Vitamin D Status at the Time of Hospitalization for Bronchiolitis and Its Association with Disease Severity

J Pediatr. 2018 Dec:203:416-422.e1. doi: 10.1016/j.jpeds.2018.07.097. Epub 2018 Sep 20.


Objective: To investigate the association between circulating 25-hydroxyvitamin D [25(OH)D] status at admission and disease severity among infants hospitalized for bronchiolitis and to determine whether the association differs by the form of 25(OH)D-total, bioavailable or free 25(OH)D.

Study design: We conducted a 17-center prospective cohort study of 1016 US infants <12 months old hospitalized with bronchiolitis. Vitamin D status was defined by total 25(OH)D levels, and by calculated levels of bioavailable and free 25(OH)D. Bronchiolitis severity was defined by requirement for intensive care and hospital length-of-stay (LOS). Logistic and Poisson regression were used for unadjusted and multivariable analyses.

Results: The median age of hospitalized infants was 3.2 months (IQR 1.6-6.0). The median total 25(OH)D was 26.5 ng/mL (IQR 18.0-33.1); 298 (29%) infants had total 25(OH)D <20 ng/mL. In multivariable models, infants with total 25(OH)D <20 ng/mL had higher risk of requiring intensive care (aOR 1.72, 95% CI 1.12-2.64) and longer LOS (adjusted rate ratio 1.39, 95% CI 1.17-1.65) compared with infants with total 25(OH)D ≥30 ng/mL. Infants with the lowest tertile of bioavailable 25(OH)D, compared with those with the highest tertile, had longer LOS (adjusted rate ratio 1.32, 95% CI 1.07-1.62); admission to the intensive care unit was not statistically significant in the adjusted model (aOR 1.39, 95% CI 0.96-2.64). Free 25(OH)D level was not associated with severity of bronchiolitis in either unadjusted or adjusted models.

Conclusion: In a large, multicenter cohort of US infants hospitalized for bronchiolitis, infants with total 25(OH)D <20 ng/mL had increased risk of intensive care and longer hospital LOS.

Keywords: acute respiratory infection; bioavailable vitamin D; free vitamin D; infants; intensive care; length of hospitalization; total vitamin D.

Publication types

  • Multicenter Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Bronchiolitis / blood*
  • Bronchiolitis / complications
  • Child, Preschool
  • Critical Care
  • Female
  • Hospitalization*
  • Humans
  • Infant
  • Intensive Care Units
  • Length of Stay
  • Male
  • Models, Statistical
  • Multivariate Analysis
  • Poisson Distribution
  • Prospective Studies
  • Severity of Illness Index
  • United States
  • Vitamin D / analogs & derivatives
  • Vitamin D / blood
  • Vitamin D Deficiency / blood*
  • Vitamin D Deficiency / complications


  • Vitamin D
  • 25-hydroxyvitamin D