Dietary vitamin D intake and colorectal cancer risk: a longitudinal approach within the PREDIMED study

Purpose We evaluated whether the intake of dietary vitamin D is associated with the incidence of both colorectal cancer (CRC) and colon cancer in the framework of the PREDIMED cohort of older adults at high cardiovascular risk. Methods We analyzed data from 7216 men and women (55-80 years) without CRC at baseline from the PREvencion con DIeta MEDiterranea study. Baseline consumption of vitamin D was assessed using a validated 137-item food frequency questionnaire. Cox proportional hazards ratios (HRs) of CRC and colon cancer incidence were estimated for quartiles and per 1-SD of baseline vitamin D intake. Results During a median follow-up of 6 years, we documented 97 incident CRC cases after the exclusion of subjects with no baseline dietary data and/or outliers of energy intake. A non-significant HRs and 95% confidence intervals (CIs) of CRC for the comparison of extreme quartiles (4th vs 1st) of vitamin D intake were observed [0.55 (0.30-1.00), P for trend = 0.072], whereas it was significant for colon cancer incidence alone [0.44 (0.22-0.90), P for trend = 0.032]. However, this association became significant in CRC and colon cancer incidence, after excluding 391 subjects consuming baseline vitamin D and/or calcium medication or prescribed supplements [0.52 (0.28-0.96) and 0.41 (0.12-0.85), respectively]. Conclusion A higher dietary intake of vitamin D was significantly associated with a reduced CRC risk in individuals at high cardiovascular risk.