Evolution of multiple sclerosis prevalence and phenotype in Latin America

Background: Literature regarding MS epidemiology and phenotype is scarce but has increased markedly over the past years. The objective of the present work is to assess the evolution of the prevalence and phenotype of MS in Latin America during recent years. Methods: Review of literature. Results: MS prevalence levels are low to medium in Latin America, although these have increased in recent years. A small latitudinal gradient has also been observed, but exceptions to this rule exist, suggesting other genetic and environmental factors ultimately influence regional prevalence rates. One of the distinctive features of the region is the complex genetic admixture arising from multiple divergent population ancestries in different countries including: Native Americans, Caucasians and Africans. Another variable which would lower MS risk in the region could be a protective effect linked to exposure to certain infections, such as parasites. Despite differences in MS epidemiology, Latin American patients show an MS phenotype very similar to that of Caucasian patients, and a progressively increasing female gender ratio as has been described worldwide. Conclusion: MS epidemiology in Latin American patients has distinctive features. Both, prevalence and incidence, are increasing.