Serum Vitamin D Levels in Children with Recurrent Respiratory Infections and Chronic Cough.

Objectives: To evaluate serum vitamin D levels in cases of recurrent respiratory infections and chronic cough and to investigate the effect of vitamin D therapy on recurrence of the diseases.

Methods: This prospective observational study was performed by comparing serum vitamin D levels in children with recurrent respiratory infections, chronic cough and healthy children. One-hundred-one children with chronic cough, ninety-eight children with recurrent respiratory infections and one-hundred-twenty-four healthy children were enrolled in the study. A structured questionnaire was completed to collect data on demography, diet, duration of breastfeeding, vitamin D supplementation and family history for allergic diseases. In patients with low serum vitamin D levels (<20 ng/ml), vitamin D therapy was administered in addition to conventional treatment for the diseases. Patients were followed up for 6 mo and their complaints were evaluated.

Results: Mean serum 25(OH) vitamin D level in the recurrent respiratory infections group was 11.97 ± 4.04 ng/ml, chronic cough group was 13.76 ± 4.81 ng/ml and control group was 31.91 ± 18.79 ng/ml. Comparison of serum 25(OH) vitamin D levels between the study groups revealed a statistically significant difference (p < 0.05). 25(OH)D deficiency in children was associated with increased frequency of recurrent respiratory infections and chronic cough.

Conclusions: To conclude, administration of supplementary vitamin D may be useful in the treatment and preventation of recurrent respiratory infections and chronic cough.