title: Prevalence of hepatitis B virus infection in non-Hodgkin lymphoma: a systematic review and meta-analysis.
abstract: OBJECTIVE
  A recent meta-analysis has demonstrated an association between hepatitis C virus and non-Hodgkin lymphoma (NHL). There is also evidence on the association between hepatitis B virus (HBV) and NHL. The aim of this study was to evaluate this evidence using a meta-analytic approach.
  
  
  METHODS
  We searched the MEDLINE database from 1962 to 2008 for case-control studies that have reported the association of HBV with NHL. We calculated the odds ratio (OR) and 95% confidence intervals (CI) to assess the prevalence of HBV infection and pooled the results using three different statistical models.
  
  
  RESULTS
  Our search yielded 12 studies with 11 studies (3262 NHL patients, 1,523,205 controls) evaluating HBV infection in NHL and one study (3888 HBV-infected individuals, 205,203 controls) that had investigated for NHL in HBV infection. The OR of detecting HBV infection in NHL when compared with the control population was 2.56 (95% CI, 2.24-2.92) by the fixed effects model; 2.61 (95% CI, 2.29-2.98) by the exact method and 2.67 (95% CI, 2.04-3.49) by the random effects model suggesting a high prevalence of HBV carrier state in lymphoma. There was evidence of statistical heterogeneity which disappeared after exclusion of retrospective studies on sensitivity analysis.
  
  
  CONCLUSIONS
  The results of this study suggest a possible causal relation between HBV infection and NHL which needs to be confirmed by experimental and epidemiological studies. In countries where prevalence of HBV infection is 1% or more, it may be prudent to screen patients with NHL for occult HBV infection.
authors.affiliation: Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: A
authors.initials: A
authors.lastname: Nath
authors.forename: R
authors.initials: R
authors.lastname: Agarwal
authors.forename: P
authors.initials: P
authors.lastname: Malhotra
authors.forename: S
authors.initials: S
authors.lastname: Varma
mesh_terms: D016022:Case-Control Studies; D006509:Hepatitis B / Q000150:complications* / Q000453:epidemiology* / Q000821:virology; D006515:Hepatitis B virus; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000150:complications* / Q000453:epidemiology* / Q000821:virology; D015995:Prevalence