Trial reportScandinavian journal of infectious diseases2012
Vitamin D supplementation did not prevent influenza-like illness as diagnosed retrospectively by questionnaires in subjects participating in randomized clinical trials.
Trial report in Scandinavian journal of infectious diseases, 2012. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 22 papers, 3 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
22 citing papers in PubMed, 3 syntheses or guidelines pooled it, 47 citations in OpenAlex.
- Association Between Vitamin D and Influenza: Meta-Analysis and Systematic Review of Randomized Controlled Trials.Frontiers in nutrition · 2021Pooled it
- Acute Respiratory Tract Infection and 25-Hydroxyvitamin D Concentration: A Systematic Review and Meta-Analysis.International journal of environmental research and public health · 2019Pooled it
- Vitamin D and Respiratory Tract Infections: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.PloS one · 2013Pooled it
- Vitamin D3 supplementation and upper respiratory tract infections in a randomized, controlled trial.Clinical infectious diseases : an official publication of the Infectious Diseases Society of America · 2013Trial
- Vitamin D in Infectious Diseases: A Narrative Review Focusing on COVID-19, Long COVID, and Influenza.Nutrients · 2026Review
- Comparative effectiveness of oral nutritional supplements in preventing respiratory tract infections among adults: a systematic review and network meta-analysis.EClinicalMedicine · 2025Article
- Review
- Polymorphisms CYP2R1 rs10766197 and CYP27B1 rs10877012 in Multiple Sclerosis: A Case-Control Study.Journal of immunology research · 2021Article
- New Roles for Vitamin D Superagonists: From COVID to Cancer.Frontiers in endocrinology · 2021Review
- Immune Modulatory Effects of Vitamin D on Viral Infections.Nutrients · 2020Review
- Vitamin D and Influenza-Prevention or Therapy?International journal of molecular sciences · 2018Review
- Impact of Childhood Malnutrition on Host Defense and Infection.Clinical microbiology reviews · 2017Review
- Vitamin D and airway infections: a European perspective.European journal of medical research · 2016Review
- Review
- Impact of vitamin D on infectious disease.The American journal of the medical sciences · 2015Review
- Association between serum 25-hydroxyvitamin D concentration and symptoms of respiratory tract infection in a Norwegian population: the Tromsø Study.Public health nutrition · 2014Article
- Effects of vitamin D supplementation on alveolar macrophage gene expression: preliminary results of a randomized, controlled trial.Multidisciplinary respiratory medicine · 2014Article
- Vitamin D status and childhood health.Korean journal of pediatrics · 2013Review
- Vitamin D - effects on skeletal and extraskeletal health and the need for supplementation.Nutrients · 2013Review
- The problems of vitamin d insufficiency in older people.Aging and disease · 2012Article
Corrections and comments
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Authors and funding
8 authors at 6 institutions in 6 countries.
Funding
Abstract
backgroundVitamin D deficiency has been associated with a number of diseases, including influenza. Whether or not this reflects a causal relationship is unknown. We therefore wanted to examine if supplementation with vitamin D would affect the incidence and severity of influenza-like disease.
methodsQuestionnaires on influenza were sent to subjects participating in ongoing placebo-controlled intervention studies with vitamin D supplementation, up until the end of April 2010.
resultsFive hundred and sixty-nine subjects from 10 different clinical trials were included in the study, of whom 289 were randomized to receive vitamin D (1111-6800 IU/day) and 280 to receive placebo. Influenza-like disease during the previous fall/winter was reported in 38 subjects in the vitamin D group and 42 in the placebo group (non-significant), of whom 25 and 26 subjects, respectively, fulfilled our clinical criteria for influenza. In these latter subjects, the duration of illness was significantly longer among those in the vitamin D group than among those in the placebo group (median 7 (range 2-60) days vs median 4 (range 2-18) days; p = 0.007). However, this difference was not statistically significant if all 38 (vitamin D) and 42 (placebo) subjects who reported symptoms were included.
conclusionOur results do not support the hypothesis that high doses of vitamin D supplementation will have a pronounced effect on influenza-like disease in populations not targeted for high influenza risk.
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What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.