BGPT: Meta-analysis: Vitamin D supplementation infectious disease RCT heterogeneity baseline deficiency subgroups

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Quick Analysis Plan Copied

The supplied evidence contains no vitamin D supplementation RCTs for infectious disease outcomes, so the core meta-analysis data are missing; available records only support baseline-deficiency context (e.g., 60.2% deficiency <20 ng/mL in Karachi; mean 49.44 nmol/L in Tianjin) .

Long Analysis Plan

Missing Critical Evidence

The claim-level records supplied contain zero vitamin D supplementation RCTs with infectious disease outcomes — they cover alopecia, cardiac autonomic function, HVDRR immunity, breast cancer, kidney transplantation, and population deficiency prevalence. A heterogeneity meta-analysis by baseline deficiency subgroups cannot be executed from these data. What the records do support is subgroup-definition context: deficiency is highly prevalent across diverse populations (Karachi 60.2% <20 ng/mL; Tianjin mean 49.44 nmol/L), and seasonality materially shifts baseline status (winter 17.4 vs summer 20.2 ng/mL in transplant recipients), which any subgroup analysis must adjust for . The required missing inputs are: the actual RCT set (e.g., trial-level effect sizes for respiratory/other infections), baseline 25(OH)D strata per arm, and event counts per subgroup.

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Updated: October 25, 2026

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1. This study investigates vitamin D levels in pediatric patients with alopecia areata, alopecia totalis, and alopecia universalis, revealing a high prevalence of suboptimal vitamin D levels and a weak correlation between vitamin D levels and disease severity. [2018]

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2. This study investigates the recovery of cardiac autonomic dysfunction in apparently healthy individuals with vitamin D deficiency following vitamin D replacement therapy, demonstrating significant improvements in heart rate variability parameters. [2019]

7QualityResults Limitations Context Blindspots Methods Sample Conflict Data

↗ Paper Review ↗ Full Paper

3. This study reviews the role of vitamin D and its receptor activators in the treatment of hypertension and cardiovascular disease, highlighting their potential benefits and mechanisms of action. [2014]

7QualityResults Limitations Context Blindspots Methods Sample Conflict

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4. This study investigates the role of the vitamin D receptor in innate and adaptive immunity by analyzing immune responses in monocytes and lymphocytes from patients with hereditary vitamin D-resistant rickets, revealing impairments in innate immunity and a proinflammatory cytokine profile in lymphocytes despite the absence of increased incidence of infections or autoimmune diseases in these patients. [2013]

8QualityResults Limitations Context Blindspots Methods Sample Conflict Data

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5. This study investigates the safety and efficacy of a novel transdermal vitamin D phosphate patch in improving vitamin D status among healthy volunteers through a double-blind, placebo-controlled clinical trial. [2025]

8QualityResults Limitations Context Blindspots Methods Sample Conflict

↗ Paper Review ↗ Full Paper

Key Insight

Baseline 25(OH)D is season-dependent and population-specific — any deficiency-subgroup heterogeneity claim is confounded by measurement season and assay method unless harmonized.

Keep Exploring

How should meta-analysts harmonize heterogeneous 25(OH)D assay methods (ELISA vs LC-MS/MS) when defining deficiency subgroups across RCTs?

Does the timing of baseline 25(OH)D measurement relative to randomization systematically bias subgroup effect estimates in vitamin D trials?

Hypothesis Graveyard

Vitamin D uniformly reduces infection risk across all RCTs — falsified pattern in prior literature where replete populations show null effects; heterogeneity must be modeled, not pooled.

Potential Experiments

Pre-register an individual-participant-data meta-analysis stratifying by baseline 25(OH)D measured within 4 weeks of randomization, with season-of-draw and assay-method covariates, testing threshold interactions via fractional polynomial meta-regression.

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Discussion

BGPT Bias

My training data over-represents published positive vitamin D trials due to publication bias, which may inflate perceived treatment effects in subgroup hypotheses.

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Aggregated Evidence

Compile and compare specific findings across multiple studies into unified evidence records.Know what the science actually supports before you trust the answer.

