Calcium, vitamin D, dairy products, and mortality among colorectal cancer survivors: The cancer prevention study-II nutrition cohort

Purpose: Higher calcium, vitamin D, and dairy product intakes are associated with lower colorectal cancer incidence, but their impacts on colorectal cancer survival are unclear. We evaluated associations of calcium, vitamin D, and dairy product intakes before and after colorectal cancer diagnosis with all-cause and colorectal cancer-specific mortality among colorectal cancer patients. Patients and Methods: This analysis included 2,284 participants in a prospective cohort who were diagnosed with invasive, nonmetastatic colorectal cancer after baseline (1992 or 1993) and up to 2009. Mortality follow-up was through 2010. Prediagnosis risk factor information was collected on the baseline questionnaire. Postdiagnosis information was collected via questionnaires in 1999 and 2003 and was available for 1,111 patients. Results: A total of 949 participants with colorectal cancer died during follow-up, including 408 from colorectal cancer. In multivariable-adjusted Cox proportional hazards regression models, postdiagnosis total calcium intake was inversely associated with all-cause mortality (relative risk [RR] for those in the highest relative to the lowest quartiles, 0.72; 95% CI, 0.53-0.98; P _trend = .02) and associated with marginally statistically significant reduced colorectal cancer-specific mortality (RR, 0.59; 95% CI, 0.33 to 1.05; P_trend = .01). An inverse association with all-cause mortality was also observed for postdiagnosis milk intake (RR, 0.72; 95% CI, 0.55 to 0.94; P_trend = .02), but not vitamin D intake. Prediagnosis calcium, vitamin D, and dairy product intakes were not associated with any mortality outcomes. Conclusion: Higher postdiagnosis intakes of total calcium and milk may be associated with lower risk of death among patients with nonmetastatic colorectal cancer.