Multiple sclerosis: introduction

Multiple sclerosis (MS) is a condition affecting the brain and spinal cord, resulting from damage to the nerve cells in the central nervous system. MS is a chronic and disabling disease that usually starts in young adulthood and is twice as common in women than men. It is generally more common in northern hemisphere countries, and within the UK, it is more common in northern areas than southern areas.

MS is a lifelong disease, commonly progressing to serious and permanent disability, although can occasionally have only mild symptoms. The main symptoms of MS vary between sufferers, and can affect any part of the body. These may include fatigue, blurred vision, difficulties with walking, balance and co-ordination, loss of bladder control, numbness throughout different parts of the body, muscle stiffness or spasms, and issues with thinking and learning.

Although in many cases it is possible to treat the symptoms, there is no curative treatment and life expectancy is slightly reduced. Some drugs (such as beta-interferon or glatiramer acetate) may modify the course of the disease.

The Scottish MS register is the most reliable source of data on the incidence of MS in Scotland.

Key statistics:

• There were 198 deaths in Scotland in 2023 where the underlying cause was multiple sclerosis including 70 males and 128 females. (International Classification of Diseases and Related Health Problems, Tenth revision (ICD10) code: G35. Source: National Records of Scotland Vital Events Reference Tables (Table 6.04).
• In 2023/24 the incidence rate of multiple sclerosis, estimated using hospital admissions data and death records, was 5.9 per 100,000 population in males and 10.1 per 100,000 for females.

Multiple sclerosis: risk factors

The causes of multiple sclerosis (MS) are not fully understood. The disease is more common in Northern-most and Southern-most latitudes (Kurtzke (1997)) and there is evidence that it is more common in Northern areas compared to Southern areas of the UK (Kurtzke (1997), Forbes and Swingler (1999)). There is some evidence of temporal and geographical clusters (Kurtzke (1997), Donnan et al (2005)). These findings have been interpreted as suggesting an environmental cause, such as an infectious agent, and some studies have found an association with infection with the Epstein-Barr virus (Lucas (2011)).

As well as being more common further away from the equator, the disease is also more common among children born in summer months (Willer et al (2005)). A number of observational studies - see reviews by Munger (2011) and Ascherio et al (2010) - have found an association between low levels of vitamin D and an increased risk of multiple sclerosis, but there is a lack of evidence about whether increasing vitamin D intake could prevent or treat MS.