Rhinitis and onset of asthma: a longitudinal population-based study

Summary Background A close relation between asthma and allergic rhinitis has been reported by several epidemiological and clinical studies. However, the nature of this relation remains unclear. We used the follow-up data from the European Community Respiratory Health Survey to investigate the onset of asthma in patients with allergic and non-allergic rhinitis during an 8·8-year period. Methods We did a longitudinal population-based study, which included 29 centres (14 countries) mostly in western Europe. Frequency of asthma was studied in 6461 participants, aged 20–44 years, without asthma at baseline. Incident asthma was defined as reporting ever having had asthma confirmed by a physician between the two surveys. Atopy was defined as a positive skin-prick test to mites, cat, Alternaria, Cladosporium , grass, birch, Parietaria , olive, or ragweed. Participants were classified into four groups at baseline: controls (no atopy, no rhinitis; n=3163), atopy only (atopy, no rhinitis; n=704), non-allergic rhinitis (rhinitis, no atopy; n=1377), and allergic rhinitis (atopy+rhinitis; n=1217). Cox proportional hazards models were used to study asthma onset in the four groups. Findings The 8·8-year cumulative incidence of asthma was 2·2% (140 events), and was different in the four groups (1·1% (36), 1·9% (13), 3·1% (42), and 4·0% (49), respectively; p