Introduction: Vitamin D plays an important role in immune system health and the regulation of anti-inflammatory processes, and its deficiency can be associated with serious respiratory problems in infants. This study aimed to investigate the association between serum vitamin D levels and the need for continuous positive airway pressure (CPAP) or mechanical ventilation in hospitalized infants.

Method: In this cross-sectional descriptive-analytical study conducted in 2024-2025 at Ali ibn Abi Talib Hospital in Rafsanjan, 71 infants requiring respiratory support were divided into two groups based on serum vitamin D levels: exposed (vitamin D level < 30 ng/mL) and unexposed (vitamin D level ≥ 30 ng/mL). Demographic information and respiratory indices were recorded, and multivariate logistic regression models were used to investigate the association between serum vitamin D levels and the odds of requiring respiratory support.

Results: In this study, 71 neonates, including 27 females (38.03%) and 44 males (61.97%), were examined on their first day of life. The mean gestational age at birth was 34.52 weeks (±3.78). The mean serum vitamin D level in the evaluated neonates was 20.03 ng/ml. Of these, 83.10% (n=59) had vitamin D levels below normal. There was no significant correlation between the vitamin D level and duration of required respiratory support (p = 0.217). According to the results of the multivariable logistic regression model, serum vitamin D level was not significantly associated with the need for respiratory support (OR: 0.98, 95% CI: 0.92-1.04).

Conclusion: There was no significant association between serum vitamin D levels and the need for respiratory support. Further research with a large sample size is needed to verify the findings.