Sun Yat-sen University Cancer Center, China (People's Republic)
Objectives: Calcium has been shown to reduce the toxic effects on epithelial cells by binding ionized fatty acids and secondary bile acids in the colon, thereby protecting against colorectal cancer (CRC). However, few studies have examined the association between dietary calcium intake and survival in CRC patients. This study aimed to explore the relationship between dietary calcium intake and overall survival, CRC-specific survival, disease-free survival and metastasis-recurrence risk among CRC survivors.
Methods: This prospective cohort study used data from the Guangdong Colorectal Cancer Cohort, enrolling patients with newly diagnosed CRC from 2010 to 2021, with follow-up until 2023. Dietary information from the year prior to diagnosis was obtained using a validated food frequency questionnaire. Multivariable Cox proportional hazard regression models were used to calculate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). Stratified analyses by tumor site and TNM stage were performed, and restricted cubic spline were used to examine the nonlinear association between dietary calcium intake and survival outcomes.
Results: A total of 2,799 CRC patients were included in the study, of whom 639 deaths were recorded during a median follow-up of 60.33 months, with 574 of those deaths attributed to CRC. Higher total dietary calcium intake was associated with improved overall survival, CRC-specific survival, disease-free survival, and a decreased risk of metastasis and recurrence. Significant associations were observed between vegetable-derived calcium intake and improved overall survival, CRC-specific survival, and disease-free survival, with adjusted HRs of 0.74 (95% CI, 0.58-0.95), 0.65 (95% CI, 0.50-0.84), and 0.78 (95% CI, 0.63-0.97) when comparing the highest to the lowest quartile. Results differed by tumor site. Nonlinear relationship was observed between calcium intake from dairy products and the risk of metastasis-recurrence (Pnonlinear = 0.020).
Conclusions: Higher total dietary calcium intake, as well as calcium derived from vegetables, were both associated with prolonged overall survival, CRC-specific survival, and disease-free survival among CRC patients. This suggests that maintaining a moderately high intake of calcium, particularly from vegetables, may have a potential benefit for the prognosis of CRC.
