Associations of circulating 25-hydroxyvitamin D concentrations with colorectal cancer risk and survival

Colorectal cancer is the third most common cancer and the second leading cause of cancer death globally. The etiology and prognosis of colorectal cancer are closely related to dietary and nutritional factors, among which vitamin D has been a topic of considerable interest. However, population-based evidence remains inconclusive regarding the associations between vitamin D status and colorectal cancer risk and survival. For risk analysis, the inconsistency is probably due to the differences in sample sizes, assays, and laboratories. Moreover, there are still very limited data on the exact dose-response association between 25(OH)D and colorectal cancer risk. For survival analysis, the observation of considerable between-study heterogeneity (e.g., populations, assay methods, and definitions of vitamin D categories) limited the validity of summary estimates. Furthermore, the different time of blood draw (including pre-diagnostic, post-diagnostic, pre-operative, and post-operative) for vitamin D measurements may confuse the results, and pre-diagnostic vitamin D status seems more stable and useful to assess the proposed prognostic value for colorectal cancer patients. Therefore, leveraging the UK Biobank resource, a large cohort with a long-term follow up, we aim to prospectively evaluate the associations of season-standardized 25(OH)D concentrations with CRC risk. We anticipate that this project will take up to 12 months. The results of this project will improve our understanding about the associations of vitamin D status with colorectal cancer risk and survival, and help to develop new strategies for colorectal cancer prevention and treatment.