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Acute respiratory infection worsened by too infrequent vitamin D supplementation – RCT June 2015

Double-blind randomised controlled trial of vitamin D3 supplementation for the prevention of acute respiratory infection in older adults and their carers (ViDiFlu).

Thorax. 2015 Jun 10. pii: thoraxjnl-2015-206996. doi: 10.1136/thoraxjnl-2015-206996. [Epub ahead of print]
Martineau AR1, Hanifa Y2, Witt KD3, Barnes NC3, Hooper RL3, Patel M3, Stevens N3, Enayat Z3, Balayah Z3, Syed A3, Knight A4, Jolliffe DA3, Greiller CL3, McLaughlin D3, Venton TR5, Rowe M5, Timms PM5, Clark D6, Sadique Z2, Eldridge SM3, Griffiths CJ3.

VitaminDWiki Comments

2.4 mg (144,000 IU) every 2 months + 400 IU daily
Which would be an average of only 2800 IU if the body did average the dose
But the body does not average the doses given less frequently that every 3 weeks

  1. Many studies have found that infrequent vitamin D supplementation provides poor results. Typically problems have not occurred with dose frequencies of 3-12 months. This is the first time I can recall of a problem with dose frequency of just 2 months. Based on many existing studies VitaminDWiki has been recommending that dose frequencies be not less than about 2/3 of a month.
  2. Have found that a UVC air purifier with a HEPA filter works wonderfully to eliminating ARI in seniors getting frequent, adequate vitamin D
  3. Will soon try UVC emitter in the ventilation system in a senior residence
    Studies decades ago measured the amount of kleenix tissue used, and found far more tissue was used on days in which the UVC system was not turned on.

See also VitaminDWiki

Low-dose vitamin D supplementation is already recommended in older adults for prevention of fractures and falls, but clinical trials investigating whether higher doses could provide additional protection against acute respiratory infection (ARI) are lacking.

To conduct a clinical trial of high-dose versus low-dose vitamin D3 supplementation for ARI prevention in residents of sheltered-accommodation housing blocks ('schemes') and their carers in London, UK.

Fifty-four schemes (137 individual participants) were allocated to the active intervention (vitamin D3 2.4 mg once every 2 months +10 μg daily for residents, 3 mg once every 2 months for carers), and 54 schemes with 103 participants were allocated to control (placebo once every 2 months +vitamin D3 10 μg daily for residents, placebo once every 2 months for carers) for 1 year. Primary outcome was time to first ARI; secondary outcomes included time to first upper/lower respiratory infection (URI/LRI, analysed separately), and symptom duration.

Inadequate vitamin D status was common at baseline: 220/240 (92%) participants had serum 25(OH)D concentration <75 nmol/L. The active intervention did not influence time to first ARI (adjusted HR (aHR) 1.18, 95% CI 0.80 to 1.74, p=0.42). When URI and LRI were analysed separately, allocation to the active intervention was associated with increased risk of URI (aHR 1.48, 95% CI 1.02 to 2.16, p=0.039) and increased duration of URI symptoms (median 7.0 vs 5.0 days for active vs control, adjusted ratio of geometric means 1.34, 95% CI 1.09 to 1.65, p=0.005), but not with altered risk or duration of LRI.

Addition of intermittent bolus-dose vitamin D3 supplementation to a daily low-dose regimen did not influence risk of ARI in older adults and their carers, but was associated with increased risk and duration of URI.

TRIAL REGISTRATION NUMBER: clinicaltrials.gov NCT01069874.

PMID: 26063508

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