Indexed on: 08 Sep '16Published on: 08 Sep '16Published in: Diabetes
Zinc transporter-8 (SLC30A8) genetic variant has been associated with postpartum risk of type 2 diabetes among women with gestational diabetes mellitus (GDM). Gestational weight gain is one of the strongest risk factors for postpartum hyperglycemia. We assessed the interaction between type 2 diabetes-associated SLC30A8 rs13266634 and gestational weight gain on 1-5 years postpartum glycemic changes in 1071 women with prior GDM in a longitudinal study. Compared with gestation 26-30 weeks, postpartum levels of fasting glucose, oral glucose tolerance test 2-h glucose, and hemoglobin A1c (HbA1c) increased across rs13266634 TT, CT, and CC genotypes in women with excessive gestational weight gain; whereas opposite genetic associations were found in women with inadequate or adequate gestational weight gain. Postpartum changes in fasting glucose per additional copy of the C allele were -0.18, -0.04, and 0.12 mmol/L in women with inadequate, adequate, and excessive gestational weight gain, respectively (P for interaction =0.002). We also found similar interactions for changes in 2-h glucose and HbA1c (P for interaction =0.003 and 0.005, respectively). Our data indicate that gestational weight gain may modify SLC30A8 variant on long-term glycemic changes, highlighting the importance of gestational weight control in prevention of postpartum hyperglycemia in women with GDM.