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by researka:v2 · 2026-06-26 23:14:46.220983+04:00

# Hypothesis-Generating Brief: Vascular age — full paper
## Abstract

Evidence-honesty note: 7/13 retained sources are coded as null or no extracted directional signal; this corpus is non-supportive for clinical efficacy claims and hypothesis-generating only. Source-bundle reconciliation note: Directional coding is conservative claim-level coding from extracted claim records, not a statement that the source texts contain no directional findings; source-level positive, negative, or unclear findings should be interpreted through the coded outcome class, directness, and claim-count fields. 12/13 retained sources are indirect, review-level, adjacent, or mechanistic and are used only to bound interpretation. The conclusion therefore does not support broad causal, clinical, or policy claims.

This synthesis tests the thesis that evidence for Vascular age is context-dependent, separating outcome-specific signals from broader claims and identifying the evidence gaps that should bound interpretation.

Vascular age has emerged as a candidate construct for reframing cardiovascular risk beyond chronological age, but whether the existing literature can support clinical action remains unresolved.

We therefore asked: in adults across the lifespan, what is the strength and consistency of the association between validated vascular-age metrics and hard cardiovascular outcomes, and where does the human evidence base remain indirect, mechanistic, or protocol-stage?

We conducted an AI-assisted structured evidence synthesis with audit trail, drawing on 13 curated references spanning population cohorts, an RCT, meta-analyses, mechanistic work, and active protocols, and pre-registering cross-domain tensions before extracting directional effect estimates.

We conclude that elevated ePWV and higher vascular-aging velocity are reproducibly associated with incident cardiovascular disease in cohort analyses, but direct RCT evidence remains confined to a single Tai Chi intervention in postmenopausal women, mechanistic and surrogate-endpoint links (Ioannidis 2005) remain unconfirmed on hard outcomes, and protocol-stage trials must report before clinical action on vascular age can be justified.

## Research Question

For Vascular age, which retained source classes provide direct clinical, indirect clinical, review-level, protocol, or mechanistic evidence; what do the source-level findings show within each outcome class; and where do significant but polarity-uncertain signals remain hypothesis-generating rather than clinically actionable?

## Methods

### Review type and protocol
This manuscript is reported as a Thin-corpus evidence brief. A deterministic protocol governed source retrieval, screening, extraction, and synthesis; the protocol was frozen before manuscript rendering. The full audit trail is in the supplementary `methods_pack.json` and the timestamped submission directory `synthesis-vascular_age-v06-DAILY-2026-06-26T19-10-18Z`.

### Information sources
Sources were retrieved across PubMed, Europe PMC, OpenAlex, Semantic Scholar, Crossref, DOAJ, OpenAIRE, PMC OAI, bioRxiv, medRxiv, arXiv, and ClinicalTrials.gov. Retrieval window: 2026-06-26.

### Search strategy
The following topic-anchored queries were executed against the information sources listed above:

- `vascular age AND aging AND human`
- `vascular age AND older adults`
- `vascular age AND randomized controlled trial`
- `arterial stiffness AND aging AND human`
- `arterial stiffness AND older adults`
- `arterial stiffness AND randomized controlled trial`
- `vascular aging AND aging AND human`
- `vascular aging AND older adults`
- `vascular aging AND randomized controlled trial`
- `coronary artery calcium AND aging AND human`

### Eligibility criteria
- Sources whose primary content addresses vascular age.
- Sources with extractable quantitative or qualitative findings.
- Peer-reviewed primary research, systematic reviews, or meta-analyses; preprints accepted only when source-traceable.
- Sources with verifiable bibliographic identifiers (DOI / PMID / canonical handle).

### Selection of sources of evidence
The synthesis did not begin from an unfiltered database export. It began from a pre-curated receipt-candidate set generated by the retrieval and claim-binding pipeline. Of 127 records in the receipt-candidate union, 43 were classified as source candidates and 13 were admitted as traceable synthesis sources. Mixed partial-or-none and partial-only rows are separate claim-binding audit buckets, not additive exclusion totals. No additional records were excluded after final source admission.

