NoneNo Change
HbA1c
Vitamin D supplementation → HbA1c
Vitamin D supplementation → HbA1c
Evidence profile
NoneNo ChangeGlycemic Control
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Research Summary
Analyzed using Evidence Intelligence™
Vitamin D may not delay diabetes in women with prediabetes
Key finding
There was no statistical significance in the incidence of diabetes in the control group as compared to the intervention group at the end of 2 years (P = 0.701).
This randomized controlled trial investigated the effects of vitamin D supplementation on women with prediabetes, finding no significant impact on diabetes incidence or related metabolic markers.
Evidence strength
Moderate confidence
Study type
RCTs
Follow-up
Extended (5–20+ y)
Some Concerns bias
Last updated July 6, 2026Quick read
Study at a glance
The essential study design details in one scan.
Population
Young Adult (19–39), Middle Aged (40-64), Female, Asia-Pacific (APAC), with T2 Diabetes
Intervention
Vitamin D supplementation
Study type
RCTs
Follow-up
Extended (5–20+ y)
Primary outcome
type 2 diabetes mellitus
Comparator
Placebo Group
Plain-language summary
What this paper says
A plain-language read of the study's main message and where it applies.
Study focus
This randomized controlled trial investigated the effects of vitamin D supplementation on women with prediabetes, finding no significant impact on diabetes incidence or related metabolic markers.
Clinical relevance
These findings are important for clinicians and patients as they suggest that vitamin D supplementation may not be an effective strategy for preventing type 2 diabetes in women with prediabetes. Understanding the limitations of vitamin D in this context can help guide treatment decisions and patient education.
Keep in mind
The study may have limited generalizability due to the specific population studied. The duration of the study may not have been sufficient to observe long-term effects. Potential unmeasured confounding factors could have influenced the results.
Published in
Journal Reference
Publication details and source links for this paper.
Puneet M, Shashi K, Anoop M, et al. Vitamin D Supplementation in Women with Prediabetes: A Randomized Controlled Trial. Journal of Family Medicine and Primary Care. 2021;10(8):3122-3129. doi:10.4103/jfmpc.jfmpc_311_21
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Main Effects
No significant difference in the incidence of type 2 diabetes between the vitamin D and placebo groups (P = 0.701).
No statistically significant effect of vitamin D supplementation on serum HbA1c levels.
No statistically significant effect of vitamin D supplementation on serum cholesterol levels.
Evidence network
How this study fits
Understand where this research contributes within the broader evidence network.
Evidence Context
This study contributes evidence to Vitamin D supplementation and HbA1c, LDL cholesterol, type 2 diabetes mellitus.
This study contributes evidence to
Primary intervention
Vitamin D supplementation
Primary outcomes
- HbA1c
- LDL cholesterol
- type 2 diabetes mellitus
Evidence topics
Primary intervention
Primary outcomes
Evidence relationships
Intervention and outcome relationships this study adds to the evidence network.
3
Evidence pairs
3
Relationships
2
Evidence topics
contributes_evidence
Editorial context
Why this study matters
See why this paper is useful beyond its individual results.
Evidence network role
This section describes how the study fits into the current evidence network. It does not determine whether an intervention works on its own.
Moderate contributionModerate confidenceNetwork score: 65
2
Related topics
3
Evidence pairs
355
Related studies
High relevance in at least one topic
Why it is useful
- Contributes to 3 evidence relationships
- Includes primary outcome data
- Linked to 2 direct semantic evidence topics
Topic contributions
Evidence topic
Contributes evidence
Evidence topic
Contributes evidence
Core evidence
Study findings
The primary outcomes reported in this study.
NoneNo Change
LDL cholesterol
Vitamin D supplementation → LDL cholesterol
Vitamin D supplementation → LDL cholesterol
Evidence profile
NoneNo ChangeMetabolic Health
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NoneNo Change
type 2 diabetes mellitus
Vitamin D supplementation → type 2 diabetes mellitus
Vitamin D supplementation → type 2 diabetes mellitus
Evidence profile
NoneNo ChangeClinical Outcomes
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Unlock full evidence analysis
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Evidence Suggest
- Vitamin D supplementation did not significantly lower diabetes incidence over two years.
