title: Association between hepatitis B virus infection and risk of multiple myeloma: a systematic review and meta-analysis.
abstract: BACKGROUND
  Hepatitis B virus (HBV) infection is a major global public health concern. Although recent findings suggest an inverse relationship between HBV infection and multiple myeloma (MM), the true relationship between these two conditions remains unclear.
  
  
  OBJECTIVE
  The primary aim of this meta-analysis was to evaluate the association between HBV infection, defined as hepatitis B surface antigen positivity, and the incidence of MM.
  
  
  METHODS
  We searched the PubMed/Medline, Cochrane Library and EMBASE databases from January 1975 to July 2014 and reviewed the reference lists of all retrieved articles. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using fixed- and random-effects models.
  
  
  RESULTS
  We identified nine case-control studies involving 30,646 patients with MM and 379,837 controls. HBV infection was not significantly associated with the development of MM (OR = 1.3; 95% CI: 0.92-1.82; P = 0.14). A similar risk of developing MM was present in different HBV-prevalent countries. However, significant heterogeneity was observed among studies (P = 0.01). A statistically significant relationship between HBV infection and increased MM risk was detected in sub-analyses evaluating high-quality studies and those with hospital-based controls (P < 0.05).
  
  
  CONCLUSIONS
  HBV infection may be associated with an increased risk of MM. However, confirmation of this relationship and the specific molecular mechanisms involved in the association between HBV infection and the development of MM require further exploration.
authors.affiliation: Cancer Center, First Hospital of Jilin University, Changchun, Jilin Province, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.affiliation: Cancer Center, First Hospital of Jilin University, Changchun, Jilin Province, China.
authors.forename: O
authors.initials: O
authors.lastname: Bai
authors.affiliation: Cancer Center, First Hospital of Jilin University, Changchun, Jilin Province, China.
authors.forename: C
authors.initials: C
authors.lastname: Liu
authors.affiliation: Cancer Center, First Hospital of Jilin University, Changchun, Jilin Province, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Du
authors.affiliation: Cancer Center, First Hospital of Jilin University, Changchun, Jilin Province, China.
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.affiliation: Cancer Center, First Hospital of Jilin University, Changchun, Jilin Province, China.
authors.forename: G
authors.initials: G
authors.lastname: Wang
authors.affiliation: Cancer Center, First Hospital of Jilin University, Changchun, Jilin Province, China.
authors.forename: W
authors.initials: W
authors.lastname: Li
mesh_terms: D016022:Case-Control Studies; D006509:Hepatitis B / Q000175:diagnosis* / Q000453:epidemiology*; D006801:Humans; D009101:Multiple Myeloma / Q000175:diagnosis* / Q000453:epidemiology*; D012307:Risk Factors
keywords: hepatitis B virus; meta-analysis; multiple myeloma