Vitamin D Supplementation and All-Cause Mortality

Details for This Review

Study Population: Adults taking vitamin D supplements

Efficacy End Points: Decrease in all-cause mortality, cancer mortality, or cardiovascular mortality

Harm End Points: None

Narrative: Vitamin D supplementation has been a topic of debate for many years. Vitamin D is essential to skeletal health and may also have other extraskeletal benefits. Observational studies have shown that those with low vitamin D levels have higher cancer and cardiovascular mortality. There is ongoing research to determine if vitamin D plays a role in decreasing all-cause mortality. Previous systematic reviews and meta-analyses have shown that oral vitamin D therapy was associated with small decreases in all-cause mortality. Recent trials with double the number of participants have shown no benefit of vitamin D supplementation on mortality.

This meta-analysis reviewed the effectiveness of vitamin D to reduce all-cause mortality, cancer mortality, cardiovascular mortality, noncancer or noncardiovascular mortality, cerebrovascular mortality, and ischemic heart disease mortality.1 It included 52 randomized controlled trials published before December 26, 2018 with a total of 75,454 participants. Intention-to-treat analysis was conducted to evaluate outcomes. Subgroup analyses were performed for dose (at least 2,000 IU per day and less than 2,000 IU per day), type of vitamin D (vitamin D₂ and vitamin D₃), timing of treatment (daily and intermittent), baseline serum 25-hydroxyvitamin D level (at least 20 ng per mL [49.92 nmol per L] and less than 20 ng per mL), and mean age at least 70 years and younger than 70 years). Retrospective subgroup analyses were also performed based on length of follow-up