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Combined vitamin D and calcium supplementation, or calcium alone, improves sleep quality in individuals with prediabetes

In a 24-week RCT of 212 Chinese adults with prediabetes, the vitamin D plus calcium group showed a significant reduction in total PSQI score compared to pre-intervention levels. Subgroup analyses indicated that calcium supplementation alone improved sleep quality in women, those with low baseline 25(OH)D (<30 ng/mL), and menopausal individuals.

Last updated: Jul 7, 2026•1 RCTs•📖 Read as article →

Evidence Score

Evidence Score44/100
Human RCT★★☆☆☆
Meta-analysis☆☆☆☆☆
Mechanism★★★★★
Safety★★★★☆
Confidencelow

Study Evidence

Study 1. Effects of vitamin D and/or calcium intervention on sleep quality in individuals with prediabetes: a post hoc analysis of a randomized controlled trial.

observational

Miao Y, Zhang L, Zhang D, Feng M, Zhang C, Zhao T, Song H, Zhong X, Jiang Z, Li L, Wei X, Li W, Li X · European journal of nutrition (2024)

Participants: N/A
Duration: 24 weeks
Intervention: Vitamin D (1600 IU/day) plus calcium (500 mg/day), vitamin D alone (1600 IU/day), calcium alone (500 mg/day), or placebo
Outcome: Sleep quality measured by Pittsburgh Sleep Quality Index (PSQI) total score and sleep efficiency subscore
Effect Size: N/A (only P values reported; significant difference in PSQI for combined group vs pre-intervention, and P<0.05 for calcium subgroup effects)
Population: 212 Chinese adults with prediabetes

Result:

PubMed: 38366270DOI: 10.1007/s00394-024-03345-7

Mechanism Graph

Calcium supplementation may improve sleep efficiency
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Improved sleep efficiency correlates with reduced insulin resistance (negative correlation between change in sleep efficiency and change in insulin efficiency scores, r=-0.264, P=0.007)
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Improved sleep efficiency also correlates with reduced islet beta cell function change (r=-0.304, P=0.002)
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Result: Potential improvement in sleep quality via metabolic pathways

Limitations

  • ⚠Post hoc analysis of a randomized controlled trial, not a primary outcome analysis
  • ⚠Subgroup analyses were exploratory and may be underpowered
  • ⚠Specific effect sizes (e.g., Cohen's d) not reported, limiting quantitative interpretation

Frequently Asked Questions

What dose of vitamin D and calcium was used in this study?▼

The study used 1600 IU/day of vitamin D and 500 mg/day of calcium, either alone or in combination.

Who benefited most from calcium supplementation for sleep?▼

Subgroup analyses showed improved sleep quality with calcium supplementation in women, individuals with low baseline vitamin D levels (<30 ng/mL), and those in menopause.

How was sleep quality measured in this trial?▼

Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI), a validated self-report questionnaire.

Was this a primary analysis or a post hoc analysis?▼

This was a post hoc analysis of a randomized controlled trial, meaning the sleep outcome was not the original primary endpoint.

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References

  1. 1.Miao Y, Zhang L, Zhang D, Feng M, Zhang C, Zhao T, Song H, Zhong X, Jiang Z, Li L, Wei X, Li W, Li X. "Effects of vitamin D and/or calcium intervention on sleep quality in individuals with prediabetes: a post hoc analysis of a randomized controlled trial.." European journal of nutrition, 2024. PMID: 38366270 DOI: 10.1007/s00394-024-03345-7
Disclaimer: This content is for educational purposes only and is not medical advice. Evidence scores reflect the quality and quantity of available research, not clinical recommendations. Always consult a healthcare professional before starting any supplement or intervention.