Can we prevent or treat multiple sclerosis by individualised vitamin D supply?

Multiple sclerosis (MS) is the most common chronic inflammatory disease of the central nervous system (CNS) in young adults in Western countries and often leads to early disability and retirement [1]. Typical clinical manifestations are optic neuritis, central paralysis, sensory disturbances, and difficulties in coordination and balance, as well as cognitive dysfunction, fatigue, and sleep disorders [1-3]. The initial course is usually relapsing-remitting, but after several years, the disease tends to convert into a secondary progressive form. A primary progressive course also exists but is much less common. It is estimated that 2.5 million people suffer from MS worldwide, and as in most autoimmune disorders, there is an obvious female preponderance of approximately 3 to 4:1 [1,4]. Importantly, most female patients are affected in their child-bearing age which may have fundamental consequences for family planning [5]. The cause of MS is not yet clear. Several genetic and environmental factors have been isolated to contribute to the risk of MS, among them vitamin D (VD) status, but the individual significance of each factor is not yet clear [6-10]. From the pathophysiological point of view, dysregulated encephalitogenic T cells are thought to initiate and to orchestrate in concert with abundant other immune cells an autoimmune multifocal CNS inflammation [11-13]. For decades, MS was considered to be a primarily demyelinating disorder predominantly affecting the CNS white matter. During recent years, however, it has become clear that MS also has a strong neurodegenerative component, which is most probably the underlying basis for the development of permanent disability [14-17]. Moreover, grey matter involvement has been increasingly recognised by means of histopathology and magnetic resonance imaging (MRI) [18-20]. Paraclinical tools for diagnosis, differential diagnosis, and monitoring of disease activity and progression in MS comprise cerebrospinal fluid examination