Welcome back to my ECTRIMS 2015 recap. In the previous post I covered some of the crucial research being undertaken to further understand how wellness impacts MS (and vice versa) as well as the effects of MS on social and economic outcomes like workforce participation and emotional wellbeing.
One of the questions I hear a lot is “what are the factors that can put me or my family members at greater risk for MS?” This is a question on a lot of researchers’ minds, and there was no shortage of seminars and poster presentations examining the various risk factors for MS. In this post I summarize the research presented at ECTRIMS on risk factors.
Risk Factors
- Although reduced sun exposure has been long considered a risk factor for developing MS, the detailed interactions between different sun exposure behaviours in children and their relationship to MS is unclear. MS Society-funded doctoral candidate Sandra Magalhaes (McGill University, Montreal, QC) used sophisticated statistical modeling to analyze sun exposure data from people with MS living in Canada, Italy and Norway as part of the EnvIMS study. She found that the interaction between sun exposure behaviour and MS risk is complex, implicating both a critical window of low sun exposure during a certain period of childhood, and total accumulated time spent with low sun exposure, as important factors for determining MS risk.
- In the same vein, MS Society of Canada-funded research Dr. Helen Tremlett (University of British Columbia, Vancouver, BC) used the rich dataset from the Nurse’s Health Study to examine the link between sun exposure and MS over the entire life course of adults, including timing of exposure and potential for sun avoidance. The results of the study confirmed the growing consensus that low exposure to ultraviolet-B radiation over the life course is a risk factor for MS; importantly, she found that people living with MS later in life in particular tended to avoid the sun, which could impact their overall vitamin D status and health. (Previously profiled)
- Clinically isolated syndrome – or CIS – refers to a single neurological episode that is suggestive of multiple sclerosis. Some people who experience CIS do not go on to develop MS, while others do. Determining who is at risk of converting to MS is of utmost importance, especially in the context of early and effective monitoring and treatment. A research group led by Dr. Xavier Montalban from Vall d’Hebron University Hospital in Barcelona Spain collected clinical and MRI data from 1,059 CIS patients from 1995 to 2014. Based on this information, they identified important variables that separated people into different MS risk categories. Ultimately they were able to develop an easy-to-use risk-calculator using the identified variables. This calculator would help determine which individuals will go on to develop MS, and may greatly improve personalized treatment.
- Although the debate about factors that influence disease often centers on “nature versus nurture”, the field of epigenetics is concerned with how “nurture” can shape “nature”; in other words, how the environment can regulate the way our genes are expressed. Dr. Heather Hanwell (whose research is part of the MS Scientific Research Foundation-funded Canadian Pediatric Demyelinating Disease Network) examined whether exposures in the prenatal environment (i.e. in the womb before birth) can affect the risk of MS by examining DNA collected from children with MS at birth and at first attack of MS, as well as in age-matched healthy controls. The study found evidence that the prenatal environment may influence MS risk through the epigenetic regulation of gene expression, paving the road for further studies to determine which cell types are particularly vulnerable to this process.
- While smoking has long been suspected as an environmental risk factor for MS, the way in which smoking interacts with genes that increase MS susceptibility has only recently attracted careful scrutiny. A research team lead by Dr. Tomas Olsson (Karolinska Institutet, Solna, Sweden) pooled datasets from four countries (Sweden, Norway, Denmark and Serbia) encompassing 3,131 people with MS and 6,085 healthy controls and analyzed the interaction between smoking behaviour and two genetic variants implicated in MS risk. Overall, smokers with both genetic risk factors had a 15-fold increased risk of MS compared to smokers with neither genetic risk factor, providing evidence of a strong interaction between environmental risk factors like smoking and certain genetic risk factors.
- A study conducted by Dr. James Sumowski (Kessler Foundation, West Orange, NJ) and collaborators in Italy and Serbia investigated the impact of lower socioeconomic status on the risk of developing greater disability in people living with MS. In a group of 307 participants living with MS in Italy and 58 in Serbia, the research team discovered that lower socioeconomic status was a strong predictor of risk of baseline disability, although the rate of disability progression over time was not influenced by socioeconomic status. The results from this study are important since they can help to identify at-risk populations for MS-related disability early and inform proactive interventions to minimize disability.
- Very little is known about a possible influence of air pollution on the risk of MS and its disease course. Dr. Emmanuelle Leray (EHESP Sorbonne Paris Cité, Rennes, France) and colleagues hypothesized that air pollution might have an impact on MS risk by influencing sunlight exposure and, thereby, vitamin D production. They examined 254 people living with MS in Strasbourg, France to determine if there was a correlation between relapse risk and exposure to the pollutant PM10 (particulates of a certain size in the air that can be breathed in). They found a significant association between relapse risk and PM10 levels in the 3 days preceding relapse. While illuminating, these results must be followed up with further studies to control for other environmental factors that could be influencing the results, and to determine whether there is a relationship with sunlight and vitamin D.
Stay tuned for part III where I will be discussing some ECTRIMS highlights on new and repurposed MS treatments as well as long-term monitoring and safety outcomes.