Clinical Implication Of Serum Vitamin D Level In Children With Acute Bronchiolitis

Background Bronchiolitis is the most common lower respiratory infection in the children from 0-2 years of age group. Clinically, it is recognized as a set of signs and symptoms, including initial viral upper respiratory manifestations followed by increased respiratory effort and wheezing. Bronchiolitis is the most common cause of hospitalization among infants during the first 12 months of life. According to the World Health Organization, an estimated 150 million new cases occur worldwide annually out of which 11-20 million(7-13%) of these cases are severe enough to require hospital admission. Recently, there has been increasing interest in the role of vitamin D in respiratory infections. After the discovery of vitamin D receptor(VDR) expression in almost all immune cells(e.g. lymphocyte B and T, neutrophils, macrophages) and respiratory epithelial cells, an entirely new role of vitamin D action has been identified. Vitamin D has been shown to play a major role in innate immunity and antimicrobial production of peptides such as cathelicidin and defensins which protect against RSV(Respiratory Syncytial Virus). Moreover, adequate vitamin D level has been found to diminish inflammation and the severity of disease in patients infected with RSV.Objective The aim of this study was to examine the prevalence of hypovitaminosis D in children with acute bronchiolitis compared with control subjects.Methods A descriptive cross sectional study was conducted from January 2016 to March 2016 in the Department of Pediatric Pulmonology, First Hospital of Jilin University, Changchun, China. Children with bronchiolitis admitted in the inpatient unit of Department of Pediatric Pulmonology were taken as cases and the control were the children admitted to the Pediatric Surgery Department for operation and had no LRTI(lower respiratory tract infection). Forty children were included in the study as cases, following inclusion and exclusion criteria and twenty two as control. At the time of enrollment an informed written consent was obtained from the parents or the legal guardian. A detailed history and physical examination was done according to a predesigned performa to elicit various potential risk factors and other relevant history. Blood samples were drawn and tested for vitamin D level by mass spectrometer and high performance liquid chromatography. The obtained values of vitamin D were categorized as deficient <15 ng/ml, insufficient 15-20 ng/ml, and normal/sufficient >20 ng/ml. All statistical analyses were performed using IBM SPSS Statistics 23(IBM SPSS Statistics? 23.Ink, New York, USA). P value <0.05(two-tailed) was considered as significant.Results Forty children diagnosed of bronchiolitis were enrolled in the study.The control group consisted of 22 children. There were no significant statistical differences according to age(p 0.37), sex(p0.58), and weight(p0.23). Serum vitamin D level in the bronchiolitis group were significantly lower than in the control group(mean 19.0 ng/ml(10.9-27.1) versus mean 30.1 ng/ml(20.8-39.4), p=0.001). In the bronchiolitis group, 15 patient(37.5%) had sufficient vitamin D level(>20 ng/ml). Prevalence of vitamin D insufficiency and deficiency(vitamin D levels between 15-20 ng/ml and <15 ng/ml respectively) was remarkably high, 25 in 40 patients(62.5%).Conclusion In conclusion, this study shows that hypovitaminosis D is highly prevalent in children with acute bronchiolitis. An adequate compliance with vitamin D prophylaxis to achieve sufficient levels of vitamin D, which may help to reduce the burden of bronchiolitis, is suggested strongly.