Hepatitis B virus (HBV) genotypes have distinct geographical distributions, and have been shown to differ with regard to clinical outcome and prognosis. However, the relationship between HBV genotypes and liver cirrhosis remains controversial and no study on exploring the association between HBV genotypes and subclinical cirrhosis in community-based population has been reported.
A research article to be published on January 21, 2010 in the World Journal of Gastroenterology addresses this question. The research team led by Prof. Cao from Department of Epidemiology, Second Military Medical University performed a large epidemiological study with 10 167 community-based residents at the age between 6 and 72 years in Eastern China. After excluding the subjects co-infected with hepatitis C or hepatitis D viruses, the hepatitis B surface antigen (HBsAg)-positive subjects were examined for HBV genotype, serum viral load, alanine aminotransferase (ALT), hepatitis B e antigen (HBeAg) status, and ultrasonographic changes. Logistic regression models were used to determine the factors independently associated with probable cirrhosis.
Of 634 HBsAg-positive subjects with HBV genotyped, 82 had probable cirrhosis. Probable cirrhosis was only found in the HBeAg-negative subjects, and more frequent in the subjects with genotype C than in those with genotype B. In HBeAg-negative subjects, high viral load was frequently associated with abnormal ALT level, while ALT abnormality was more frequent in those with probable cirrhosis than those without. Ultrasonographic fatty liver was not found in the subjects with probable cirrhosis. HBV genotype C, age (≥ 45 years), male sex, and ALT abnormality were demonstrated to be major risk factors of probable cirrhosis for the residents chronically infected with HBV.
Clinical relevance and public health importance of HBV genotypes are different in a given population. HBV genotype B and C are major HBV genotypes endemic in East Asia. HBV genotype B is associated with acute hepatitis and tends to be self-limiting and shorter lived. However, genotype C is associated with longer duration of liver damage in the HBeAg-negative subjects, which may be the main reason for liver cirrhosis. Genotype C HBV-infected male residents at the age of 45 years or older should be routinely examined for active hepatitis and early cirrhosis. Early intervention to the HBV-infected subjects with high risks of cirrhosis might be effective for decreasing overall mortality of liver cirrhosis.
HBV infection is a serious public health problem. Approximately 2 billion people worldwide have been exposed to HBV, and more than 300 million are chronically infected with HBV. Chronic HBV infection is the most important risk factor of liver cirrhosis and hepatocellular carcinoma in HBV endemic areas.
Second Military Medical University is one of the top comprehensive medical research and education institution in China. It contains Basic Medical School, Pharmacology School, Nursing School, Chinese Traditional Medicine School, Navy Medical School, Preventive Medicine Branch, and three affiliated hospitals (clinical medical colleges).
Reference: Yin JH, Zhao J, Zhang HW, Xie JX, Li WP, Xu GZ, Shen J, Dong HJ, Zhang J, Wang L, Han JK, Wang HY, Cao GW. HBV genotype C is independently associated with cirrhosis in community-based population. World J Gastroenterol 2010; 16(3): 379-383
Correspondence to: Dr. Guang-Wen Cao, Professor of Medicine, Chairman, Department of Epidemiology, Second Military Medical University, 800 Xiangyin Rd., Shanghai 200433, China. email@example.com
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World Journal of Gastroenterology (WJG), a leading international journal in gastroenterology and hepatology, has established a reputation for publishing first class research on esophageal cancer, gastric cancer, liver cancer, viral hepatitis, colorectal cancer, and H pylori infection and provides a forum for both clinicians and scientists. WJG has been indexed and abstracted in Current Contents/Clinical Medicine, Science Citation Index Expanded (also known as SciSearch) and Journal Citation Reports/Science Edition, Index Medicus, MEDLINE and PubMed, Chemical Abstracts, EMBASE/Excerpta Medica, Abstracts Journals, Nature Clinical Practice Gastroenterology and Hepatology, CAB Abstracts and Global Health. ISI JCR 2008 IF: 2.081. WJG is a weekly journal published by WJG Press. The publication dates are the 7th, 14th, 21st, and 28th day of every month. WJG is supported by The National Natural Science Foundation of China, No. 30224801 and No. 30424812, and was founded with the name of China National Journal of New Gastroenterology on October 1, 1995, and renamed WJG on January 25, 1998.