What does adolescent undiagnosed-wheeze represent? Findings from the Isle of Wight Cohort

We sought to characterise adolescent wheeze in the absence of asthma, which we termed “undiagnosed-wheeze”.The Isle of Wight Birth Cohort (N=1456) was reviewed at 1, 2, 4, 10 and 18-years. Using questionnaire responses, “Asthma” was defined as “ever had asthma” plus either “wheezing in the last 12-months” or “taking asthma treatment in the last 12-months”, “Undiagnosed-wheeze” as “wheeze in the last 12-months” but “no” to “ever had asthma” and remaining subjects termed “non-wheezers”.Undiagnosed-wheeze (prevalence 4.9%) accounted for 22% of wheezing at 18-years. This was largely adolescent-onset with similar symptom frequency and severity to diagnosed asthma. However, undiagnosed-wheezers had significantly higher FEV1/FVC ratio, less bronchodilator reversibility and bronchial hyper-responsiveness, and were less frequently atopic than asthmatics. Undiagnosed-wheezers had earlier smoking onset, higher smoking rates and monthly paracetamol use than non-wheezers. Logistic regression identified paracetamol use (OR 1.11, [95%CI 1.01–1.23]; p=0.03), smoking at 18-years (2.54, [1.19–5.41], p=0.02), rhinitis at 18 (2.82, [1.38–5.73], p=0.004) and asthmatic family history (2.26, [1.10–4.63], p=0.03) as significant independent risk factors for undiagnosed-wheeze.Undiagnosed-wheeze is relatively common during adolescence, differs from diagnosed asthma and has strong associations to smoking and paracetamol use. Better recognition of undiagnosed-wheeze and assessment of potential relevance to adult health is warranted