Coffee consumption and risk of hepatocellular carcinoma and intrahepatic cholangiocarcinoma by sex: The liver cancer pooling project

Background: Coffee consumption has been reported to be inversely associatedwith hepatocellular carcinoma (HCC), themost common type of liver cancer. Caffeine has chemopreventive properties, but whether caffeine is responsible for the coffee-HCC association is not well studied. In addition, few studies have examined the relationship by sex, and no studies have examined whether there is an association between coffee and intrahepatic cholangiocarcinoma (ICC), the second most common type of liver cancer. Methods: In the Liver Cancer Pooling Project, a consortium of U.S.-based cohort studies, data from 1,212,893 individuals (HCC, n = 860; ICC, n = 260) in nine cohorts were pooled. Multivariable- adjusted hazard ratios (HR) and 95% confidence intervals (CI) were estimated using proportional hazards regression. Results: Higher coffee consumption was associated with lower risk of HCC (HR_{>3 cups/day vs. non-drinker}, 0.73; 95% CI, 0.53-0.99; P_{trend cups/day} = <0.0001). More notable reduced risk was seen among women than men (P_interaction = 0.07). Women who consumed more than three cups of coffee per day were at a 54% lower risk of HCC (HR, 0.46; 95% CI, 0.26-0.81), whereas men had more modest reduced risk of HCC (HR, 0.93; 95% CI, 0.63-1.37). The associations were stronger for caffeinated coffee (HR_{>3 cups/day vs. non-drinker}, 0.71; 95% CI, 0.50-1.01) than decaffeinated coffee (HR, 0.92; 95% CI, 0.55-1.54). There was no association between coffee consumption and ICC. Conclusions: These findings suggest that, in a U.S. population, coffee consumption is associated with reduced risk of HCC. Impact: Further research into specific coffee compounds and mechanisms that may account for these associations is needed.