Trends in asthma incidence in children: a UK population-based cohort study

Background: Evidence suggests that asthma incidence has steadily declined in the past decade, especially in children. These trends have not been thoroughly explored across age groups in the UK.Aim: To quantify recent trends in asthma incidence in a UK paediatric population using a large population-based cohort.Methods: We identified 498,503 new asthma cases in patients aged 1-17 years contributing data to the Clinical Practice Research Datalink Aurum database from 1/1/07-31/12/19. We calculated annual asthma incidence rates for 3 different age groups (1-5, 6-11, 12-17), stratified by gender.Results: Overall annual incidence rate fell continuously from 1,470 (95% CI;1449–1490) in 2007 to 634 (623–645) per 105 person years (pys) in 2019 (57% decline). Decline was similar between genders. The most pronounced decrease was in the 1-5 age group (Fig), in whom incidence dropped from 2813 (2762–2864) to 759 (735–783) per 105 pys (73% decline). The corresponding data for the 6-11 and 12-17 age group were 1156 (1126 – 1187) to 727 (707 – 747) (37% decline) and 550 (529 – 573) to 430 (415 – 447) (22% decline) per 105 pys, respectively.Conclusion: The rate of new asthma diagnosis has fallen substantially in UK children since 2007. The pronounced decline in the 1-5 age group may be due to a change in diagnostic criteria for wheeze and asthma. Whilst there was some decrease in the 6-11 age group, incidence in 12-17year olds was relatively stable