Environmental factors may be playing a much greater role in the onset of multiple sclerosis than previously realized, according to early research led by Queen Mary University of London and Barts Health NHS Trust. The theory is based on new findings showing that Black people and South Asians in east London have a higher prevalence of MS compared to those groups in their ancestral countries, indicating a strong environmental influence on the disease that could be driving higher MS rates in London.
The researchers, led by Dr. Klaus Schmierer, used electronic records from general practices in four east London boroughs (Tower Hamlets, Newham, Hackney and City of London) which were reviewed for the number of MS-diagnosed patients, grouped by ethnicity. What they found was that MS appeared to be several times more prevalent among African people and South Asians living in London compared to those groups living in their ancestral territory. While prevalence differences could be explained by fewer MS diagnoses occurring in less resourced countries, the authors said it is unlikely to explain the gulf in prevalence between these territories. They said that an alternative, or additional, explanation would be increased exposure in the UK to environmental agents or behaviors that facilitate the development of MS.
Lead author Schmierer said, "MS is a disease where genetic ancestry and environmental factors play a role, however to what degree these two aspects are driving the risk of developing MS remains unknown. We found that people of Asian and African extraction in London are far more likely to have MS than people of the same ethnicity living in their ancestral countries. Our early results suggest that environmental factors play a pivotal role in the risk of developing MS, whilst the individual genetic backdrop may be of lesser importance."
The study was published in Multiple Sclerosis Journal.