Background Epidemiological phenotypes for childhood wheeze were first proposed by the Tucson Children’s Respiratory Study (TCRS), describing four distinct phenotypes. A new, six phenotype, characterisation has recently been proposed by the Avon Longitudinal Study of Parents And Children (ALSPAC). No previous cohort has included 1 year atopic sensitisation data with infant lung function in their analysis.

Objectives To classify infant and 6 year lung function and allergic sensitisation data at 1, 3 and 6 years from the Southampton Women’s Survey (SWS) cohort according to the ALSPAC 6 class pheno type model. To contrast this with TCRS phenotypes to assess clinical and epidemiological utility.

Methods At 6 years, 926 children had assessment of respiratory symptoms. Spirometry was measured in 791 children, with exhaled nitric oxide (n=589) and methacholine challenge (n=234). At 5–14 weeks of age 95 of these children had lung function measured. Symptom data on wheeze status obtained at 6m, 12m, 2y, 3y and 6y follow up classified children into groups proposed from analyses of ALSPAC (never, early, transient, intermediate-onset, late-onset and persistent wheeze).

Results Persistent and intermediate-onset wheeze were significantly associated with atopy at 1, 3 and 6 years, and exhaled nitric oxide at 6 years. Late-onset wheeze was not associated with atopic sensitisation until 3 years. Persistent wheezers had lower infant(V’maxFRC p<0.05) and 6 year lung function (FEV1, FEV1/FVC and FEF25–75, p<0.05), whilst late- and intermediate-onsetwheezers showed no lung function deficits. Transient wheezers were non-atopic but showed persistent lung function deficits (FEF25–75, p<0.05 and V′maxFRC, p<0.001), except for those who wheezed only in the first year of life (early phenotype).

Conclusion The SWS cohort data maps well into the ALSPAC phenotype classification, demonstrating useful subdivision of TCRS wheeze phenotypes. Lung function and atopy successfully differentiate persistent, late-onset and intermediate-onset wheeze, whilst the classical ‘transient early’ wheeze phenotype can be sub-classified into groups that reflect early lung function. This has potential significance for research into childhood wheeze and long term respiratory morbidity of children in these phenotypes.