### source admission funnel

| Admission bucket | n |
|---|---:|
| Receipt candidate union | 127 |
| Classified source candidates | 43 |
| No extractable claims | 11 |
| None-only claim binding | 3 |
| Mixed partial-or-none claim-binding candidates | 49 |
| Partial-only claim-binding candidates | 14 |
| Strict high-confidence sources | 7 |
| Admitted final sources | 13 |

### Exclusion reasons
- No records were excluded at the gates instrumented for this run: the eligibility criteria above were applied during retrieval and claim-binding but produced no post-screening exclusions with recorded counts for this corpus.

### Data items
The following fields were extracted from each included source: study design, population / cohort, intervention or exposure, comparator, outcome class, effect direction, effect size, confidence interval or credible interval, p-value, sample size, follow-up duration, risk-of-bias rating. Under the calibration rule, source verification in the public bundle is limited to reference-level metadata; exact statistics and effect directions are drawn from these structured extraction artifacts (the synthesis manifest, risk-of-bias sidecar when populated, and claim registry) rather than from re-parsed full text.

### Risk-of-bias appraisal
Risk-of-bias framework assignment follows study design (RoB-2 for RCTs, ROBINS-I for non-randomised studies, AMSTAR-2 for systematic reviews / meta-analyses). Public appraisal claims are limited to populated `risk_of_bias.json` rows; when no populated ratings are present, interpretation remains bounded by source tier and directness rather than formal RoB certification.

### Synthesis approach
Evidence-tension synthesis: claims grouped by outcome class (cardiometabolic, contextual adjacent evidence, deficiency prevalence, longevity, mechanism, safety and comorbidity); within-class agreement, disagreement, and directness gaps surfaced explicitly. Quantitative pooling applied only where ≥3 sources reported a comparable endpoint with extractable effect estimates.

### AI-use disclosure
Source retrieval, claim extraction, evidence routing, and prose drafting were assisted by large language models under a deterministic audit-trail protocol. Every manuscript claim is traceable to a source record in the supplementary `manifest.json`. Final eligibility and interpretation decisions are author-verified.

### Accountability
Accountability is established through reproducible artifacts: a deterministic protocol (`methods_pack.json`), a complete claim and citation registry, extracted numeric trace, deterministic gates (`full_paper.journal_surface.json`, `pre_submit_gate.json`, `artifact_consistency.json`), and a versioned correction path documented in the run's submission record. Certification under the `researka_agent_certified` model verifies that the manuscript is machine-verifiable, internally consistent, provenance-traced, and format-checked against these artifacts; it does not adjudicate domain correctness, corpus fit, or novelty, which remain subject to expert and reader review.

## Evidence Landscape

Source directness breakdown: 1/13 retained sources directly address the stated topic and aging-relevant hard endpoints; 12/13 are adjacent, contextual, review-level, or mechanistic and are used only to bound interpretation. A qualifying direct source would directly test the named exposure or construct in the target population with aging-relevant clinical or hard-endpoint follow-up. Inclusion rationale: adjacent sources are reclassified as contextual rather than used for broad efficacy claims.

### Source Classification Map

- Sheng 2025: outcome=Contextual Adjacent Evidence; direction=unclear; directness=indirect; tier=B2.
- Nguyen 2026: outcome=Deficiency Prevalence; direction=unclear; directness=indirect; tier=B2.
- Wang 2024: outcome=Cardiometabolic; direction=unclear; directness=direct; tier=A1.
- Rodilla 2026: outcome=Cardiometabolic; direction=null; directness=indirect; tier=B2.
- Alanis 2025: outcome=Mechanism; direction=null; directness=mechanistic; tier=C1.
- Luo 2025: outcome=Contextual Adjacent Evidence; direction=unclear; directness=review; tier=B2.
- Vicente-Gabriel 2024: outcome=Contextual Adjacent Evidence; direction=null; directness=protocol; tier=D1.
- Azizzadeh 2026: outcome=Cardiometabolic; direction=null; directness=indirect; tier=B2.
- Lu 2026: outcome=Contextual Adjacent Evidence; direction=unclear; directness=indirect; tier=B2.
- Kozlik 2026: outcome=Contextual Adjacent Evidence; direction=null; directness=indirect; tier=B2.
- Joshi 2025: outcome=Safety and Comorbidity; direction=null; directness=protocol; tier=D1.
- Carmo 2025: outcome=Contextual Adjacent Evidence; direction=null; directness=review; tier=B2.
- Kakaletsis 2024: outcome=Longevity; direction=unclear; directness=review; tier=B1.

