Secondhand Smoke Respiratory Health Study

The objective of this research plan is to investigate the hypothesis that subclinical airflow limitation and air trapping in never-smoking SHS-exposed individuals with preserved ratio impaired spirometry (PRISm) causes reduced exercise capacity . This in turn will adversely affect their symptoms and quality of life. Furthermore, we hypothesize that exercise capacity, symptoms, and quality of life will improve with the use of inhaled bronchodilators. We proposed to investigate the above hypotheses through the following specific aims: Aim 1- Determine whether airflow limitation in never-smoking SHS-exposed individuals with airflow limitation or air trapping is associated with reduced exercise capacity and adverse health and health-related quality of life (HRQL). We propose to measure (1) maximum level of exercise (watts) and maximum oxygen uptake (VO2) in the laboratory setting, (2) level of physical activity during the subjects' routine daily life using an activity monitor, and (3) measure HRQL using survey tools. We propose to then explore associations between these measures and indices of air trapping at rest (RV/TLC) and progressive airflow limitation with exercise (end expiratory lung volume (EELV)and dynamic hyperinflation (DH)). Aim 2: Determine whether relief of airflow limitation using bronchodilators could improve exercise capacity in never-smoking SHS-exposed individuals with airflow limitation or air trapping in a double blind crossover placebo-controlled randomized clinical trial. We propose to examine the effect of bronchodilators on airflow limitation and air trapping and their effects in turn on exercise capacity, daily level of physical activity, and HRQL to show a cause-and-effect relationship. In this way, we plan to explore the utility of bronchodilators as a treatment option for the observed reduced exercise capacity.