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COVID-19 home confinement & vitamin D levels alteration
Amene Raouf Rahmati1, Ramiar Kamal Kheder2, Tola Abdulsattar Faraj3
1Immunology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; Immunology Department, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
Journal of Infection and Public Health
|July 11, 2026
Summary
The COVID-19 pandemic impacted vitamin D levels, with a significant decrease in deficiency prevalence observed over time. Mean vitamin D3 concentrations increased post-vaccination, indicating a positive shift in population vitamin D status.
Area of Science:
- Endocrinology
- Public Health
- Nutritional Science
Background:
- COVID-19 pandemic led to home confinement, reduced sunlight exposure, and limited vitamin D intake.
- Lifestyle changes during the pandemic raised concerns about widespread vitamin D deficiency.
Purpose of the Study:
- To investigate the impact of the COVID-19 pandemic on vitamin D3 status in a large population.
- To analyze trends in vitamin D levels during different phases of the pandemic and vaccination rollout.
Main Methods:
- Retrospective, repeated cross-sectional laboratory study of 9,686 individuals in northeastern Iran.
- Vitamin D3 levels were measured pre-pandemic (2019), during the pandemic (2020), and post-vaccination (2021).
Main Results:
- Vitamin D insufficiency was prevalent across all study periods.
- Mean vitamin D3 levels increased from 35±19 ng/mL pre-pandemic to 38±16 ng/mL post-vaccination.
- Prevalence of vitamin D deficiency decreased significantly from 19% pre-pandemic to 9% post-vaccination.
Conclusions:
- Serum vitamin D concentrations generally increased during and after the COVID-19 pandemic.
- The prevalence of vitamin D deficiency showed a decreasing trend over the observed periods.
- Findings suggest a dynamic change in population vitamin D status related to pandemic phases and interventions.
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