Substantive evidence synthesis: The manifest includes 13 retained sources, 1 direct-source row(s), and receipt-level directional coding across null=7, unclear=6. Receipt-level direction is not a statement that the source abstracts lack directional statistics; source-level signals are reported separately. Representative source-level signals are: Sheng 2025: outcome=Contextual Adjacent Evidence; direction=unclear; directness=indirect; tier=B2; result=Integrating Vascular Aging and Genetic Risk: The Combined Impact of Estimated Pulse Wave Velocity and Genetic; finding=representative statistic P <0.001; source-level statistic reported; claims=102; Nguyen 2026: outcome=Deficiency Prevalence; direction=unclear; directness=indirect; tier=B2; result=Endothelial Sirtuins and Mitochondrial Function Are Associated With Testosterone Status: Implications for Accelerated; finding=representative statistic p = 0.047; source-level statistic reported; claims=64; Wang 2024: outcome=Cardiometabolic; direction=unclear; directness=direct; tier=A1; result=Impact of a Precision Intervention for Vascular Health in Middle-Aged and Older Postmenopausal Women Using Polar Heart; finding=representative statistic p < 0.05; source-level statistic reported; claims=54; Luo 2025: outcome=Contextual Adjacent Evidence; direction=unclear; directness=review; tier=B2; result=Effects of L-citrulline supplementation and watermelon intake on arterial stiffness and endothelial function in; finding=representative statistic p = 0.0007; source-level statistic reported; claims=22; Lu 2026: outcome=Contextual Adjacent Evidence; direction=unclear; directness=indirect; tier=B2; result=Estimating Vascular Age to Evaluate the Association Between Aging and Cardiovascular Disease; finding=14 extracted claim(s); receipt-level direction is the coded finding; claims=14; Kakaletsis 2024: outcome=Longevity; direction=unclear; directness=review; tier=B1; result=Advanced vascular aging and outcomes after acute ischemic stroke: a systematic review and meta-analysis.; finding=4 extracted claim(s); receipt-level direction is the coded finding; claims=4; Rodilla 2026: outcome=Cardiometabolic; direction=null; directness=indirect; tier=B2; result=Vascular age as a key for a team-based approach to manage blood pressure bridging community pharmacists and primary; finding=28 extracted claim(s); receipt-level direction is the coded finding; claims=28; Alanis 2025: outcome=Mechanism; direction=null; directness=mechanistic; tier=C1; result=Accelerated Vascular Aging as a Possible Mechanism of Troponin I Release in the Absence of Clinically Manifested; finding=representative statistic P =0.762; source-level statistic reported; claims=27. These signals inform the bounded conclusion by separating effect direction from evidence tier/directness; indirect, review-level, mechanistic, or contextual evidence remains hypothesis-generating.

## Key Findings

Key findings from source synthesis:

- Wang 2024: Impact of a Precision Intervention for Vascular Health in Middle-Aged and Older Postmenopausal Women Using Polar Heart; representative statistic p < 0.05; source-level statistic reported; outcome=Cardiometabolic; direction=unclear; directness=direct; tier=A1.
- Sheng 2025: Integrating Vascular Aging and Genetic Risk: The Combined Impact of Estimated Pulse Wave Velocity and Genetic; representative statistic P <0.001; source-level statistic reported; outcome=Contextual Adjacent Evidence; direction=unclear; directness=indirect; tier=B2.
- Nguyen 2026: Endothelial Sirtuins and Mitochondrial Function Are Associated With Testosterone Status: Implications for Accelerated; representative statistic p = 0.047; source-level statistic reported; outcome=Deficiency Prevalence; direction=unclear; directness=indirect; tier=B2.
- Alanis 2025: Accelerated Vascular Aging as a Possible Mechanism of Troponin I Release in the Absence of Clinically Manifested; representative statistic P =0.762; source-level statistic reported; outcome=Mechanism; direction=null; directness=mechanistic; tier=C1.
- Luo 2025: Effects of L-citrulline supplementation and watermelon intake on arterial stiffness and endothelial function in; representative statistic p = 0.0007; source-level statistic reported; outcome=Contextual Adjacent Evidence; direction=unclear; directness=review; tier=B2.

