Effect of Vitamin D in Long COVID Patients

Ramsen Ghasan Hikmet*, Christian Wejse, Jane Agergaard

*Corresponding author for this work

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review


Vitamin D deficiency has been studied in the context of acute coronavirus disease 2019 (COVID-19), revealing associations with increased severity and mortality. Yet, the influence of vitamin D on long COVID symptoms remains unknown. The purpose of this study is to examine the effect of vitamin D on long COVID symptoms. Over the study period, 50,432 individuals within the catchment area of the outpatient COVID-19 clinic tested positive for SARS-CoV-2 via PCR, with 547 patients subsequently referred to a specialized Post-COVID Clinic, and 447 of them enrolled in the study. Patient-reported symptoms and paraclinical measures including vitamin D were evaluated in 442 patients. The majority of participants were female (72%, n = 320/442). The consumption of alcohol and number of current smokers were low. Low vitamin D was observed in 26% (n = 115/442) of the patients, most commonly in male participants (odds ratio (OR) = 1.77, 95% confidence interval (CI) (1.12, 2.79), p = 0.014). Additionally, low vitamin D was correlated with a younger mean age of 41 years (standard deviation (SD) = 12) as opposed to 48 years (SD = 13) in patients with normal vitamin D levels (OR = 0.96, 95% CI (0.94, 0.97), p < 0.001). While our study population indicated a potentially higher prevalence of vitamin D insufficiency in this population compared to the general population, no significant differences in prevalence of symptom or symptom severity scores were observed between the low and normal vitamin D groups. In patients in a Post-COVID Clinic, we found no association between vitamin D levels and long COVID symptoms.

Original languageEnglish
Article number7058
JournalInternational Journal of Environmental Research and Public Health
Number of pages13
Publication statusPublished - Nov 2023


  • Humans
  • Female
  • Male
  • Adult
  • Vitamin D
  • Post-Acute COVID-19 Syndrome
  • COVID-19/epidemiology
  • SARS-CoV-2
  • Vitamins
  • Vitamin D Deficiency/epidemiology


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