Treatment for vitamin D deficiency: here and there do not mean everywhere

Excerpt

The optimal levels of vitamin D and the best treatment for vitamin D deficiency are the object of intense discussion. As for the threshold value of 25-hydroxyvitamin D (25(OH)D) defining a sufficient vitamin D status, a dedicated Committee of the Institute of Medicine recently stated that a serum concentration of at least 50 nmol/L meets the needs of at least 97.5% of the population [1, 2]. The corresponding recommended dietary allowance (RDA) in adults is 600 IU per day up to 70 years of age and 800 IU daily thereafter. Notably, these intakes are based on an assumption of minimal or no sun exposure. The IOM Committee’s members considered bone health as the only outcome consistently and causally linked to vitamin D and concluded that studies about the potential positive effects of vitamin D on calcium absorption and balance, physical performance, and risk of falls are still inconclusive as to causality. However, many experts deem the evidence that vitamin D supplementation improves calcium metabolism and skeletal muscle strength and function (with ensuing reduced risk of falls) strong enough to include calcium and muscle health among the outcomes influenced by vitamin D [3, 4]. In addition, serum parathyroid hormone plateaus in adults when 25(OH)D concentration is higher than 78 nmol/L [5] and mineralization defects of bone are not found in iliac crest biopsies from patients with serum 25(OH)D higher than 75 nmol/L [6]. Guidelines thus appeared where it is criticized the IOM position and suggested to target a 25(OH)D value above 75 nmol/L to maximize vitamin D’s effect on bone, calcium, and muscle [3]. Nevertheless, there is general agreement that minimum levels of 25(OH)D must be higher than 50 nmol/L, in order to prevent rickets and osteomalacia [1‐3]. …