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Open WellbeingWhat the studies actually measured

Heart and blood pressure

Calciumand Diastolic blood pressure

Only one source here so far, and it measured lower diastolic blood pressure.

How sure anyone can be

Moderate certainty, level 3 of 4

Further research may change this.

The numbers reported

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

-2.23-1.45 mmHg-0.67

This range stays on one side of the no-difference line.

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

One source, 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, 2022 · 17 studies pooled · 3,039 participants

    Moderate certainty, level 3 of 4

    Calcium supplementation for prevention of primary hypertension.

    Cochrane Database Syst Rev. 2022;1(1):CD010037. doi:10.1002/14651858.CD010037.pub4. PMID:35014026.

    This source later carried a notice: Update of Cochrane Database Syst Rev. 2021 Aug 10;8:CD010037. doi: 10.1002/14651858.CD010037.pub3. The number below is exactly as the source gave it.

    Number reported
    -1.45 mmHg
    Which way it went
    Lower
    Likely range
    -2.23 to -0.67
    Source’s own words
    mm Hg mean difference in diastolic blood pressure vs placebo/control
    Who was studied
    Normotensive people
    Compared with
    placebo or control
    Amount taken
    Pooled across dose bands — one amount does not apply
    For how long
    Not in the abstract
    Disagreement between studies
    I2 = 45%
    Kind of record
    Journal article

    Results by amount

    The source pooled a separate result for each reported amount band.

    • doses less than 1000 mg

      Number reported
      -0.41 mmHg
      Likely range
      -2.07 to 1.25 mmHg
      People who took part
      201
      Studies pooled
      2
      Disagreement between studies
      I2 = 0
      Source-reported certainty
      Moderate

    • doses 1000 to 1500 mg

      Number reported
      -2.03 mmHg
      Likely range
      -3.44 to -0.62 mmHg
      People who took part
      1,017
      Studies pooled
      8
      Disagreement between studies
      Not in the abstract
      Source-reported certainty
      Not in the abstract

    • doses more than 1500 mg

      Number reported
      -1.35 mmHg
      Likely range
      -2.75 to -0.05 mmHg
      People who took part
      1,821
      Studies pooled
      8
      Disagreement between studies
      I2 = 51%
      Source-reported certainty
      High
    How this rating was reachedstarts at High, one step down: imprecision
    1. Starts at High
    2. Imprecision brought it down to Moderatethe interval excludes no effect but spans a 3-fold range of effect size, from trivial to largeReported in the abstract
    3. Ends at ModerateOne step down.
    Checked, nothing to step it down for
    risk of bias and indirectness
    Inconsistency
    No high disagreement reported between the 17 studies it pooled

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

    Source saved; quote checked byte-for-byte against it by software; no signature.

    Read the abstract on PubMed

What is still missing from these readings

  • 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

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.