IMPACT OF VITAMIN D DEFICIENCY ON IMMUNE RESPONSE IN PATIENTS WITH RESPIRATORY INFECTIONS

Dr. Rajeshkumar Rameshbhai Patel; Dr. Milan R. Modi; Dr. Aumkar R Trivedi

Authors

Dr. Rajeshkumar Rameshbhai Patel MD Medicine, Associate Professor, Department of Medicine, Banas Medical College and Research Institute, Palanpur, Gujarat, India. Author
Dr. Milan R. Modi MS Orthopaedics, Associate Professor, Department of Orthopaedics, Banas Medical College and Research Institute, Palanpur, Gujarat, India. Author
Dr. Aumkar R Trivedi Professor & Head, Department of Dentistry, GMERS Medical College and Hospital, Vadnagar, Gujarat, India. Author

Keywords:

Vitamin D Deficiency, Respiratory Infections, Immune Response, Cellular Immunity, Inflammatory Markers, Clinical Outcomes.

Abstract

Background: Vitamin D plays a crucial role in immune modulation and host defense against respiratory pathogens. However, the specific impact of vitamin D deficiency on immune parameters in patients with respiratory infections remains inadequately characterized. This study investigated the relationship between vitamin D status and immune response markers in adults with respiratory tract infections. Methods: A prospective observational study was conducted among 324 adult patients diagnosed with acute respiratory tract infections at a tertiary care hospital. Serum 25-hydroxyvitamin D [25(OH)D] concentrations, immune markers (including CD4+ T cells, CD8+ T cells, natural killer cells, interleukin-6, C-reactive protein, and total immunoglobulin levels), and clinical outcomes were assessed. Vitamin D deficiency was defined as 25(OH)D <20 ng/mL. Participants were categorized into three groups: deficient (<20 ng/mL), insufficient (20-29.9 ng/mL), and sufficient (≥30 ng/mL). Results: Overall, 58.6% of patients exhibited vitamin D deficiency, with mean 25(OH)D concentration of 18.7 ± 8.4 ng/mL. Patients with vitamin D deficiency demonstrated significantly lower CD4+ T cell counts (687 ± 142 cells/μL vs. 912 ± 178 cells/μL, p < 0.001), reduced natural killer cell percentages (8.4 ± 2.3% vs. 13.7 ± 3.1%, p < 0.001), and elevated inflammatory markers including interleukin-6 (42.3 ± 15.8 pg/mL vs. 24.1 ± 9.2 pg/mL, p < 0.001) compared to those with sufficient levels. Vitamin D deficiency was independently associated with prolonged hospital stay (OR = 2.87, 95% CI: 1.76-4.68, p < 0.001), increased disease severity (OR = 3.14, 95% CI: 1.92-5.13, p < 0.001), and higher risk of secondary bacterial infections (OR = 2.43, 95% CI: 1.48-3.99, p < 0.001). Conclusion: Vitamin D deficiency is highly prevalent among patients with respiratory infections and is associated with impaired cellular immunity, dysregulated inflammatory responses, and adverse clinical outcomes. These findings support the need for vitamin D screening and targeted supplementation strategies in respiratory infection management.