CHAMGAP
APPROVEDReviewed and approved by the Chamgap Editorial Team (2026-08-07). The draft was written by AI, the existence of all 3 cited sources was verified at the original page, and the verdict passed blind grading and adversarial audit. Methodology v0.7.
Verdict No. 2353 · Search date 2026-08-07 · Methodology v0.7

Calcium-only supplement,
does it really help with Increased myocardial-infarction risk?

30-Second Summary
C
Evidence Grade C · 56 · Safety caution
An initial harm signal was not confirmed after more complete event ascertainment.
High-dose calcium can cause constipation and kidney stones, while cardiovascular harm remains uncertain. People with kidney disease, hypercalcemia, or stone history need clinical advice.
What the
research shows
C. Cardiovascular events were prespecified secondary endpoints rather than post hoc collection. Adjudicated reported MI was 21/732 versus 10/739, RR 2.12 (1.01–4.47), while national-data ascertainment yielded 31/732 versus 21/739, RR 1.49 (0.86–2.57).
What the
ads claim
Calcium-only supplements, calcium plus vitamin D, and dietary calcium must not be merged.
*

Useful facts when choosing a product

  • Verdict 069 is C with 45 points for bone health, BMD, and fracture prevention; this verdict concerns MI harm.
  • The positive adjudicated-report analysis became nonsignificant after national-database events were added.
  • Regulatory judgments were not used as grading evidence.
Gap Measurement · Verdict 2353 · C 56
What advertising claims
What independent, higher-quality research supports
△ GAP
01

What the research actually shows

With complete ascertainment, MI was 31/732 (4.2%) versus 21/739 (2.8%), RR 1.49 (0.86–2.57); stroke was 34/732 (4.6%) versus 25/739 (3.4%), RR 1.37 (0.83–2.28); and death was 34/732 (4.6%) versus 29/739 (3.9%), RR 1.18 (0.73–1.92). Every interval included 1. The primary skeletal outcomes showed BMD differences of 1.8% at the spine, 1.6% at the total hip, and 1.2% for total body, but symptomatic fracture HR was 0.90 (0.71–1.16). An independent calcium-only trial reported 104 versus 103 five-year atherosclerotic vascular events, adjusted HR 0.938 (0.690–1.275).

02

Why this is classified as C (56)

The grade rises to C with 56 points because cardiovascular events were prespecified secondary endpoints, not post hoc collection. They were not primary endpoints, and complete ascertainment plus an independent calcium-only trial did not confirm harm.

Counterpoint. The confidence interval does not exclude substantial harm.

Rejudgment record. New verdict — The prespecified secondary cardiovascular endpoint became nonsignificant when unreported national-database events were included

Scoring profile behind this grade
EndpointHHard endpoint - actual events such as death
ReplicationR1Single confirmatory trial
IndependenceI2Decisive evidence is publicly or non-profit funded
Effect sizeE+Meets the clinically important threshold
PrecisionC0The confidence interval leaves room for benefit

The scoring table and the verdict agree (C).

Sub-claim grades by effect

This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.

Effect (sub-claim)GradeBasis
Increased myocardial infarctionCNull with complete ascertainment

Cross-check — Codex and Claude

This verdict was drafted by Codex through literature review and source-existence checks, cross-checked through blind grading and adversarial audit, and settled by reapplying the methodology boundary rules. Cases with split grades were resolved through rejudgment.
03

Evidence Table

StudyDesignSampleFundingEndpointResultWeight
Bolland et al. 2008Prespecified secondary cardiovascular analysis of a five-year randomized placebo-controlled trial739Health Research Council of New Zealand and University of Auckland School of Medicine FoundationMyocardial infarction, stroke, and deathComplete-ascertainment MI RR 1.49 (0.86–2.57); stroke 1.37 (0.83–2.28); death 1.18 (0.73–1.92)Pivotal RCT secondary safety analysis
Lewis et al. 2011Five-year calcium-only randomized trial with 4.5-year follow-up1,460As reported in the verified source recordAtherosclerotic vascular hospitalization or deathFive-year events 104 versus 103; adjusted HR 0.938 (0.690–1.275); 9.5-year HR 0.919 (0.737–1.146)Independent calcium-only trial
§

Receipt — 3 References

All 3 cited sources were verified for existence at the original page (as of 2026-08-07).

Bolland MJ, Barber PA, Doughty RN, Mason B, Horne A, Ames R, Gamble GD, Grey A, Reid IR. Vascular events in healthy older women receiving calcium supplementation: randomised controlled trial. BMJ. 2008;336:262-266. DOI: 10.1136/bmj.39440.525752.BE.
checked
Bolland MJ, Avenell A, Baron JA, et al. Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis. BMJ. 2010;341:c3691. DOI: 10.1136/bmj.c3691.
checked
Lewis JR, Calver J, Zhu K, Flicker L, Prince RL. Calcium supplementation and the risks of atherosclerotic vascular disease in older women: results of a 5-year randomized controlled trial and a 4.5-year follow-up. J Bone Miner Res. 2011;26(1):35-41. DOI: 10.1002/jbmr.176.
checked
Draft and rewrite: Codex (AI) · Verification: Codex blind grading and adversarial audit · Final adjudication: Claude
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-08-07 · Corrections: none

Cite this verdict

Calcium supplements × increased myocardial-infarction risk Evidence Grade C card
[Chamgap] Calcium supplements × increased myocardial-infarction risk — Evidence Grade C·56. 3 cited sources checked. Source: https://chamgap.com/en/verdicts/heart/calcium-supplement-myocardial-infarction-harm/ · CC BY 4.0

CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.

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What this document does and does not do

Chamgap is an information source. It reports what research has and has not confirmed; it does not tell readers what to take or buy. That decision belongs to readers and, when needed, medical or legal professionals. This verdict reflects literature available up to the search date and may change as new research appears. Nothing here is medical advice.