At least one percent of Americans are chronically infected with the hepatitis C virus, which over time can severely damage the liver, according to a new study.
"Hepatitis C has a severe impact on the health and well-being of millions of Americans, especially baby boomers (those born from 1945 through 1965)," Dr. Scott D. Holmberg told Reuters Health in an email. He worked on the study at the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia.
"The new data from a nationally representative survey of the general United States population (the National Health and Nutrition Examination Survey, or NHANES) found about 2.7 million people have chronic hepatitis C infection," he added.
"This number should be considered a minimum estimate for those infected in the U.S., because some populations known to be at high risk for hepatitis C, such as those who are homeless or incarcerated, are not included in the sample," Holmberg said.
The hepatitis C virus (HCV) is spread through contact with contaminated blood.
Baby boomers represent about 81 percent of chronically infected people, Holmberg noted.
His team's study included roughly 30,000 people who participated in NHANES between 2003 and 2010. As part of the survey, their blood was drawn and tested for HCV.
The estimated prevalence of HCV infection was one percent among people ages six and older, which corresponds to 2.7 million people across the U.S.
Even more people had antibodies against the virus in their blood, suggesting they had been exposed to it in the past.
People with HCV were more likely than those who had never been infected to be in their 40s or 50s, male and black and to have been born in the U.S., the authors reported in the Annals of Internal Medicine. They were less likely be well-off or to have education past high school.
Among young and middle-aged adults, those with chronic HCV infection were more likely to have received a blood transfusion before mandatory viral testing began in 1992. They were also more likely to have ever injected illicit drugs or had 10 or more lifetime sexual partners than similarly aged people who had never had HCV infection.
"Undiagnosed hepatitis C places millions at serious risk of liver disease, cancer and death," Holmberg said. "Unfortunately, half or more of those with hepatitis C do not know they are infected."
He said it can be 20 or 30 years between when a person is infected with the virus and when symptoms related to hepatitis C begin to appear.
"This study underscores the importance of CDC and U.S. Preventive Services Task Force recommendations that all persons born between 1945 and 1965, who face a prevalence of chronic hepatitis C infection six times greater than other adults, should get tested at least once for hepatitis C virus," Holmberg said.
"Getting tested, knowing your status, and, if infected, getting linked to proper care and treatment are all essential to reducing the burden of hepatitis C," he added.
Chronic HCV is typically treated with combinations of anti-viral drugs.
"One finding of (this new) study was that only half of hepatitis C-positive participants aged 20 to 59 years reported a history of transfusion or illicit injection drug use," Mark H. Kuniholm told Reuters Health in an email.
Kuniholm, from Albert Einstein College of Medicine in Bronx, New York, has studied rates of HCV infection but wasn't involved in the new research.
The data reinforce the idea that only testing people who would seem to be at especially high risk "is unlikely to identify most U.S. individuals with hepatitis C," he said.
Kuniholm echoed the CDC recommendation for screening. "All U.S. adults, especially those adults born between 1945 and 1965, should be offered hepatitis C diagnostic testing," he said.
SOURCE: http://bit.ly/1e2JmUN Annals of Internal Medicine, online March 4, 2014.