Supplementary Material for: Waist Circumference and Risk of Liver Cancer: A Systematic Review and Meta-Analysis of over 2 Million Cohort Study Participants

Purpose: Liver cancer is the sixth most common type of cancer worldwide, and waist circumference (WC) is associated with its risk beyond body mass index (BMI). This dose-response meta-analysis was performed to investigate the association between WC and the risk of incident liver cancer using prospective cohort studies. Methods: A comprehensive systematic search was conducted in MEDLINE/PubMed, Web of Science databases, Scopus, and Coch­rane from inception to May 2019. Studies with retrospective or prospective cohort design that reported hazard ratio (HR), risk ratio, or odds ratio, and the corresponding 95% confidence intervals (CI) for liver cancer based on WC categories were included in this meta-analysis. Combined HRs with 95% CIs was estimated by DerSimonian and Laird random-effects models. Results: Associations between WC and liver cancer were reported in 5 articles with 2,547,188 participants. All studies were published between 2013 and 2019. Pooled results showed a strong significant association with minimum heterogeneity between WC and risk of liver cancer (HR 1.59, 95% CI 1.38–1.83, p_{heterogeneity} = 0.42: I² = 0%). Moreover, a dose-response model indicated a significant positive association between WC and risk of liver cancer (exp(b) = 1.018, p < 0.001). Conclusions: This systematic review and dose-response meta-analysis highlights WC as a significant risk factor related to the incidence of liver cancer.