Childhood asthma as a life-course disease: Recent advances, environmental determinants, and biomarkers

Childhood asthma as a life-course disease: Recent advances, environmental determinants, and biomarkers Asthma is one of the most common chronic diseases of childhood.Although its prevalence has recently plateaued or even gradually declined in developed countries, including Japan, 1,2 it still affects approximately 10% of children.Asthma attacks can be severe and sometimes fatal, and the disease therefore remains of major clinical importance. 1 Indeed, precisely because asthma is so common, its clinical importance can easily be overlooked; it is a disease that must not be underestimated.In recent years, increasing emphasis has been placed on understanding asthma as a life-course disease.Several cohort studies have shown that, when asthma is not adequately controlled in childhood, lung function may fail to reach its full potential or may begin to decline early, with deficits persisting into adulthood and becoming difficult to reverse.3,4 Follow-up of participants in the Childhood Asthma Management Program showed that a substantial proportion of children with persistent asthma either did not follow a normal trajectory of lung function growth or had already begun to show an early decline.3 A low lung function trajectory in childhood has also been associated with the risk of chronic obstructive pulmonary disease in adulthood.4 Understanding the mechanisms operating in childhood, when asthma begins, and achieving good control during this period are important not only for managing current symptoms but also for protecting lifelong respiratory, cardiovascular, metabolic, and overall health.We planned this Review Series with the aim of providing an overview of childhood asthma from three distinct perspectives: recent advances, environmental factors, and biomarkers.In doing so, we sought to highlight both the current state of the field and the questions that remain.Bush provides a comprehensive overview of recent advances in childhood asthma.5 Particularly valuable is his extensive discussion of preschool asthma, one of the most challenging areas in the field.Wheeze phenotypes have long been discussed, 6 but preschool wheeze is highly heterogeneous in its pathophysiology and remains poorly understood.This contrasts with school-age asthma, in which 80-90% of patients show typical type 2 inflammation.Dr. Bush points out the limitations of conventional classification based on symptom patterns and discusses the importance of the treatable-traits approach, which focuses on underlying features such as eosinophilic inflammation and infection.