Previous epidemiological studies have shown that coffee consumption may reduce liver cancer risk. The present study aimed to summarize the evidence for this association in the Japanese population by performing a meta-analysis of the results of relevant cohort studies conducted in Japan. We searched studies published prior to September 1, 2018 in PubMed. Extracted data were analyzed using a random effects model. A total of six cohort studies from five publications were included in the final analysis. The pooled estimate of relative risk with 95% confidence interval (CI) for the group with highest coffee consumption was 0.50 (95% CI: 0.38-0.66, p < 0.001) compared with non-coffee drinkers or those who almost never drink coffee. No evidence of publication bias was observed (p for Begg's test = 0.85). This meta-analysis suggested that coffee consumption among Japanese people has a significant role in preventing liver cancer.
Keywords: Coffee; Cohort study; Japan; Liver cancer; Meta-analysis.