Proportion of Gestational Diabetes Mellitus Attributable to Overweight/Obesity Among South Asian Women: A Retrospective Cohort Study in Delhi, India.

To assess the variability in the population attributable fraction (PAF) of GDM to overweight/obesity and the relationship of BMI and GDM across three diagnostic criteria: IADPSG, NICE and Diabetes in Pregnancy Study Group India (DIPSI). The PAF of GDM to overweight/obesity and the relationship of GDM and BMI were estimated using Poisson regression models in a retrospective cohort of 4317 women who underwent GDM screening during the 2013-2017 period. Multiple linear regression models were applied to associate BMI with fasting, 1-h and 2-h plasma glucose values. The PAF of GDM to overweight/obesity for IADPSG, NICE and DIPSI criteria was 34.84%, 28.17% and 18.44%, respectively. There was a quadratic relationship between BMI and GDM for all criteria, and the peak BMI values for IADPSG, NICE and DIPSI criteria were 34.26, 33.28 and 32.01 kg/m2, respectively. The relationship between BMI and PG values was also quadratic, with peaks in FPG, 1-h and 2-h PG at BMI values of 40.91, 35.50 and 33.04 kg/m2, respectively. PAF of GDM to overweight/obesity among South Asian women varies by the GDM diagnostic criteria. The quadratic relationship between BMI and GDM probability and between BMI and plasma glucose values is a novel observation.