High-Dose Monthly Vitamin D for Prevention of Acute Respiratory Infection in Older Long-Term Care Residents: A Randomized Clinical Trial

J Am Geriatr Soc. 2017 Mar;65(3):496-503. doi: 10.1111/jgs.14679. Epub 2016 Nov 16.


Objectives: To determine the efficacy and safety of high-dose vitamin D supplementation for prevention of acute respiratory infection (ARI) in older long-term care residents.

Design: Randomized controlled trial investigating high-dose vs standard-dose vitamin D from 2010 to 2014.

Setting: Colorado long-term care facilities.

Participants: Long-term care residents aged 60 and older (n = 107).

Intervention: The high-dose group received monthly supplement of vitamin D3 100,000 IU, the standard-dose group received a monthly placebo (for participants taking 400-1,000 IU/d as part of usual care) or a monthly supplement of 12,000 IU of vitamin D3 (for participants taking <400 IU/d as part of usual care).

Measurements: The primary outcome was incidence of ARI during the 12-month intervention. Secondary outcomes were falls and fractures, 25-hydroxyvitamin D levels, hypercalcemia, and kidney stones.

Results: Participants (55 high dose, 52 standard dose) were randomized and included in the final analysis. The high-dose group had 0.67 ARIs per person-year and the standard-dose group had 1.11 (incidence rate ratio (IRR) = 0.60, 95% confidence interval (CI) = 0.38-0.94, P = .02). Falls were more common in the high-dose group (1.47 per person-year vs 0.63 in standard-dose group; IRR = 2.33, 95% CI = 1.49-3.63, P < .001). Fractures were uncommon and similar in both groups (high dose 0.10 vs standard dose 0.19 per person-year; P = .31). Mean trough 25-hydroxyvitamin D levels during the trial were 32. ng/mL in the high-dose group and 25.1 ng/mL in the standard-dose group. There was no hypercalcemia or kidney stones in either group.

Conclusion: Monthly high-dose vitamin D3 supplementation reduced the incidence of ARI in older long-term care residents but was associated with a higher rate of falls without an increase in fractures.

Keywords: falls; immunosenescence; nursing home; respiratory infection; vitamin D.

Publication types

  • Clinical Trial, Phase II
  • Randomized Controlled Trial

MeSH terms

  • Accidental Falls / statistics & numerical data
  • Aged, 80 and over
  • Assisted Living Facilities
  • Cholecalciferol / administration & dosage*
  • Colorado / epidemiology
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Female
  • Fractures, Bone / epidemiology
  • Humans
  • Male
  • Respiratory Tract Infections / epidemiology
  • Respiratory Tract Infections / prevention & control*
  • Skilled Nursing Facilities
  • Vitamin D / analogs & derivatives
  • Vitamin D / blood
  • Vitamins / administration & dosage*


  • Vitamins
  • Vitamin D
  • Cholecalciferol
  • 25-hydroxyvitamin D