Evidence Library

Scientific References

The research behind Metabolicum's evidence-based approach

How We Evaluate Evidence

Not all research is equal. We assign confidence grades to each source based on study design, sample size, replication status, and methodology. This helps you understand how confident you can be in each finding.

Click any grade to learn more

Grade A

High Confidence

Replicated findings across multiple well-designed studies

Grade B

Good Confidence

Well-designed single studies with strong methodology

Grade C

Moderate Confidence

Observational data with consistent patterns

Grade D

Emerging Evidence

Mechanistic or theoretical - interpret cautiously

Grade E

Clinical Consensus

Practitioner experience without formal trials

Understanding the Reproducibility Crisis

Why are we so careful about evidence grading? Because a significant portion of published research fails to replicate.

Study	Finding	Grade
Begley & Ellis, 2012	Only 21% of landmark cancer studies could be replicated	A
Open Science Collaboration, 2015	Only 36% of psychology studies replicated	A
Ioannidis, 2005	Theoretical framework explaining why most findings are false	A

This doesn't mean you should distrust all research. It means:

•Single studies warrant caution — Replication matters
•Peer review is necessary but not sufficient — Many peer-reviewed findings are later overturned
•Effect size matters more than p-values — Statistical significance ≠ practical importance
•Longer studies are generally more reliable — Short-term biomarker changes may not reflect long-term outcomes

We grade evidence honestly so you can calibrate your confidence appropriately.

Research Library

In-depth analysis of foundational studies with translated summaries

Showing studies cited on: TG/HDL Calculator

Topic

Paradigm

Evidence Grade

Study Type

Cited On

Showing 4 studies

Cross-Sectional Study

McLaughlin 2003: TG/HDL Ratio for Insulin Resistance Screening

McLaughlin T, et al. • Annals of Internal Medicine • 2003

TG/HDL ratio ≥3.0 (mg/dL) or ≥1.3 (mmol/L) identifies insulin-resistant individuals with ~64-79% sensitivity

Insulin ResistanceLipid MetabolismMetabolic Syndrome

Cohort Study

McLaughlin 2005: TG/HDL Works Regardless of Body Weight

McLaughlin T, et al. • American Journal of Cardiology • 2005

TG/HDL ratio ≥3.5 identifies insulin-resistant, dyslipidemic individuals with sensitivity and specificity comparable to metabolic syndrome criteria

Insulin ResistanceCardiovascularLipid Metabolism

Case-Control Study

Gaziano 1997: TG/HDL Ratio Predicts Heart Attack Risk

Gaziano JM, et al. • Circulation • 1997

TG/HDL ratio highest vs lowest quartile showed relative risk of 16.0 for myocardial infarction—the strongest lipid predictor

CardiovascularLipid Metabolism

Cohort Study

Vega 2014: TG/HDL Predicts Both Heart Disease Death and Diabetes

Vega GL, et al. • Journal of Investigative Medicine • 2014

TG/HDL ratio ≥3.5 predicted cardiovascular mortality and doubled diabetes incidence in large prospective cohort

CardiovascularDiabetesLipid Metabolism+1 more

How We Use References

In Calculators

Primary thresholds come from Grade A sources. When Grade A evidence suggests a range rather than a single value, we present the range with context.

In Educational Content

We draw on Grades A-C for educational claims, clearly labeling evidence quality. Grade D and E content is marked as theoretical or practitioner-derived.

In Paradigm Frameworks

Standard Medical: Grade A (established guidelines)
Research Consensus: Grade A-B (outcome research)
Metabolic Optimization: Grade B-E (intervention research + clinical consensus)

Evidence Grades

Grade A: High ConfidenceReplicated findings across multiple studies Grade B: Good ConfidenceWell-designed single studies Grade C: Moderate ConfidenceObservational data with consistent patterns Grade D: Emerging EvidenceMechanistic or theoretical Grade E: Clinical ConsensusPractitioner consensus

Other Pages

Our MethodologyHow we approach health information Four Clinical FrameworksWhy we show multiple interpretations

Our Methodology

This bibliography contains the research supporting Metabolicum's evidence-based approach.

Last comprehensive review: December 2025