Dietary and lifestyle inflammation scores in relation to colorectal cancer recurrence and all-cause mortality: A longitudinal analysis

Aim: The aim of this study was to longitudinally investigate dietary and lifestyle inflammation scores and their interaction in relation to risk of colorectal cancer (CRC) recurrence and all-cause mortality. Methods: Data of two prospective cohort studies among CRC survivors was used. Information about diet and/or lifestyle was available for 2739 individuals for at least one of the following time points: at diagnosis, six months after diagnosis and two years after diagnosis. The dietary and lifestyle inflammation scores (DIS and LIS) were used to evaluate the inflammatory potential of diet and lifestyle. Joint modelling, combining mixed models and Cox proportional hazards regression, were used to assess associations between DIS and LIS over time and CRC recurrence and all-cause mortality. Interactions between DIS and LIS were assessed using time-dependent Cox proportional hazard regression. Results: The median follow-up time was 4.8 (IQR 2.9–6.9) years for recurrence and 5.7 (IQR 3.5–8.5) years for all-cause mortality, with 363 and 453 events, respectively. A higher DIS as well as LIS was associated with a higher risk of all-cause mortality (HR_{DIScontinuous} 1.09 95%CI 1.02; 1.15; HR_{LIScontinuous} 1.24 95%CI 1.05; 1.46). Individuals who were in the upper tertile of both DIS and LIS had the highest all-cause mortality risk (HR 1.62 95%CI 1.16; 2.28), compared to the individuals in the lowest tertile of both DIS and LIS. No consistent associations with recurrence were observed. Conclusion: A more pro-inflammatory diet and lifestyle was associated with a higher risk of all-cause mortality, but not recurrence, in CRC survivors.