Despite a higher prevalence of overweight/obesity in Black South African women compared to men, the prevalence of type 2 diabetes (T2D) does not differ. We explored if this could be due to sex differences in insulin sensitivity, clearance and/or beta-cell function and also sex-specific associations with total and regional adiposity.
This cross-sectional study included 804 Black South African men ( n = 388) and women ( n = 416). Dual-energy X-ray absorptiometry was used to measure total and regional adiposity. Insulin sensitivity (Matsuda index), secretion (C-peptide index) and clearance (C-peptide/insulin ratio) were estimated from an oral glucose tolerance test.
After adjusting for sex differences in the fat mass index, men were less insulin sensitive and had lower beta-cell function than women ( P < 0.001), with the strength of the associations with measures of total and central adiposity being greater in men than women ( P < 0.001 for interactions). Further, the association between total adiposity and T2D risk was also greater in men than women (relative risk ratio (95% CI): 2.05 (1.42–2.96), P < 0.001 vs 1.38 (1.03–1.85), P = 0.031).