Ponte EV, Lima A, Almeida PCA, et al. - In this case-control study, researchers compared asthma severity among people with asthma that migrated from rural areas to a large urban center in Brazil vs those with asthma who were born and always resided in the urban area. The goal was to determine the contribution of rural-urban migration to the worsening of asthma burden in the cities. This study included 486 individuals with moderate-severe asthma and 432 with mild asthma, who were currently inhabiting in a large urban center in Brazil. Findings revealed more severe asthma in rural-urban migrants in Brazil vs urban-born people. In this study, a link was suggested between rural-urban migration and a high burden of asthma in the urban area.