Geoepidemiology of Sjögren's syndrome in Latin America

Objective: To evaluate the geoepidemiology of Sjögren's syndrome (SS) in Latin America. Methods: This was a three phase study in which original data from a Colombian cohort of patients with SS is presented, followed by a systematic review of Colombian and Latin American studies. Lastly, the geoepidemiology of SS in Latin America was assessed by comparing the clinical characteristics of the region with those of the rest of the world by means of a meta-analysis approach. Results: Data from 2970 patients from Latin America and 18019 patients from Europe, North America and Asia were analyzed. Colombian patients have a lower age at disease onset than those from other Latin American countries and a higher rate of positivity of antinuclear antibodies and rheumatoid factor. A significant difference in the proportion of female patients in Latin America compared with Europe and North America was observed. The spectrum of disease in Latin American was similar to North American patients, while strong differences were noticed between Latin American and European and Asian patients. Noteworthy, a paucity of reports including African and African-descendent patients was observed. Conclusions: The clinical spectrum of SS differs between countries and continents. Genetic differences relying upon ancestry could explain these findings. However, environmental factors have proven to be important determinants in the development of autoimmune diseases (i.e., autoimmune ecology). Thus, ancestry and the autoimmune ecology should be considered in studies aimed to evaluate the geoepidemiology of SS and other autoimmune diseases.