Rural to urban migration contributes to the high burden of asthma in the urban area.

Introduction: It is unknown whether rural-urban migration contributes to worse the burden of asthma in the cities.

Objectives: The aim of this study was to evaluate whether subjects with asthma that migrated from rural areas to a large urban center in Brazil have more severe disease than asthmatic subjects that was born and always lived in the urban area.

Methods: This is a case-control study.

Eosinophilic asthma, according to a blood eosinophil criterion, is associated with disease severity and lack of control among underprivileged urban Brazilians.

Background: Asthma is a syndrome with multiple phenotypes. Peripheral blood eosinophil counts might be the ideal biomarker to identify subjects with eosinophilic asthma. It is available, inexpensive, and it is associated with eosinophilia in sputum.

Age is associated with asthma phenotypes.

Background And Objective: The relationship between age and asthma phenotypes is important as population is ageing, asthma is becoming common in older ages and recently developed treatments for asthma are guided by phenotypes. The aim of this study is to evaluate whether age is associated with specific asthma phenotypes.

Methods: This is a cross-sectional study.