Increased coffee consumption is associated with a decreased risk of liver cancer, but there is no evident association between coffee consumption and risk of biliary tract cancer, according to data published in Nutrients.
Justyna Godos, MSc, from the Department of Medical and Surgical Sciences and Advanced Technologies at the University of Catania in Catania, Italy, and colleagues conducted a meta-analysis that included 5 studies examining the risk of biliary tract cancer and 13 studies on liver cancer risk. The researchers assessed the dose-response relationship with a restricted cubic spline model and multivariate random-effect meta-regression.
The results showed no significant association between coffee consumption and risk of biliary tract cancer, but there was evidence of an inverse correlation between coffee consumption and liver cancer risk. The association was consistent when considering potential confounding factors, including smoking status and hepatitis.
The researchers note that increasing coffee consumption by 1 cup per day was associated with a 15% reduced risk of liver cancer (relative risk, 0.85). Compared with participants who did not drink coffee, the relative risks for liver cancer were 0.82 for 1 cup per day, 0.68 for 2 cups per day, 0.57 for 3 cups per day, 0.47 for 4 cups per day, 0.39 for 5 cups per day, 0.33 for 6 cups per day, and 0.27 for 7 cups per day.
“Coffee may represent a valid functional food for liver protection,” the authors of the study wrote. “Current evidence is sufficient to guide future clinical randomized trials to test the hepatoprotective effects of coffee, which in turn may lead to more definitive recommendations. However, further observational studies with better in depth analyses of potential confounding factors are needed to test the association between coffee consumption and [biliary tract cancer].”
Godos J, Micek A, Marranzano M, Salomone F, Del Rio D, Ray S. Coffee consumption and risk of biliary tract cancers and liver cancer: A dose-response meta-analysis of prospective cohort studies [published online August 28, 2017]. Nutrients. doi:10.3390/nu9090950