title: Excess body weight and the risk of primary liver cancer: an updated meta-analysis of prospective studies.
abstract: OBJECTIVE
  To provide a quantitative assessment of the association between excess body weight (EBW) and the risk of primary liver cancer (PLC), we performed an updated meta-analysis of prospective observational studies.
  
  
  METHODS
  We searched PUBMED and EMBASE for studies of body mass index and the risk of PLC published through 15 th September 2011. Summary relative risks (SRRs) with their corresponding 95% confidence intervals (CIs) were calculated using a random-effects model. The meta-regression and stratified methods were used to examine heterogeneity across studies.
  
  
  RESULTS
  A total of 26 prospective studies, including 25,337 PLC cases, were included in this analysis. Overall, excess body weight (EBW: body mass index (BMI) ≥ 25 kg/m2) and obesity (BMI ≥ 30 kg/m2) were associated with an increased risk of PLC, with significant heterogeneity (EBW: SRRs 1.48, 95% CIs 1.31-1.67, P(h)<0.001, I2=83.6%; Obesity: SRRs 1.83, 95% CIs 1.59-2.11, P(h)<0.001, I2=75.0%). Subgroup analyses revealed that the positive associations were independent of geographic locations, alcohol consumption, history of diabetes or infections with hepatitis B (HBV) and/or hepatitis C virus (HCV). Obese males had a higher risk of PLC than obese females did (P=0.027). A stronger risk of PLC with EBW was observed for patients with HCV (but not HBV) infection or cirrhosis compared with the general population.
  
  
  CONCLUSIONS
  Findings from this meta-analysis strongly support that EBW or obesity is associated with an increased risk of PLC in both males and females.
authors.affiliation: Department of Interventional Radiology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Wang
authors.forename: Jianhua
authors.initials: J
authors.lastname: Wang
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Yan
authors.forename: Jianjun
authors.initials: J
authors.lastname: Luo
mesh_terms: D001208:Asia / Q000453:epidemiology; D015992:Body Mass Index; D001835:Body Weight; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000453:epidemiology*; D008297:Male; D009765:Obesity / Q000175:diagnosis / Q000453:epidemiology*; D050177:Overweight / Q000175:diagnosis / Q000453:epidemiology*; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D014481:United States / Q000453:epidemiology