Sex-specific modulation of circulating growth differentiation factor-15 in patients with type 2 diabetes and/or obesity

Objective: Growth differentiation factor-15 (GDF15), a key metabolic regulator, is associated with obesity and diabetes in which sex-specific differences have been reported. Thus, we assessed whether GDF15 could be dependent on sex in diabetes and/or obesity groups. Methods: We measured serum GDF15 levels by ELISA in eight lean women and men (n = 16), eight women and eight men having obesity (n = 16), eight women and eight men with type 2 diabetes (T2D, n = 16), and seven women and nine men with both diabetes and obesity (n = 16). Estimation of the difference in the means of each group was performed by two-way ANOVA. The interdependence of the different variates was addressed by multivariate analysis. Correlations between GDF15 levels and HOMA-IR, HbA1c, triglycerides, HDL, and LDL were explored by linear regression. Results: Being a woman and having obesity alone or in combination with diabetes decreased GD F15 serum levels (beta = -0.47, CI = -0.95, 0.00, P = 0.052; beta= -0.45, CI = -0.94, 0.05, P= 0.075). Diabetes independently of metformin treatment and obesity were not predictive of low GD F15 levels (beta = 0.10, CI = -0.36, 0.57, P = 0.7). Correlation analysis showed that HOMA-I R (r = 0.45, P = 0.008) and triglycerides (r = 0.41, P = 0.017) were positively correlated and HDL (r = -0.48, P = 0.005) was negatively correlated with GDF15 levels in men. Conclusions/interpretation: GDF15 level was significantly different between men and women, as well as between the groups. Sex and group interaction revealed that being a woman and having obesity alone or in combination with diabetes decreased GDF15 levels.