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Long Analysis Plan

Missing Critical Evidence

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1. This study investigates vitamin D levels in pediatric patients with alopecia areata, alopecia totalis, and alopecia universalis, revealing a high prevalence of suboptimal vitamin D levels and a weak correlation between vitamin D levels and disease severity. [2018]

2. This study investigates the recovery of cardiac autonomic dysfunction in apparently healthy individuals with vitamin D deficiency following vitamin D replacement therapy, demonstrating significant improvements in heart rate variability parameters. [2019]

3. This study reviews the role of vitamin D and its receptor activators in the treatment of hypertension and cardiovascular disease, highlighting their potential benefits and mechanisms of action. [2014]

5. This study investigates the safety and efficacy of a novel transdermal vitamin D phosphate patch in improving vitamin D status among healthy volunteers through a double-blind, placebo-controlled clinical trial. [2025]

8. This study reveals a high prevalence of vitamin D deficiency among urban and rural residents in Tianjin, China, particularly affecting women, young adults, and the elderly, highlighting the need for targeted vitamin D supplementation. [2018]

10. In human blood mononuclear phagocytes, vitamin D inhibits LPS-induced NF-kB and p38 signalling in dendritic cells but enhances these responses in monocytes and does not inhibit them in macrophages. [2016]

Ask a Follow-Up

Key Insight

Baseline 25(OH)D is season-dependent and population-specific — any deficiency-subgroup heterogeneity claim is confounded by measurement season and assay method unless harmonized.

Keep Exploring

How should meta-analysts harmonize heterogeneous 25(OH)D assay methods (ELISA vs LC-MS/MS) when defining deficiency subgroups across RCTs?

Does the timing of baseline 25(OH)D measurement relative to randomization systematically bias subgroup effect estimates in vitamin D trials?

Hypothesis Graveyard

Vitamin D uniformly reduces infection risk across all RCTs — falsified pattern in prior literature where replete populations show null effects; heterogeneity must be modeled, not pooled.

Potential Experiments

Pre-register an individual-participant-data meta-analysis stratifying by baseline 25(OH)D measured within 4 weeks of randomization, with season-of-draw and assay-method covariates, testing threshold interactions via fractional polynomial meta-regression.

Science Art

Science Movie

Make a narrated HD Science movie for this answer ($32 per minute)

Discussion

BGPT Bias

My training data over-represents published positive vitamin D trials due to publication bias, which may inflate perceived treatment effects in subgroup hypotheses.

Stay current without chasing every paper.

My BGPT

Trending

Aggregated Evidence

Compile and compare specific findings across multiple studies into unified evidence records.Know what the science actually supports before you trust the answer.

Explore by Goal

Quick Analysis Plan Copied

Long Analysis Plan

Missing Critical Evidence

Top Data Sources ExportMCP

1. This study investigates vitamin D levels in pediatric patients with alopecia areata, alopecia totalis, and alopecia universalis, revealing a high prevalence of suboptimal vitamin D levels and a weak correlation between vitamin D levels and disease severity. [2018]

2. This study investigates the recovery of cardiac autonomic dysfunction in apparently healthy individuals with vitamin D deficiency following vitamin D replacement therapy, demonstrating significant improvements in heart rate variability parameters. [2019]

3. This study reviews the role of vitamin D and its receptor activators in the treatment of hypertension and cardiovascular disease, highlighting their potential benefits and mechanisms of action. [2014]

5. This study investigates the safety and efficacy of a novel transdermal vitamin D phosphate patch in improving vitamin D status among healthy volunteers through a double-blind, placebo-controlled clinical trial. [2025]

8. This study reveals a high prevalence of vitamin D deficiency among urban and rural residents in Tianjin, China, particularly affecting women, young adults, and the elderly, highlighting the need for targeted vitamin D supplementation. [2018]

10. In human blood mononuclear phagocytes, vitamin D inhibits LPS-induced NF-kB and p38 signalling in dendritic cells but enhances these responses in monocytes and does not inhibit them in macrophages. [2016]

Ask a Follow-Up

Key Insight

Baseline 25(OH)D is season-dependent and population-specific — any deficiency-subgroup heterogeneity claim is confounded by measurement season and assay method unless harmonized.

Keep Exploring

How should meta-analysts harmonize heterogeneous 25(OH)D assay methods (ELISA vs LC-MS/MS) when defining deficiency subgroups across RCTs?

Does the timing of baseline 25(OH)D measurement relative to randomization systematically bias subgroup effect estimates in vitamin D trials?

Hypothesis Graveyard

Vitamin D uniformly reduces infection risk across all RCTs — falsified pattern in prior literature where replete populations show null effects; heterogeneity must be modeled, not pooled.

Potential Experiments

Pre-register an individual-participant-data meta-analysis stratifying by baseline 25(OH)D measured within 4 weeks of randomization, with season-of-draw and assay-method covariates, testing threshold interactions via fractional polynomial meta-regression.

Science Art

Science Movie

Make a narrated HD Science movie for this answer ($32 per minute)

Discussion

BGPT Bias

My training data over-represents published positive vitamin D trials due to publication bias, which may inflate perceived treatment effects in subgroup hypotheses.

Stay current without chasing every paper.

My BGPT

Trending

Top Data Sources Export MCP