Populations have become increasingly mobile as education, inexpensive travel and flexible labour markets have induced young people to migrate to new countries to seek work. This has presented a number of issues for neurologists, but also provided an opportunity to learn more about a number of disorders, including multiple sclerosis and stroke. These massive population changes have an impact on the type of neurologic disorders present in the different areas, as well as their phenotypic presentations, which may differ substantially from those of known conditions.1 A discussion at the 4th Congress of the European Academy of Neurology (EAN), chaired by Antonio Federico, EAN Scientific Committee Chair and Professor, Clinical Neurology and Neurometabolic Diseases, University of Siena, Italy, highlighted some of these challenges and opportunities.2,3
It has been suggested that new immigrants to North America, most of whom are under the age of 50 years, may experience stress of resettlement, restricted availability of health care services or lower income level, that can place them at higher risk of stroke. The Canadian PRESARIO study matched 965,829 new immigrants to 3,272,393 long-term residents by year of birth, sex, and location. The mean age of the participants at study entry was about 34 years. New immigrants had a 34% reduced risk of acute stroke.4 There are several possible reasons for this, including the fact that medical examination for entry into a country generally prevent unhealthy people for immigrating. There may also be a ‘honeymoon period’ of good health following immigration.5 Prof. Federico commented that that the risk of suffering a stroke was “less a question of genetics, but more down to environmental factors such as diet.”3
Multiple sclerosis (MS) is another condition whose prevalence is affected by migration. A number of studies both between and within countries have shown that immigrants moving from high-risk to low-risk areas have a higher rate of MS than that in their new homeland, but often lower than that of their place of origin.6,7 An analysis of the 2012 Norwegian prevalence study found that European and North-American immigrants had the highest prevalence of MS, whereas African and Asian immigrants had the lowest.8 In addition, a recent study showed phenotypic differences between 80 first-generation and 167 second-generation North Africans with MS living in France. North African patients born in France had a similar disability progression profile to that of patients of European origin, whereas those born in their country of origin had a higher risk of advanced Expanded Disability Status Scale scores than Europeans.9 Another recent study of 1,866 Caucasian and 83 ethnic minority people living with MS in the UK, found that ethnic minority patients reached early levels of fixed disability more rapidly than Caucasian patients, but this effect diminishes at later stages of the disease.10 These studies reflect the importance of both genetic and environmental risk factors in the epidemiology of MS, and have implications for the clinical management of these patients.
Another issue that neurologists must consider is the broad spectrum of conditions presented by immigrants that they would not normally come into contact with. For example, Behçet’s disease is extremely rare in Europe, but is relatively common in parts of Asia Minor, the Middle East and the Far East. Early diagnosis and treatment of the condition is essential to avoid serious neurological and cognitive complications. There is a growing number of cases in the Polish population, emphasizing the need for increased awareness of the condition.11
Refugees from war zones also present a challenge since they are likely to arrive in a traumatized state and face difficulties adapting to their new country. Prof. Federico explained that “This ongoing physical and psychological burden can trigger neurological conditions in refugees such as chronic tension headaches.” If the refugees have been accommodated in overcrowded quarters they may have contracted infectious diseases such as varicella zoster virus infection, influenza, hepatitis, tuberculosis, brucellosis and typhus, all of which may all have a detrimental effect on the nervous system. While these diseases have no impact on European epidemiology, screening programmes are essential to ensure prompt treatment of the affected individual.12
Cultural and language barriers also affect the treatment of immigrants presenting with neurological complaints. Immigrants may arrive with a lack of knowledge of the healthcare system of their new country and may not be fluent in the language. Some brain disorders such as epilepsy are stigmatised in certain cultures, leading to underdiagnosis and undertreatment.3 An Italian study found that the use of neurological services by migrants is less than their demographic share.13 In addition, the aging population will soon result in large increases in the number of elderly migrants with dementia and age-related cognitive impairment, conditions that are also likely to be subject to stigma. The diagnosis of cognitive disorders can be challenging if the patient is not fluent in the language of the host country; there is a need for specific neuropsychological tests adapted to the language and culture of every immigrant population. The care of migrants with dementia and cognitive impairment must take into account social origin, cultural and religious beliefs of these patients.14
It is clear from this discussion that our increasingly mobile population presents issues that all neurologists must consider. Prof. Federico said: “While the major immigration and refugee movements over the past years have brought some major challenges for neurology, they have also turned up some previously undreamed-of opportunities to gather fresh insights into brain disorders, diseases such as multiple sclerosis and stroke. We have to make the most of this potential.”3
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3. European Academy of Neurology (EAN) press release. Immigration and flight: challenges and potential insights for neurology. Available at: www.ean.org/lisbon2018/fileadmin/user_upload/05_Migration-and-neurological_diseases.pdf (accessed 25 June 2018).
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