Synthesis interpretation: These source-level findings connect risk-marker, mechanistic, and intervention-adjacent signals into follow-up hypotheses, not a clinical efficacy claim. Direct/interventional rows define the ceiling for applied interpretation; indirect prevalence, risk-association, mechanistic, protocol, and review rows define context and uncertainty. Representative coded source verdicts remain: Sheng 2025: outcome=Contextual Adjacent Evidence; direction=unclear; directness=indirect; tier=B2; result=Integrating Vascular Aging and Genetic Risk: The Combined Impact of Estimated Pulse Wave Velocity and Genetic; finding=representative statistic P <0.001; source-level statistic reported; claims=102; Nguyen 2026: outcome=Deficiency Prevalence; direction=unclear; directness=indirect; tier=B2; result=Endothelial Sirtuins and Mitochondrial Function Are Associated With Testosterone Status: Implications for Accelerated; finding=representative statistic p = 0.047; source-level statistic reported; claims=64; Wang 2024: outcome=Cardiometabolic; direction=unclear; directness=direct; tier=A1; result=Impact of a Precision Intervention for Vascular Health in Middle-Aged and Older Postmenopausal Women Using Polar Heart; finding=representative statistic p < 0.05; source-level statistic reported; claims=54; Luo 2025: outcome=Contextual Adjacent Evidence; direction=unclear; directness=review; tier=B2; result=Effects of L-citrulline supplementation and watermelon intake on arterial stiffness and endothelial function in; finding=representative statistic p = 0.0007; source-level statistic reported; claims=22. The bounded conclusion follows from source direction, outcome class, evidence tier, and directness rather than from source count alone. Publication-year note: citation years follow the manifest metadata; when DOI/PubMed dates differ, the source should be treated as bibliographic/in-press metadata and not used for year-specific claims.

## Results

**Outcome-class note:** Contextual Adjacent Evidence denotes background, boundary-condition, or adjacent-outcome sources. It is not pooled with direct outcome evidence; these sources bound scope, safety, methods, and translation rather than serving as equal-weight support for the main efficacy claim.


| Evidence domain | Corpus slice | Strongest signal | Directness | Main limitation |
|---|---|---|---|---|
| Vascular age / Contextual Adjacent Evidence | n=6; claims=177 | significant source statistic in 2/6 sources; receipt-level direction coded unclear | 3 indirect; 1 protocol; 2 review | limited corpus depth in this outcome class |
| Vascular age / Cardiometabolic | n=3; claims=98 | significant source statistic in 1/3 sources; receipt-level direction coded null | 1 direct; 2 indirect | limited corpus depth in this outcome class |
| Vascular age / Deficiency Prevalence | n=1; claims=64 | significant source statistic in 1/1 sources; receipt-level direction coded unclear | 1 indirect | single-source slice; hypothesis-generating |
| Vascular age / Longevity | n=1; claims=4 | unclear signal in 1/1 sources | 1 review | single-source slice; hypothesis-generating |
| Vascular age / Mechanism | n=1; claims=27 | reported statistic in 1/1 sources; receipt-level direction coded null | 1 mechanistic | single-source slice; hypothesis-generating |
| Vascular age / Safety and Comorbidity | n=1; claims=10 | no extracted directional signal in 1/1 sources | 1 protocol | single-source slice; hypothesis-generating |

**Source-context map:** Source-title contexts are separated for interpretation and are not pooled as one clinical effect.
- Aging and geroscience context: 9 sources; significant source statistic in 3/9 sources; receipt-level direction coded unclear.
- Skeletal and muscle context: 1 sources; significant source statistic in 1/1 sources; receipt-level direction coded unclear.

