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Randomized trial · measured the question itself

5-year trial in 21,315 older Australians: no clear change in infection hospital stays

Pham and colleagues · The American journal of clinical nutrition · 2023

Original title: Vitamin D supplementation and hospitalization for infection in older adults: A post-hoc analysis of data from the Australian D-Health Trial.

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What the study found

No difference

Hospital stays for any infection: incidence rate ratio 0.95 (95% CI 0.86, 1.05). For respiratory infection: 0.93 (0.81, 1.08). Stays longer than 6 days: 0.80 (0.65, 0.99).

The study at a glance

Type of study
Randomized trial
Who or what was studied
21,315 people · Australians aged 60 to 84, mean age 69, mostly not low in vitamin D
What was tested
60,000 IU of vitamin D3 a month vs placebo for 5 years
What it measured
The question itself: colds, flu and other respiratory infections
Daily amount
60000 IU/month
How long
260 weeks
Trial registration
ACTRN12613000743763
Who has a stake
No disclosure in PubMed
No disclosure in PubMed.
Journal
The American journal of clinical nutrition, 2023
Source
PubMed record 36811576. This page is based on the abstract only.

How much this study counts

  • ✓Randomized: people were put into groups by chance, so the groups start out alike.
  • ✓Compared with a placebo, a dummy treatment.
  • ✓Large: 21,315 people.
  • ✓Long: about 5 years.
  • ✓Measured the question itself: colds, flu and other respiratory infections.
  • •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

Each dot is one on-topic paper on this question. Steps near the top answer the question more directly.

↑ Stronger evidence

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

    10

    2 benefit, 8 no difference

    ↑ This study is the ringed dot

  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

Of the other 9 papers on the same step: 2 benefit, 7 no difference. This one found no difference. It agrees with most of them.

Other papers on the same step

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 differed. The reviewer checked the abstract and kept the first read. 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
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