Correlation between serum vitamin D levels and immune function & clinical course in children with severe pneumonia: a single-center retrospective study.

BACKGROUND: To investigate the potential relationship between serum vitamin D levels and immune function as well as the clinical course of the illness in children with severe pneumonia. METHODS: Clinical data from 78 pediatric patients with severe pneumonia admitted to the First People's Hospital of Zunyi from January 2021 to November 2023 were retrospectively analyzed. According to the serum 25-hydroxy vitamin D3 (25-(OH)D3) standard, the patients were grouped into normal and low classes. The differences in baseline characteristics, immune function, and clinical course between the two groups were compared. RESULTS: There were statistically significant differences in clinical course and levels of IgA, IgG, and IgM between the two groups (P < 0.05). The OR values for IgA, IgG, IgM, and clinical course were 21.477, 17.639, 26.808, and 1.490, respectively. Serum vitamin D levels showed a positive correlation with IgA, IgG, and IgM (r = 0.530, 0.523, 0.606, P < 0.05) and a negative correlation with clinical course (r=-0.610, P < 0.05). The AUC values of IgA, IgG, IgM, and clinical course in predicting serum vitamin D levels in children with severe pneumonia were 0.824, 0.823, 0.871, and 0.739, respectively. CONCLUSION: Serum vitamin D levels in children with severe pneumonia are significantly correlated with immune function and clinical course.