Asthma: NHLBI Workshop on the Primary Prevention of Chronic Lung Diseases

Abstract

Asthma is a common disease with enormous public health costs, and its primary prevention is an ambitious and important goal. Understanding of how host and environmental factors interact to cause asthma is incomplete, but persistent questions about mechanisms should not stop clinical research efforts aimed at reducing the prevalence of childhood asthma. Achieving the goal of primary prevention of asthma will involve integrated and parallel sets of research activities in which mechanism-oriented studies of asthma inception proceed alongside clinical intervention studies to test biologically plausible prevention ideas. For example, continued research is needed, particularly in young children, to uncover biomarkers that identify asthma risk and provide potential targets of intervention, and to improve understanding of the role of microbial factors in asthma risk and disease initiation. In terms of clinical trials that could be initiated now or in the near future, we recommend three interventions for testing: (1) preventing asthma through prophylaxis against respiratory syncytial virus and human rhinovirus infections of the airway; (2) immune modulation, using prebiotics, probiotics, and bacterial lysates; and (3) prevention of allergen sensitization and allergic inflammation, using anti-IgE. These interventions should be tested while other, more universal prevention measures that may promote lung health are also investigated. These potential universal lung health measures include prevention of preterm delivery; reduced exposure of the fetus and young infant to environmental pollutants, including tobacco smoke; prevention of maternal and child obesity; and management of psychosocial stress.

Figure 1.

The risk for developing asthma is age dependent, with the majority of incident asthma beginning in the preschool years. Box sizes represent estimates of the relative importance of each developmental period in childhood.

Figure 2.

An integrated portfolio across the translational research spectrum is needed moving forward toward primary prevention of asthma. The figure illustrates how basic research efforts must continue alongside specific clinical intervention trials. RSV = respiratory syncytial virus; RV = human rhinovirus. *Covariates such as vitamin D should be assessed in asthma prevention trials; additional vitamin D trials may be necessary depending on the results of ongoing trials.