SEARCHSYSTEMATIC_REVIEWendocrinology, obstetrics

systematic_review·endocrinology, obstetrics, pulmonology, orthopedics, nephrology, oncology, geriatrics, rheumatology, pediatrics, neurology·PMC10027242

What do Cochrane systematic reviews say about interventions for vitamin D supplementation?

São Paulo Medical Journal · 7 authors, 5 centres

AI SUMMARY

FIDELITY 100%

POPULATIONHealthy individuals or those diagnosed with any clinical condition, regardless of age, ethnicity or sex

INTERVENTIONVitamin D supplementation in any form, presentation, dose, regimen or duration, as a single intervention

COMPARISONPlacebo, no intervention, or active comparators depending on the individual review

This summary was generated by AI from a single paper. It has not been reviewed by a clinician and is not clinical advice. Verify against the source before acting on it.

AGENT 01 · STRUCTURED SUMMARY

TRACE TO SOURCE

“

TL;DR

This review of 27 Cochrane systematic reviews found moderate-to-high quality evidence that vitamin D supplementation benefits pregnant women (reducing preterm birth and low birthweight risk) and asthma patients (reducing severe exacerbations), but no benefit for preventing fractures when used without calcium. For all other conditions evaluated, the evidence was low quality or insufficient to support any recommendation. These findings highlight the gap between widespread vitamin D use and the limited high-quality evidence supporting its clinical benefits.

Full summary

4,081 CHARS

**Background:** Vitamin D supplementation is highly prevalent, with approximately 40% of US adults using it, yet its efficacy and safety remain controversial. The number of published clinical trials on vitamin D has increased substantially, but heterogeneity in dosages, formulations, and clinical conditions has led to confusing conclusions. This review aimed to systematically identify and summarize all Cochrane systematic reviews evaluating vitamin D supplementation for preventing or treating any clinical condition.

**Methods:** A systematic search of the Cochrane Database of Systematic Reviews (CDSR) was conducted on April 4, 2017, using the MeSH term "Vitamin D" in titles, abstracts, and keywords. Two authors independently screened titles and abstracts. Completed Cochrane systematic reviews of any publication date were included if they assessed vitamin D supplementation as a single or combined intervention where the effect of vitamin D could be isolated. Protocols, withdrawn, or outdated reviews were excluded. No limitation was placed on participants, outcomes, or clinical conditions. Data were synthesized descriptively.

**Key Results:** The search retrieved 53 references; 27 Cochrane systematic reviews met inclusion criteria (10 on prevention, 17 on treatment). Key findings included: - **Asthma (9 RCTs, n=1,093):** Vitamin D reduced risk of exacerbations requiring systemic corticosteroids (RR 0.63; 95% CI 0.45 to 0.88; high-quality evidence) and risk of exacerbation requiring emergency visit or hospitalization (OR 0.39; 95% CI 0.19 to 0.78; high-quality evidence). No difference was found for lung function or asthma control. - **Pregnancy (15 RCTs, n=2,833):** Vitamin D reduced preterm birth risk (RR 0.36; 95% CI 0.14 to 0.93; moderate-quality evidence) and low birthweight risk (RR 0.40; 95% CI 0.24 to 0.67; moderate-quality evidence). No significant difference was found for preeclampsia, gestational diabetes, or adverse effects. - **Fracture prevention (53 RCTs, n=91,791):** Vitamin D alone showed no benefit for hip fracture (RR 1.12; 95% CI 0.98 to 1.29) or any new fracture (RR 1.03; 95% CI 0.96 to 1.11). - **Cancer prevention (18 RCTs, n=50,623):** No reduction in cancer risk (RR 1.00; 95% CI 0.94 to 1.06; moderate-quality evidence). All-cause mortality was reduced (RR 0.93; 95% CI 0.88 to 0.98; low-quality evidence) and cancer-related mortality was reduced with cholecalciferol (RR 0.88; 95% CI 0.78 to 0.98; low-quality evidence). - **Mortality prevention (56 RCTs with usable data, n=95,286):** Cholecalciferol reduced all-cause mortality (RR 0.94; 95% CI 0.91 to 0.98; NNT=150; moderate-quality evidence) and cancer-related mortality (RR 0.88; 95% CI 0.79 to 0.98; moderate-quality evidence). Cholecalciferol plus calcium increased nephrolithiasis risk (RR 1.07; 95% CI 1.02 to 1.34). - **Falls in elderly in care facilities:** Vitamin D reduced fall rate (RR 0.63; 95% CI 0.46 to 0.86) but not risk of falling (RR 0.99; 95% CI 0.9 to 1.08). No benefit was found for community-dwelling elderly. - For conditions including atopic eczema, sickle cell disease, multiple sclerosis, epilepsy, chronic pain, cystic fibrosis, hip fracture recovery, LADA, CKD (all stages), kidney transplant, ADPKD, HIV, tuberculosis, and stroke, evidence was insufficient or showed no benefit.

