WHAT IS MS?
Multiple sclerosis (MS) is a demyelinating autoimmune condition that affects the central nervous system (CNS). It is a disorder in which the immune system mistakenly attacks the insulating layer around nerve cells in the brain and spinal cord, known as the myelin sheath. This slows down the transmission of nerve signals between the brain and the body, impacting how you think, feel, move, and learn (Panou, T. et al, 2012).
FIRST SIGNS OF MS
Patients can experience problems with balance, limb movement and bladder function. In severe cases it can lead to blindness, and paralysis. Cognitive function can become significantly impaired causing a deficit to your attention and memory skills. You may also suffer from chronic fatigue, reducing your ability to take part in meaningful activities (Lassmann, H. 2019).
It is not clear why people develop MS, but it is believed to be due to a combination of genetic and environmental factors (Waubant, E, et al. 2019).
GENETICS
Research shows that MS is not a directly inherited condition. However, if someone in your family has the disease, then you will have a greater chance of acquiring it. In the UK, studies around the history of MS in families show that;
1 in 67 will develop MS if they have a parent with the condition.
1-37 for siblings.
1-5 for identical twins (Definition of MS, 2015).
VITAMIN D
MS has been shown to be more common in areas of the world that are further from the equator. This indicates a connection between vitamin D levels and MS. Although, these findings are not conclusive, and it is currently unknown as to whether vitamin D supplements reduce the likelihood of developing the disease (Definition of MS, 2023).
SMOKING
Research shows that people who smoke are twice as likely than those who do not smoke to develop MS
OBESITY
Several studies suggest there is an increased risk of developing MS if you are obese. In particular, there is a connection to obesity during early adolescence
GENDER
Females have been found to be 3 times more likely to develop MS. The reason for this is unknown, but it is thought to be related to female immune systems working differently to their male counterparts (Airas, L. 2015).
VIRUSES
Some viruses and bacteria such as Epstein-Barr virus (EBV), Chlamydia pneumonia, measles, and certain strains of the herpes virus have been investigated as possible causes of MS. However, it is unknown whether viruses are a causal factor, or if they are part of an environmental trigger on the immune system leading to the development of the disease. Growing research shows that previous EBV infection incurs a significant contribution to the disease.
(NHS England, 2022)
In this short video above, Neurologist Dr Thrower describes the potential causes of MS.
He describes how it tends to be a mixture of genetic and environmental factors. Further how the immune system mistakenly attacks Myelin sheath cells when it fails to distinguish between a virus and normal cells.
He also discusses the geographical prevalence of MS, and how the development of MS may not be simply related to vitamin D levels, but may also have to do with a greater number of viruses present in these areas, or other environmental factors to which we are exposed (The Multiple Sclerosis Foundation, 2011).
Recent government statistics from studies conducted in 2018, estimated the prevalence of individuals living with MS in England, is 105,800. Showing 190 cases of 100,000 population (GOV.UK, 2018). 75% of both males and females diagnosed with the condition are between 40-74 years of age. On average a total of 4,950 cases of MS are diagnosed annually in the UK.
The highest prevalence rate for both sexes is among people aged between 60-69 years. Females show a greater likelihood of developing the disease (598 females compared with 228 males per 100,000 population.) Females have a 2.5 higher prevalence rate for the disease (GOV.UK, 2018).
MS prevalence is higher is people who smoke and ex-smokers alike. Findings show a higher proportion of MS patients were ex-smokers (male and female) when compared with non-MS patients, whilst 23% of males and 15% of females with MS were still classified as smokers (GOV.UK, 2018).
GEOGRAPHICAL LOCATION
Growing research conducted on the distribution of MS patients indicates that the disease follows geographical patterns (Hecker, M. et al, 2021). It is commonly the case that MS is more prevalent in people who live further away from the equator. It is well known that sunlight contributes to absorption of vitamin D which is essential for healthy immune system and brain functioning (GOV.UK, 2018).
What we are exposed to in our environment can differ depending on where we live. For example, a study from 2016 showed that colder regions such as Canada and New Zealand, display higher levels of MS (Wallin, T.M, et al, 2016). This indicates some evidence for how environmental factors such as temperature, may act as a predictor of MS.
For instance, for patients who move from low-risk locations situated closer to the equator such as Eastern Africa and islands around Fiji, to a high-risk area before the onset of puberty, it can increase their risk of developing the disease (Waubant, E. et al. 2019). The reasons are somewhat unknown, but scientists hypothesise that viruses (such as the Epstein Barr virus that has been strongly associated with MS onset), are more likely to thrive in colder regions, due to people spending more time in confined spaces.
DIET
Diet can also vary depending upon where we live. It has been suggested that people who live in coastal regions are more likely to consume fish containing immune boosting nutrients. Recent studies from Norway detected a higher incidence of MS in people who live inland. This also suggests a link between geographical location and MS prevalence (Hecker, M. et al, 2021).
IS THIS ALWAYS THE CASE?
It may be possible that a lack of MS cases in certain areas produces a shortage of data for research investigating individual causes of the disease. Whilst these environmental patterns have been identified, it has also been found that certain locations such as, United States, London, Vancouver and other cities (at a similar distance to the equator as those mentioned above) have twice as many cases of MS (Wallin, T.M, et al. 2016). With the growing prevalence of MS, future research of this kind will help to identify the range of causes for the disease.