Vitamin D status and ventilator-associated pneumonia in critically ill patients: A case-control study in northern Iran

Ventilator-associated pneumonia (VAP) is a major contributor to illness and death among patients in intensive care units (ICUs). While vitamin D deficiency is known to compromise immune defenses and elevate the risk of infections, its specific association with VAP has yet to be clearly established. So, we aimed to evaluate vitamin D in patients with VAP admitted to the ICU. In this case-control study, 141 ICU patients from two hospitals in northern Iran were enrolled. Serum 25-hydroxyvitamin D levels were measured within 48 hours of ICU admission. VAP diagnosis was based on clinical and microbiological criteria ≥48 hours after mechanical ventilation. Demographic data, laboratory parameters, and mechanical ventilation duration were recorded. Vitamin D insufficiency was present in 73.7% of patients. The mean serum vitamin D level did not differ significantly between VAP and non-VAP groups; however, sufficiency was nearly twice as common in the non-VAP group. Multivariate analysis identified elevated white blood cell count (OR = 2 per 1000 cells/µL, p < 0.001) and reduced platelet count (OR = 0.98, p = 0.005) as independent predictors of VAP, while vitamin D status was not statistically significant. Vitamin D deficiency is highly predominant in ICU patients but was not an independent predictor of VAP in this study. Nevertheless, the observed trend toward higher vitamin D sufficiency in non-VAP patients, along with previous evidence, suggests potential benefits of supplementation. Larger randomized controlled trials are warranted to clarify its preventive role in VAP.