Comparison of 25-Hydroxyvitamin D levels linked to pediatric pneumonia severity during non-COVID-19 and COVID-19 periods

Objective: To investigate the association between 25-hydroxyvitamin D (25(OH)D) levels and the severity of pneumonia during non-COVID-19 and COVID-19 periods, while also comparing the risk factors for pneumonia severity between these two periods. Methods: A total of 1018 children were recruited from 10 hospitals between November 2019 and November 2020. After applying exclusion criteria, the final sample consisted of 593 children, including 165 with pneumonia during the non-COVID-19 period and 428 during the COVID-19 period. Results: During non-COVID-19 periods, 25(OH)D showed a protective effect on the severity of pneumonia (0.91 [0.83-0.99], p=0.022). However, this protective effect of 25(OH)D was not observed during the COVID-19 period. Furthermore, a comparison between the two periods revealed differences in the risk factors for the severity of pneumonia. In non-COVID-19 periods, there was a positive correlation between the severity of pneumonia and the length of hospitalization in patients with 25(OH)D deficiency. However, no significant correlation was found between the severity of pneumonia and the length of hospitalization in patients with normal 25(OH)D levels. Interestingly, this phenomenon was not observed during the COVID-19 period. Conclusion: The research findings indicate that during non-COVID-19 periods, there was a significant correlation between 25(OH)D levels and the severity of pneumonia. However, during the COVID-19 period, no significant correlation between 25(OH)D levels and the severity of pneumonia was observed