Effect of Vitamin D3 Supplements on Development of Advanced Cancer
...randomized clinical trial with 25 871 patients, from November 1, 2011, to December 31, 2017.
...supplementation with vitamin D3 reduced the incidence of advanced (metastatic or fatal) cancer in the overall cohort,
...with strongest risk reduction in individuals with normal weight
...and no reduction among individuals with overweight or obesity.
Objective To follow up on the possible reduction in cancer death in the Vitamin D and Omega-3 Trial (VITAL)
The VITAL study was a randomized, double-blind, placebo-controlled, 2 × 2 factorial trial that examined the benefits and risks of vitamin D3 (cholecalciferol, 2000 IU/d) and marine omega-3 fatty acids (1 g/d) for primary prevention of cancer and cardiovascular disease among 25 871 participants (men aged ≥50 years and women aged ≥55 years).
Doses (cholecalciferol, 2000 IU/d) and marine omega-3 fatty acids (1 g/d)
participants were in the USA and included men aged 50 years or older and women aged 55 years or older who were free of cancer and cardiovascular disease at baseline.
HR Hazard Ratio: The hazard ratio is the ratio of (chance of an event occurring in the treatment arm)/(chance of an event occurring in the control arm)
A hazard ratio of 0.5 means that half as many patients in the active group have an event at any point in time compared with placebo, proportionately.
significant reduction for the vitamin D arm in incident metastatic or fatal cancer among those with normal BMI (BMI<25: HR, 0.62 [95% CI, 0.45-0.86]) but not among those with overweight or obesity (BMI 25-<30: HR, 0.89 [95% CI, 0.68-1.17]; BMI≥30: HR, 1.05 [95% CI, 0.74-1.49]) (P = .03 for interaction by BMI).
Compared with placebo in the Vitamin D and Omega-3 Trial (VITAL),6 the hazard ratio (HR) for the vitamin D arm for incident total invasive cancer was 0.96 (95% CI, 0.88-1.06),
...but for total cancer mortality was 0.83 (0.67-1.02),
...suggesting a potential role of vitamin D in reducing metastatic or lethal cancers (HR 0.96-0.83=0.13).
Moreover, incident cancers were reduced in those with normal body mass index (BMI) but not in those with overweight or obesity
...prostate cancer was associated with a lower but nonsignificant reduction in incidence with vitamin D supplementation; excluding metastatic /fatal prostate cancer results (HR, 0.85; 95% CI, 0.71-1.02; P = .08).
Vitamin D deficiency prevalence is high in cancer patients ref 25,26, with 1 study reporting vitamin D deficiency in 72% of cancer patients; ref 19,27
Removing prostate cancer from analyses did not attenuate the observed effect of vitamin D supplementation on advanced cancer, suggesting the results were not driven by prostate cancer alone.
Our findings suggest that vitamin D supplementation may be operating through a general, rather than site-specific, mechanism to reduce the risk of advanced cancer.
