Update on Low Levels of 25ohd and Outcomes: Our Experience

Abstract

There is a general agreement regarding the increase on vitamin D deficiency which can be evaluated by assessing the levels of 25OHD. To achieve an adequate vitamin D nutritional status is important not only by a nutritional point of view, but also for the effectiveness of anticatabolic treatments. The levels of 25OHD and PTH follow an inverse correlation where the point at which it reaches a plateau has been used to identify a lower 25OHD threshold level. However, the critical reference range of 25OHD levels to ensure the endocrine and paracrine functions of vitamin D for overall health and well being is controversial. In addition, it is necessary to know at which point calcium intake could alter this range. However, an important question to be taken into account is the difficulties related to the 25OHD assay. Indeed, the results informed by several laboratories are very different for a same concentration of 25OHD. One of the reasons can be explained by the fact that circulating levels of 25OHD are the sum of two compounds of different origin: D3 or cholecalciferol and D2 or ergocalciferol. In this regard, there are several methods to measure 25OHD levels that varying in accuracy and sensitivity and not all of them detect simultaneously the two compounds. The objective of the present review is to make an update on these issues and to share our clinical and experimental investigations on vitamin D insufficiency/deficiency.