April 23, 2018

expert reaction to observational study of vigorous physical activity and motor neurone disease

Researchers publishing in The Journal of Neurology Neurosurgery & Psychiatry investigate the association between physical activity (PA) and amyotrophic lateral sclerosis (ALS) in population-based case-control studies in three European countries using a validated and harmonised questionnaire

Nick Cole, Head of Research at the Motor Neurone Disease Association said:

“Motor neurone disease is a fatal, often rapidly progressing disease that affects the brain and spinal cord. It has a devastating impact and there is a desperate need to better understand the causes of MND for the development of effective treatments and prevention.

“The MND Association always welcomes good quality, well designed studies that attempt to find potential causative or risk factors of MND. Neurologists sometimes comment that they do tend to see more MND patients who have a record of physical activity than would be expected in the general population, however evidence for this has been sparse and previous studies contradictory.

“This recent study shows a link between exercise and the development of MND later in life, but this only becomes apparent when large numbers of people are studied, indicating that any such effect is a very subtle one. It does not mean that exercise causes MND.

“Put in context, it is a small increased risk and one of multiple factors, from genetic to environmental, likely to be needed in a combination to develop MND.

“Given that exercise has been shown to offer significant protection against many diseases it would not be advisable to adopt a sedentary lifestyle in order to avoid a very small increased risk of developing MND.”

Dr Jemeen Sreedharan, van Geest Postdoctoral Fellow in Neurodegeneration, Institute of Psychiatry, Psychology & Neuroscience at King’s College London, said:

“The research group have conducted a well thought out study to address an important but tough question and conclude that exercise could increase risk of ALS.

“Their study is not entirely consistent with previous studies, which have suggested that exercise may actually reduce risk of ALS. Indeed, the authors of the current study found that not all the populations they studied showed a strong link between increased physical activity and ALS. The Dutch group was by far the largest cohort they studied yet showed the weakest association with ALS. It is possible that genetic or environmental differences (e.g. diet) between different populations could act in concert with exercise to influence disease risk in different regions.

“The overall benefits of exercise to general physical and mental health probably outweigh any increased risk of ALS due to physical activity.”

Prof Tara Spires-Jones, Deputy Director of the Centre for Discovery Brain Sciences at the University of Edinburgh, said:

“This study by Prof van den Berg and colleagues shows that more physical activity is associated with an increased risk of developing the Amyotrophic lateral sclerosis (ALS). This is a large study comparing physical activity levels of over 1,500 people with ALS and over 2,900 people without ALS.

“While this study was well conducted, this type of data does not prove that physical activity directly causes the disease as other factors that increase with activity levels could be the cause of the risk.

“This study is important as it is part of a large effort to understand the causes of ALS in order to develop effective treatments and preventions for this devastating disease.  It is important to keep in mind that ALS is a relatively rare disease affecting around 2 in every 100,000 people and that physical activity protects us from much more common diseases including Alzheimer’s, heart disease, diabetes and cancer, which together affect more than 10 million people in the UK today.”

* ‘Multicentre, cross-cultural, population-based, case– control study of physical activity as risk factor for amyotrophic lateral sclerosis’ by Anne E Visser et al. will be published in the Journal of Neurology Neurosurgery & Psychiatry on Monday 23 April 2018.

Declared interests

None to declare.