Active form and Reservoir form of Vitamin D in Children with Acute Lower Respiratory Infections and Its Association with Severity of the Infection

Background: VitaminDplays an important role in regulating theimmunesystem, calciumandphosphorus homeostasis, andbone formation. This micronutrient plays an important role in the incidence and severity of respiratory infections. Objectives: The aim of this study was to evaluate the vitamin D serum level in children with acute lower respiratory infections (ALRIs) and its association with the severity of infection with vitamin D serum level. Methods: This cross-sectional study was conducted on 99 children with ALRIs aged 20.13 17.55 months who were selected with a simple random sampling technique. The children were examined and evaluated at the time of admission. Their data, including demographic characteristics and the findings of the physical examination and laboratory, were recorded in the questionnaires. Serum level of 1,25-dihydroxy vitamin D3 [1,25(OH)2D] and 25-hydroxyvitamin D3 [25(OH)D] were measured by HPLC method. Results: children with severe acute lower respiratory infection had a significant lower level of 25(OH) D (P = 0.02). Indeed, data analysis showed a level of 25(OH) D inversely associated with severity of acute lower respiratory infections in children (B = -0.7, P = 0.00). Conclusions: The severity of the lower respiratory tract infections was inversely proportional to the level of 25(OH)D, and it may be hoped that increasing 25(OH)D level may reduce the severity of ALRIs.