- Large RCT (n=21,315) fails to find significant effect of vitamin D supplementation on all-cause mortality; HR 1.04 [95% CI 0.93–1.18]. Excluding the first 2 years of follow-up, researchers also found a higher hazard of cancer mortality among the vitamin D group; HR 1.24 [95% CI 1.01–1.54]. https://www.thelancet.com/journals/landia/article/PIIS2213-8587(21)00345-4/fulltext 24 comments science