The prevalence of hepatitis C virus infection in the United States, 1999 through 2002.
BACKGROUND
Defining the primary characteristics of persons infected with hepatitis C virus (HCV) enables physicians to more easily identify persons who are most likely to benefit from testing for the disease.


OBJECTIVE
To describe the HCV-infected population in the United States.


METHODS
Nationally representative household survey.


METHODS
U.S. civilian, noninstitutionalized population.


METHODS
15,079 participants in the National Health and Nutrition Examination Survey between 1999 and 2002.


METHODS
All participants provided medical histories, and those who were 20 to 59 years of age provided histories of drug use and sexual practices. Participants were tested for antibodies to HCV (anti-HCV) and HCV RNA, and their serum alanine aminotransferase (ALT) levels were measured.


RESULTS
The prevalence of anti-HCV in the United States was 1.6% (95% CI, 1.3% to 1.9%), equating to an estimated 4.1 million (CI, 3.4 million to 4.9 million) anti-HCV-positive persons nationwide; 1.3% or 3.2 million (CI, 2.7 million to 3.9 million) persons had chronic HCV infection. Peak prevalence of anti-HCV (4.3%) was observed among persons 40 to 49 years of age. A total of 48.4% of anti-HCV-positive persons between 20 and 59 years of age reported a history of injection drug use, the strongest risk factor for HCV infection. Of all persons reporting such a history, 83.3% had not used injection drugs for at least 1 year before the survey. Other significant risk factors included 20 or more lifetime sex partners and blood transfusion before 1992. Abnormal serum ALT levels were found in 58.7% of HCV RNA-positive persons. Three characteristics (abnormal serum ALT level, any history of injection drug use, and history of blood transfusion before 1992) identified 85.1% of HCV RNA-positive participants between 20 and 59 years of age.


CONCLUSIONS
Incarcerated and homeless persons were not included in the survey.


CONCLUSIONS
Many Americans are infected with HCV. Most were born between 1945 and 1964 and can be identified with current screening criteria. History of injection drug use is the strongest risk factor for infection.
Armstrong
Gregory L
GL
National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. GArmstrong@cdc.gov
Wasley
Annemarie
A
Simard
Edgar P
EP
McQuillan
Geraldine M
GM
Kuhnert
Wendi L
WL
Alter
Miriam J
MJ
D000328:Adult; D000410:Alanine Transaminase / Q000097:blood; D001803:Blood Transfusion; D003430:Cross-Sectional Studies; D005260:Female; D016174:Hepacivirus / Q000276:immunology; D006526:Hepatitis C / Q000453:epidemiology* / Q000208:ethnology; D018937:Hepatitis C Antibodies / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012367:RNA, Viral / Q000097:blood; D012307:Risk Factors; D012725:Sexual Behavior; D015819:Substance Abuse, Intravenous; D014481:United States / Q000453:epidemiology
D018937:Hepatitis C Antibodies; D012367:RNA, Viral; D000410:Alanine Transaminase