Abstract
Background: Asthma is regarded as a chronic disease but recovery in children is common. The natural history of asthma in adults in a long term perspective is rarley studied.
Aim: To investigate the participation in a long term follow-up of asthma in adults.
Methods: The participants were recruited from The Obstructive Lung Disease in Northern Sweden (OLIN) Studies. Subjects with asthma or suspected asthma were identified by clinical examinations of 5 representative cohorts from the general population, recruited from 1985 to 2001. Base-line data included a lung function test and structured interview covering respiratory symptoms and medications, smoking habits, socio-economic status, profession, early life events. Skin prick test and bronchial reactivity test were performed in 3 cohorts. Follow-ups started in 2012 and included structured interview, lung function test, skin prick test, specific IgE, and inflammatory markers in blood.
Results: In total 2,056 subjects fulfilled the inclusion criteria, aged 20-69 years at inclusion. The follow-up time ranges from 11 to 30 years. At the follow-up, 1,425 subjects were alive and still lived in the area, and 70% participated, Of non-participaants, 85 subjects could not participate due to illness, 15 had moved, 14 had died after 2012, 242 reported lack of time or interest, and 70 could not be traced. Non-participation due to illness was more common among the elderly while more young people did not participate due to lack of time or interest.
Conclusion: The large, representative sample and high participation rate constitute an excellent base for long term study of asthma. To increase the participation rate, the scheduled visit time must meet the individual's needs.
- © 2014 ERS
