Multiple Sclerosis and Geographic Location
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The number of people who have multiple sclerosis (MS) increases the farther away they are from the equator.
In areas near the equator, MS occurs in fewer than 1 out of 100,000 people. In areas farther from the equator-such as northern Europe and northern North America-MS occurs in around 30 to 80 out of 100,000 people. footnote 1 When moving south of the equator, the number of people with MS is less dramatic, but the same trend is seen.
Some evidence suggests that people who move from a high-risk to a low-risk area before the age of 15 reduce their chances of developing MS. But the same is true in reverse. In those who move from a low-risk area to a high-risk area before the age of 15, the risk of getting MS increases. Those older than 15 when they move to a new area retain the risk associated with their old area. footnote 1
Most experts agree that this unusual relationship between geographic location and MS suggests that an environmental factor is partly responsible for causing the disease.
- Ropper AH, et al. (2014). Multiple sclerosis and other inflammatory demyelinating diseases. In Adams and Victor's Principles of Neurology, 10th ed., pp. 1060-1131. New York: McGraw-Hill Education.
Other Works Consulted
- Spelman T, et al. (2014). Seasonal variation of relapse rate in multiple sclerosis is latitude dependent. Annals of Neurology, published online October 4, 2014. DOI: 10.1002/ana.24287. Accessed October 31, 2014.
Primary Medical Reviewer Adam Husney, MD - Family Medicine
Anne C. Poinier, MD - Internal Medicine
E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer Karin M. Lindholm, DO - Neurology
Current as ofOctober 9, 2017
Current as of: October 9, 2017
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