Ethnic differences in BMI, subcutaneous fat, and serum leptin levels during and after pregnancy and risk of gestational diabetes

Objective: To explore the differences between Europeans and South Asians in BMI, subcutaneous fat, and serum leptin (s-leptin) levels during and after pregnancy and their relationship with gestational diabetes (GDM). Design: Multi-ethnic population-based cohort study, whereof 353 Europeans (93.1% of the included) and 190 South Asians (95.0% of the included). Methods: S-leptin, BMI, and subcutaneous fat (sum of triceps, subscapular, and suprailiac skinfolds) were measured at 14 and 28 weeks of gestation, and 14 weeks after delivery. GDM was diagnosed with the WHO criteria 2013. Results: South Asians had similar thickness of the triceps and suprailiac skinfolds, thicker subscapular skinfold, and higher s-leptin than Europeans in early pregnancy, despite lower BMI. South Asians retained more subcutaneous fat (mean (95% CI) 10.0 (7.4-12.7) mm vs 3.8 (1.9-5.8) mm) and BMI (1.5 (1.2-1.8) kg/m(2) vs 0.1 (-0.1 to 0.3) kg/m(2)) than Europeans 14 weeks after delivery and s-leptin decreased less in South Asians than Europeans (-0.13 (-0.27 to -0.00) mu g/l vs -0.47 (-0.57 to -0.37) mu g/l, P < 0.001 for all). The prevalence of GDM was 23.8% (n=84) in Europeans and 42.6% (n=81) in South Asians. BMI, subcutaneous fat, and s-leptin were all positively associated with GDM, also after adjustment for covariates. Conclusions: The relatively high amounts of subcutaneous fat and s-leptin in South Asians in early pregnancy contributed to their increased risk of GDM. South Asians retained more weight and subcutaneous fat after delivery, potentially increasing their risk of adiposity and GDM in future pregnancies.