Adolescent undiagnosed-wheeze; an unrecognised state associated with significant morbidity, tobacco and paracetamol use

Background: Adolescent undiagnosed-wheeze is poorly understood. Aims: We characterised adolescent undiagnosed-wheeze hypothesising associations with behaviour-linked exposures. Methods: The Isle of Wight Birth Cohort (UK) was recruited in 1989 (N=1456) and reviewed at 1, 2, 4, 10 and 18-years. At 18-years, “Asthma” was defined as “ever had asthma” plus either “wheezing in the last 12 months” or “asthma treatment in the last 12 months”, “Undiagnosed-wheeze” as “wheeze in the last 12 months” but “no” to “ever had asthma”, with remaining subjects termed “non-wheezers”. Testing included questionnaires, skin prick tests, spirometry, bronchodilator reversibility and methacholine bronchial challenge. Results: Undiagnosed-wheeze accounted for 22% of wheezing at 18-years. This was mostly adolescent onset with similar symptom frequency/severity to asthma. However, undiagnosed-wheezers had higher FEV 1 /FVC ratio (p=0.002) but lower bronchodilator reversibility (p Conclusions: Undiagnosed-wheeze occurred in 5% of adolescents. It had many distinctive characteristics from asthma plus strong associations to smoking and paracetamol use that merit further study.