β-Cell Function Declines Within the First Year Postpartum in Women With Recent Glucose Intolerance in Pregnancy
- Ravi Retnakaran, MD1,2,
- Ying Qi, MSC1,
- Mathew Sermer, MD3,
- Philip W. Connelly, PHD2,4,
- Anthony J.G. Hanley, PHD1,2,5 and
- Bernard Zinman, MD1,2
- 1Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, Toronto, Canada;
- 2Division of Endocrinology, University of Toronto, Toronto, Canada;
- 3Division of Obstetrics and Gynecology, Mount Sinai Hospital, Toronto, Canada;
- 4Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Canada;
- 5Department of Nutritional Sciences, University of Toronto, Toronto, Canada.
- Corresponding author: Ravi Retnakaran, .
OBJECTIVE Both gestational diabetes mellitus (GDM) and mild glucose intolerance in pregnancy identify women at increased risk of future type 2 diabetes. In this context, we queried whether metabolic changes that occur in the 1st year postpartum vary in relation to gestational glucose tolerance status.
RESEARCH DESIGN AND METHODS Three-hundred-and-ninety-two women underwent glucose challenge test (GCT) and oral glucose tolerance test (OGTT) in pregnancy followed by repeat OGTT at both 3 months' postpartum and 12 months' postpartum. The antepartum testing defined four gestational glucose tolerance groups: GDM (n = 107); gestational impaired glucose tolerance (GIGT) (n = 75); abnormal GCT with normal glucose tolerance (NGT) on OGTT (abnormal GCT NGT) (n = 137); and normal GCT with NGT on OGTT (normal GCT NGT) (n = 73).
RESULTS The prevalence of dysglycemia progressively increased across the groups from normal GCT NGT to abnormal GCT NGT to GIGT to GDM at both 3 months' postpartum (2.7% to 10.2% to 18.7% to 34.6%, P < 0.0001) and 12 months' postpartum (2.7% to 11.7% to 17.3% to 32.7%, P < 0.0001). Between 3 and 12 months' postpartum, the groups did not differ with respect to changes in waist circumference, weight, or insulin sensitivity. Importantly, however, they exhibited markedly different changes in β-cell function (Insulin Secretion-Sensitivity Index-2 [ISSI-2]) (P = 0.0036), with ISSI-2 declining in both the GDM and GIGT groups. Furthermore, on multiple linear regression analysis, both GDM (t = −3.06, P = 0.0024) and GIGT (t = −2.18, P = 0.03) emerged as independent negative predictors of the change in ISSI-2 between 3 and 12 months' postpartum.
CONCLUSIONS Women with GDM and GIGT exhibit declining β-cell function in the 1st year postpartum that likely contributes to their future diabetic risk.
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- © 2010 by the American Diabetes Association.
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