Multiple sclerosis (MS) is the most
common neurological disorder diagnosed in young adults. Its
causes are not yet fully understood and researchers continue to
search for answers. MS is not contagious and does not shorten
the life expectancy of those who are diagnosed with the disease.
Although the disease may not be cured or prevented at this time,
treatments are available to reduce severity and delay
MS is a disease of the central nervous
system (CNS). The CNS consists of the brain, optic nerves and
spinal cord. This disorder damages the protective insulation
(known as "myelin") surrounding the nerves (known as "axons"),
and may also damage theses nerves within the CNS. As a result,
nerve impulses carrying messages from the brain and spinal cord
may short circuit, causing reduced or lost bodily function.
The effects of MS differ with each
individual. Some people experience symptoms for a short period
of time and afterward may remain symptom-free for periods or
months or years. While others may experience a more steady
progression of the disease.
Most researchers believe MS is an
"autoimmune disease" -- one in which white blood cells, meant to
fight infection or disease, are misguided to target and attack
the body's own cells. This attack causes inflammation in the
CNS, which may damage the myelin and ultimately injure the
Areas of inflammation are known as
“lesions” or “plaques.” The changes in size, number, and
location of these lesions may determine the type and severity of
symptoms. Frequently, however, MS may be “clinically silent,”
showing no increase in symptoms while continuing to show signs
of disease activity within the CNS.
Additionally, areas of thick scar
tissue may eventually form along the areas of damaged myelin.
The term “multiple sclerosis” originates from the discovery of
these hardened plaques. Multiple refers to many; sclerosis
refers to scars.
Researchers have studied a variety of
possible causes for MS, and a combination of factors appears to
be involved. A popular theory looks at commonly known
slow-acting viruses (one that could remain dormant for many
years), such as measles, herpes, human T-cell lymphoma, and
Epstein-Barr. After being exposed to one of these viruses, some
researchers theorize that MS may develop in genetically
susceptible people. Research to identify the specific genes
involved in MS is also ongoing.
Some scientists are looking for a
connection between MS and nutritional factors, including fat
intake, as well as deficiencies in fish oil and vitamin D. In
addition to food and supplements, vitamin D is also derived from
sunlight, which may be involved in the development of MS. As
noted in the following section, populations living closer to the
equator (and exposed to more sunlight) experience a lower
incidence of MS.