Association of coffee intake with risk of all-cause and colorectal cancer-specific mortality among individuals with colorectal cancer in the Multiethnic Cohort Study
Coffee may influence colorectal cancer (CRC) survival, but prior studies had limited generalizability. We analyzed 1,098 participants from the Multiethnic Cohort study diagnosed with CRC between 1993–2008 who completed a food frequency questionnaire after diagnosis and were followed through 2019. Multivariable Cox proportional hazards regression models were used to examine coffee (total, caffeinated, decaffeinated) in relation to all-cause and CRC-specific mortality. Secondarily, we examined caffeine intake and explored associations by race and ethnicity. Overall, coffee intake was not associated with risk of mortality. However, decaffeinated coffee was associated with lower risk of all-cause mortality (HR ≥1 vs. 0 cups/day: 0.71; 95% CI [0.55 – 0.91]). Additionally, associations were observed between total and caffeinated coffee in relation to all-cause mortality among Native Hawaiian participants (HR per 1 cup/day: 0.62 [0.41 – 0.94] and 0.55 [0.31 – 0.97], respectively); and with CRC-specific mortality among White participants (HR per 1 cup/day: 0.48 [0.25–0.94] and 0.45 [0.23 – 0.90], respectively). In the total cohort, caffeine intake was associated with 22% lower risk of all-cause mortality (HR 4th quartile vs. 1st quartile: 0.78 [0.62—0.99]) and 52% lower risk of CRC-specific mortality (HR 0.48 [0.27—0.87]). Overall, coffee intake after CRC diagnosis was not associated with all-cause or CRC-specific mortality. Decaffeinated coffee was associated with lower risk of all-cause mortality, and caffeine was associated with lower risk of all-cause and CRC-specific mortality.