Coffee consumption and mortality in colorectal cancer patients: does the co-existence of cardiometabolic disease matter?

Background: Although coffee consumption may have a U-shaped nonlinear relationship with all-cause mortality in colorectal cancer (CRC) patients, it is unclear whether this association could differ in the presence of prevalent cardiometabolic disease (CMD). Therefore, we assessed the association of coffee consumption with mortality in CRC patients stratified by CMD status at diagnosis.

Methods: We used data from a prospective cohort of 1,769 patients with stage I-III CRC. Coffee consumption was self-reported using a food frequency questionnaire at diagnosis. Mortality data were retrieved from the Personal Records Database. CMD was defined as prevalent cardiovascular disease (CVD) or diabetes at diagnosis of CRC. We estimated hazard ratios (HR) and 95% confidence intervals (CI) using Cox proportional hazards models with and without restricted cubic splines (RCS) while adjusting for relevant confounders.

Results: During a median (quartile1, quartile 3) follow-up of 7.7 (5.6, 9.3) years, we observed 128 deaths in participants without CMD and 250 deaths in those with CMD. The five-year survival rate was 88% and 83% for participants without and with CMD, respectively. Among participants without CMD, consuming 2-4 cups/d and > 4 cups/d of coffee compared to < 2 cups/d was associated with a 60% (HR: 0.40, 95% CI: 0.26-0.63) and a 41% (HR: 0.59, 95% CI: 0.39-0.89) lower risk of mortality, respectively. In participants with CMD, consuming 2-4 cups/d of coffee compared to < 2 cups/d was associated with a 31% (HR: 0.69, 95% CI: 0.51-0.93) lower risk of mortality, while no association was observed for > 4 cups/d (HR:0.82, 95%CI:0.59-1.14). The RCS showed a U-shaped, nonlinear inverse association between coffee consumption and mortality in participants without and with CMD (P-value for nonlinearity: 0.001), but the inverse association was stronger in those without CMD.

Conclusion: We observed a U-shaped, nonlinear inverse association between coffee consumption and mortality in CRC patients regardless of their CMD status. More mechanistic studies are needed to understand how consuming coffee may lower mortality risk in CRC patients.