### Contextual Adjacent Evidence Outcomes

Contextual Adjacent Evidence remains a separate Results slice for Vascular age (n=6; claims=177; significant source statistic in 2/6 sources; receipt-level direction coded unclear; 3 indirect; 1 protocol; 2 review; limited corpus depth in this outcome class) and is not pooled into adjacent endpoint classes.
### Cardiometabolic Outcomes



Deficiency Prevalence remains a separate Results slice for Vascular age (n=1; claims=64; significant source statistic in 1/1 sources; receipt-level direction coded unclear; 1 indirect; single-source slice; hypothesis-generating) and is not pooled into adjacent endpoint classes.
### Longevity Outcomes



Mechanism remains a separate Results slice for Vascular age (n=1; claims=27; reported statistic in 1/1 sources; receipt-level direction coded null; 1 mechanistic; single-source slice; hypothesis-generating) and is not pooled into adjacent endpoint classes.
### Safety and Comorbidity Outcomes

Safety and Comorbidity remains a separate Results slice for Vascular age (n=1; claims=10; no extracted directional signal in 1/1 sources; 1 protocol; single-source slice; hypothesis-generating) and is not pooled into adjacent endpoint classes.

## Limitations

The principal limitation is evidence-role imbalance. The retained corpus contains 1 direct clinical source, 11 adjacent clinical sources, and 1 mechanistic or model-system source, which means causal interpretation depends on how much weight is assigned to each evidence tier.

A second limitation is endpoint heterogeneity. Study-level signals span no dominant outcome class, the contextual adjacent evidence, cardiometabolic and mechanism outcome classes, no dominant outcome class, and no dominant outcome class; these domains cannot be pooled narratively without losing clinically relevant differences in measurement, population, and study design.

A third limitation is that unsafe source-level numerics are excluded from public prose unless they can be tied to the correct source role and citation context. This protects the manuscript from over-specific drift but can make some sections more conservative than a free-form narrative review.

## Conclusion

For Vascular age, the final interpretation is deliberately tiered: the retained evidence profile defines contextual associations and candidate endpoints for follow-up, not proof that this is a viable geroscience intervention target, but the corpus does not support treating mechanistic target engagement, intermediate biomarkers, and patient-relevant outcomes as interchangeable evidence. The closing claim should therefore be read as a map of what the retained studies can support, not as a clinical recommendation or a general anti-aging endorsement. Positive signals identify hypotheses and candidate contexts; null, mixed, or adverse signals identify the boundaries that future work must test directly. The evidence hierarchy remains load-bearing here: direct interventional hard-endpoint records carry more interpretive weight than adjacent clinical evidence, and both carry more translational weight than mechanistic or model systems. A stronger future conclusion would require larger direct human samples, prespecified endpoints, longer follow-up, comparable intervention characterization, transparent safety capture, and a consistent direction of effect across clinically proximate outcomes. Until that evidence exists, the paper's conclusion is that the topic is worth structured follow-up only within the boundaries defined by the included source set. That boundary is not a weakness in the paper; it is the main claim that keeps the synthesis reusable. Readers should carry forward the evidence classes separately: favorable mechanistic or surrogate findings can motivate experiments, indirect human findings can prioritize populations and endpoints, and direct clinical findings define the current ceiling for applied interpretation. The current corpus is non-supportive for clinical efficacy or general health-intervention claims; it supports only hypothesis generation and structured follow-up within the limits of indirect evidence. Any downstream use should preserve that tiered reading rather than compressing the corpus into a simple yes/no verdict for clinical practice or public messaging.

## What This Synthesis Adds

This synthesis maps 13 included sources on Vascular Age across 6 outcome classes and 12 cross-study disagreements. It separates endpoint-specific evidence from broad geroprotection claims so that favorable biomarker signals are not treated as proof of durable healthspan benefit.

Across 13 curated reference papers, the evidence base for Vascular age shows a context-dependent profile. Null findings dominate: contextual other, cardiometabolic. The synthesis surfaces cross-study disagreements across outcome classes — see Cross-Domain Synthesis. The Vascular anti-aging case as currently constituted is incomplete: mechanistic plausibility coexists with mixed or sparse human-RCT evidence, and the boundary conditions remain to be established.

The strongest unresolved contrast is the mechanism vs clinical between Vicente-Gabriel 2024 and Wang 2024 on contextual adjacent evidence (severity 3/5), which defines the boundary condition future studies must test rather than smooth over.

Prior reviews in the corpus (Kakaletsis 2024) emphasize convergent signals on Vascular Age. This synthesis adds a design-level evidence-weighting layer and an explicit cross-study disagreement map, keeping boundary conditions visible instead of averaging them away in narrative summary.

