PREVALENCE AND INCIDENCE OF ASTHMA AND RHINOCONJUNCTIVITIS IN SWEDISHTEENAGERS

In 1987, we studied the prevalence of asthma and rhinoconjunctivitis i n 1112 grade-eight students in the town of Umea, northern Sweden, The present study is based on the same cohort. reinvestigated in 1991, We aimed to estimate the changes in the prevalence of asthma and rhinocon junctivitis and to examine some presumed risk factors of asthma and rh inoconjunctivitis. A postal questionnaire on present asthma, rhinoconj unctivitis symptoms from the upper and lower airways, and the need for medication was used. Questions about living conditions, smoking, and present education were also included. The questionnaire was answered b y 89% (990) of the subjects. The prevalence of self-reported asthma wa s 10.8% (boys 7.9%, girls 13.7%). The incidence rate/year was 1.1%, th e remission rate/year was 5.7% and the relapse rate/year was 10%, The risk factors for developing asthma appeared to be atop. having a famil y history of asthma or rhinoconjunctivitis. and smoking. The prevalenc e of self-reported rhinoconjunctivitis was 14.3% (boys 15.6%, girls 13 .1%), The incidence rate/year was 1%, the remission rate/year was 22%, and the relapse rate/year was 11%. Stopping smoking and having no fam ily history of rhinoconjunctivitis or asthma appeared to favor remissi on in rhinoconjunctivitis.