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Bone strength

Calciumand Fracture Risk (incidence)

Both sources here found no clear difference in fracture Risk (incidence).

How sure anyone can be

Moderate certainty, level 3 of 4

Further research may change this.

The most certain of the two findings here; each record carries its own.

The numbers reported

One source’s range, drawn against its own line of no difference and scaled to its own numbers.

0.971.53 risk ratio2.42

This range crosses the no-difference line, so these numbers fit a real difference and no difference at all equally well.

Bar the confidence interval — the range the true effect is likely to sit inNotch the number the source reportedLine where there would be no difference at all

Two sources, newest first

What we read is the published abstract, not the full paper, so a blank below may still be printed in the paper itself. A fixed rule worked this out from the source’s own fields. Nobody checked this rating by hand.

  • Systematic review, 2025

    Low certainty, level 2 of 4

    The effects of combined calcium and vitamin D supplementation on bone mineral density and fracture risk in postmenopausal women with osteoporosis: a systematic review and meta-analysis of randomized controlled trials.

    BMC Musculoskelet Disord. 2025;26(1):928. doi:10.1186/s12891-025-09089-7. PMID:41063100.

    Number reported
    0.98 risk ratio
    Which way it went
    No clear difference
    Likely range
    0.89 to 1.07
    Source’s own words
    risk ratio for fracture, combined calcium plus vitamin D vs control
    Who was studied
    Postmenopausal women with osteoporosis
    Compared with
    placebo or control
    Amount taken
    Not in the abstract
    For how long
    Not in the abstract
    Disagreement between studies
    I2 = 0% in the large-trial fracture analysis
    Kind of record
    Journal article
    How this rating was reachedstarts at High, 2 steps down: risk of bias and imprecision
    1. Starts at High
    2. Risk of bias brought it down to Moderatethe abstract reports no risk-of-bias or quality appraisal, so study limitations cannot be ruled outNot in the abstract
    3. Imprecision brought it down to Lowthe confidence interval includes no effectReported in the abstract
    4. Ends at Low2 steps down.
    Checked, nothing to step it down for
    indirectness
    Inconsistency
    No disagreement reported, and no count of studies behind it

    Imprecision stops at the first check that applies; others may apply too.

    AI-reviewed & signed — an AI agent re-read this finding against the saved source and checked that the quote, the numbers, the units and the direction match it. No person read it. The owner authorised the agent to sign the batch with the owner's key, and every build rechecks that signature against these exact bytes.

    Read the abstract on PubMed

  • Systematic review, 2017

    Moderate certainty, level 3 of 4

    Association Between Calcium or Vitamin D Supplementation and Fracture Incidence in Community-Dwelling Older Adults: A Systematic Review and Meta-analysis.

    JAMA. 2017;318(24):2466-2482. doi:10.1001/jama.2017.19344. PMID:29279934.

    Number reported
    1.53 risk ratio
    Which way it went
    No clear difference
    Likely range
    0.97 to 2.42
    Source’s own words
    risk ratio for hip fracture, calcium supplements vs placebo or no treatment
    Who was studied
    Older adult
    Compared with
    placebo or no treatment
    Amount taken
    Not in the abstract
    For how long
    Not in the abstract
    Disagreement between studies
    Not in the abstract
    Kind of record
    Journal article
    How this rating was reachedstarts at High, one step down: imprecision
    1. Starts at High
    2. Imprecision brought it down to Moderatethe confidence interval includes no effectReported in the abstract
    3. Ends at ModerateOne step down.
    Checked, nothing to step it down for
    risk of bias and indirectness
    Inconsistency
    No disagreement reported, and no count of studies behind it

    Imprecision stops at the first check that applies; others may apply too.

    AI-reviewed & signed — an AI agent re-read this finding against the saved source and checked that the quote, the numbers, the units and the direction match it. No person read it. The owner authorised the agent to sign the batch with the owner's key, and every build rechecks that signature against these exact bytes.

    Read the abstract on PubMed

What is still missing from these readings

  • Two do not say how many people took part.
  • Amount taken — Not in the abstract.
  • For how long — Not in the abstract.

Something nobody wrote down is never a zero and never a guess.

Still to read for Calcium

Three of the nine things on our list for Calcium have no reading here yet:

  • HDL cholesterol
  • LDL cholesterol
  • Parathyroid Hormone (PTH)

Still to read means nobody here has got to it, not that it was tried and did nothing or that no research exists. A pairing on no list is not a gap: we never set out to read it.

Read next

  • Calcium

    Five other questions read for it

  • Bone strength

    Ten questions read under it

  • Fracture Risk (incidence)

    No other ingredients read against it

    Alphabetical, and by nothing else.

This is a library, not advice. No recommendation, no dose, no diagnosis, no ranking. We never ask about your symptoms, and nothing here is tailored to you.