title: Association between chronic viral hepatitis infection and breast cancer risk: a nationwide population-based case-control study.
abstract: BACKGROUND
  In Taiwan, there is a high incidence of breast cancer and a high prevalence of viral hepatitis. In this case-control study, we used a population-based insurance dataset to evaluate whether breast cancer in women is associated with chronic viral hepatitis infection.
  
  
  METHODS
  From the claims data, we identified 1,958 patients with newly diagnosed breast cancer during the period 2000-2008. A randomly selected, age-matched cohort of 7,832 subjects without cancer was selected for comparison. Multivariable logistic regression models were constructed to calculate odds ratios of breast cancer associated with viral hepatitis after adjustment for age, residential area, occupation, urbanization, and income. The age-specific (<50 years and ≥50 years) risk of breast cancer was also evaluated.
  
  
  RESULTS
  There were no significant differences in the prevalence of hepatitis C virus (HCV) infection, hepatitis B virus (HBV), or the prevalence of combined HBC/HBV infection between breast cancer patients and control subjects (p = 0.48). Multivariable logistic regression analysis, however, revealed that age <50 years was associated with a 2-fold greater risk of developing breast cancer (OR = 2.03, 95% CI = 1.23-3.34).
  
  
  CONCLUSIONS
  HCV infection, but not HBV infection, appears to be associated with early onset risk of breast cancer in areas endemic for HCV and HBV. This finding needs to be replicated in further studies.
authors: School of Public Health, College of Public Health and Nutrition, Taipei Medical University, 250 Wu-Hsing Street, 11031 Taipei, Taiwan.
authors: Fu-Hsiung
authors: FH
authors: Su
authors: Shih-Ni
authors: SN
authors: Chang
authors: Pei-Chun
authors: PC
authors: Chen
authors: Fung-Chang
authors: FC
authors: Sung
authors: Chien-Tien
authors: CT
authors: Su
authors: Chih-Ching
authors: CC
authors: Yeh
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology*; D016022:Case-Control Studies; D005260:Female; D019694:Hepatitis B, Chronic / Q000453:epidemiology*; D019698:Hepatitis C, Chronic / Q000453:epidemiology*; D006801:Humans; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011159:Population Surveillance; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult