Study Examines Interaction Between Solvent Exposure and Genetic Predisposition to Multiple Sclerosis

A new study has found that people who have been exposed to paint, varnish and other solvents AND have a genetic predisposition to multiple sclerosis (MS) are much more likely to develop MS than those who experienced solvent exposure OR are susceptible due to their genetic makeup.[i]

Multiple sclerosis is an autoimmune condition by which the immune system mistakenly attacks the brain or spinal cord. More specifically, the immune system attacks the layer that surrounds the nerves, meaning that the nerves underneath can be damaged and the messages travelling along the nerves can be slowed or disrupted.

MS is usually a lifelong condition and is most commonly diagnosed in individuals in their 20s and 30s. It is estimated that there are more than 100,000 MS patients in the UK, and women are more likely to be affected than men.

In many cases it is possible to treat the symptoms, though MS can cause serious disability in some cases. Symptoms vary in cases and may include fatigue, difficulty walking, vision problems, bladder control problems, numbness or tingling in various body parts, muscle stiffness and spasms, balance and co-ordination problems and problems with thinking and learning[ii].

In the recent study, researchers compared 2,042 MS patients with 2,947 controls, and investigated their genetics, smoking habits and exposure to organic solvents.

Overall, exposure to organic solvents increased the risk of MS. Having a gene variant (known as HLA-DRB1*15) and lacking a gene variant (known as HLA-A-*02) appeared to interact with solvent exposure and increase the risk of developing MS. This relationship was found among those who smoked and those who never smoked.

Those who were exposed to solvents were 50% more likely to develop MS than those who were not. However, those who were exposed to solvents AND had the HLA-DRB1*15 gene were approximately 7 times more likely to develop MS than the controls. The risk was even greater in smokers (30 times more likely to develop MS than the controls).

Lead author, Anna Hedström, stated:

‘These are significant interactions where the factors have a much greater effect in combination than they do on their own’.[iii]

However, a limitation of the study was that subjective data collection could have biased the results.

 

[i] Hedström, A. K. et al. Organic solvents and MS susceptibility: Interaction with MS risk HLA genes. Neurology (2018). doi:10.1212/WNL.0000000000005906 https://www.ncbi.nlm.nih.gov/pubmed/29970406 (Accessed 20 July 2018)

[ii] Multiple sclerosis. NHS Choices. https://www.nhs.uk/conditions/multiple-sclerosis/ (Accessed 20 July 2018)

[iii] Exposure to paint, varnish, other solvents linked to increased risk of MS. ScienceDaily. 3 July 2018 https://www.sciencedaily.com/releases/2018/07/180703190751.htm (Accessed 20 July 2018)