Fardin Nabizadeh1,2, Parya Valizadeh3, Maryam Yazdani Tabrizi4, Kimia Moayyed5, Niousha Ghomashi6, Omid Mirmosayyeb7. 1. Neuroscience Research Group (NRG), Universal Scientific Education and Research Network (USERN), Tehran, Iran. 2. School of Medicine, Iran University of Medical Sciences, Tehran, Iran. 3. School of Medicine, Tehran University of Medical Science, Tehran, Iran. 4. Shahid Beheshti University of Medical Sciences, Tehran, Iran. 5. Tehran University of Medical Science, Tehran, Iran. 6. School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. 7. Isfahan Neurosciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran. omid.mirmosayyeb@gmail.com.
Abstract
BACKGROUND: Multiple Sclerosis (MS) relapses are episodes of transient disease exacerbation. There are contradictory findings regarding seasonal variation in MS relapses. In this systematic review and meta-analysis, we aimed to investigate the seasonal and monthly variation in relapse rates among patients with MS. METHODS: We systematically queried PubMed, Scopus, and Web of Science for published papers until February 30, 2022. RESULTS: A total of 24 studies were included in this systematic review and meta-analysis with a total of 29,106 patients with MS. We found that the relapse rate was significantly lower in fall compared to the average relapse rate in other seasons with a risk ratio (RR) of 0.97 (95% CI 0.95-0.98). Furthermore, patients with MS experienced a higher number of relapses in April (RR: 1.06, 95% CI 1.01-1.11) and March (RR: 1.08, 95% CI 1.00-1.16) compared to other months. Also, the risk of relapse was lower in August (RR: 0.92, 95% CI.85-0.98), September (RR: 0.97, 95% CI.94-0.99), October (RR: 0.92, 95% CI.89-0.96), and November (RR: 0.93, 95% CI.89-0.97). CONCLUSION: Our systematic review and meta-analysis confirm the temporal fluctuations in the relapse of MS through a comprehensive review of the existing literature, with a lower relapse rate during late summer and fall and a higher relapse rate during early spring.
BACKGROUND: Multiple Sclerosis (MS) relapses are episodes of transient disease exacerbation. There are contradictory findings regarding seasonal variation in MS relapses. In this systematic review and meta-analysis, we aimed to investigate the seasonal and monthly variation in relapse rates among patients with MS. METHODS: We systematically queried PubMed, Scopus, and Web of Science for published papers until February 30, 2022. RESULTS: A total of 24 studies were included in this systematic review and meta-analysis with a total of 29,106 patients with MS. We found that the relapse rate was significantly lower in fall compared to the average relapse rate in other seasons with a risk ratio (RR) of 0.97 (95% CI 0.95-0.98). Furthermore, patients with MS experienced a higher number of relapses in April (RR: 1.06, 95% CI 1.01-1.11) and March (RR: 1.08, 95% CI 1.00-1.16) compared to other months. Also, the risk of relapse was lower in August (RR: 0.92, 95% CI.85-0.98), September (RR: 0.97, 95% CI.94-0.99), October (RR: 0.92, 95% CI.89-0.96), and November (RR: 0.93, 95% CI.89-0.97). CONCLUSION: Our systematic review and meta-analysis confirm the temporal fluctuations in the relapse of MS through a comprehensive review of the existing literature, with a lower relapse rate during late summer and fall and a higher relapse rate during early spring.
Authors: Kassandra L Munger; Joan Bentzen; Bjarne Laursen; Egon Stenager; Nils Koch-Henriksen; Thorkild I A Sørensen; Jennifer L Baker Journal: Mult Scler Date: 2013-04-02 Impact factor: 6.312
Authors: Iaf van der Mei; R M Lucas; B V Taylor; P C Valery; T Dwyer; T J Kilpatrick; M P Pender; D Williams; C Chapman; P Otahal; A-L Ponsonby Journal: Mult Scler Date: 2015-07-21 Impact factor: 6.312