Assertion: vitamin d | /r/HasProperty | compared with placebo
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text: Interestingly, in a meta-analysis evaluating the effects of vitamin D supplementation on overall mortality risk, a subgroup analysis (n = 13 in studies) of long-term vitamin D supplementation for at least 3 years revealed a reduction in mortality only when vitamin D plus calcium was compared with placebo but not when compared with calcium, and not when vitamin D alone was compared with placebo.