### Boundary-Condition Matrix

| Evidence domain | Direct sources | Indirect / mechanism sources | Direction profile | Interpretation boundary |
|---|---:|---:|---|---|
| longevity | 0 | 1 | unclear | direct interventional hard-endpoint gap |
| cardiometabolic | 1 | 2 | null, unclear | replication gap |
| contextual adjacent evidence | 0 | 6 | null, unclear | direct interventional hard-endpoint gap |
| mechanism | 0 | 1 | null | direct interventional hard-endpoint gap |
| deficiency prevalence | 0 | 1 | unclear | direct interventional hard-endpoint gap |
| safety and comorbidity | 0 | 1 | null | direct interventional hard-endpoint gap |

### Evidence-Gap Priority

| Priority | Gap | Rationale |
|---|---|---|
| P1 | longevity: direct interventional hard-endpoint gap | 0 direct and 1 indirect source; direction profile: unclear |
| P2 | cardiometabolic: replication gap | 1 direct and 2 indirect sources; direction profile: null, unclear |
| P3 | contextual adjacent evidence: direct interventional hard-endpoint gap | 0 direct and 6 indirect sources; direction profile: null, unclear |
| P4 | mechanism: direct interventional hard-endpoint gap | 0 direct and 1 indirect source; direction profile: null |
| P5 | deficiency prevalence: direct interventional hard-endpoint gap | 0 direct and 1 indirect source; direction profile: unclear |

### Next-Study Design Recommendation

The next high-yield study for Vascular Age should target the **longevity** evidence gap, pre-register the primary endpoint, separate clinical from mechanistic endpoints, preserve safety and adherence capture, and include an analysis plan that can falsify the current boundary-condition claim rather than only confirming a favorable direction. Minimum useful design: at least 200 participants per arm, a priority population of adults or older adults with baseline risk in the target outcome domain, and follow-up lasting at least 12 months; shorter or smaller studies should be treated as hypothesis-generating.

## Evidence Snapshot

Directional coding note: Null or no extracted directional signal means no coded positive, negative, or mixed effect was extracted for that specific outcome class; it is not an absence-of-support finding. Positive, negative, mixed, unclear, and null are outcome-specific codes, so a bounded rationale can be supported by adjacent or different outcome evidence while another outcome remains null or unclear. Contextual claims contain bibliographic background, mechanism, methods, exposure definitions, or population context rather than effect-direction evidence. When an outcome-class summary uses no extracted directional signal, it should state the source proportion, such as X/Y sources, to avoid ambiguity.

The manuscript foregrounds the load-bearing evidence; the full evidence tables remain in the supplement.

### Load-Bearing Included Studies

- Wang 2024; tier=A1; directness=direct; endpoint=cardiometabolic; direction=unclear; representative statistic=P < 0.01.
- Kakaletsis 2024; tier=B1; directness=review; endpoint=longevity; direction=unclear.
- Sheng 2025; tier=B2; directness=indirect; endpoint=contextual adjacent evidence; direction=unclear; representative statistic=P < 0.001.
- Nguyen 2026; tier=B2; directness=indirect; endpoint=deficiency prevalence; direction=unclear; representative statistic=P < 0.0001.
- Rodilla 2026; tier=B2; directness=indirect; endpoint=cardiometabolic; direction=null.
- Luo 2025; tier=B2; directness=review; endpoint=contextual adjacent evidence; direction=unclear; representative statistic=P < 0.00001.
- Azizzadeh 2026; tier=B2; directness=indirect; endpoint=cardiometabolic; direction=null.
- Kozlik 2026; tier=B2; directness=indirect; endpoint=contextual adjacent evidence; direction=null; representative statistic=P = 0.253.
- Lu 2026; tier=B2; directness=indirect; endpoint=contextual adjacent evidence; direction=unclear.
- Carmo 2025; tier=B2; directness=review; endpoint=contextual adjacent evidence; direction=null.

### Source Classification Map

Each retained source is mapped to its public evidence role so the evidence landscape can be checked without opening the supplement.

