Background: Obstructive airway diseases are common worldwide and in the Nordic countries. They contribute to high costs, low quality of life and are associated with environmental and lifestyle factors. Research regarding obstructive airway diseases has been performed in Sweden and Finland with identical methods since 1996 and with similar methods in Norway.
Aim: To identify preventable risk factors related to asthma, COPD and respiratory symptoms through a multidisciplinary research approach. In particular, the impact of different socio-economic markers will be studied by taking account of similarities and differences in health care consumption, treatment and mortality in Sweden, Norway and Finland, in a life-course perspective.
Method: Based on existing epidemiological data about obstructive airway diseases and allergy in Sweden, Norway and Finland, a common database will be created. Data from approximately >19,000 adult subjects in Sweden, >12,000 in Finland, and >65,000 in Norway recruited in 1995-96 are included, and a large part of the subjects have been examined longitudinally. Register-based data will be added to this database. This merged database will include detailed epidemiological data regarding respiratory symptoms, physician-diagnosis of asthma and COPD, treatment, co-morbidity, smoking habits, occupation and occupational exposures, height, weight, body mass index, lung-function, allergy and markers of systemic inflammation are available for subsamples.
In Sweden, the National Board of Health and Welfare (Socialstyrelsen) collect data in the Cause of death register, the Patient register (hospitalizations and outpatient specialist care by diagnosis), and the Prescription register (prescribed and delivered medications from pharmacies since 2005) and there are comparable registers in Finland and Norway (prescribed and delivered medications from pharmacies since 2004). Data on socioeconomic factors such as income, education and sick-leave will be collected from Statistics Sweden (SCB), Statistics Finland (Statistikcentralen) and Statistics Norway (SSB).
Significance: The combination of the multidisciplinary large scale epidemiological studies with detailed categorizations of health outcomes in a life course perspective and the objective data from national registers is unique. This knowledge will improve prevention and care, and thus also the respiratory health in the general population.