People living with chronic hepatitis C virus (HCV) in the United States have a much higher risk of death than the general population. But it’s not just the liver virus that’s to blame. According to a new study published in Hepatology, health risk behaviors like alcohol use, cigarette smoking and unhealthy diets contribute equally toward mortality in HCV-positive patients as the infection itself, Healio reports.

Study authors said the surprising analysis highlights the importance of a health response to hepatitis C that includes more than just testing and access to direct-acting antiviral medications. Instead, they recommend that doctors across the country also address coexisting health risk behaviors—including difficult-to-treat issues like substance use, alcoholism and obesity.

For the study, researchers analyzed the survey responses of 27,468 adults who participated in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2010, including 363 people with chronic hepatitis C. Each participant was asked a series of questions about his or her alcohol use, cigarette smoking, physical activity, diet and illicit drug use over time. 

At the end of the study’s follow-up (a mean of 6.2 years), 2,599 patients had died, 43 of them as a result of their hepatitis C infection. After adjusting for sociodemographic factors as well as several comorbid medical conditions, researchers found that the mortality rate for patients with chronic HCV remained significantly higher than the rest of the cohort.

They also found that prevalence of health risk behaviors was significantly higher among patients with chronic hepatitis C. Compared with the rest of the study group, HCV patients were far more likely to report heavy use of alcohol (39.6 percent versus 19.1 percent), smoke (63.8 percent versus 28.2 percent) and have an unhealthy diet (74.7 percent versus 65.8 percent). Those with chronic HCV were also more likely to report former drug use (30.8 percent versus 1.3 percent) compared with their peers. 

However, in a subgroup analysis of participants ages 45 to 70, researchers noted that this excess mortality risk decreased considerably following patients’ adjustment for health risk behaviors as they aged. This gives hope to people with chronic HCV, said study authors, and further underlines the importance of tackling issues like alcohol use, poor diets and smoking alongside hep C treatment.