Airflow Limitation clinical trials at UCSF

Exposure to secondhand tobacco smoke (SHS) is associated with diverse health effects in nonsmokers. Flight attendants (FA) who worked on commercial aircraft before the ban on tobacco smoking (exposed FAs) had high, long-term levels of occupational exposure to SHS and are a unique population for the study of long-term health effects of chronic exposure to SHS. In previous studies, we have shown that many never-smoking SHS-exposed FAs to have curvilinear flow-volume loops, decreased airflow at mid- and low-lung volumes, and static air trapping (elevated residual volume to total lung capacity ratio [RV/TLC]), abnormalities that are not diagnostic of overt Chronic Obstructive Pulmonary Disease (COPD), but do implicate the presence of an obstructive ventilatory defect, and are consistent with what has been recently described as preserved ratio impaired spirometry (PRISm). The main objective of the study is to determine the effect of a bronchodilator to counter the physiologic abnormalities that are observed in the population of never-smoking SHS-exposed FAs as both proof of concept of the presence of an obstructive lung disease and as a possible therapeutic option to counteract the adverse respiratory effects of chronic exposure to SHS.