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MS experts estimate number of Canadians with MS is 55,000 to 75,000
Medical Update Memo
May 2, 2006
SUMMARY
The Multiple Sclerosis Society of Canada, in consultation with
Canadian experts in the epidemiology of MS, has announced a
revision to the estimated number of Canadians who have MS.
The MS Society now estimates that there are likely between
55,000 and 75,000 Canadians living with this unpredictable
disease.
DETAILS
Since the 1980s, the MS Society of Canada has estimated the
number of Canadians with MS to be approximately 50,000 based
on a number of studies conducted at that time. More recently,
several studies have found prevalence rates that are significantly
higher than previously reported. Prevalence is the number of
known cases existing at one time within a particular population
(region, city or country). In MS, prevalence rates are usually
classified as high (greater than 30 cases per 100,000 population),
medium (between five and 29 cases per 100,000) and low (less
than five per 100,000).Canada is known for having one of the
highest rates of MS in world.
In October 2005, researchers at the University
of Calgary reported in the journal Multiple Sclerosis that
the overall weighted estimate of MS prevalence in Canada is
240 per 100,000 individuals. The researchers included Dr. Cynthia
Beck, Dr. Luanne Metz, and Dr. Scott Patten, University of
Calgary, and Lawrence Svenson, Alberta Health and Wellness.
They used data from the Statistics Canada 2001 Canadian Community
Health Survey (CCHS) to compare MS prevalence across regions
at a single time point, taking demographics into account. (For
more information about the study, see the MS Society medical
update memo Study reports regional variation of MS rates across
Canada. It is available at www.mssociety.ca under
Research/ Research & Medical Library.)
The researchers also provided prevalence
information by region:
BC – 240 per 100,000; Prairie region
– 340 per 100,000; Ontario 230 per 100,000; Quebec –
180 per 100,000; and Atlantic region – 350 per 100,000.The
overall weighted estimate of MS prevalence in Canada was reported
to be 240 per 100,000.
In addition, Dr. Virender Bahn and colleagues
at Dalhousie University reported in 2005 on MS prevalence in
Nova Scotia. Prevalence estimates from their work range from
158 to 218 per 100,000 with a best estimate in the upper range
of 200 to 218 per 100,000.
The revision in the estimated range of MS
in Canada came after a consultation with experts in epidemiology
who are members of the MS Society of Canada Medical Advisory
Committee. (Epidemiology is the study of disease patterns,
which takes into account variations in geography, demographics,
socioeconomic status, genetics, and infectious causes.) The
experts examined the data from the new studies and concluded
the estimated range of MS cases in Canada is from 55,000 to
75,000.
The revised numbers may suggest that the
risk of MS is increasing in Canada, but they may also reflect
improvements in diagnostic technology. Compared to even 10
years ago, magnetic resonance imaging technology has enabled
neurologists to make a diagnosis of MS earlier in the course
of the disease than in the past. In addition, parallel improvements
in treatments and medical care for individuals living with
MS have also resulted in many people living with the disease
well into old age, pointed out Dr. Christina Wolfson. The professor
of epidemiology and biostatistics at McGill University took
part in the review. She noted the new studies should lead to
further research to verify these findings and to identify the
reasons for the apparent differences between regions.
ASK MS Information System Code: 2.3.z
National Research Department
National Marketing and Communications Department
Disclaimer
The Multiple Sclerosis Society of Canada is an independent,
voluntary health agency and does not approve, endorse or
recommend any specific product or therapy but provides information
to assist individuals in making their own decisions.
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