25-Hydroxyvitamin D Sufficiency Is Associated With Reduced Atelectasis in Common Variable Immunodeficiency: A Cross-Sectional Study.

BACKGROUND Common variable immunodeficiency (CVID) is an inborn error of immunity characterized by impaired antibody production, poor vaccine responses, and reduced serum immunoglobulin levels, resulting in respiratory manifestations that can progress to pulmonary complications. Although vitamin D has been associated with pulmonary outcomes in other populations, the association between serum 25-hydroxyvitamin D [25(OH)D] status and pulmonary manifestations, particularly atelectasis, in CVID remains unclear. MATERIAL AND METHODS We conducted a retrospective cross-sectional study of 48 adult patients with CVID stratified by serum 25(OH)D concentration (<30 ng/mL [insufficient] vs ≥30 ng/mL [sufficient]). Pulmonary outcomes (atelectasis, bronchiectasis, recurrent pneumonia, and chronic obstructive pulmonary disease [COPD]) were obtained from medical records. Associations were assessed via Fisher's exact test. Exploratory analyses included a longitudinal imaging review and descriptive Kaplan-Meier curves illustrating atelectasis-free disease duration by baseline 25(OH)D status. RESULTS Among 48 patients, 35 (73%) had 25(OH)D concentrations below 30 ng/mL. Atelectasis was more frequent in the insufficient group (15/35; 43%) (odds ratio=0.12; 95% confidence interval, 0.01-0.97; P=0.02). No significant associations were observed for bronchiectasis (63% vs 46%; P=0.53), recurrent pneumonia (91% vs 84%; P=0.49), or COPD (3% vs 8%; P=0.46). Kaplan-Meier curves did not show an apparent separation between groups. CONCLUSIONS Serum 25(OH)D sufficiency was associated with lower atelectasis prevalence in patients with CVID. This finding reflects a cross-sectional association and does not establish causality; it supports a potential link between 25(OH)D status and atelectasis. Prospective studies are needed to further evaluate this relationship.