**Clinical Implications:** Based on moderate-to-high quality evidence, vitamin D supplementation benefits pregnant women (reducing preterm birth and low birthweight) and asthma patients (reducing severe exacerbations). Vitamin D alone does not prevent fractures. For all other conditions, evidence is low quality or insufficient. Eight reviews provided no reliable evidence on benefits or harms. Most trials had methodological limitations including small sample sizes, short follow-up, and inadequate randomization or blinding. Older Cochrane reviews may lack the methodological rigor of current standards (e.g., GRADE, Risk of Bias tables). Well-designed RCTs are urgently needed for conditions where off-label vitamin D use is already common in practice.

PICO

PPOPULATION

Healthy individuals or those diagnosed with any clinical condition, regardless of age, ethnicity or sex

IINTERVENTION

Vitamin D supplementation in any form, presentation, dose, regimen or duration, as a single intervention

OOUTCOME

Any clinical or laboratory outcomes evaluated by the authors of the systematic reviews

STUDY TYPE

systematic_review

SPECIALTY

endocrinology

SUMMARISED BY

AI pipeline

FIDELITY CHECK

100% · A

ORIGINAL PAPER

PMC10027242

What do Cochrane systematic reviews say about interventions for vitamin D supplementation?

São Paulo Medical Journal

READ THE FULL PAPER

ABSTRACT

ABSTRACT CONTEXT AND OBJECTIVE: Despite the high prevalence of vitamin D supplementation, its use remains controversial. The objective of this review was to identify and summarize the evidence from Cochrane systematic reviews regarding vitamin D supplementation for preventing or treating any clinical condition. DESIGN AND SETTING: Review of systematic reviews, conducted in the Discipline of Evidence-Based Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo. METHODS: A search was conducted to identify all Cochrane systematic reviews that fulfilled the inclusion criteria. Titles and abstracts were screened by two authors. RESULTS: We included 27 Cochrane systematic reviews: 10 assessing use of vitamin D for prevention and 17 for treatment. The reviews found moderate to high quality of evidence regarding the benefit of vitamin D for pregnant women (prevention of adverse events: preterm birth risk [rate ratio, RR 0.36; 95% confidence interval, CI 0.14 to 0.93] and low birthweight risk [RR 0.40; 95% CI 0.24 to 0.67]) and for asthma patients (reduction of severe exacerbations [RR 0.63; 95% CI 0.45 to 0.88]). No benefit was found regarding vitamin D supplementation alone (without calcium) for preventing hip or any new fracture. For all other outcomes assessed under various conditions, the current quality of evidence is low or unknown, and therefore insufficient for any recommendation. CONCLUSION: Based on moderate to high quality of evidence, the Cochrane systematic reviews included here showed that there were some benefits from vitamin D supplementation for pregnant women and asthma patients and no benefits for preventing fractures. KEY WORDS: Review, Vitamin D, Evidence-based medicine, Evaluation of results of therapeutic interventions, Evidence-based practice

CITATION EXPORT

Mariana Vendramin Mateussi, Carolina de Oliveira Cruz Latorraca, Júlia Pozetti Daou et al.. What do Cochrane systematic reviews say about interventions for vitamin D supplementation?. São Paulo Medical Journal. (2017). https://doi.org/10.1590/1516-3180.2017.0230150817

AUTHORS

7 · 5 CENTRES

Mariana Vendramin Mateussi, Carolina de Oliveira Cruz Latorraca, Júlia Pozetti Daou, Ana Luiza Cabrera Martimbianco, Rachel Riera, Rafael Leite Pacheco, Daniela Vianna Pachito

IUndergraduate Medical Student, Escola Paulista de Medicina - Universidade Federal de São Paulo (EPM-Unifesp), São Paulo (SP), Brazil.
IIMSc. Psychologist and Postgraduate Student, Postgraduate Evidence-Based Health Program, Universidade Federal de São Paulo (Unifesp), and Assistant Researcher, Cochrane Brazil, São Paulo (SP), Brazil.
IIIMSc, PhD. Physical Therapist and Assistant Researcher, Cochrane Brazil, São Paulo (SP), Brazil.
IVMD, MSc, PhD. Rheumatologist and Adjunct Professor, Discipline of Evidence-Based Medicine, Escola Paulista de Medicina - Universidade Federal de São Paulo (EPM-Unifesp); Assistant Coordinator, Cochrane Brazil, São Paulo (SP), Brazil.
VMD, MSc. Neurologist and Postgraduate Student, Postgraduate Evidence-Based Health Program, Universidade Federal de São Paulo (Unifesp), and Assistant Researcher, Cochrane Brazil, São Paulo (SP), Brazil.