Genetic Predisposition to Polycystic Ovary Syndrome, Postpartum Weight Reduction, and Glycemic Changes: A Longitudinal Study in Women With Prior Gestational Diabetes.

CONTEXT Polycystic ovary syndrome (PCOS) is a common condition in reproductive-aged women and a major female-specific risk factor of obesity, impaired glucose tolerance, and diabetes. OBJECTIVE We examined whether the genetic variation predisposing to PCOS 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. DESIGN, SETTING, AND PARTICIPANTS This is a longitudinal study in Tianjin, China. We genotyped 7 genome-wide association study-identified PCOS single nucleotide polymorphisms and assessed gestational weight gain and changes in glycemic traits and weight at 1 to 5 years postpartum in 1133 women with prior GDM. MAIN OUTCOME MEASURES The main outcome measure was postpartum glycemic changes. RESULTS The PCOS genetic risk score significantly interacted with postpartum weight reduction on changes in fasting glucose and 2-h glucose (P for interaction = .032 and .007; respectively) after multivariable adjustment. In women with postpartum weight reduction of ≥ 5 kg/y, the genetic risk score was associated with decreased fasting and 2-h glucose, whereas an opposite genetic effect was found in women who lost less weight. The association between postpartum weight reduction and glycemic improvement was more significant among women with a higher 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 PCOS may interact with postpartum weight reduction on long-term glycemic changes, emphasizing the importance of postpartum weight management in prevention of diabetes in this subgroup of women.