Epidemiology

Four million people in US infected with hepatitis C virus

Last Updated: 2006-05-15 17:00:32 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Findings from a nationwide study suggest that 4.1 million people in the US have been infected with hepatitis C virus (HCV), most of these individuals have chronic infection. However, the current prevalence of infection, 1.6%, is actually slightly lower than a decade ago when the rate was 1.8%.

The findings are based on analysis of data for 15,079 participants in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2002. In addition to answering detailed questions about their health and lifestyles, the subjects submitted blood samples for HCV testing and liver panel analysis.

The new findings build on those from the previous NHANES, conducted between 1988 and 1994, according to the report in the Annals of Internal Medicine for May 16.

As noted, the prevalence of anti-HCV antibodies was 1.6%, and 1.3% of all subjects had chronic HCV infection, lead author Dr. Gregory L. Armstrong, from the Centers for Disease Control and Prevention in Atlanta, and colleagues note.

Subjects in their 40s had the highest prevalence of anti-HCV antibodies -- 4.3%, the researchers point out.

The biggest risk factor for HCV infection was injection drug use: nearly half of anti-HCV-positive subjects between 20 and 59 years of age reported injecting drugs. The majority of anti-HCV-positive injection drug users said they had not used drugs for at least 1 year prior to being surveyed.

Blood transfusion before 1992 and 20 or more lifetime sexual partners were also significant risk factors for HCV infection, the report indicates.

Nearly 59% of HCV RNA-positive subjects had abnormal serum ALT levels. When combined with any history of injection drug use and blood transfusion before 1992, this parameter identified 85.1% of HCV RNA-positive subjects between 20 and 59 years of age.

In a related commentary, Dr. Jules L. Dienstag, from Harvard Medical School in Boston, comments that "the new data build on those reported previously to paint a vivid portrait of hepatitis C in the US. A self-limited epidemic of injection drug use over several decades amplified the transmission of HCV, and we are now seeing the delayed, bitter harvest of chronic liver disease."

Ann Intern Med 2006;144:705-714,770-771.