Relationship of UV exposure to prevalence of multiple sclerosis in England

Abstract

Objective: To assess the potential relationship of ultraviolet B radiation (UVB) and Epstein-Barr virus (EBV) exposure in explaining the period prevalence of multiple sclerosis (MS) in England. Methods: English national Hospital Episode Statistics covering all admissions to National HealthService hospitals in England in the 7 years from 1998 to 2005 were used to obtain the period prevalences of MS and infectious mononucleosis (IM) in England. The United States National Aeronautics and Space Administration's data on UVB intensity for England from the Nimbus 7 satellite was collected. The relationships among the 3 variables (MS prevalence, IM prevalence, and UVB intensity) were investigated. Results:The regression of MS against UVB intensity for all seasons had an r 2 of 0.61; when including the interaction of IM with seasonal UVB, the r 2 rose to 0.72. Conclusions:UVB exposure and IM together can explain a substantial proportion of the variance of MS. The effect of UVB on generating vitamin D seems the most likely candidate for explaining its relationship with MS. There is a pressing need to investigate the role of vitamin D and EBV and how they might interact to influence MS risk to identify potential prevention strategies. Multiple sclerosis (MS) is the most common disease of the CNS in young adults of Northern European descent. 1 MS seems unlikely to result from a single causative event; instead, the disease seems to develop in genetically susceptible populations as a result of environmental exposures. 2The most striking illustration of the importance of the environment in MS is its geographical distribution.3 Within regions of temperate climate, MS incidence and prevalence are thought to increase with latitude.3,4 The latitudinal trend starts around 42 degrees of latitude North.5 A cutoff at this latitude implicates solar wavelengths in the shorter UV range (ultraviolet B [UVB]) as UVB is strongly affected by the solar zenith angle.6 There is also a month of birth effect for MS, 7 which is also indicative of solar-correlated processes, and this effect is itself strongly latitude-dependent.We have recently reported period prevalence values for MS across England. 8 Epstein-Barr virus (EBV) is a B-lymphotropic human DNA herpesvirus that infects most individuals asymptomatically but in some people causes infectious mononucleosis (IM) upon infection.9 Because the risk of MS is increased in individuals with a clinical history of IM, [10][11][12] we also compared the geography of MS with the distribution of IM, and observed a strong correlation, but this was From the

Multiple sclerosis genetics

“…Multiple studies showed that 25-OH vitamin D levels are lower in MS cases compared to controls in both European-descended and African American populations (Munger et al, 2006;Islam et al, 2007;Gelfand et al, 2011;Ramagopalan et al, 2011b (Ramagopalan et al, 2009). Vitamin D receptor-binding elements have been identified in the majority of MS-associated genes, implying that expression of many of these genes could also be controlled by vitamin D (Ramagopalan et al, 2010).…”

Human skin pigmentation, migration and disease susceptibility

“…It is an inflammatory and degenerative disease of the central nervous system characterized by demyelination and axonal loss. A pronounced latitudinal gradient in MS prevalence starting at about 428 of latitude implicates solar wavelengths in the UVB range [66][67][68] (figure 2). This is also indicated by a month-of-birth effect, and changes in the timing of the month-ofbirth effect according to the strength of UVB.…”

Frequency of Multiple Sclerosis (MS) Among Relatives of MS Patients in Hamadan Society, Iran

“…Multiple sclerosis is more common in people who live far from the equator (59). Distribution of MS is explained by ultraviolet B radiation exposure (8,45,46). MS relates to an interaction between genetic factors and vitamin D deficiency (5,56,57,60).…”

“…The separate areas are recognized as inflammation, demyelination, axonal loss, and gliosis (plaques) in the CNS (4). Different factors, such as autoimmune mechanisms, genetic background (5-7), and environmental factors (8)(9)(10)(11), have been known to play roles in the occurrence of MS even though the main etiology of this disease is unidentified.…”