Researching asthma across the ages: Insights from the National Heart, Lung, and Blood Institute's Asthma Network

Clinical asthma studies across different age groups, or ‘cross-age’ studies, can potentially offer insight into the similarities, differences and relationships between childhood and adult asthma. The National Institutes of Health Asthma Research Network (AsthmaNet) is unique and innovative in that it has merged pediatric and adult asthma research into one clinical research network. This combination enhances scientific exchange between pediatric and adult asthma investigators and encourages the application of ‘cross-age’ studies that involve participants from multiple age groups who are generally not studied together. The experience from AsthmaNet in the development of ‘cross-age’ protocols highlights some of the issues in the evaluation of cross-age research in asthma. The aim of this review is to summarize these challenges, including the selection of parallel, cross-age clinical interventions, identification of appropriate controls, measurement of meaningful clinical outcomes, as well as various ethical and logistical issues.