Vitamin D status of Arab Gulf residents screened for SARS-CoV-2 and its association with COVID-19 infection: a multi-centre case-control study.
Level 4 - case-series / case-control
Case-control study
PubMed 33902635 · doi:10.1186/s12967-021-02838-x
What was done
This multi-center case-control study assessed 220 adult Arab Gulf residents presenting with no to mild symptoms who were screened for SARS-CoV-2 (138 RT-PCR-positive cases and 82 negative controls). Investigators recorded medical history, measured anthropometrics, and collected non-fasting blood samples to evaluate serum 25(OH)D levels, glucose, lipids, and inflammatory markers.
What was found
After adjusting for age and BMI, serum 25(OH)D levels were significantly lower in SARS-CoV-2-positive participants compared to negative controls (52.8 ± 11.0 nmol/L vs. 64.5 ± 11.1 nmol/L; p = 0.009). Independent of age, sex, and obesity, significant risk factors for infection were age > 60 years (OR 6, 95% CI 2–18; p = 0.001), type 2 diabetes (OR 6, 95% CI 3–14; p < 0.001), and low HDL cholesterol (OR 6, 95% CI 3–14; p < 0.001).
Why it matters
It demonstrates an observational association between lower 25(OH)D levels and SARS-CoV-2 positivity in an Arab Gulf population while showing that age and cardiometabolic dysregulation are strong independent risk factors.
Limits
The retrospective/case-control design cannot establish causality or exclude reverse causation, as acute infection may suppress 25(OH)D. The sample size was modest (n = 220), blood draws were non-fasting, and only asymptomatic to mildly symptomatic patients were evaluated.
Cited by
- supports A study showed that symptomatic patients who tested positive for COVID-19 had significantly lower vitamin D levels than symptomatic patients who tested negative.