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Where You Live Could Be a Risk Factor for MS

April 5, 2016

A research team led by Queen Mary University of London and Barts Health NHS Trust has concluded that immigration could increase the risk of developing multiple sclerosis. It has been previously noted that environmental factors could lead to the development of the disease, and now it has now become clear that there is something to that theory.

Dr. Klaus Schmierer led a study focused on east London, where he found that black residents and those from South Asia had a higher prevalence of MS compared with the same groups living in their ancestral countries. The study was done in one of the most ethnically diverse parts of the UK. East London lends itself to investigate the impact of migration from territories of very low MS prevalence to the U.K., where MS prevalence is very high.

Schmierer found in his study that the number of occurrences of MS based on geography is significant. For example, in Ghana the incidence of MS was 0.24 per 100,000 people, the highest in sub-Saharan Africa. The prevalence of MS in the east London population was 74 per 100,000 people.

“The magnitude of this effect in our dataset is stunning,” he said. “Whilst Mendelian genetics may influence the disease course once MS is established, the risk of actually getting the disease seems only weakly influenced by genetics. Note, however, X/Y chromosomes do play an important role in MS risk, with women being two to three times more frequently affected than men.”

He added another interesting tidbit “If you look at a map of the world, you’ll see that the risk increases as you move farther away from the Equator.”

In other words, developed countries, “and ones with better sanitation,” have a higher prevalence of MS. That raises the question of whether we are too rigorous in killing microorganisms, both good and bad.