By Bhavana KunkalikarMay 6 2022Reviewed by Aimee Molineux

In a recent study published in the European Review for Medical and Pharmacological Sciences journal, researchers assessed the presence of vitamin D deficiency in coronavirus disease 2019 (COVID-19)-recovered patients.

Background

A limited number of studies have indicated that vitamin D deficiency may play a crucial role in COVID-19 infections and severity. However, no currently available studies have explored the frequency of vitamin D deficiency in patients suffering from long-COVID-19.

About the study

In the present study, researchers investigated the frequency of vitamin D deficiency in patients suffering from long-COVID-19 and assessed the impact of vitamin D deficiency on persistent symptoms.

The study comprised participants who were aged 18 years and above and reported at the post-COVID-19 clinic at Assiut University Hospital, for a COVID-19 follow-up program held between November 2020 and May 2021. The eligible participants had a confirmed COVID-19 test result in the three months before attending the program. This program estimated the clinical and functional status, sleep disorders, pulmonary functions, and any need for rehabilitation.

The team designed a cross-sectional and single-center study and obtained data as well as medical records using the case record format of the post-COVID-19 out-patients clinic. Symptoms reported by the patients were classified into: (1) constitutional symptoms including myalgia, fever, arthralgia, tachycardia, restriction of daily activity, headache, excessive sweating, and dizziness; (2) respiratory symptoms including sputum, cough, sore throat, chest pain, dyspnea, and rhinorrhea; (3) gastrointestinal tract (GIT) symptoms including gastritis, diarrhea, abdominal pain, anorexia, and dysphagia; and (4) neuropsychiatric symptoms including sleeping problems, anosmia and/or ageusia, anxiety and/or depression, tinnitus, loss of concentration, memory loss, and peripheral neuropathy.

Patients reporting symptoms for one or more of the symptom categories were considered positive for that category. The team further evaluated symptom scores for acute as well as posy-COVID-19 symptoms to represent symptom severity.

The team also determined levels of serum urea, serum calcium, serum ferritin, creatinine, and c-reactive protein (CRP). The amount of 25-hydroxy vitamin D in the serological samples was also evaluated using an enzyme-linked immunosorbent assay (ELISA). The normal levels of 25-hydroxy vitamin D were defined as 30 ng/ml or more while insufficient serum levels were defined to be between 20 ng/ml and 30 ng/ml.

Results

The study findings showed no statistically significant variation between acute and post-COVID-19 symptoms with normal, insufficient, and deficient levels of vitamin D considering the patient demographic data, medical data, and related comorbidities. With respect to the laboratory parameters for serum samples with normal and low levels of vitamin D, the CRP values were 5.0±3 and 6.2±0.4, serum calcium levels were 8.6±1.8 and 8.4±2.1, the serum ferritin levels were 113.6±50 and 151±138.3, serum urea levels were 67.2±54 and 69.4±75.0, and creatinine levels were 1.6±1.0 and 5.2±1.5, respectively.   

Conclusion

The study findings showed no substantial association of vitamin deficiency with post-COVID-19 symptoms. Furthermore, it was observed that the pathophysiology of COVID-19 symptoms was more complex than was previously assumed.

The researchers believe that further studies are necessary to assess the role and impact of vitamin D supplementation in improving COVID-19 outcomes.