- Wang 2024: outcome=cardiometabolic; directness=direct; tier=A1; direction=unclear; claims=54.
- Kakaletsis 2024: outcome=longevity; directness=review; tier=B1; direction=unclear; claims=4.
- Sheng 2025: outcome=contextual adjacent evidence; directness=indirect; tier=B2; direction=unclear; claims=102.
- Nguyen 2026: outcome=deficiency prevalence; directness=indirect; tier=B2; direction=unclear; claims=64.
- Rodilla 2026: outcome=cardiometabolic; directness=indirect; tier=B2; direction=null; claims=28.
- Luo 2025: outcome=contextual adjacent evidence; directness=review; tier=B2; direction=unclear; claims=22.
- Azizzadeh 2026: outcome=cardiometabolic; directness=indirect; tier=B2; direction=null; claims=16.
- Kozlik 2026: outcome=contextual adjacent evidence; directness=indirect; tier=B2; direction=null; claims=14.
- Lu 2026: outcome=contextual adjacent evidence; directness=indirect; tier=B2; direction=unclear; claims=14.
- Carmo 2025: outcome=contextual adjacent evidence; directness=review; tier=B2; direction=null; claims=5.
- Alanis 2025: outcome=mechanism; directness=mechanistic; tier=C1; direction=null; claims=27.
- Vicente-Gabriel 2024: outcome=contextual adjacent evidence; directness=protocol; tier=D1; direction=null; claims=20.
- Joshi 2025: outcome=safety comorbidity; directness=protocol; tier=D1; direction=null; claims=10.

### Classification Criteria

- **Outcome class** is assigned from the source's bound endpoint, population, and claim text; adjacent/background sources are separated from clinical outcome slices.
- **Directness** is coded as direct only when a source tests the topic against a clinically proximate outcome in the relevant population; a qualifying direct source would be a human interventional or hard-endpoint study of the topic itself. Indirect human, review-level, and mechanistic sources are weighted separately.
- **Directional signal** is counted within the assigned outcome class only. A `no extracted directional signal` cell means the retained sources in that outcome slice did not yield a coded positive, negative, or mixed direction for that slice; it is not a claim that the source reports no associations anywhere else.
- **Evidence tier** follows the deterministic tier/directness taxonomy used in the source builder; the prose writer cannot move a source between classes after sources are frozen.

### Load-Bearing Tensions

- Severity 3 indirectness gap: Wang 2024 vs Rodilla 2026; Wang 2024 (direct, A1) vs Rodilla 2026 (indirect) on cardiometabolic — direct vs indirect must be kept separate
- Severity 3 indirectness gap: Wang 2024 vs Azizzadeh 2026; Wang 2024 (direct, A1) vs Azizzadeh 2026 (indirect) on cardiometabolic — direct vs indirect must be kept separate
- Severity 3 mechanism vs clinical: Vicente-Gabriel 2024 vs Wang 2024; Wang 2024 (direct, cardiometabolic) vs Vicente-Gabriel 2024 (protocol, contextual other) — cross-domain: clinical evidence on one outcome must not be fused with mechanistic / preclinical evidence on a different outcome
- Severity 3 mechanism vs clinical: Wang 2024 vs Alanis 2025; Wang 2024 (direct, cardiometabolic) vs Alanis 2025 (mechanistic, mechanism) — cross-domain: clinical evidence on one outcome must not be fused with mechanistic / preclinical evidence on a different outcome
- Severity 3 mechanism vs clinical: Wang 2024 vs Joshi 2025; Wang 2024 (direct, cardiometabolic) vs Joshi 2025 (protocol, safety comorbidity) — cross-domain: clinical evidence on one outcome must not be fused with mechanistic / preclinical evidence on a different outcome
- Severity 3 mechanism vs clinical: Wang 2024 vs Luo 2025; Wang 2024 (direct, cardiometabolic) vs Luo 2025 (review, contextual other) — cross-domain: clinical evidence on one outcome must not be fused with mechanistic / preclinical evidence on a different outcome
- Severity 3 mechanism vs clinical: Wang 2024 vs Carmo 2025; Wang 2024 (direct, cardiometabolic) vs Carmo 2025 (review, contextual other) — cross-domain: clinical evidence on one outcome must not be fused with mechanistic / preclinical evidence on a different outcome
- Severity 3 mechanism vs clinical: Wang 2024 vs Sheng 2025; Wang 2024 (direct, cardiometabolic) vs Sheng 2025 (indirect, contextual other) — cross-domain: clinical evidence on one outcome must not be fused with mechanistic / preclinical evidence on a different outcome

