Evaluation of the effectiveness of vitamin D deficiency correction in children with cystic fibrosis in St. Petersburg: results of a 12-month prospective study

Background. Vitamin D deficiency is a frequent problem in the patients with cystic fibrosis (CF). Adequate vitamin D supplementation need for normal bone mineralization and different systems functioning. The aim of our study was to evaluate the efficacy of vitamin D deficiency correction in CF pediatric patients in Saint Petersburg. Materials and methods. In the study were included 92 CF children aged from 0 to 17 years (49 boys and 43 girls) who had not previous vitamin D3 treatment. 25(OH)D levels were measured 3 times during the study (0-6-12 months). Vitamin D3supplementation was made according to contemporary consensuses. During the study the vitamin D3 doses correction was made. The patient’s adherence to treatment was evaluated on the basis of the personal communications. For assessment of bone metabolism we checked levels of total and ionized calcium, phosphorus, parathormone, alkaline phosphatase. In all patients anthropometry, ultrasound distal radius densitometry was performed. Statistical analysis was made with Statistica 10.0 software. Mann-Whitny, Kruskall-Wallis, Wilcoxon matched paired test, chi2 and Fisher’s exact tests, Mac-Nemar and Fridman’s test and Spearman’s correlation analysis were utilized. Results. Vitamin D deficiency (25OHD < 30 ng/ml) was detected in the 80% of the patients. Only 66 (71.7%) patients were complaint. The majority of the complaint patients increased 25OHD level during 12 months trial on the 33.7%. The best 25OHD increment indicators had young patients with initially higher levels of the 25OHD. Patients who were less 25(ОН)D deficient required proportionally lower vitamin D3 doses for correction. Conclusions: founded differences in the possibility to 25(OH)D normalization related with age and initial 25(OH)D level.