Dr. Karen Lee's Blog https://drkarenlee.ca An Inside Look at MS Research Thu, 31 May 2018 19:54:18 +0000 en-US hourly 1 https://wordpress.org/?v=4.6.11 120353486 Faces Behind the Science: Diane Nakamura https://drkarenlee.ca/faces-behind-the-science-diane-nakamura/ https://drkarenlee.ca/faces-behind-the-science-diane-nakamura/#respond Thu, 31 May 2018 19:54:18 +0000 https://drkarenlee.ca/?p=1816 Research Profile- Diane Nakamura

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Incidence and Prevalence: What do they mean, how new numbers are identified and why they are important? https://drkarenlee.ca/incidence-and-prevalence-what-do-they-mean-how-new-numbers-are-identified-and-why-they-are-important/ https://drkarenlee.ca/incidence-and-prevalence-what-do-they-mean-how-new-numbers-are-identified-and-why-they-are-important/#comments Wed, 30 May 2018 11:47:54 +0000 https://drkarenlee.ca/?p=1809 Incidence and prevalence are two terms that are frequently used in epidemiology but are often mixed up or used incorrectly. Epidemiology is a branch of research that studies the distribution and determinants of health and illness within populations. Data generated from epidemiological research informs public health and can help understand the history of a disease and determine who is at risk of developing a disease. Distinguishing these two terms is important when discussing the patterns, causes, and effects of MS in the population.

What do incidence and prevalence mean?

Although incidence and prevalence are both measures of how a disease affects a population, they have very different meanings. Incidence is a measure of the number of new cases (newly diagnosed) of a disease or condition in the population during a specific period of time, usually a year.

Prevalence, on the other hand, is a measure of the total number of people living with a disease or condition in a population. In other words, prevalence is like taking a snapshot of a disease or condition to see how widespread it is in a population at a given time, regardless of whether the cases of disease are new or diagnosed at some point in the past.

What’s the challenge in obtaining these estimates?

Like many other chronic conditions, it is a challenge to have accurate, up-to-date incidence and prevalence rates for MS. Why? Well, there are different ways of figuring out prevalence and incidence rates.  One method is to use surveys, such as Statistics Canada’s Canadian Community Health Survey (CCHS) which randomly selects people in a population so that the group selected is representative of the whole population in terms of age and sex.  In addition to various other questions, the CCHS survey asks respondents to report on the number of people in the household who are diagnosed with MS.  Another method to measure incidence and prevalence rates is through the use of registries (databases). When someone is diagnosed with MS, they are entered in to a registry and the information is tracked. Finally, a third way to measure incidence and prevalence rates is through information generated by health claims, where people diagnosed with MS are identified through health care system databases.

Each of these methodologies can produce slightly different estimates of incidence and prevalence rates in MS— which makes collecting an accurate representation of this information in a population quite challenging and difficult to interpret!

How are the newest rates of MS identified and what do they mean?

Canada has one of the highest rates of MS in the world, a fact that becomes strikingly evident when you look at our epidemiological data.  The method used to calculate the incidence and prevalence rates of MS in 2014-2015 reported that more than 77,000 Canadians are living with MS; this estimate was recently released by Public Health Agency of Canada using the Canadian Chronic Disease Surveillance System (CCDSS) and allows us to calculate the nationwide prevalence and incidence of MS using health data claims. These estimates also mean that approximately 1 in every 385 Canadians are living with MS and an estimated 11 Canadians are diagnosed with MS every day.

These numbers were based on the following process:

i and p
So, are these new numbers reliable? The newer numbers may be lower than those previously reported but over the course of many years, using health claims data will capture nearly everyone living with MS. Although not everyone may visit their doctor every year, over the course of their lifetime an individual living with MS will have paid at least one visit to their doctor or a hospital, allowing this system to capture them in the incidence and prevalence rates for MS.

Tracking the incidence and prevalence rates of MS is important. These fundamental pieces of information inform us of the needs of the community and assist in identifying the risk of developing MS. For example, if there is an increase in the number of newly diagnosed cases of MS in Canada, it means that the risk of developing MS is increasing. Population statistics like these are critical for researchers to understand how MS impacts a population and to further pursue work into the potential causes and risk factors underlying MS in that population. Prevalence rates are important as they help inform the Canadian healthcare systems, government policies and programming and patient group organizations such as the MS Society of Canada about the medical, social and financial needs of individuals living with MS.


Canadian Chronic Disease Surveillance System 2000/2001-2013-2014

Canadian Chronic Disease Surveillance System Public Health Infobase

Prevalence and Incidence of MS Infographic

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Faces Behind the Science: Kate Parham https://drkarenlee.ca/faces-behind-the-science-kate-parham/ https://drkarenlee.ca/faces-behind-the-science-kate-parham/#respond Mon, 28 May 2018 17:06:52 +0000 https://drkarenlee.ca/?p=1804 Research Profile- Kate Parham

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Faces Behind the Science: Ana Citlali Márquez https://drkarenlee.ca/faces-behind-the-science-ana-citlali-marquez/ https://drkarenlee.ca/faces-behind-the-science-ana-citlali-marquez/#respond Tue, 22 May 2018 17:59:15 +0000 https://drkarenlee.ca/?p=1798 Research Profile- Ana Citlali Marquez

