Gestational Diabetes and the Incidence of Type 2 Diabetes
A systematic review
- 1Division of General Internal Medicine, University of Michigan, Ann Arbor, Michigan
- 2Center for Health Studies, Group Health Cooperative, Seattle, Washington
- 3Division of Metabolism, Endocrine and Nutrition, University of Washington, Seattle, Washington
OBJECTIVE—To examine factors associated with variation in the risk for type 2 diabetes in women with prior gestational diabetes mellitus (GDM).
RESEARCH DESIGN AND METHODS—We conducted a systematic literature review of articles published between January 1965 and August 2001, in which subjects underwent testing for GDM and then testing for type 2 diabetes after delivery. We abstracted diagnostic criteria for GDM and type 2 diabetes, cumulative incidence of type 2 diabetes, and factors that predicted incidence of type 2 diabetes.
RESULTS—A total of 28 studies were examined. After the index pregnancy, the cumulative incidence of diabetes ranged from 2.6% to over 70% in studies that examined women 6 weeks postpartum to 28 years postpartum. Differences in rates of progression between ethnic groups was reduced by adjustment for various lengths of follow-up and testing rates, so that women appeared to progress to type 2 diabetes at similar rates after a diagnosis of GDM. Cumulative incidence of type 2 diabetes increased markedly in the first 5 years after delivery and appeared to plateau after 10 years. An elevated fasting glucose level during pregnancy was the risk factor most commonly associated with future risk of type 2 diabetes.
CONCLUSIONS—Conversion of GDM to type 2 diabetes varies with the length of follow-up and cohort retention. Adjustment for these differences reveals rapid increases in the cumulative incidence occurring in the first 5 years after delivery for different racial groups. Targeting women with elevated fasting glucose levels during pregnancy may prove to have the greatest effect for the effort required.
- GDM, gestational diabetes mellitus
- NDDG, National Diabetes Data Group
- OGTT, oral glucose tolerance test
- WHO, World Health Organization
Address correspondence and reprint requests to Catherine Kim, 300 NIB, Room 7C27, Box 0429, Ann Arbor, MI 48109. E-mail:.
Received for publication 30 December 2001 and accepted in revised form 27 June 2002.
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