A systematic review and meta-analysis of circulating 25-hydroxyvitamin D concentration and vitamin D status worldwide.
Level 3 - non-randomized controlled study
Systematic review of observational (cross-sectional and cohort) studies
PubMed 40652566 · doi:10.1093/pubmed/fdaf080
What was done
A systematic review and random-effects meta-analysis (PROSPERO CRD42021242466) searched MEDLINE, Embase, Web of Science, Global Index Medicus, and grey literature for cross-sectional and cohort studies published since 2011. The authors included general, healthy populations of all ages to pool mean circulating 25-hydroxyvitamin D [25(OH)D] concentrations and estimate prevalence according to thresholds (< 30, < 50, and < 75 nmol/L) globally and across continents, countries, latitudes, sexes, age groups, seasons, assays, and study quality.
What was found
Across 586 eligible publications representing 2,370,136 participants from 102 countries, the pooled mean circulating 25(OH)D concentration was 53.9 nmol/L (95% CI: 52.6–55.1; 529 publications, 1,412,281 participants). The pooled prevalence of circulating 25(OH)D < 30 nmol/L was 18%, < 50 nmol/L was 47%, and < 75 nmol/L was 75% (403 studies, 1,508,830 participants).
Why it matters
This study provides broad global benchmarks for vitamin D status, demonstrating that nearly half of healthy individuals worldwide have circulating 25(OH)D below 50 nmol/L. These findings provide evidence to support public health interventions and regional supplementation strategies.
Limits
The analysis relies entirely on observational cross-sectional and cohort studies with substantial methodological and geographical heterogeneity. Varying laboratory assay methods across studies complicate cross-study comparisons. Only studies published since 2011 were included, and clinical health endpoints were not evaluated.
Cited by
- supports Vitamin D is clinically deficient in a high percentage of the population and subclinically low in the vast majority.