Chronic hepatitis B virus (HBV) infections and colorectal cancer (CRC) are prevalent in Taiwan. We carried out a population-based case-control study to assess the association between HBV infection and CRC risk. Using the National Health Insurance Research Database of Taiwan, we identified 69,478 newly diagnosed patients with CRC from 2005 to 2011. We further randomly selected 69,478 age- and gender-matched controls without CRC from the same database. Odds ratios (ORs) were calculated to evaluate the association between chronic HBV infection and CRC using a logistic regression analysis. HBV infection was found to be associated with the risk of CRC (OR = 1.27, 95% confidence interval (CI) = 1.20–1.33). This relationship was similar in men and women. Age-specific analysis revealed that the CRC risk associated with HBV decreased with age. The adjusted ORs for patients aged <55, 55–64, and 65–74 years were 1.63 (95% CI = 1.48–1.79), 1.24 (95% CI = 1.13–1.37), and 1.02 (95% = 0.92–1.13), respectively. In conclusion, this study suggests that chronic HBV infection is significantly associated with an increased risk of CRC. Monitoring the risk of CRC development in young patients with HBV infection is crucial.

AimStudies evaluating colorectal cancer (CRC) risk associated with chronic hepatitis C virus (HCV) infection are limited.MethodsIn this case-control study, we identify 67,670 CRC cases newly diagnosed from 2005 to 2011 and randomly selected 67,670 controls without HCV and CRC from the same database, frequency matched by age and sex of cases.ResultsResults of logistic regression analysis revealed that the adjusted odds ratio (aOR) of CRC was 1.16 (95% confidence interval [CI] = 1.08–1.24, p &lt; 0.001) in association with chronic HCV. The CRC risk was slightly greater for women than for men. The risk decreased with age, with the aOR decreased from 2.26 (95% CI = 1.32–3.87, p = 0.003) in patients under 45 years old to 1.31 (95% CI = 1.10–1.55, p = 0.03) in patients aged 50–59, and 1.10 (95% CI = 1.00–1.22, p = 0.061) in patients aged over 70.ConclusionsOur findings suggested that patients with chronic HCV infection are at an elevated risk of developing CRC. Our data also imply that the CRC prevention programs are needed to target younger HCV patients.