have determined that levels of hepatitis C virus (HCV) found among
injection drug users (IDUs) were higher in individuals who are male or
African American even after differences in other factors were
considered. The study, which was funded by the National Cancer
Institute and performed with collaborators from the National Institutes
of Health Clinical Center and the University of California – San
Francisco, was the first to simultaneously examine the association of
demographic, viral and human genetic factors on HCV RNA levels.
Results of the study published in the July issue of Hepatology,
a journal of the American Association for the Study of Liver Diseases
(AASLD), also showed higher levels of HCV among IDUs who were
co-infected with human immunodeficiency virus (HIV).
A 2010 report from the Centers for Disease Control
and Prevention (CDC) estimates that up to 3.9 million Americans have
chronic HCV—a leading cause of liver cancer, end-stage liver disease and
liver transplantation. According to the CDC 17,000 new cases and 2,800
acute cases of HCV were reported in 2010. Previous epidemiologic
studies suggest one-third of those 18 to 30 year-old IDUs and up to 90%
of older IDUs are infected with HCV.
“With such a high incidence and prevalence of
hepatitis C virus infection among IDUs, it is important to understand
the characteristics of the infection in this group,” explains lead
author Dr. Thomas O’Brien of the Division of Cancer Epidemiology and
Genetics at the National Cancer Institute in Rockville, MD. “The HCV
RNA level is an important predictor of response to treatment in patients
with chronic hepatitis C. Our study is the first to examine
simultaneously the viral, demographic, and genetic factors that impact
HCV levels in ethnically diverse IDUs.”
Participants were originally recruited for the Urban
Health Study—a multi-ethnic group of IDUs in San Francisco. Researchers
used interview data and biological samples from participants to analyze
demographic, viral and host characteristics of cancer-causing viruses. A
total of 1701 participants had detectable HCV RNA and were included in
the present study. The median age at enrollment was 46 years and median
age of first illicit drug injection was 18 years. Close to 75% of
participants were men and 56% were African American, 34% European
(non-Hispanic) and 7% Latino (non-African American).
Adjusted analysis revealed that age, gender, racial
ancestry, HIV-1 infection, and IL28B rs12979860 genotype were all
independently associated with the HCV RNA level. “We know that the level
of HCV is an important predictor of treatment response and that these
levels seem to be influenced by a number of demographic, clinical, viral
and human genetic factors,” concludes Dr. O’Brien.
Full citation: “HCV RNA Levels in a
Multi-Ethnic Cohort of Injection Drug Users:Human Genetic, Viral and
Demographic Associations.” Lorenzo Uccellini, Fan-Chen Tseng, Alessandro
Monaco, Fatma M. Shebl, Ruth Pfeiffer, Myhanh Dotrang, Dianna Buckett,
Michael P. Busch, Ena Wang, Brian R. Edlin, Francesco Marincola, Thomas
R. O’Brien. Hepatology; (DOI: 10.1002/hep.25652); Print Issue Date: July, 2012.
About the Author: Dr. Thomas O’Brien is with
the Division of Cancer Epidemiology and Genetics at the National Cancer
Institute in Rockville, Maryland.
To arrange an interview with Dr. O’Brien please contact the NCI Office of Media Relations at email@example.com or at 301-496-4441.
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