Hepatitis C virus (HCV) infection may contribute to the development of diabetes mellitus. This relationship has not been investigated at the population level, and its biological mechanism remains unknown.

To examine the prevalence of type 2 diabetes among persons with HCV infection in a representative sample of the general adult population of the United States.

Cross-sectional national survey.

The Third National Health and Nutrition Examination Survey, 1988–1994.

9841 persons older than 20 years of age for whom data on HCV infection and diabetes were complete.

The presence of diabetes was ascertained by using American Diabetes Association guidelines based on fasting plasma glucose measurement and medication history. Presence of HCV infection was assessed by testing for serum HCV-specific antibodies (anti-HCV).

Of the 9841 persons evaluated, 8.4% had type 2 diabetes and 2.1% were anti-HCV positive. Type 2 diabetes occurred more often in persons who were older, were nonwhite, had a high body mass index, and had low socioeconomic status. Type 2 diabetes was less common in persons who acknowledged previous illicit drug use. After adjustment for these factors, persons 40 years of age or older with HCV infection were more than three times more likely than those without HCV infection to have type 2 diabetes (adjusted odds ratio, 3.77 [95% CI, 1.80 to 7.87]). None of the 19 persons with type 1 diabetes were anti-HCV positive.

In the United States, type 2 diabetes occurs more often in persons with HCV infection who are older than 40 years of age.