Besides the well-recognised function of vitamin D on the skeleton, also extraskeletal actions and association of hypovitaminosis D with disorders of all body systems have been acknowledged. Some mechanisms of action are at least partly explained, e.g.: immunomodulatory effect by stimulation of the innate and suppression of adaptive immunity, anti-inflammatory actin by suppression of proinflammatory cytokines, stimulation of differentiation and apoptosis in some malignant cell models, etc.
Studies on vitamin D deficiency in various diseases have not been supported by causative associations in prospective clinical trials and meta-analyses, and hypovitaminosis D can be considered as the consequence of diseases.
The interest to establish hypovitaminosis D, regardless of clinical decision criteria (<50 nmol/L or <75 nmol/L) is in epidemic proportions. Commercial production of assays for 25-OH D and automatization enabled easy access to 25-OH D measurement as an indicator of vitamin D hypvitaminosis. Differences between methods and different manufacturers and disparities in results also became apparent to the medical community. Consequently, actions were initiated to standardize reference measurement methods and reference standards by several international institutions in 2010. To ensure progress in quality, proficiency testing was established by an independent group of experts (DEQAS). In comparison to the gold standard (tandem mass spectrometry), none of the commercial assays performs currently with high reliability. In consequence, clinical assessment of hypovitaminosis D and vitamin D therapy monitoring must take into account methodological limitations.
The webinar will also cover the classical use of vitamin D in the prevention and treatment of rickets, and discuss current and national guidelines for detection of hypovitaminosis D and its treatment in the pediatric population.