Abstract P076: Genetic Predisposition to Hemoglobin A1 c , Postpartum Weight Reduction, and Glycemic Changes: A Longitudinal Study in Women With Prior Gestational Diabetes

Abstract

Introduction: Hemoglobin A 1c (HbA 1c ) is a common marker for glycemic control and a major risk factor for diabetes and cardiovascular disease. Hypothesis: We examined whether the genetic variation predisposing to HbA 1c affected glycemic changes in women with prior gestational diabetes mellitus (GDM) and whether such an effect was modified by changes in body adiposity, especially during and after pregnancy. Methods: This is a longitudinal study in Tianjin, China. We genotyped 10 genome-wide association study-identified HbA 1c single nucleotide polymorphisms and assessed weight at 1 to 5 years postpartum and changes in glycemic traits in 1156 women with prior GDM. The genetic risk score was calculated based on 10 HbA 1c -associated loci. Main Outcome Measures: The main outcome measure was postpartum glycemic changes. Results: The HbA 1c genetic risk score significantly interacted with postpartum weight reduction on changes in 2-h glucose and HbA 1c (P for interaction = 0.02 and 0.03; respectively) after multivariable adjustment. In women with postpartum weight reduction of ≥8kg/y, the genetic risk score was associated with decreased HbA 1c . The association between postpartum weight reduction and glycemic improvement was more significant among women with a lower genetic risk score. Conclusions: In a large cohort of Chinese women with a history of GDM, our data for the first time indicate that the genetic predisposition to HbA 1c may interact with postpartum weight reduction on long-term glycemic changes. Figure 1. Changes in glycemic traits according to weight reduction and HbA 1C genetic risk score tertiles.