Vitamin D influences many other physiological processes, including muscle function, cardiovascular homeostasis, nerve function, and immune response. Furthermore, accumulated evidence suggests that vitamin D also mediates the immune system response to infection.

Infections are very common in patients from neurosurgical intensive care units.

A recent study published in the Neural Regeneration Research (Vol. 8, No. 16, 2013) detected serum vitamin D level in 15 patients with clinically suspected infection and 10 patients with confirmed infection, who came from neurosurgical intensive care units. Serum level of 25-hydroxyvitamin D, the primary circulating form of vitamin D, was significantly decreased in patients with suspected or confirmed infection after a 2-week neurosurgical intensive care unit hospitalization, while serum level of 1,25-dihydroxyvitamin D, the active form of vitamin D, was significantly decreased in patients after a 4-week neurosurgical intensive care unit hospitalization.

These findings suggest that vitamin D deficiency is linked to the immunological status of neurosurgical intensive care unit patients and vitamin D supplementation can improve patient's immunological status.