Meta-analysis of all-cause mortality according to serum 25-hydroxyvitamin D.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of observational studies
PubMed 24922127 · doi:10.2105/AJPH.2014.302034
What was done
Authors searched biomedical databases from January 1, 1966, to January 15, 2013, for articles assessing serum 25-hydroxyvitamin D (25[OH]D) across two or more categories in relation to all-cause mortality. Data from 32 identified studies were pooled in a meta-analysis.
What was found
Comparing the lowest category of serum 25(OH)D (0–9 ng/mL) to the highest category (>30 ng/mL), the pooled hazard ratio for all-cause mortality was 1.9 (95% CI: 1.6, 2.2; P < .001). Concentrations of 25(OH)D ≤30 ng/mL were associated with significantly higher all-cause mortality than concentrations >30 ng/mL (P < .01).
Why it matters
The findings demonstrate a significant inverse association between serum vitamin D levels and all-cause mortality, suggesting that the threshold for mortality reduction may be above 30 ng/mL rather than the 20 ng/mL cutoff proposed by the National Academy of Sciences.
Limits
The pooled evidence is observational, which precludes causal inference due to potential residual confounding and reverse causality. The abstract does not report the total participant count, population characteristics, follow-up durations, or specific adjustment covariates across the included studies.
Cited by
- supports Having serum vitamin D levels above 30 ng/mL is associated with lower all-cause mortality, particularly lower cancer mortality and respiratory disease mortality.
- context Studies demonstrate that serum 25-hydroxyvitamin D levels around 80 ng/mL are associated with lower all-cause mortality.