Introduction

Multiple sclerosis (MS) affects one in 1,000 people today.

The cause of this disease is not known, but several factors, such as gender, ethnic background, environment, affected relatives, and even lifestyle have been shown to increase one's risk of developing MS.

Although research has provided an enormous amount of information about MS, many details have yet to be uncovered. The latter is certainly not because of a lack of interest… major studies and clinical trials with MS are being conducted in many parts of the world. MS is frequently in the news; thousands of articles, along with several books, are available on research and treatments.

New information is being discovered at an exciting pace, and researchers are working hard to develop new theories and treatments. As studies become more complex, the need increases for better means of measurement and analysis. Laboratory tests, animal models of the disease, and MRI techniques have been dramatically improved and fine-tuned to meet these challenges.

Until 1993 when interferon beta-1b (Betaseron®) was approved for use in the US for relapsing-remitting MS, no long-term treatment was available to people with MS in this country. Since that time, the number of approved treatments has quadrupled - and many more are being developed and tested.

Researchers are gaining new insights into MS every day. More and more evidence points to the diversity of MS, and the possibility of a combination of causes and a combination of cellular processes being involved in the development and manifestation of this disorder. The different types of MS may even be distinct from one another. These observations have led to the idea that a combination of treatments may be necessary to slow or stop the disease, as well as different therapies for different MS types.

In this fourth edition of MSAA’s “Multiple Sclerosis, The Process and Medical Treatments,” information is presented regarding the origin and development of the disease, as well as drug therapies and new research. This information is not intended to replace the care and advice of a medical professional, but rather to give readers a better understanding of MS, its symptoms, and its treatments.

MS types

In this fourth edition of MSAA's "Multiple Sclerosis, The Process and Medical Treatments," information is presented regarding the origin and development of the disease, as well as drug therapies and new research. This information is not intended to replace the care and advice of a medical professional, but rather to give readers a better understanding of MS, its symptoms, and its treatments.

Epidemiology: Who is at risk and where MS occurs

Approximately 350,000 individuals have been diagnosed with MS in the US and one million worldwide, with an estimated 10,000 new cases diagnosed in the US annually. Most people with MS experience their first symptoms and are diagnosed between the ages of 15 and 50.

The distribution of this disease is not totally random.

On average, women are three times as likely than men to develop MS. No verifiable explanation has been given as to why a woman's risk is higher; however, the fact that MS improves with pregnancy and worsens in the postpartum period suggest that a connection may exist between the immune system and sex hormones.

The occurrence of this disorder is positively correlated with latitude. Those living beyond the 40-degree mark north or south of the equator are far more likely to develop MS than those living in the warmer climates near the equator. This is especially true for people in North America, Europe, and southern Australia, while Asia continues to have a low incidence.

More prevalent among those of northern European or Scandinavian ancestry, whites are far more likely than blacks to develop this disease. MS is more common among American blacks than among African or Caribbean blacks. Asians, regardless of where they live, have a low incidence of MS, while some groups appear to be virtually immune to MS. These include Inuits (commonly known as Eskimos), Gypsies, and the Aborigines of Australia and New Zealand.

MS susceptibility is also increased if a family member has MS. The average risk of developing MS is one in 1,000, or one tenth of one percent. For first-degree relatives of a person with MS (such as a sibling or child), the risk increases to three or four percent. This is not true for adopted or half-siblings, whose risk is the same as unrelated individuals. In instances where one identical twin has been diagnosed with MS, the other twin has a 31 percent risk of developing the disease. The risk for twins who are not identical is five percent - similar to that of other siblings.

Another factor that has been linked to MS and women is cigarette smoking. Women who smoke are 1.6 times more likely to develop MS than women who are non-smokers. This risk significantly increases for those who continue to smoke for a long period of time.