Multiple sclerosis epidemiology

Answer 1

Epidemiology is the study of diseases using patterns and frequencies identified in the known cases of persons with the disease. Much can be inferred through the use of epidemiological studies regarding the risk for developing certain diseases, but epidemiology by itself cannot determine a cause, or find a cure.

Epidemiological studies show that MS has a geographic component, a familial historical component, an ancestral component, and most researchers believe that exposure to some infectious trigger initiates the disease process.

FAMILY HISTORY: Statistics show that the average person in the United States has about one chance in 750 of developing MS. But close (first-degree) relatives of people with MS, such as children, siblings or non-identical twins, have a higher chance, anywhere from one in 100 to one in 40.

ETHNICITY: MS is more common among Caucasians (particularly those of northern European ancestry) than other ethnic groups, and is almost unheard of in some populations, such as Inuit, Yakutes, Hutterites, Hungarian Romani, Norwegian Lapps, Australian Aborigines, and New Zealand Maoris.

GEOGRAPHY: MS occurs with greatest frequency in higher latitudes (above 40° latitude) away from the equator, than in lower latitudes, closer to the equator. This may have something to do with vitamin D production in the skin, and the vitamin's prophylactic effect on the development of MS. The exact details about vitamin D's involvement with the prevention of MS, however, is still unclear. Moving from one geographic area to another seems to alter a person's risk of developing MS. Studies show that families and their children will assume the new risk level (higher or lower) of the area to which they move. Those who move before the age of 15 generally take on the new risk themselves. Those who move after the age of 15 may not see the new risk appear until the next generation.

INFECTIOUS TRIGGER: Scientists have been searching for years for an infectious agent that might trigger MS. While many different viruses have been suggested, including rabies, herpes simplex virus, measles, corona virus, canine distemper virus, HTLV-1, Epstein-Barr virus, among others, none has yet been confirmed. Chlamydia pneumoniae, a bacteria which 90% of the population has been exposed to over their lifetime, has also been suggested but never proven. Although no trigger has yet been identified, most MS experts believe that some infectious agent is involved in initiating the disease process.