Meta-analysisindependent cross-checkabstract checked I-SUP-110 in-depth review

Calcium pills and heart disease: meta-analysis

Calcium Supplements and Risk of Cardiovascular Disease: A Meta-Analysis of Clinical Trials.

Overview

Myung SK et al.. Nutrients 2021 · PMID 33530332 · DOI 10.3390/nu13020368

Pooling 13 placebo-controlled trials, calcium pills were linked to about 15% more cardiovascular disease, mainly in healthy postmenopausal women.

Does the study support the specific claim? Yes · Methodological quality: moderate

Study explained simply

What did the researchers want to find out?: To check whether calcium pills raise heart disease risk.
How was the study done?: Meta-analysis of double-blind trials.
How many people, animals or samples were studied?: 13 trials, about 43,000 people.
What was actually found?: About 15% more CVD and CHD.
How large was the observed effect?: CVD RR 1.15 (1.06-1.25).
What do the results mean in everyday life?: Calcium pills may slightly raise heart risk.
What are the study's limitations?: Heart outcomes were not the main aim of the trials.
What does it say about Elawady's specific claim?: Supports the direction of C-SUP-04.
Do the results apply to Germany and Europe?: Applicable.
What can explicitly not be concluded from this study?: Does not settle the question; other analyses disagree.

Authors: Myung SK et al.
Journal: Nutrients
Year: 2021
Identifier: PMID 33530332 DOI 10.3390/nu13020368 · PMC7910980
Verification: verified – PubMed efetch 2026-10-26; Crossref works API 2026-10-26
Retracted: no
Corrections: none
Extent checked: abstract only
Conflicts of interest and funding: COI statement in record: The authors declare no conflict of interest.

Do calcium supplements increase cardiovascular disease risk?

Study design: Meta-analysis – Meta-analysis of double-blind placebo-controlled RCTs
Population: Adults in double-blind RCTs of calcium supplements (mainly postmenopausal women)
Country: Multinational
Period: Search November 2020
Sample size: 13 RCTs; 28,935 intervention and 14,243 control participants
Inclusion and exclusion criteria: Double-blind placebo-controlled RCTs

Results: Calcium supplements increased CVD (RR 1.15, 1.06-1.25; I2 0%) and CHD (RR 1.16, 1.05-1.28; I2 0%), specifically in healthy postmenopausal women; subgroup: dietary calcium 700-1000 mg/day or supplementary 1000 mg/day increased CVD and CHD risk.
Absolute risks: not reported in abstract
Authors' conclusion: Calcium supplements increased CVD risk by about 15% in healthy postmenopausal women.

Orienting tool: AMSTAR 2
Type of assessment: simplified assessment (abstract only)
Full formal assessment: no
Overall risk of bias: some concerns
Rationale: Abstract only; outcome ascertainment in source trials not designed for CVD.

CIs are log-symmetric (stats/C-SUP-04_calcium.py). Same author group as I-SUP-115 (Myung).

Supports a modest CVD excess with calcium supplements (with or without vitamin D), in line with the claim's direction.

I-SUP-112 (Sim 2023, 12 RCTs) and I-SUP-06 (Chung 2016) found no association.

Applicable.

Adds support but the evidence remains conflicting.

Multidimensional assessment
Multidimensional assessment
Authenticity of the source	verified
Methodological quality	moderate
Risk of bias	some concerns
Precision of results	moderate
Directness	direct
Reproducibility	partly replicated
Consistency with the overall evidence	inconsistent
Regional transferability	high
Adequacy of the interpretation (by the archive)	not applicable

Whether the effect depends on dietary calcium and dosing pattern.