THURSDAY, June 5 (HealthDay News) -- Diabetes doubles the risk of liver cancer in patients with chronic hepatitis C with advanced fibrosis, or cirrhosis, a Dutch study reports.

Researchers at the Erasmus MC University Medical Center in Rotterdam analyzed data on 541 European and Canadian patients with chronic hepatitis C with advanced cirrhosis. Of those patients, 85 had diabetes. Patients with more severe fibrosis were more likely to have diabetes.

"The prevalence of diabetes mellitus was 10.5 percent for patients with Ishak fibrosis score 4, 12.5 percent for Ishak-score 5 and 19.1 percent for Ishak-score 6," the researchers wrote.

The patients were followed for a median of four years. During that time, 11 patients with diabetes and 27 patients without diabetes developed liver cancer. The five-year liver cancer occurrence rate was 11.4 percent and 5.0 percent, respectively. The study also found that being male and older were significantly associated with increased risk of liver cancer.

Among patients with diabetes, there was a trend toward higher liver cancer risk as fasting glucose levels increased, which suggests that hyperinsulinemia might explain the increased liver cancer risk among diabetic patients, the study authors suggested.

Whatever the mechanism, it's clear that diabetes increases the risk of liver cancer in patients with chronic hepatitis C and advanced cirrhosis, the researchers concluded.

The study was published in the June issue of the journal Hepatology.

The American Liver Foundation has more about liver cancer.