Vitamin D and mortality: meta-analysis of individual participant data from a large consortium of cohort studies from Europe and the United States.
Level 3 - non-randomized controlled study
Meta-analysis of individual participant data from prospective cohort studies
PubMed 24938302 · doi:10.1136/bmj.g3656
What was done
Meta-analysis of individual participant data from eight prospective cohort studies in Europe and the United States. The analysis included 26,018 men and women aged 50–79 years from the general population to assess the association between serum 25-hydroxyvitamin D (25(OH)D) concentrations and all-cause, cardiovascular, and cancer mortality, accounting for potential variation by age, sex, season, and country.
What was found
During follow-up, 6,695 participants died (2,624 from cardiovascular diseases and 2,227 from cancer). Serum 25(OH)D varied by season (higher in summer), country (higher in US and northern Europe), and sex (higher in men), with no consistent age trend. Comparing bottom versus top quintiles of 25(OH)D showed a pooled risk ratio of 1.57 (95% CI 1.36 to 1.81) for all-cause mortality. Cardiovascular mortality showed similar risk ratios in subjects with and without baseline cardiovascular disease. Cancer mortality was elevated only in participants with a history of cancer (risk ratio 1.70, 95% CI 1.00 to 2.88). Dose-response curves were curvilinear and inverse, with low heterogeneity and no major age, sex, season, or country differences.
Why it matters
This large-scale individual participant meta-analysis confirms a remarkably consistent observational link between low vitamin D levels and higher all-cause and cardiovascular mortality. However, intervention trials are required before recommending routine vitamin D supplementation for longevity.
Limits
The observational cohort design cannot rule out residual confounding or reverse causation, where illness itself lowers vitamin D levels. The abstract does not report specific 25(OH)D cut-off values or duration of follow-up, and associations with cancer mortality were restricted to those with pre-existing disease.
Cited by
- context Studies demonstrate that serum 25-hydroxyvitamin D levels around 80 ng/mL are associated with lower all-cause mortality.