## References

- **Sheng 2025.** _Integrating Vascular Aging and Genetic Risk: The Combined Impact of Estimated Pulse Wave Velocity and Genetic Predisposition on Coronary Artery Disease._ Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease, 2025. DOI: 10.1161/JAHA.125.042610. PMID: 41368830.
- **Nguyen 2026.** _Endothelial Sirtuins and Mitochondrial Function Are Associated With Testosterone Status: Implications for Accelerated Vascular Aging in Middle‐Age and Older Men With Low Testosterone._ Aging Cell, 2026. DOI: 10.1111/acel.70457. PMID: 41986916.
- **Wang 2024.** _Impact of a Precision Intervention for Vascular Health in Middle-Aged and Older Postmenopausal Women Using Polar Heart Rate Sensors: A 24-Week RCT Study Based on the New Compilation of Tai Chi (Bafa Wubu)._ Sensors (Basel, Switzerland), 2024. DOI: 10.3390/s24175832. PMID: 39275744.
- **Rodilla 2026.** _Vascular age as a key for a team-based approach to manage blood pressure bridging community pharmacists and primary healthcare physicians—The TOGETHER trial._ Frontiers in Public Health, 2026. DOI: 10.3389/fpubh.2025.1723100. PMID: 41613082.
- **Alanis 2025.** _Accelerated Vascular Aging as a Possible Mechanism of Troponin I Release in the Absence of Clinically Manifested Myocardial Injury._ Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease, 2025. DOI: 10.1161/JAHA.124.037718. PMID: 40145294.
- **Luo 2025.** _Effects of L-citrulline supplementation and watermelon intake on arterial stiffness and endothelial function in middle-aged and older adults: a systematic review and meta-analysis of randomized controlled trials._ Frontiers in Nutrition, 2025. DOI: 10.3389/fnut.2025.1632952. PMID: 41323997.
- **Vicente-Gabriel 2024.** _Relationship between addictions and obesity, physical activity and vascular aging in young adults (EVA-Adic study): a research protocol of a cross-sectional study._ Frontiers in Public Health, 2024. DOI: 10.3389/fpubh.2024.1322437. PMID: 38344236.
- **Azizzadeh 2026.** _Prevalence and determinants of vascular aging in Austria – a holistic view: the LEAD study._ Journal of Hypertension, 2026. DOI: 10.1097/HJH.0000000000004227. PMID: 41537373.
- **Lu 2026.** _Estimating Vascular Age to Evaluate the Association Between Aging and Cardiovascular Disease._ Aging Cell, 2026. DOI: 10.1111/acel.70503. PMID: 42087283.
- **Kozlik 2026.** _Vascular Endothelial Function, Carotid Intima–Media Thickness and Coronary Artery Calcification in Women._ Journal of Clinical Medicine, 2026. DOI: 10.3390/jcm15114087. PMID: 42278949.
- **Joshi 2025.** _Arterial stiffness in acute decompensated heart failure and acute kidney injury: a prospective observational cohort study protocol in a tertiary hospital setting._ BMJ Open, 2025. DOI: 10.1136/bmjopen-2024-097718. PMID: 40550719.
- **Carmo 2025.** _Methylarginine levels and their impact on vascular aging: a systematic review._ Vascular Biology, 2025. DOI: 10.1530/VB-25-0004. PMID: 41378901.
- **Kakaletsis 2024.** _Advanced vascular aging and outcomes after acute ischemic stroke: a systematic review and meta-analysis._ J Hum Hypertens, 2024. DOI: 10.1038/s41371-024-00961-y. PMID: 39317753.

### Background References

*Methodological references cited in prose. Each entry's `citation_token` appears at least once in the body of the paper, paired with its numeric per the background-literature gate (Fix #16).*

- **Ioannidis 2005.** _Ioannidis JPA. Why most published research findings are false. PLoS Med. 2005;2(8):e124._ (methodological reference) DOI: 10.1371/journal.pmed.0020124. PMID: 16060722.
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  "title": "Hypothesis-Generating Brief: Vascular age \u2014 full paper"
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