Association between Vitamin D Deficiency and Recurrent Respiratory Tract Infections in Children

Abstract

Background: Vitamin D plays an important role in the regulation of the immune system, and deficiency has been linked to increased susceptibility to respiratory infections. This study aimed to assess the relationship between vitamin D deficiency and recurrent respiratory tract infections (RTIs) in children. Methods: A comparative case-control study was carried out in 60 children, including 30 with recurrent RTIs and 30 controls. Demographic, nutritional, environmental, and clinical characteristics were recorded. The serum level of 25-hydroxyvitamin-D [25(OH) D] was assessed, and vitamin D deficiency was considered to have a serum level <20 ng/mL. The association between vitamin D deficiency and recurrent RTIs was assessed using logistic regression. Results: The mean serum 25(OH) D level was significantly lower in cases than in controls (p<0.001). A higher frequency of vitamin D deficiency was observed in the cases (66.7%) than in the controls (36.7%) (p=0.020). Vitamin D-deficient children had higher odds of recurrent RTIs (p=0.023). Vitamin D deficiency was still significantly associated with recurrent RTIs (p=0.046) when adjusted for age, sex, passive smoke exposure, socioeconomic status, nutritional status, immunization, and breastfeeding. Conclusions: Vitamin D deficiency was found to be significantly linked to recurrent RTIs among children. Additional prospective and interventional studies are needed to further clarify the causal relationship and determine the possible beneficial effect of correcting vitamin D deficiency.