Post-diagnostic multivitamin supplement use and colorectal cancer survival: A prospective cohort study

Abstract

Background: Use of multivitamin supplements has been associated with lower incidence of colorectal cancer (CRC). However, its influence on CRC survival remains unknown. Methods: Among 2424 patients with stage I–III CRC who provided detailed information about multivitamin supplements in the Nurses’ Health Study and Health Professionals Follow-up Study, the authors calculated multivariable hazard ratios (HRs) of multivitamin supplements for all-cause and CRC-specific mortality according to post-diagnostic use and dose of multivitamin supplements. Results: During a median follow-up of 11 years, the authors documented 1512 deaths, among which 343 were of CRC. Compared to non-users, post-diagnostic users of multivitamin supplements at a dose of 3–5 tablets/week had lower CRC-specific mortality (HR, 0.55; 95% confidence interval [CI], 0.36–0.83, p =.005), and post-diagnostic users at doses of 3–5 and 6–9 tablets/week had lower all-cause mortality (HR, 0.81; 95% CI, 0.67–0.99, p =.04; HR, 0.79; 95% CI, 0.70–0.88), p <10 tablets/week had a lower all-cause mortality (HR, 0.81; 95% CI, 0.71–0.94, p =.005), whereas new users at a dose of ≥10 tablets/week (HR, 1.58; 95% CI, 1.07–2.33) and discontinued users (HR, 1.35; 95% CI, 1.14–1.59) had a higher risk of mortality. Conclusions: Use of multivitamin supplements at a moderate dose after a diagnosis of nonmetastatic CRC is associated with lower CRC-specific and overall mortality, whereas a high dose (≥10 tablets/week) use is associated with higher CRC-specific mortality.