Vitamin D deficiency: implications for acute care in the elderly and in patients with chronic illness.

There is evidence that the vast majority of hospitalized patients have vitamin D deficiency. Vitamin D deficiency is a poorly recognized pandemic with evidence to indicate inadequate testing and monitoring of response to treatment in high-risk populations. Vitamin D receptors are ubiquitous in the human body and while the endocrine effects of vitamin D are well recognized, the autocrine and paracrine effects of this steroid hormone are less well appreciated. These functions include antimicrobial and immunomodulation effects as well benefits on cardiovascular health, autoimmune disease, cancer and metabolism. Vitamin D deficiency increases mortality and even a modest amount of vitamin D may enhance longevity. Emerging evidence suggests that a vitamin D replete state carries significant health benefits in acute illness. In this review, we discuss the role of vitamin D deficiency and potential benefits in treating this deficiency focusing on the implications for managing acute illness in elderly patients and those with an underlying chronic illness.