Original scientific paper
https://doi.org/10.3325/cmj.2021.62.49 5
The effect of standarddose wintertime vitamin D supplementation on influenza infection in immunized nursing home elderly residents
Ana Godan Hauptman
; Division for Metabolic Diseases, Department of Internal Medicine, University Hospital Center Zagreb, Zagreb, Croatia
Amarela Lukić-Grlić
; Department of Clinical Microbiology, Children’s Hospital Zagreb, Zagreb, Croatia
Jasmina Vraneš
; University of Zagreb School of Medicine, Zagreb, Croatia
Milan Milošević
; Department of Environmental Health, Occupational and Sports Medicine, Andrija Štampar School of Public Health, University of Zagreb, School of Medicine, Zagreb, Croatia
Alenka Gagro
; University of Zagreb School of Medicine, Zagreb, Croatia
Abstract
Aim To investigate whether three-month oral vitamin D
supplementation (800 IU in drops) reduces the risk of in
-
fluenza infection in elderly nursing home residents vacci
-
nated against influenza.
Methods This cross-sectional observational study enrolled
97 participants (73.2% women) who received one dose of
seasonal trivalent 2016-2017 influenza vaccine. The patients
were randomized into an experimental group, which re
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ceived vitamin D supplementation for three months start
-
ing on the day of vaccination, and a control group, which
did not receive vitamin D supplementation. The primary
outcome was the number of influenza infections labora
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tory-confirmed using a rapid point-of-care test based on
nasal swabs collected during vitamin D supplementation.
The secondary outcome was serum 25-hydroxyvitamin D
level at the end of the study.
Results The mean age ±standard deviation was 78.5± 8.8
years. All participants had vitamin D deficiency at baseline.
Twenty-three participants who developed signs of respira
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tory infections during the study were tested for influenza
virus. Although the number of influenza-positive partici
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pants was lower in the group receiving vitamin D supple
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mentation as compared with the control group (5 vs 12),
this difference was not significant. Vitamin D supplemen
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tation failed to increase 25(OH)D levels after three months
of supplementation.
Conclusion Elderly nursing home residents in Zagreb
County have a significant vitamin D deficiency. The recom
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mended national supplementation of 800 IU daily failed to
lead to vitamin D sufficiency and did not reduce the risk of
influenza infection among the vaccinated elderly.
Keywords
Hrčak ID:
278793
URI
Publication date:
21.10.2021.
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