Associations between hepatitis B virus infection and risk of colorectal Cancer: a population-based prospective study.

BACKGROUND: Previous studies have observed a close association between hepatitis B virus (HBV) infection and hepatocellular carcinoma (HCC) as well as extrahepatic cancers. However, research concerning the effect of HBV infection on the risk of colorectal cancer (CRC) is rare and inconsistent. This study aims to determine the relationship between HBV infection and new-onset CRC. METHODS: We prospectively examined the relationship between HBV infection and new-onset CRC among 93,390 participants from Kailuan Cohort study. Cox proportional hazards regression models, subgroup analyses and competing risk analyses were used to evaluate the association between HBV infection and the risk of new-onset CRC. RESULTS: During a median follow-up of 11.28 years, 448 incident CRC cases were identified. The adjusted HR (95%confidence interval (CI)) for the association of HBsAg Seropositive with CRC was 1.85(1.15 ~ 2.96) in the Cox regression. Subgroup analyses showed that the HBsAg seropositive group was associated with increased risk of new-onset CRC among male, middle-aged, normal weight, smokers and non-drinker participants, respectively. A positive association of HBV infection with the risk of CRC was observed in the adjusted sub-distribution proportional hazards (SD) models (HRSD = 1.77, 95% CI:1.11-2.84) and cause-specific hazards (CS) models (HRCS = 1.79, 95% CI: 1.13-2.91). CONCLUSIONS: Our results have found a significant association between HBV infection and the risk of incident CRC among Chinese participants. TRIAL REGISTRATION: Kailuan study, ChiCTR-TNRC-11001489. Registered 24 August 2011 - Retrospectively registered, http:// http://www.chictr.org.cn/showprojen.aspx?proj=8050.