PARATHYROIDS, BONE AND MINERAL METABOLISM: Edited by Vin TangprichaAn update on vitamin D for cliniciansHansen, Karen E.; Johnson, Michael G. Author Information Department of Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA Correspondence to Karen E. Hansen, MD, MS, Department of Medicine, University of Wisconsin–Madison, Room 4124 MFCB 1685 Highland Avenue, Madison, WI 53705-2281, USA. Tel: +1 608 263 0517; fax: +1 608 263 7353; e-mail: [email protected] Current Opinion in Endocrinology & Diabetes and Obesity: December 2016 - Volume 23 - Issue 6 - p 440-444 doi: 10.1097/MED.0000000000000288 Buy Metrics Abstract Purpose of review The clinical benefits of vitamin D therapy have received substantial attention over the past decade. Recently, several trials looked to clarify the optimal vitamin D dose or serum level needed to promote human health. The purpose of this review is to highlight selected studies published since January 2015. Recent findings Several recent trials challenge whether serum vitamin D levels at least 30 ng/ml promote human health. In postmenopausal women with 25-hydroxyvitamin D [25(OH)D] levels 21 ± 3 ng/ml, high-dose vitamin D for 1 year increased calcium absorption by 1%, without changes in bone mineral density, physical function, or falls when compared with low-dose vitamin D and placebo. High-dose vitamin D increased risk of falling in 200 adults 78 ± 5 years old with baseline 25(OH)D levels of ∼19 ± 9 ng/ml. High-dose vitamin D in adults increased the number and duration of upper respiratory tract infections compared with placebo. Asthma patients achieving 25(OH)D levels more than 30 ng/ml during a trial experienced more respiratory infections than those not achieving such levels. Summary Recent studies are congruent with the Institute of Medicine's conclusion that humans are vitamin D replete when their serum 25(OH)D levels are at least 20 ng/ml. Higher levels seem to promote falls and respiratory infections. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.