Huang GQ, Cheng HR, Wu YM, et al. - By performing this study with 863 consecutive acute ischemic stroke patients, researchers examined the potential link between serum vitamin D levels and stroke-associated pneumonia (SAP). They defined in-hospital SAP as a complication that happened following a stroke, during hospitalization, that was verified radiographically. Within 24 hrs of admission, measurements of serum vitamin D levels were obtained, and patients were classified as vitamin D sufficient (> 50 nmol/L), insufficient (25–50 nmol/L), and deficient. They detected significantly lower vitamin D levels in patients with SAP vs those without SAP. Patients with vitamin D deficiency vs those with vitamin D insufficiency or sufficiency exhibited a significantly higher incidence of SAP. An independent link of vitamin D deficiency and insufficiency with SAP was revealed following adjustment for confounders. A linear relation to the risk of SAP was demonstrated by vitamin D levels in multiple-adjusted spline regression. Overall, decreased vitamin D was identified as a potential risk factor of in-hospital SAP, which can assist clinicians to recognize high-risk SAP patients.