Latitudinal variation in MS incidence in Scotland

Low Sun Exposure Is Associated with Both Progressive-Onset and Relapse-Onset Multiple Sclerosis Risk: A Case-Control Study

BACKGROUND

Sun exposure has consistently been associated with multiple sclerosis (MS) onset, but case samples are predominantly relapse-onset MS (ROMS), and risk estimates have rarely been reported separately for ROMS and progressive-onset MS (POMS). We aimed to determine whether sun exposure prior to disease onset was associated with POMS and whether the effect differed between POMS and ROMS.

METHODS

This nationwide case-control study included 153 POMS cases, 204 incident ROMS cases, and 558 community controls with data from two separate datasets: the PPMS Study (2015-2021) and the Ausimmune Study (2003-2006). Information on time spent in the sun before the first MS symptom, skin phenotype, and sun protection behavior was collected. Satellite data on ambient ultraviolet radiation (UVR) were used to calculate cumulative UVR dose. Unconditional logistic regression was used with adjustment for covariates.

RESULTS

There were consistent dose-response associations, with higher levels of UVR exposure associated with a reduced risk of POMS, both for leisure-time and occupational UVR from age 6 to symptom onset. Associations were overall stronger for POMS than ROMS. For example, cumulative leisure-time UVR dose (per 100 kJ/m2 increment) was associated with POMS (aOR 0.93, 95% CI: 0.91-0.95) and the association was slightly weaker for ROMS (aOR 0.96, 95% CI: 0.94-0.99) for age 6 to symptom onset (test for interaction p < 0.001).

CONCLUSIONS

Low levels of sun exposure, throughout the whole lifespan, are associated with an increased risk of POMS and ROMS onset. The sun effects are usually stronger for POMS than ROMS.

Use of geographical information systems in multiple sclerosis research: A systematic scoping review

INTRODUCTION

Geographical information system (GIS) and spatial analysis have an emerging role in the understanding and management of health-related outcomes. However, there is a knowledge gap about the extent to which GIS has supported multiple Sclerosis (MS) research. Therefore, this review aimed to explore the types of GIS applications and the complexity of their visualisation in MS research.

METHODS

A systematic scoping review was conducted based on York's five-stage framework. PubMed, Scopus and Web of Science were searched for relevant studies published between 2000 and 2020 using a comprehensive search strategy based on the main concepts related to GIS and MS. Grounded, inductive analysis was conducted to organize studies into meaningful application areas. Further, we developed a tool to assess the visualisation complexity of the selected papers.

RESULTS

Of 3,723 identified unique citations, 42 papers met our inclusion criteria for the final review. One or more of the following types of GIS applications were reported by these studies: (a) thematic mapping (37 papers); (b) spatial cluster detection (16 papers); (c) risk factors detection (16 papers); and (d) health access and planning (two papers). In the majority of studies (88%), the score of visualisation complexity was relatively low: three or less from the range of zero to six.

CONCLUSIONS

Although the number of studies using GIS techniques has dramatically increased in the last decade, the use of GIS in the areas of MS access and planning is still under-researched. Additionally, the capacity of GIS in visualising complex nature of MS care system is not yet fully investigated.

The epidemiology of multiple sclerosis in the Scottish Highlands: Prevalence, incidence and time to confirmed diagnosis and treatment initiation

INTRODUCTION

Although multiple sclerosis (MS) is frequent in the northern hemisphere, there have not been recent epidemiological studies in the Scottish Highlands about MS.

OBJECTIVES

To get updated data regarding MS prevalence, incidence and mortality in the Highlands. Time between symptom onset and MS diagnosis was also evaluated in incident MS cases and the pattern of use of disease-modifying therapies (DMTs) was analysed.

METHODS

Study population was people with MS under the care of the Highland Health and Social Care Partnership. The catchment area included North area (Wick, Thurso, Brora, Invergordon), Center (Inverness, Aviemore, Nairn, Fort William), and West coast (Ullapool, Skye). Data were obtained from the MS database at Raigmore hospital (prevalence, midyear 2017) and the prospective hospital-register based study (diagnosis) that was carried out over a 12-month period, in 2016. The 2010 McDonald criteria for diagnosis of new MS cases were used. Crude prevalence and incidence and 95% confidence interval (CI) were calculated for the MS adult onset population, and data was standardised to the European standard population 2013; cause-specific mortality rate was analysed. Pattern of use of DMTs during the first year of diagnosis was also registered.

RESULTS

745 patients were registered in the MS database. 75.4% (562 cases) were females, and female/male ratio was 3:1. Mean age of population was 54.1 ± 14.1 years (range: 15-95 years). Mean number of years since diagnosis was 8.5 ± 4.6 years. Estimated prevalence for the population aged 15 and older was 376 cases per 100,000 inhabitants (95% CI: 354-399). 36 incident MS cases were registered in 2016 (88.8% females; mean age 40.4 ± 12.1 years). Annual incidence in Highlands was 18.2 per 100,000 inhabitants (95% CI: 14-24). The mean period of time from symptom onset to diagnosis was 38.8 ± 43.2 months. 47.2% (17/36) did not take any DMT during the first year after the diagnosis.

CONCLUSION

Prevalence and incidence of MS in the Scottish Highlands is high. Although the gap period between symptom onset and diagnosis is moderate, a significant proportion of recently diagnosed MS patients were not keen to start a DMT the first year after the diagnosis.