Predictors of reduced serum vitamin D levels among Egyptian children with interstitial lung disease

Abstract EN

Background / aim : Patients with interstitial lung disease (ILD) appear to be at an increased risk of vitamin D deficiency for reasons that are not clear.

This study was designed to determine the serum vitamin D level and to evaluate the relationship between the serum level of vitamin D and the underlying etiology, the clinical severity, and pulmonary functions among children with ILD.

Patients and methods : This cross-sectional case–control study was conducted on 40 patients aged 4–16 years with ILD from those regularly attending the Pediatric Chest Clinic and Pediatric Allergy and Immunology Clinic, Children’s Hospital, Ain Shams University.

They were divided into two subgroups : 20 patients with nonconnective tissue disease-associated ILD constituted group I and 20 patients with connective tissue disease-associated ILD constituted group II.

Twenty apparently healthy children of matched age and sex were recruited as the control group.

Results : The mean serum vitamin D (25-hydroxyvitamin D) level was significantly lower among patients with ILDs compared with controls (21.15 ± 4.6 vs.

48 ± 40.76 ng / ml, respectively, P < 0.05), and there was no significant difference between patients’ subgroups.

The mean alkaline phosphatase level was significantly higher in patients with ILDs compared with controls (P < 0.05).

Our patients had a highly significant increase in the total leukocytic count, erythrocyte sedimentation rate, and C-reactive protein in connective tissue disease-associated ILD as compared with nonconnective tissue disease-associated ILD.

Serum vitamin D levels showed a significant positive correlation with forced vital capacity and significant negative correlations with the age and the duration of steroid therapy.

By linear regression analysis, patients’ age and the duration of steroid therapy were significant predictors of low serum vitamin D levels (at P = 0.045 and 0.01, respectively).

Conclusion : Children with ILD appear to be at an increased risk of vitamin D deficiency and insufficiency, particularly those with reduced lung function.

All patients with ILD receiving long-term corticosteroid therapy should be considered at increased risk for bone fracture.

Preventive measures and routine estimation of vitamin D (25-hydroxyvitamin D) should be recommended and vitamin D supplementation is advised on an individual basis.