S83 Preschool wheezing phenotypes in a representative UK birth cohort

Introduction and objective The 2008 ERS Task Force1 recommended that preschool wheezing be classified as episodic (viral) wheeze (EVW) or multiple trigger wheeze (MTW). We investigated the relationship between these phenotypes and reported wheeze and medication use in later childhood. Methods Between 1993 and 1995, 658 consecutive mothers attending for routine ante-natal care (93% of those eligible) were recruited; they subsequently gave birth to 642 children. Detailed respiratory data were collected annually until the child reached the age of 5½ years (n=602; 94%). Further information was collected at age 8 (n=593; 92%) and 14 (n=497; 77%) years. EVW was defined as occasional wheeze in the past 12 months which occurred when the child had a cold or other infection; all other reported wheeze was defined as MTW. Using data from birth to age 5½, children were categorised as never wheezing (n=238); only EVW wheeze (n=208); both EVW and MTW wheeze (n=100) and only MTW wheeze (n=56). Results The prevalence of EVW fell from 32% at age 0–1 to 7% at age 4–5½; MTW prevalence was approximately 10% each year. Compared with never wheezers, in each wheezing group there was a higher proportion of boys (54%, 65%, 61%), (48%); p=0.02, higher exposure to ETS, and a greater prevalence of maternal and paternal asthma (p<0.001, p<0.001, p=0.06, respectively). Respiratory outcomes at 8 and 14 years were higher amongst the three wheezing groups, especially for those with MTW (see Abstract S83 Table 1). There was a higher prevalence of current wheeze and medication use at 8 and 14 years for those with a higher frequency of wheezing between birth and age 5½; and a lower prevalence of the same outcomes for those who only wheezed between birth and age two, compared to those who wheezed later. Conclusion At 8 and 14 years of age, never wheezers and pure EVW had lower prevalences of atopy, wheeze and current medication use than those with any MTW. These data provide external validity to the ERS phenotypes, and suggest that they provide useful prognostic information.