Gestational Diabetes and the Incidence of Type 2 Diabetes

A systematic review

  1. Catherine Kim, MD, MPH1,
  2. Katherine M. Newton, PHD2 and
  3. Robert H. Knopp, MD3
  1. 1Division of General Internal Medicine, University of Michigan, Ann Arbor, Michigan
  2. 2Center for Health Studies, Group Health Cooperative, Seattle, Washington
  3. 3Division of Metabolism, Endocrine and Nutrition, University of Washington, Seattle, Washington

    Abstract

    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.

    Footnotes

    • Address correspondence and reprint requests to Catherine Kim, 300 NIB, Room 7C27, Box 0429, Ann Arbor, MI 48109. E-mail: cathkim{at}umich.edu.

      Received for publication 30 December 2001 and accepted in revised form 27 June 2002.

      A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.

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