Secondhand Smoke Lung Mechanisms Study

2016-06-13 16:53:27 | BioPortfolio


The Secondhand Smoke Study is a medical research study investigating the physiologic, radiographic, and inflammatory responses of lungs to chronic exposure to secondhand tobacco smoke. Exposure to secondhand tobacco smoke (SHS) is associated with diverse health effects in nonsmokers. Although some of the toxic effects and underlying pathogenic mechanisms of acute exposure to SHS have been demonstrated through in vitro, animal, and controlled human exposure studies, the health effects of chronic exposure to SHS in humans have not been well established because of limitations with long term "natural" or manipulated SHS exposure experiments.

Over the past few years, we have recruited a cohort of flight attendants with history of "natural" chronic exposure to SHS to characterize its long-term health effects. Flight attendants (FA's) who worked on commercial aircraft before the ban on tobacco smoking (pre-ban FAs) had very high levels of occupational exposure to SHS over many years. Chemical analysis of post-flight urine samples from FAs in the pre-smoking ban era showed very high levels of urinary cotinine, the major metabolite of nicotine, in the range close to the levels currently observed in known "light" and in confirmed "experimental" smokers. This history of chronic high-intensity exposure, which better lends itself to quantification through employment history, makes the pre-ban FAs a unique population in which to study the long-term health effects of chronic exposure to SHS.


In previous study of pulmonary function tests (PFT) in the cohort, the investigators showed these never-smoking asymptomatic pre-ban FAs to have decreased flow at mid- and low-lung volumes and curvilinear flow-volume loops suggestive of mild airflow obstruction. More impressively, over half of the cohort had significantly reduced diffusing capacity (Dco) below the lower 95% prediction limit based on standard reference equations. Furthermore, in maximum effort (symptom-limited) cardiopulmonary exercise testing of this cohort, the investigators found that the pre-ban FAs with reduced Dco at rest had:

1. decreased exercise capacity (maximum workload and oxygen uptake) that was directly associated with the participants' forced expiratory volume in one second (FEV1):

2. reduced pulmonary capillary bed recruitment as indicated by lower exercise-induced increase in the participants' Dco and lower ratio of Dco to pulmonary blood flow with exercise; and

3. an inverse association between the participants' Dco during exercise and the years of exposure to SHS in the aircraft cabin in those FAs with over 10 years of pre-ban experience.

These findings are intriguing as they suggest lasting lung damage from remote but intense exposure to SHS in the aircraft cabin. Accordingly, the preliminary longitudinal data suggests that pre-ban FAs may have an accelerated decline in their lung function beyond what is expected from the aging process. Meanwhile, despite the progress in understating the mechanisms of SHS-induced lung damage, the health relevance of the observed respiratory abnormalities in this cohort remains unknown.

Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Crossover Assignment, Masking: Double Blind (Subject, Investigator)


Secondhand Smoke


Albuterol, Placebo


VA Medical Center
San Francisco
United States




University of California, San Francisco

Results (where available)

View Results


Published on BioPortfolio: 2016-06-13T16:53:27-0400

Clinical Trials [266 Associated Clinical Trials listed on BioPortfolio]

Reduction of Secondhand Smoke Exposure in Healthy Infants

The purpose of this study is to assess the effects of a health center based counselling method for the prevention of infant exposure to secondhand smoke.

NICU Asthma Education and Secondhand Smoke Reduction Study

Premature infants have a significantly increased risk for developing respiratory illnesses and asthma. Secondhand smoke (SHS) also is clearly associated with increased breathing problems ...

Adverse Health Effects of Mainstream and Secondhand Hookah Smoke in NYC Hookah Bars

The primary purpose of this study is to examine the health effects of mainstream and secondhand hookah (i.e. water pipe) smoke on pulmonary and cardiovascular functions as well as serum le...

Cotinine Feedback as an Intervention to Change Parental/Caregiver Smoking Behavior Around Children With Cancer

RATIONALE: Providing parent/caregivers of children with cancer with education and evidence of secondhand smoke exposure can protect the child from future exposure to tobacco smoke. PURPOS...

An RCT of SHS Among Non-smoking Children

This is a school- and family-based prospective study in randomly selected clusters among Primary/Grade 3-4 (P3-4) students in all the 5 regions of Hong Kong, which aims at reducing childre...

PubMed Articles [1191 Associated PubMed Articles listed on BioPortfolio]

Exposure to Secondhand Smoke Among Nonsmokers - United States, 1988-2014.

Exposure to secondhand smoke from burning tobacco products can cause sudden infant death syndrome, respiratory infections, ear infections, and asthma attacks in infants and children, and coronary hear...

Healthcare Costs of Secondhand Smoke Exposure at Home for U.S. Children.

The purpose of this study is to estimate healthcare utilization and healthcare costs due to secondhand smoke exposure at home for children in the U.S.

Secondhand smoke exposure and depressive symptoms in children: a longitudinal study.

We investigated whether secondhand smoke (SHS) exposure is associated with depressive symptoms in a population-based sample of children.

Secondhand smoke knowledge, sources of information, and associated factors among hospital staff.

To evaluate knowledge of secondhand smoke (SHS) risks, sources of information, and associated factors and behaviors among hospital staff.

Secondhand smoke alters arachidonic acid metabolism and inflammation in infants and children with cystic fibrosis.

Mechanisms that facilitate early infection and inflammation in cystic fibrosis (CF) are unclear. We previously demonstrated that children with CF and parental-reported secondhand smoke exposure (SHSe)...

Medical and Biotech [MESH] Definitions

A racemic mixture with a 1:1 ratio of the r-isomer, levalbuterol, and s-albuterol. It is a short-acting beta2-adrenergic agonist with its main clinical use in ASTHMA.

A combined pharmaceutical preparation of Ipratropium Bromide and Albuterol Sulfate that is used to treat the symptoms of ASTHMA and CHRONIC OBSTRUCTIVE PULMONARY DISEASE.

Prohibition against tobacco smoking in specific areas to control TOBACCO SMOKE POLLUTION.

Contamination of the air by tobacco smoke.

Pulmonary injury following the breathing in of toxic smoke from burning materials such as plastics, synthetics, building materials, etc. This injury is the most frequent cause of death in burn patients.

More From BioPortfolio on "Secondhand Smoke Lung Mechanisms Study"

Quick Search


Relevant Topic

Benign Prostatic Hyperplasia (BPH) Erectile Dysfunction Urology Urology is the branch of medicine concerned with the urinary tract and diseases that affect it. Examples include urethritis, urethrostenosis and incontinence. Urology is a su...

Searches Linking to this Trial