Does Coffee Consumption Reduce the Risk of Type 2 Diabetes in Individuals With Impaired Glucose?

  1. Besa Smith, MPH,
  2. Deborah L. Wingard, PHD,
  3. Tyler C. Smith, MS,
  4. Donna Kritz-Silverstein, PHD and
  5. Elizabeth Barrett-Connor, MD
  1. From the Division of Epidemiology, Department of Family and Preventive Medicine, University of California San Diego, La Jolla, California
  1. Address correspondence and reprint requests to Deborah L. Wingard, PhD, Department of Family and Preventive Medicine, University of California San Diego, 9500 Gilman Dr. 0607, La Jolla, CA 92093-0607. E-mail: dwingard{at}


OBJECTIVE—The purpose of this study was to investigate the association between coffee intake and incident diabetes based on an oral glucose tolerance test (OGTT) and examine coffee habits in those with impaired glucose separately from those with normal glucose at baseline.

RESEARCH DESIGN AND METHODS—In this prospective study, 910 adults aged ≥50 years without diabetes at baseline in 1984–1987 were followed to 1992–1996, an average of 8 years after assessment of coffee intake. Logistic regression models were adjusted for sex, age, physical activity, BMI, smoking, alcohol, hypertension, and baseline fasting plasma glucose.

RESULTS—Past and current coffee drinkers had a reduced risk of incident diabetes (odds ratio 0.38 [95% CI 0.17–0.87] and 0.36 [0.19–0.68], respectively) compared with those who never drank coffee. The 317 participants with baseline impaired glucose who were past or current coffee drinkers were also at reduced risk for incident diabetes (0.31 [0.11–0.87] and 0.36 [0.16–0.83], respectively).

CONCLUSIONS—This study confirms a striking protective effect of caffeinated coffee against incident diabetes and extends these findings to incident diabetes based on OGTT independent of multiple plausible confounders.


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

    The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C Section 1734 solely to indicate this fact.

    • Accepted July 28, 2006.
    • Received May 25, 2006.
| Table of Contents