varying degrees of glucose tolerance. Based on data of 75g OGTT in Japanese individuals without diabetic medication, individuals were classified as normal (NGT), impaired glucose tolerance (IGT), and diabetes (DM). In each group, 25 subjects were consecutively recruited [total 75 individuals, age: 65±11 (mean±SD); BMI: 24.9±3.8]. Matsuda index (MI) was calculated as an index of IS. M0 was assayed using HPLC. Normally-distributed loge-transformed (ln-) values were used for MI and leptin. Although fasting plasma glucose (G0), HbA1c, and ln-MI were significantly different among 3 groups, age, sex, BMI, and M0 were not different. In simple regression analysis, ln-MI was negatively correlated with BMI (NGT: r=-0.639, IGT: r=-0.466, DM: r=-0.613) and ln-leptin (NGT: r=-0.480, IGT: r=-0.447, DM: r=-0.593) in all 3 groups. Interestingly, although ln-MI was not significantly correlated with M0 in NGT (r=0.241, P=0.245) and IGT (r=-0.296, P=0.152), it was moderately and negatively correlated in DM (r=-0.626, P<0.001). In DM, ln-MI was slightly correlated with G0 (r=-0.484, P=0.014). In multiple regression analysis in DM, ln-MI was independently predicted by BMI (β=-0.400) and M0 (β=-0.426), accounting for 51.2% (P<0.001) of the variability, which was larger than that in the prediction by BMI alone (37.6%).
In conclusion, in our study, fasting plasma mannose was associated with insulin sensitivity independent of BMI in Japanese individuals with diabetes.
E. Amano: None. S. Funakoshi: None. K. Yoshimura: None. S. Hirano: None. S. Ohmi: None. Y. Terada: None. S. Fujimoto: None.