Vitamin D Levels in SARS-CoV-2: Do Current Adequacy Thresholds Reflect Clinical Risk? Insights From a Large Turkish Cohort (COVIDVIT)

February 3, 2026 updated by: Taner Dandinoğlu, Bursa City Hospital
Blood vitamin D levels may be associated with severity of viral infections. To find out If there is a statistically significant relation between blood 25-hydroxy vitamin D (25(OH)D) levels and disease severity, patients with Covid-19 viral infection were investigated.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Purpose:

Vitamin D a steroid hormone has profound effects on human immunity. Active vitamin D, 1,25(OH)2D acts as an immune system modulator, preventing excessive expression of inflammatory cytokines and increasing the 'oxidative burst' potential of macrophages. Epidemiological data has linked vitamin D deficiency to increased susceptibility to acute viral respiratory infections.

There is evidence that some patients with severe COVID-19 experience a cytokine storm with production of large quantities of interleukins, specifically IL-1 and IL-6. Moreover it was hipotiesied that the sufficient vitamin D levels may help to decrease IL-6 levels like tocizulamab which is a potent blocking agent of the IL-6 receptor.

In this observational study, possible relation between the disease and vitamin D levels were investigated in COVİD-19 patients.

Material and Methods:

To find out vitamin D levels and it's relation with the disease severity serum 25-hydroxy-vitamin D levels will be measured in nearly 1100 confirmed COVİD-19 patients. Same patients will also be evaluated for vital signs, laboratory and pulmoner CT findings. Demographic and medical data will also be collected. Statically significant positive or negative results and the comparison of these findings will be presented.

Presenting blood vitamin- D levels and it's possible assosiation with disease severity may inspire new perspectives for future trials spesifically focusing vitamin D levels.

Study Type

Observational

Enrollment (Actual)

1100

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

1100 confirmed COVİD-19 patients (PCR)

Description

To find out vitamin D levels and it's relation with the disease severity serum 25-hydroxy-vitamin D levels, 1100 confirmed Covid-19 patients with available laboratory findings were included.

Exlucion Criterias:

Using immunsuppresan medical treatment. Using vitamin D or replacement history of vitamin D in last 3 months. Patients with malnutrition, immun deficiency, chronic infections, chronic other diseases such as rheumatoid arthritis, ankylosing spondilitis, lupus, hemplegia, paraplegia etc.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
laboratory measured vitamin D levels
Time Frame: 12 months
serum 25-hydroxy-vitamin D levels
12 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Bursa City Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 1, 2020

Primary Completion (Actual)

May 15, 2021

Study Completion (Actual)

August 30, 2025

Study Registration Dates

First Submitted

May 18, 2020

First Submitted That Met QC Criteria

May 18, 2020

First Posted (Actual)

May 19, 2020

Study Record Updates

Last Update Posted (Actual)

February 5, 2026

Last Update Submitted That Met QC Criteria

February 3, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2020-PMR-1

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

Research data will be available upon request from authors

(Taner Dandinoglu MD. e-mail: dandinoglu@gmail.com, Sinem Akselim MD e-mail: sinemakselim@gmail.com)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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