title: Role of vitamin D in diabetes mellitus and chronic kidney disease.
abstract: Approximately 30%-50% of people are recognized to have low levels of vitamin D, and insufficiency and deficiency of vitamin D are recognized as global health problems worldwide. Although the presence of hypovitamin D increases the risk of rickets and fractures, low vitamin D levels are also associated with hypertension, cancer, and cardiovascular disease. In addition, diabetes mellitus (DM) and chronic kidney disease (CKD) are also related to vitamin D levels. Vitamin D deficiency has been linked to onset and progression of DM. Although in patients with DM the relationship between vitamin D and insulin secretion, insulin resistance, and β-cell dysfunction are pointed out, evidence regarding vitamin D levels and DM is contradictory, and well controlled studies are needed. In addition, vitamin D influences the renin-angiotensin system, inflammation, and mineral bone disease, which may be associated with the cause and progression CKD. There is increasing evidence that vitamin D deficiency may be a risk factor for DM and CKD; however, it remains uncertain whether vitamin D deficiency also predisposes to death from DM and CKD. Although at this time, supplementation with vitamin D has not been shown to improve glycemic control or prevent incident DM, clinical trials with sufficient sample size, study periods, and optimal doses of vitamin D supplementation are still needed. This review focuses on the mechanism of vitamin D insufficiency and deficiency in DM or CKD, and discusses the current evidence regarding supplementation with vitamin D in patients with these diseases.
authors.affiliation: Akio Nakashima, Keitaro Yokoyama, Takashi Yokoo, Division of Nephrology and Hypertension, Department of Internal Medicine, Jikei University School of Medicine, Tokyo 105-8461, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Nakashima
authors.affiliation: Akio Nakashima, Keitaro Yokoyama, Takashi Yokoo, Division of Nephrology and Hypertension, Department of Internal Medicine, Jikei University School of Medicine, Tokyo 105-8461, Japan.
authors.forename: Keitaro
authors.initials: K
authors.lastname: Yokoyama
authors.affiliation: Akio Nakashima, Keitaro Yokoyama, Takashi Yokoo, Division of Nephrology and Hypertension, Department of Internal Medicine, Jikei University School of Medicine, Tokyo 105-8461, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yokoo
authors.affiliation: Akio Nakashima, Keitaro Yokoyama, Takashi Yokoo, Division of Nephrology and Hypertension, Department of Internal Medicine, Jikei University School of Medicine, Tokyo 105-8461, Japan.
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Urashima
keywords: Cardiovascular disease; Chronic kidney disease; Diabetes mellitus; Vitamin D; Vitamin D deficiency