Sufficient 25-hydroxyvitamin D levels two years after colorectal cancer diagnosis are associated with a lower risk of all-cause mortality

Background: Whether changes in vitamin D (25(OH)D3) levels after colorectal cancer (CRC) diagnosis influence clinical outcomes is unclear. We investigated the association of trajectories of 25(OH)D3 levels with recurrence and all-cause mortality. Methods: In total, 679 patients were included in our data-analyses. Trajectories of 25(OH)D3 levels were defined on vitamin D status at diagnosis, and at six months and two years after diagnosis. Observed trajectories of 25(OH)D3 levels were consistent deficient levels (20%), consistent sufficient levels (39%), increasing levels (20%) and a temporary drop in levels (13%). Associations of trajectories of 25(OH)D3 with recurrence and all-cause mortality were assessed using multivariable Cox proportional hazard regression models. Results: During a follow-up time of 2.2 years for recurrence and 3.5 years for all-cause mortality, 31 and 65 events occurred, respectively. No statistically significant associations were observed for vitamin D trajectories and the risk of recurrence. Patients who were consistently sufficient compared to patients who were consistently deficient had a lower risk of all-cause mortality (HR 0.39 95%CI 0.21-0.73). The risk of all-cause mortality seems lower in patients with increasing levels or a temporary drop in levels (HR 0.54 95%CI 0.27-1.10 and HR 0.40 95%CI 0.17-0.93) relative to patients with consistent deficient levels. Conclusions: CRC patients following a trajectory characterized by sufficient levels of 25(OH)D3 two years after diagnosis all appeared to have a lower risk of all-cause mortality compared to patients having consistent deficient levels. Impact: Further studies should investigate how trajectories of 25(OH)D3 levels are associated with CRC recurrence.