Ischemic stroke produces irreversible damage in the brain and is one of the main causes of disability and mortality. In recent years, scientific research has progressively documented the role of vitamin D (VitD) in a wide range of physiological functions, beyond its classic role of regulating the homeostasis of calcium and phosphorus. In particular, it has been shown that VitD deficiency is associated with numerous chronic diseases, including cardiovascular, musculoskeletal, infective and autoimmune diseases as well as tumors.
Low vitamin D levels are a common symptom in patients with cardiovascular pathologies such as ischemic stroke, myocardial infarction and hypertension; they are further linked to a greater risk of future cardio- and cerebrovascular events. Epidemiologic studies have demonstrated that VitD deficiency is a risk factor for stroke. Patients who have suffered stroke show a high incidence of VitD deficiency, which may be attributed to reduced mobility and diminished exposure to sunlight, on one hand, and to an inadequate dietary regime, on the other. Reduced vitamin D levels can increase the risk of a future cerebrovascular event and contribute to functional deficits subsequent to a stroke. It is further necessary to note a seasonal variation in the incidence of ischemic stroke, with lower percentages during summer when exposure to sunlight allows for increased synthesis of active vitamin D metabolites.