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

Detecting seasonal trends in optic neuritis within the Ottawa region

OBJECTIVE

In this study we aim to determine seasonal patterns underlying optic neuritis (ON) onset that may provide valuable epidemiologic information and help delineate causative or protective factors.

DESIGN

Single-centre retrospective chart review.

METHODS

A database search of centralized electronic health records was completed using diagnostic codes employed at the Ottawa Eye Institute for data collection. Charts were reviewed for documentation supporting a diagnosis of ON falling into the following categories: multiple sclerosis ON and clinically isolated syndrome ON, myelin oligodendrocyte glycoprotein ON, neuromyelitis optica ON, and idiopathic ON. Date of onset, biological sex, and age were extracted from each chart. Data were analyzed for calculation of frequency by season and overall pooled seasonal trends of all cases of ON.

RESULTS

From the 218 included patients with ON, there was no statistically significant seasonal correlation. The overall trend of ON was lowest in winter and spring (22% and 23%, respectively) and highest in summer and fall (28% and 27% respective). Divided further, multiple sclerosis ON or clinically isolated syndrome ON rates (n = 144) were lowest in the spring (21%) and highest in fall (29%); myelin oligodendrocyte glycoprotein ON rates (n = 25) were lowest in winter (16%) and highest in summer and fall (both at 32%); neuromyelitis optica ON rates (n = 16) were lowest in fall (12.5%) and highest in winter and summer (both at 31.25%); and idiopathic ON rates (n = 33) were lowest in fall (18%) and highest in spring (33%).

CONCLUSIONS

The overall ON seasonal trend appears to have a predilection for the summer and fall months, which may be explained by warmer weather and viral infections as risk factors for multiple sclerosis relapse during those seasons.

Seasonal and monthly variation in multiple sclerosis relapses: a systematic review and meta-analysis

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.

Seasonal effects on gene expression

Many health conditions, ranging from psychiatric disorders to cardiovascular disease, display notable seasonal variation in severity and onset. In order to understand the molecular processes underlying this phenomenon, we have examined seasonal variation in the transcriptome of 606 healthy individuals. We show that 74 transcripts associated with a 12-month seasonal cycle were enriched for processes involved in DNA repair and binding. An additional 94 transcripts demonstrated significant seasonal variability that was largely influenced by blood cell count levels. These transcripts were enriched for immune function, protein production, and specific cellular markers for lymphocytes. Accordingly, cell counts for erythrocytes, platelets, neutrophils, monocytes, and CD19 cells demonstrated significant association with a 12-month seasonal cycle. These results demonstrate that seasonal variation is an important environmental regulator of gene expression and blood cell composition. Notable changes in leukocyte counts and genes involved in immune function indicate that immune cell physiology varies throughout the year in healthy individuals.

The aetiology of acute neurological decline in multiple sclerosis: Experience from an open-access clinic

Background:

Multiple sclerosis (MS) relapses contribute to disability and influence treatment decisions. Many centres now provide open access to specialist services for patients with new symptoms. However, there is scarce literature on the spectrum of presentations encountered in this setting.

Objective:

The objective of this paper is to characterise presentations to an open, rapid-access MS relapse clinic and the impact on disease management.

Methods:

A retrospective review of outpatient episodes over a three-year period was conducted. Demographic and service data, symptoms, disability, diagnosis and management were recorded according to a standardised proforma.

Results:

A total of 371 attendances were analysed. A new MS relapse was diagnosed in 216 (58%) episodes, of which 56 (26%) patients had an additional diagnosis which had also contributed to their presentation. Of 266 reports of non-relapse-related symptoms, 73 were unrelated to MS. Treatment interventions were made in almost all relapsing patients and in 70% of patients presenting with acute, non-relapse-related symptoms of MS. Changes to disease-modifying therapies were considered in 28% of consultations.

Conclusion:

Diagnosing MS relapses is crucial for disease management and yet remains challenging. Clinicians should be aware of differential diagnoses and confounding factors. The high incidence of therapeutic interventions observed suggests that rapid-access clinics represent an effective platform for responsive disease management.