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Faces Behind the Science: Kevin Thorburn https://drkarenlee.ca/faces-behind-the-science-kevin-thorburn/ https://drkarenlee.ca/faces-behind-the-science-kevin-thorburn/#respond Fri, 18 May 2018 13:38:52 +0000 https://drkarenlee.ca/?p=1793 Research Profile- Kevin Thorburn

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Faces Behind the Science: Evelyn Peelen https://drkarenlee.ca/faces-behind-the-science-evelyn-peelen/ https://drkarenlee.ca/faces-behind-the-science-evelyn-peelen/#comments Mon, 14 May 2018 14:23:59 +0000 https://drkarenlee.ca/?p=1789 Research Profile- Evelyn Peelen

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Faces Behind the Science: Matthew Lincoln https://drkarenlee.ca/faces-behind-the-science-matthew-lincoln/ https://drkarenlee.ca/faces-behind-the-science-matthew-lincoln/#respond Fri, 11 May 2018 13:46:44 +0000 https://drkarenlee.ca/?p=1785 Research Profile- Matthew Lincoln

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American Academy of Neurology: Multiple Sclerosis risk factors and susceptibility https://drkarenlee.ca/american-academy-of-neurology-multiple-sclerosis-risk-factors-and-susceptibility/ https://drkarenlee.ca/american-academy-of-neurology-multiple-sclerosis-risk-factors-and-susceptibility/#comments Wed, 09 May 2018 21:00:17 +0000 https://drkarenlee.ca/?p=1777  

artificial-intelligence-3382507__340During the annual American Academy of Neurology meeting, researchers shared their thoughts and presented recent discoveries on risk factors and susceptibility in multiple sclerosis (MS)—a hot topic in the field. Who develops this chronic illness and why are questions that are still puzzling the research community. In general, it’s agreed that a combination of genes and environmental factors likely play a role in the development of MS.

There is an expanding list of risk factors associated with MS including those that fall in the following categories: environmental, infectious and genetic. The studies reported in this blog will focus primarily on environmental risk factors.

Dr. Dalia Rotstein (University of Toronto): environmental factors in Canada are potentially associated with higher risk of developing MS in immigrants

Rotstein-DaliaSupported by MS Society of Canada, Dr. Rotstein and her research team are interested in understanding the risk of developing MS in individuals that migrated and settled in Ontario between 1994 and 2014, compared to individuals that were born in Canada. The results from this study have the potential to help the scientific community to better understand and identify environmental factors that might influence the development of the disease. Indeed, Canada is a country with a high risk of MS, whereas most of the immigrants to Canada arrive from low-risk countries. So, when the research team evaluated the risk of developing MS in immigrants, they found that the longer the immigrants stayed in Canada, the greater the risk to develop MS. The research team were also surprised to see that a higher risk of developing MS was associated with people arriving from the Middle East. Although MS risk declined with increasing age at migration, the risk was still present in adult population, suggesting that exposure to environmental factors during adulthood may contribute to the development of MS.

Being aware that environmental factors can influence the development of MS could encourage the efforts towards preventive strategies and raise awareness in individuals that are arriving in Canada.

Dr. Ilana Katz Sand (Corinne Goldsmith Dickinson Center for MS): cholesterol levels and heart rate may influence cortical atrophy in males, but not females with early MS

Dr. Sand and collaborators presented their recent findings on the relationship between vascular risk and the atrophy of the brain region called cortex in 150 individuals with early MS, taking into consideration the influence of sexes. This prospective study showed that there is a relationship between thickness of the cortex and higher levels of blood cholesterol as well as heart rate in men but not women with MS. This difference could explain why men have a worse disease course and greater disability than women, once the disease is established.

Dr. Annette Langer-Gould (Southern California Medical School): High fish intake is associated with lower MS risk

pexels-photo-629093Dr. Langer-Gould discussed how fish consumption could affect the risk of developing MS. Indeed, she proposed the idea that a diet rich in fish, and hence Omega-3, might be associated with a lower MS risk. 1,153 participants, half of whom diagnosed with MS or clinically isolated syndrome, were involved in the study and their fish consumption was evaluated through a questionnaire. High fish intake was defined as consuming fish once or more per week or 1-3 servings/month of fish oil supplements, while low intake was defined as less than one serving of fish per month and no fish oil supplement. In their study, the team showed a 45 percent reduction in the risk of developing MS when the participants indicated high fish intake compared to low consumption of fish or supplements. The study will need to be replicated for further validation and identify the mechanisms by which fish intake might help reduce risk of developing MS. Nonetheless, the results are very encouraging and support the idea that higher consumption of fish and omega-3 through a diet may reduce the risk of developing MS.

The MS Society just developed a new Hot Topics webpage on Risk and prognostic factors. Check it out here.


Have a question on risk factors and MS? Leave it below.

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Faces behind the science: Carina Graf https://drkarenlee.ca/faces-behind-the-science-carina-graf/ https://drkarenlee.ca/faces-behind-the-science-carina-graf/#respond Tue, 08 May 2018 14:18:37 +0000 https://drkarenlee.ca/?p=1760 Research Profile- Carina Graf

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Faces behind the science: Nathan Michaels https://drkarenlee.ca/faces-behind-the-science-nathan-michaels/ https://drkarenlee.ca/faces-behind-the-science-nathan-michaels/#comments Fri, 04 May 2018 13:08:58 +0000 https://drkarenlee.ca/?p=1747 Stay tuned in the month of May for Research Profiles of MS Society supported trainees #bringinguscloser to #endMS.Research Profile- Nathan Michaels

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