Association Between Time Spent Outdoors and Risk of Multiple Sclerosis

Neurology ◽  
2021 ◽  
pp. 10.1212/WNL.0000000000013045
Author(s):  
Prince Sebastian ◽  
Nicolas Cherbuin ◽  
Lisa F Barcellos ◽  
Shelly Roalstad ◽  
Charles Casper ◽  
...  

Objective:This study aims to determine the contributions of sun exposure and ultraviolet radiation (UVR) exposure to risk of paediatric-onset multiple sclerosis (MS).Methods:Children with MS and controls recruited from multiple centres in the USA were matched on sex and age. Multivariable conditional logistic regression was used to investigate the association of time spent outdoors daily in summer, use of sun protection, and ambient summer UVR dose in the year prior to birth and the year prior to diagnosis, with MS risk, adjusting for sex, age, race, birth season, child’s skin colour, mother’s education, tobacco smoke exposure, being overweight, and Epstein-Barr virus infection.Results:332 children with MS (median disease duration: 7.3 months) and 534 controls were included after matching on sex and age. In a fully adjusted model, compared to spending <30 minutes outdoors daily during the most recent summer, greater time spent outdoors was associated with a marked reduction in the odds of developing MS, with evidence of dose-response (30 minutes to 1 hour: adjusted odds ratio (AOR)=0.48, 95% confidence interval [95%CI] 0.23-0.99, p=0.05; 1-2 hours: AOR=0.19, 95%CI 0.09-0.40, p<0.001). Higher summer ambient UVR dose was also protective for MS (AOR=0.76 per kJ/m2, 95%CI 0.62-0.94, p=0.01).Conclusions:If this is a causal association, spending more time in the sun during summer may be strongly protective against developing paediatric MS, as well as residing in a sunnier location.

1994 ◽  
Vol 15 (2) ◽  
pp. 63-68
Author(s):  
William A. Durbin ◽  
John L. Sullivan

Introduction Virtually all humans become infected with Epstein-Barr virus (EBV). The vast majority of these infections are inapparent, occur early in life, and are associated with lifelong latent infection and persistent shedding of virus. Epidemiology The prevalence of antibody to EBV has been determined in many age groups throughout the world. In developing and tropical areas, infection takes place early in life and is inapparent, with most children demonstrating antibody by age 6 years. Infection is believed to be related to hygiene and crowding as well as to cultural patterns that lead to exposure to saliva (eg, prechewing of food). In contrast, infection in Western Europe and the United States in childhood is less common, with only 35% to 50% of 5-year-olds demonstrating antibody. Infectious mononucleosis (IM) emerges as a significant clinical entity only in populations where a sizable percentage of young adults lack immunity to EBV. Thus, IM is unknown among college freshman in Thailand or the Philippines, virtually all of whom have antibody to EBV at the time of admission. On the other hand, in schools in the USA and England, where the susceptibility percentage is in the range of 35% to 50%, infection is seen commonly. In such university settings, approximately 12% of susceptible students become infected with EBV during the freshman year.


Author(s):  
Bert A. ‘t Hart

Abstract Using a non-human primate model of the autoimmune neuroinflammatory disease multiple sclerosis (MS), we have unraveled the role of B cells in the making and breaking of immune tolerance against central nervous system myelin. It is discussed here that B cells prevent the activation of strongly pathogenic T cells present in the naïve repertoire, which are directed against the immunodominant myelin antigen MOG (myelin oligodendrocyte glycoprotein). Prevention occurs via destructive processing of a critical epitope (MOG34-56) through the lysosomal serine protease cathepsin G. This effective tolerance mechanism is abrogated when the B cells are infected with Epstein–Barr virus, a ubiquitous γ1-herpesvirus that entails the strongest non-genetic risk factor for MS.


Brain ◽  
2009 ◽  
Vol 132 (12) ◽  
pp. 3318-3328 ◽  
Author(s):  
Simon N. Willis ◽  
Christine Stadelmann ◽  
Scott J. Rodig ◽  
Tyler Caron ◽  
Stefan Gattenloehner ◽  
...  

2013 ◽  
Vol 325 (1-2) ◽  
pp. 86-89 ◽  
Author(s):  
Lekha Pandit ◽  
Chaitra Malli ◽  
Anita D'Cunha ◽  
Rajesh Shetty ◽  
Bhim Singhal

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