(MS) is the most widespread disabling neurological condition of young adults around the world. You can get MS at any age, but most people are diagnosed between the ages of 20 and 40.
There are relapsing/remitting types of MS and progressive types, but the course is never predictable. Researchers still don’t fully understand the causes of MS or why the rate of progression is so difficult to determine.
Despite much research, solid numbers about how many people have MS are hard to come by. There is no national or global registry for new MS cases, so figures are only estimates. The good news is that many people with MS do not become severely disabled and most live a normal or near-normal lifespan.
It’s estimated that more than 400,000 people in the United States and about 2.5 million people around the world have MS. In the United States, about 200 new cases are diagnosed each week.
Rates of MS are higher farther from the equator. It’s estimated that in southern states (below the 37th parallel), the rate of MS is 57 to 78 cases per 100,000 people. In northern states (above the 37th parallel), the rate is twice as high, at about 110 to 140 cases per 100,000. The incidence of MS is also higher in colder climates.
No matter where they live, people of northern European descent have the highest risk of developing MS. The lowest risk appears to be among Native Americans, Africans, and Asians.
Interestingly, a child who relocates from an area of low risk to an area of high risk (or the other way around) takes on the risk level of the new location. However, if the child relocates after reaching puberty, he or she retains the risk level of the original location.
Among the general population, the risk of developing MS is .001 percent. The ratio of women with MS to men with the disease is two to one.
MS is not considered an inherited disorder, but researchers believe there may be a genetic predisposition to developing the disease. For example, if you have a parent or sibling with MS, you have a one to three percent chance of developing MS. An identical twin with MS raises your risk to 30 to 33 percent.
Researchers still aren’t certain what causes MS. One theory is that it’s a genetic predisposition combined with an environmental or viral factor. People with other autoimmune diseases, especially type 1 diabetes, thyroid disease, or inflammatory bowel disease are at slightly increased risk of developing MS.
Researchers are also studying the relationship between MS and infections such as Epstein-Barr, herpes, and varicella-zoster, among others. However, MS itself is not contagious.
Frequency of Types
1. Relapsing-remitting MS (RRMS) is characterized by clearly defined relapses of increased disease activity and worsening symptoms. These are followed by remissions in which the disease doesn’t progress. Symptoms may improve or disappear during remission. Approximately 85 percent of patients are diagnosed with RRMS at onset.
2. Untreated, about 50 percent of people with RRMS transition to secondary-progressive (SPMS) within a decade of the initial diagnosis.
3. Primary-progressive MS (PPMS) is diagnosed in about 10 percent of MS patients at onset. People with PPMS experience a steady progression of the disease with no clear relapses or remissions. The rate of PPMS is equally divided between men and women. Symptoms usually begin between the ages of 35 and 39.
4. Progressive-relapsing MS (PRMS) is the rarest form of MS, representing about 5 percent of MS patients. People with PRMS have clear relapses combined with a steady progression of the disease.
Approximately 10 to 20 percent of people with MS have a “benign” course of the disease. This means they have only mild symptoms and little disease progression. However, long-term studies show that some of these patients experience some progression after 10 to 20 years. About one percent of patients develop an aggressive form of MS that progresses very rapidly.
Symptoms and Treatment
Symptoms vary a great deal from one patient to another—no two people have the same combination of symptoms. Approximately 45 percent of people diagnosed with MS don’t have severe symptoms.
The most common early symptoms of MS are:
- vision problems
- tingling and numbness
- muscle weakness, muscle spasms
- problems with balance and coordination
Other, less common symptoms include:
- speech and swallowing problems
- cognitive dysfunction
- bladder and bowel dysfunction
- sexual dysfunction
- mood swings, depression
There is no cure for MS. Medications are designed to lessen frequency of relapses and slow the progression of the disease, but they don’t address individual symptoms. Currently, there are 10 disease-modifying medications approved by the U.S. Food and Drug Administration (FDA):
- teriflunomide (Aubagio)
- interferon beta-1a (Avonex)
- interferon beta-1b (Betaseron)
- glatiramer acetate (Copaxone)
- interferon beta-1b (Extavia)
- fingolimod (Gilenya)
- mitoxantrone (Novantrone)
- interferon beta-1a (Rebif)
- dimethyl fumarate (Tecfidera)
- natalizumab (Tysabri)
Some MS medications can be transmitted to the baby during gestation or through breast milk. If you have MS and are considering becoming pregnant, talk to your doctor about your MS medications.
Other Surprising Facts About MS
Women with MS can safely carry a baby to term, and pregnancy doesn’t generally affect MS in the long term. Often, women with MS experience a relief from symptoms during pregnancy. However, about 20 to 40 percent of pregnant women with MS have a relapse within a few months of giving birth.
MS is an expensive disease to treat. Direct and indirect health care costs range from $8,528 to $54,244 per patient per year in the United States. Compared with other chronic conditions, MS ranks second only to congestive heart failure in terms of costliness.
There’s no single “MS test.” Diagnosis requires a neurological examination, patient history, and a series of tests. These may include MRI, spinal fluid analysis, blood tests, and evoked potentials.
Since the exact cause of MS is still unknown, there is no known prevention.