Vitamin D deficiency in children with cystic fibrosis:is there a link with the microflora of the lower respiratory tract, the frequency of hospitalizations and the volumeof antibiotic therapy?

Background. Cystic fibrosis (CF) – a hereditary disease which is characterized by a chronic infection and inflammation in airways and leads to the progressing of the lung damage and an early disability. The aim of our study to evaluate the relationship between vitamin D deficiency and degree of the contamination of the lower airways (LA) by the main pathogens and requirement in intravenous (IV) antibacterial therapy and hospital admission duration. Materials and methods. The study included 92 children with CF aged from 0 to 17 years. During the research (18 months) the serum 25(OH)D levels were evaluated trice. Vitamin D₃ titration dosage was made according the 25(OH)D level and data about treatment compliance collected. According to the register of patients the number of flares and days of antibacterial therapy for 3 periods was counted: during 1 year before inclusion in the study (2016), for 2017 (during treatment) and in 2018. Statistical analysis was carried out with Statistica 10.0 software. Results. From 92 people, only 66 were compliant and in 38/66 the normal level of 25(OH)D was reached. At children with initially normal level of vitamin D the requirement in IV antibacterial therapy within the first year of observation decreased. In patients who had normal 25(OH)D serum level (>30 ng/ml) we observed decreased number of in-patient department admission and decreased frequency of gram-negative bacteria of LA detection. Conclusions. The maintenance of normal blood vitamin D level was a perspective therapeutic strategy in CF patients which may reduce the frequency of a chronic infection and as a result, the requirements in hospital admission and IV antibacterial therapy.