Association of low vitamin D status with Childhood Pneumonia Severity in Hospitalized Bulgarian Patients

Abstract

Lower respiratory tract infections are among the most important causes of morbidity and mortality in the pediatric population worldwide. Despite advances in treatment and prevention, childhood pneumonia is a major reason for hospital admissions and remains a leading cause of death, claiming an estimated 800,000 children’s lives in 2018. Globally, over 1.23 million children died of pneumonia before reaching their 5th birthday - the equivalent of over 3.400 deaths per day  worldwide. There is growing evidence that vitamin D plays an important role in the immune system by modulating both innate and adaptive immunity. Vitamin D is an additional factor in the inflammatory response regulation. Its action is mediated via the vitamin D receptor (VDR), which is present in almost all types of immune cells, including activated CD4+ and CD8+ cells, B cells, macrophages, neutrophils and dendritic cells. Vitamin D deficiency is associated with decreased host defenses against infections. Therefore, our aim was to investigate whether low vitamin D status was a risk factor for pneumonia complications, usage of multiple antibiotics and prolonged hospital stay among hospitalized pediatric patients with community-aquired pneumonia. Total of 200 children (102 healthy controls and 98 with severe pneumonia) from 11 days to 17 years old were included in the study. Cases with severe pneumonia were subdivided into groups with and without complications (36 and 62, respectively). Electro-chemiluminescence immunoassay was used to measure the serum 25-hydroxyvitamin D levels. The control group showed lower values than the study group. Cases with complicated pneumonia had significantly lower levels 29.7-68.0 nmol/l, compared with 49.1-88.6 nmol/l in cases without complications. A significant negative correlation was found between vitamin D concentrations and duration of hospital stay, the number of antibiotics used for treatment, and serum levels of inflammatory markers. The low status of vitamin D is related to the severity of the disease, but has not been associated with the incidence/frequency of the disease. Children with low vitamin D levels may be at higher risk of developing life-threatening complications, intensive care admissions and a higher inflammatory response.