Remission of asthma: A prospective longitudinal study from Northern Europe (RHINE study)

¹ Dept of Occupational and Environmental Medicine, Sahlgrenska University Hospital, Göteborg, Sweden
² Dept of Thoracic Medicine and Centre for Clinical Research, Haukeland University Hospital, Bergen, Norway
³ Dept of Pulmonary Medicine, Lanspitali University Hospital, Reykjavik, Iceland
⁴ Foundation Tartu University Clinics, Lung Clinic, Tartu, Estonia
⁵ Dept of Pulmonary Medicine and Allergology, University Hospital of Northern Sweden, Umeå, Sweden.
⁶ Dept of Medical Sciences, Respiratory Medicine and Allergology, Uppsala University, Uppsala, Sweden
⁷ Dept of Occupational and Environmental Medicine, Sahlgrenska University Hospital, Göteborg, Sweden; and Dept of Respiratory Medicine and Allergology, Sahlgrenska University Hospital, Göteborg, Sweden

^* To whom correspondence should be addressed. E-mail: Kjell.Toren{at}amm.gu.se.

	Abstract

The aim was to study the remission rate of adult asthma in a general population sample in relation to age, sex, asthma symptoms, allergic rhinitis and smoking.

A follow-up of the random population samples from the European Community Respiratory Health Survey in Northern Europe was conducted between 1999 and 2001 on 1,153 individuals (26-53 yrs) with reported asthma. Remission was defined as no asthmatic symptoms in two consecutive years and no current use of asthma medication. Remission rates per 1000 person-years were calculated and Cox regression models, adjusting for confounders, were used for estimating Hazard Ratios (HR) with 95% confidence intervals (CI).

An average remission rate of 20.2/1000 person-years was found. There was no significant difference according to sex, in women the remission rate was 21.7/1000 person-years and in men it was 17.8/1000 person-years. An increased remission rate was observed among subjects quitting from smoking during the observation period. Subjects with no reporting of any asthma symptom at baseline had an increased remission rate. In the Cox regression model ex-smoking (HR 1.65, 95% CI 1.01-2.71) was associated with increased remission rate, and reporting of any asthma symptom at baseline was associated with decreased remission rate (HR 0.7, 95% CI 0.40-0.90).

In conclusion, this prospective longitudinal study quitting smoking and presence of mild disease appeared to favour remission.