Vitamin D for skeletal and non-skeletal health: What we should know.
Level 5 - mechanism / opinion, no new human data
Narrative review and expert summary without systematic search or meta-analysis
PubMed 31708633 · doi:10.1016/j.jcot.2019.07.004
What was done
This is a narrative review summarizing vitamin D physiology, metabolism, clinical guidelines, and epidemiological associations. The authors synthesize diagnostic criteria defined by the Endocrine Society and review observational evidence regarding skeletal and non-skeletal health outcomes without systematic search methodology.
What was found
The abstract reports diagnostic thresholds for serum 25(OH)D: deficiency (<20 ng/mL), insufficiency (21–29 ng/mL), and sufficiency (30–100 ng/mL). It cites an estimated global prevalence of 1 billion people with vitamin D deficiency or insufficiency. Observational studies are referenced linking serum levels between 40–60 ng/mL to lower mortality and reduced risk of chronic diseases. No primary comparative data, effect sizes, or confidence intervals are reported.
Why it matters
It provides a broad overview of vitamin D biology for clinical practice, emphasizes targeted screening in high-risk populations (such as patients with osteoporosis or fall history), and notes the risk of underestimation when laboratory assays measure only 25(OH)D3 rather than total 25(OH)D.
Limits
As a narrative review, it lacks systematic search criteria, quality appraisal, or meta-analytic pooling. Assertions regarding chronic disease prevention and mortality rely on observational correlations subject to confounding, with no trial data presented to establish causality.
Cited by
- supports Vitamin D3 is metabolized in the liver to 25-hydroxyvitamin D, and then converted in the kidneys into the active steroid hormone 1,25-dihydroxyvitamin D.