Historical changes of seasonal differences in the frequency of multiple sclerosis clinical attacks: a multicenter study

Abstract

Previous papers show discordant patterns of monthly and seasonal differences in the frequency of multiple sclerosis relapses. Attacks are more often reported in spring and summer, but there are many variations, mainly as to summer peaks. This paper, an MSBase collaboration substudy, reports multiple series of relapses from 1980 to 2010, comparing ultradecennal trends of seasonal frequency of attacks in different countries. The MSBase international database was searched for relapses in series recording patient histories from 1980 up to 2010. The number of relapses by month was stratified by decade (1981-1990, 1991-2000, 2001-2010). Positive spring versus summer peaks were compared by odds ratios; different series were compared by weighted odds ratio (Peto OR). Decade comparison of the 1990s versus 2000s shows inversion of spring-summer peak (2000s = March; 1990s = July), significant in the whole group (Peto odds ratio = 1.31, CI = 1.10-1.56, p = 0.003) and in Salerno series (OR = 1.97, CI = 1.14-1.40). The global significance persisted also excluding Salerno series (Peto odds ratio = 1.25, CI = 1.04-1.50, p = 0.002). Multicentric data confirm a summer peak of relapses in the 1991-2000 decade, significantly different from the spring peak of 2001-2010. Seasonal frequency of relapses shows long-term variations, so that other factors such as viral epidemics might have more relevance than ultraviolet exposure.

How to run a multiple sclerosis relapse clinic

“…Relapse rates vary according to season, 13 with peaks in early winter and summer; thus rapid-access clinic demand may fluctuate throughout the year and capacity should allow for this. Clinicians require adequate time to cover the wide range of issues arising in the context of an acute deterioration in MS (see below); our own rapid access has 40-min clinic slots.…”

Multiple Sclerosis Relapses: Epidemiology, Outcomes and Management. A Systematic Review

“…Studies from several smaller patient cohorts showed variable results, some reporting a spring [26] and other earlier works reporting a summer peak [27,28] of relapse incidence ( table 1 ). A hypothesis was proposed that the seasonality of the peak relapse incidence may show a long-term trend towards phaseshift [29] , but this view requires further validation.…”

Detecting Permafrost in Plateau and Mountainous Areas by Airborne Transient Electromagnetic Sensing

“…However, a large amount of permafrost with high thermal sensitivity in these areas would bring great potential dangers to railway transportation [3][4][5][6][7][8][9]. Geophysical data can provide important information to detect the permafrost [10][11][12]. Hence, identifying the geological conditions of the railway subgrade and locating the permafrost are crucial for the railway construction in Western China.…”