Airway function throughout the lifespan: Pediatric origins of adult respiratory disease

Abstract

Chronic obstructive pulmonary disease (COPD) is a leading cause of disability and death of adults in the USA and worldwide. While environmental factors such as smoking and air pollution are major contributors to COPD, pediatric respiratory disease and more specifically early childhood wheezing are frequent predisposing factors. It is therefore possible that aggressive prevention and treatment of childhood respiratory illness may modify adult COPD risk. This article reviews some of the physiological factors that may explain the pediatric origins of childhood lung disease. One such factor is the "tracking" of normal lung function which occurs with growth. The maximal expiratory flow volume (MEFV) curve is an ideally suited tool to monitor tracking of airway function over the lifespan, as its relative effort independence makes it highly reliable. Study of the MEFV curve has demonstrated that individuals with similar lung volumes can have large differences in maximal flows, reflecting a disconnection between airway and lung growth ("dysanapsis"). Less than average airway size due to dysanaptic airway growth or airway remodeling may be independent risk factors for the development of COPD and the asthma/COPD overlap syndrome in adult life. There are intriguing early data suggesting that perhaps at least some of this risk is modifiable by improving asthma control with inhaled corticosteroids and minimizing asthma exacerbations.

Keywords: Airway remodeling; Asthma; Asthma/COPD overlap syndrome; Childhood origins; Chronic obstructive pulmonary disease (COPD); Dysanapsis; Lung function; Maximal expiratory Flow volume curve; Prevention; Wavespeed theory; equal pressure point; flow limitation; tracking.