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Opinion or narrative review

Review and 20-country comparison: lower vitamin D linked to more COVID-19 cases, not deaths

Ali · Journal of infection and public health · 2020

Original title: Role of vitamin D in preventing of COVID-19 infection, progression and severity.

Under review. A person has not yet checked this summary against the paper. It is written from the PubMed abstract. Until a person checks it, search engines are asked not to list this page.

What the study found

Mixed

Countries with lower average vitamin D had more COVID-19 cases per million (p=0.033) but not more deaths. The author says there is not enough evidence on vitamin D and COVID-19 severity and mortality.

The study at a glance

Type of study
Opinion or narrative review
Who or what was studied
People at risk of COVID-19 and other respiratory infections; 20 European countries
What was tested
Review of vitamin D and COVID-19 and other respiratory infections, plus a country-level comparison of average vitamin D vs COVID-19 cases
What it measured
Several kinds of outcomes
Who has a stake
No disclosure in PubMed
No disclosure in PubMed.
Journal
Journal of infection and public health, 2020
Source
PubMed record 32605780. This page is based on the abstract only.

How much this study counts

  • –An opinion or narrative review: no new data, and no set method for choosing which studies to discuss.
  • •The PubMed record has no conflict-of-interest statement.
  • •Summarized from the PubMed abstract only. The full paper may hold details the abstract leaves out.

✓ Strength– Limit• Note

These points come from fixed rules about the type of study, its size and length, what it measured, and who has a stake. Every study on Digestery gets the same rules.

Where this study sits

This paper is not on the ladder. It is a opinion or narrative review, and reviews and opinion pieces discuss studies that are already counted on the steps below.

↑ Stronger evidence

  1. Trials in people: colds, flu and chest infections

    10

    2 benefit, 8 no difference

  2. Trials in people: other measures

    5

    1 benefit, 1 mixed, 2 no difference, 1 harm

  3. Trials in people: lab tests or safety

    1

    1 no difference

  4. Population studies

    1

    1 no difference

  5. Blood levels and genes

    4

    3 benefit, 1 no difference

↓ Weaker evidence

  • Points to benefit
  • Mixed
  • No difference
  • No direction
  • Points to harm

How it fits with the other research

The short answer to “Does vitamin D prevent colds and infections?”

Not clearly; any effect looks small.

Confidence: low. Based on 33 on-topic papers.

Read the full answer
  • Listed with the other papers, but not quoted in the page’s main findings.

Other opinion on this question

See all 33 studies on this question

How this page was made

Label

First read of the abstract
Claude Sonnet
Independent second read
Claude Haiku
Differences settled
The two reads agreed on every checked field. Claude Opus 5.5.
Headline
Claude Sonnet, from the checked study record. A script checked its numbers and wording.
Numbers
Checked against the abstract by a script
“How much this study counts”
Fixed rules, the same for every study
Source check by a person
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