Secondhand Smoke Respiratory Health Study

Running, not enrolling · Phase 4 · Has a placebo group

Conditions studied: Secondhand Smoke, Air Trapping, Tobacco, Airflow Limitation, Hyperinflation, Obstructive Lung Disease

In brief

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.

Key facts

Study ID

NCT02797275

Run by

University of California, San Francisco

People needed

107

Starts

2016-06-06

Expected to finish

2026-12-31

Last updated by the study team

2026-06-04

Who can join

Age: 40 and older, up to 80. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

• Never Smoking SHS-exposed Flight Attendants:
• aircraft cabin SHS exposure of >1 year while working for airlines
• Never smoker as defined by use of <100 cigarettes lifetime and none within the last year.
• Normal forced expiratory volume (FEV) FEV1/ forced vital capacity (FVC) ratio
• One of the following evidence of airflow obstruction:
• Presence of any airflow limitation on spirometry during the baseline visit
• Development of airflow limitation on spirometry during any stages of exercise testing
• Residual volume to total lung capacity ratio of >0.35
• Exclusion Criteria:
• History of active cardiac disease, uncontrolled hypertension, congestive heart failure
• History of direct tobacco use of over 100 cigarettes in their lifetime
• History of established respiratory diseases such as asthma, emphysema, chronic bronchitis, interstitial lung disease, or sarcoidosis
• History of debilitating chronic illnesses such as severe lupus or rheumatoid arthritis
• History of other illnesses or therapy for illnesses that could affect lung function such as radiation therapy for breast cancer
• Physical inability to perform exercise testing
• BMI >30 kg/m2
• History of marijuana use of >100 joints lifetime, and none within the last year
• History of other recreational drug use

Where it is running

• VA Medical Center — San Francisco, California, United States
• University of California San Francisco — San Francisco, California, United States

Full record on ClinicalTrials.gov

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