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West Sweden Asthma Study


West Sweden Asthma Study is the name of the strategic venture at the Cancer Research Center (KRC). The study's main financier is Herman Krefting’s Foundation for Allergy and Asthma Research / VBG GROUP Center for Asthma and Allergy Research. The study includes several sub-studies and also engages in several international and national collaborative projects. Internationally, the main collaborative project is the EU-supported GA2LEN project, the European Community Respiratory Health Survey (ECRHS) and its Nordic-Baltic Respiratory Health in Northern Europe (RHINE) and FinEsS-studies in Finland, Estonia and Sweden. Bilateral international research collaboration also occurs. In Sweden, collaborative research primarily include the OLIN-studies and the Västra Götaland children study in addition to those projects that fully or partially funded by the KRC. Several researchers are involved and researchers responsible for different modules are listed in a supplement (Research teams within the framework of WSAS).

The West Sweden Asthma Study has several purposes. The short-term aim is to investigate if asthma and respiratory symptoms and allergic rhinitis continue to increase in society. In the long-term perspective, the purpose is to find well-defined and clinically relevant major phenotypes, or subgroups, of asthma. Asthma is a heterogeneous disease, in reality a syndrome, consisting of several disease groups with different clinical picture, different prognosis, different risk factor patterns and different response to treatment. Knowledge of the main phenotypes is still extremely limited and fragmentary. It is very important for patients with asthma to get a quick diagnosis and to benefit from a relevant and for each individual correct treatment. In order to implement the phenotyping of asthma both a large statistical power, so that findings are not to be explained by chance, and a good representation, i.e. that people with asthma in the study corresponds to asthma in the community, are required.

WSAS was initiated in 2008 when a major survey was conducted (WSAS I), and followed up in 2016 (WSAS II). In WSAS I, a sample of 30,000 randomly selected persons aged 16-75 was in Västra Götaland. Over 18,000 people answered the extensive survey. A special non-response study was conducted among a selection of those who did not answer the questionnaire. The second phase of the study was conducted in 2009-2012 and consisted of extensive clinical studies in subgroups of respondents. Firstly, a random sample of 2,000 people was invited and, secondly, all individuals who reported that they had asthma, more than 1,500 people. A total of 2006 individuals participated in the clinical examinations. In 2016, a follow-up of WSAS I was conducted when responders to the questionnaire in 2008 were invited to respond to the questionnaire again, almost 12 500 participated. At the same time WSAS II was initiated when a new random selection of residents in Västra Götaland was done. This time, 50,000 people were invited in the ages 16-75, of whom more than 24,500 answered the questionnaire. Currently, clinical trials are being conducted among those who answered the questionnaire in 2016. Initially, asthmatics from WSAS II and individuals in WSAS I who had incident asthma since 2008 are invited. Later, a random sample from WSAS II and follow-up of those who participated in the 2009-2012 clinical trials will be conducted.

Summary of main results
Although a fivefold increase in the use of asthma medicine has occurred since the early 1990s, and the use of inhalation steroids has increased from 1.5 to 7.7% in the population, the adherence to asthma medication has been shown to be low. There are several factors that affect adherence and through data collected in the clinical part of WSAS I we have, among other things, demonstrated that personality traits and perceptions of medications are important for asthmatics' adherence. There is an improvement potential in asthma care to improve adherence in general with asthmatics and thus asthma control. By using only a few questions in the WSAS I postal survey, a group with multiple symptoms could be identified despite treatment with asthma medication; these accounted for 2% of the population and 25% of all asthmatics. The multi-symptom asthma definition was associated with clinical signs of more severe disease and were not due to less adherence. Nearly 60% of asthmatics who participated in the clinical trials did not have sufficiently controlled asthma with persistent symptoms despite relatively high levels of asthma medication. An increased rate of cough indicated an asthma that is more difficult to control, which should be considered in patient contacts. By defining symptoms indicative of severe asthma and investigating these phenotypic signs, we could show that at least 1/3 of all asthmatics has at least one sign of severe disease and the diversity is high. The prevalence of a phenotype with asthma-COPD overlap constituted 3% of the population and these have lower lung function and more clinical symptoms than those with asthma or COPD only. Smoking has a negative effect on the respiratory system after only a few years of smoking, which is particularly evident among young women which smoke more than young men, they also have an earlier smoking initiation and they have a higher incidence of bronchial symptoms. In cooperation with the OLIN-studies, we have shown that the use of e-cigarettes is the most common among smokers, and those who use both common cigarettes and e-cigarettes have a higher incidence of respiratory symptoms. In terms of allergic rhinitis, we have been able to show that the protective effect of growing up on a farm on the occurrence of allergic rhinitis, as previously shown in studies on children, remains throughout life. In the case of allergic sensitization, particular pollen sensitization has increased as well as multi-sensitization, where the latter co-exist strongly with asthma. Occupational exposure to gas, dust and smoke appears to act as an adjuvant that supports sensitization to mites and mite sensitized individuals may be particularly sensitive to inhaled occupational exposure.

Patient - lungundersöks
Page Manager: Marie Megitt|Last update: 8/28/2018

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