Excess body weight and the risk of primary liver cancer: An updated meta-analysis of prospective studies

Aims: 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/m(2)) and obesity (BMI >= 30 kg/m(2)) 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, I-2 = 83.6%; Obesity: SRRs 1.83, 95% CIs 1.59-2.11, P-h < 0.001, I-2 = 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. (c) 2012 Elsevier Ltd. All rights reserved.