- No impact on HbA1c levels was observed with vitamin D supplementation.
- Cholesterol levels remained unchanged despite vitamin D intake.
Who this applies to
- Women diagnosed with prediabetes.
- Individuals at risk for developing type 2 diabetes.
Keep in Mind
- The findings may not apply to men or other age groups.
- Results are specific to the supplementation dosage and duration used in the study.
- Further research is needed to explore other potential benefits of vitamin D supplementation.
Between the Lines
- The study may have limited generalizability due to the specific population studied.
- The duration of the study may not have been sufficient to observe long-term effects.
- Potential unmeasured confounding factors could have influenced the results.
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Connected Evidence
Explore related studies, evidence collections, and research questions.
Relationships organized using the Dediabetes Evidence Intelligence™ framework.
This study contributes to evidence on Vitamin D supplementation and HbA1c, Vitamin D supplementation and Diabetes Incidence and Prevention.
Related evidence relationships
Explore in Evidence ArchiveThis study contributes to the evidence on the following intervention-outcome relationships.
Included in these evidence collections
Curated evidence collections and hubs this study is part of.
HbA1c Evidence Hub
All studies measuring HbA1c
5 studies
outcome_hubMeasures HbA1c as a key outcome.
Vitamin D supplementation Evidence Hub
All studies on Vitamin D supplementation
5 studies
intervention_hubContributes to Vitamin D supplementation evidence base.
Adipokine and Angiogenic Markers Evidence Hub
All studies measuring Adipokine and Angiogenic Markers
2 studies
outcome_hubMeasures Adipokine and Angiogenic Markers as a key outcome.
Diabetes Incidence and Prevention Evidence Hub
All studies measuring Diabetes Incidence and Prevention
2 studies
outcome_hubMeasures Diabetes Incidence and Prevention as a key outcome.
Explore more in the evidence archive
Jump to pre-filtered views in the evidence archive.
All studies on Vitamin D supplementation and HbA1c
Intervention: Vitamin D supplementationOutcome: HbA1c
5 results
All studies on Vitamin D supplementation and type 2 diabetes mellitus
Intervention: Vitamin D supplementationOutcome: type 2 diabetes mellitus
2 results
All studies on Vitamin D supplementation
Intervention: Vitamin D supplementation
5 results
All studies measuring HbA1c
Outcome: HbA1c
5 results
All studies measuring type 2 diabetes mellitus
Outcome: type 2 diabetes mellitus
2 results
Questions answered by this study
Generated from the study's connected evidence using Evidence Intelligence™.
Does Vitamin D supplementation improve HbA1c?
Emerging Evidence
Vitamin D supplementation may improve HbA1c.
ConsensusScore™: Results are generally consistent across studies.
Ranked evidence signals
- 1
HbA1c
EvidenceScore™ Emerging | EvidenceScore™ 55.2 | moderate positive | ConsensusScore™ Generally Consistent | 1 study
Why this answer: This answer is based on a single supporting study.
Limitations
- Only one supporting study is available.
- Population details are unavailable.
Does Vitamin D supplementation improve type 2 diabetes mellitus?
Emerging Evidence
Current evidence does not show a clear benefit of Vitamin D supplementation for type 2 diabetes mellitus.
ConsensusScore™: Results are consistent across studies.
Ranked evidence signals
- 1
type 2 diabetes mellitus
EvidenceScore™ Emerging | EvidenceScore™ 40.2 | neutral | ConsensusScore™ Consistent | 1 study
Why this answer: This answer is based on a single supporting study.
Limitations
- Only one supporting study is available.
- Population details are unavailable.
Does Vitamin D supplementation improve ldl cholesterol?
Limited Evidence
Current evidence does not show a clear benefit of Vitamin D supplementation for LDL cholesterol.
ConsensusScore™: Results are consistent across studies.
Ranked evidence signals
- 1
LDL cholesterol
EvidenceScore™ Limited | EvidenceScore™ 39.0 | neutral | ConsensusScore™ Consistent | 1 study
Why this answer: This answer is based on a single supporting study.
Limitations
- Only one supporting study is available.
- Population details are unavailable.
Next steps
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