Clinical trial NCT04013256: Controlled Exposure of Healthy Nonsmokers to Secondhand and Thirdhand Cigarette Smoke
Official title: Controlled Human Exposure and THS Generation Core
Study type: INTERVENTIONAL
Overall status: SUSPENDED
Phase: NA
Conditions: Pollution; Exposure
Smoke Inhalation
Exposure to Pollution
Lead sponsor: University of California, San Francisco
Sponsor class: OTHER
Collaborators: name: Tobacco Related Disease Research Program
First posted: 2019-07-09
Enrollment: 66
Sex: ALL
Minimum age (years): 18
Maximum age (years): 50
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: Crossover assignment
Primary purpose: BASIC_SCIENCE

Brief summary: This study compares the health effects of dermal and inhalational exposure to thirdhand cigarette smoke to those of inhalational exposure to secondhand cigarette smoke in healthy, adult nonsmokers. Our hypothesis is that dermal exposure increases exposure to the tobacco specific carcinogen, NNK and may affect both endothelial function and epidermal integrity.

Detailed description: Thirdhand cigarette smoke is the smoke chemicals that persist in the environment after smoking. Indoors, they can be found both on surfaces and in the air. Thirdhand smoke derives from secondhand smoke and contains the chemicals that stick to surfaces, are re-emitted into the air and that form by chemical reactions both on surfaces and in the air.

Thirdhand smoke can contain higher concentrations of the tobacco-specific nitrosamine and known carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) than secondhand smoke, because nicotine reacts to form NNK in the indoor environment. Dermal exposure to thirdhand smoke includes nicotine, NNK and other tobacco-specific nitrosamines, polycyclic aromatic hydrocarbons, and volatile organic compounds. Inhalational exposure to thirdhand smoke includes nicotine, ultrafine particles and volatile organic compounds. Previous studies have shown that inhalational exposure to secondhand cigarette smoke causes endothelial dysfunction, which is a risk factor for heart disease and heart attacks.

Eligibility criteria: Inclusion Criteria:

* Healthy on the basis of medical history, blood pressure and test of C-reactive protein, lipids and blood sugar.
* Non-smoker not exposed to second-hand smoke (SHS) as determined by saliva cotinine \< 10 ng/ml and tetrahydrocannabinol (THC) \< 50 ng/ml.
* Flow mediated dilation of 4% or greater at screening visit.

Exclusion Criteria:

* Age 18 \< or \> 50 Physician diagnosis of asthma, heart disease, hypertension, thyroid disease, diabetes, renal or liver impairment or glaucoma.

Unstable psychiatric condition (such as current major depression, history of schizophrenia or bipolar disorder) or current use of more than two psychiatric medications Systolic blood pressure \> 150 Diastolic blood pressure \> 100 Blood glucose \> 110 LDL \>130 Pregnancy or breastfeeding (by urine Human Chorionic Gonadotropin (hCG) and/or history) Alcohol or illicit drug dependence within the past 5 years BMI \> 35 and \< 18 Current illicit drug use (by history or urine test) More than 1 pack year smoking history Ever a daily marijuana smoker Smoked anything within the last 3 months Unable to hold allergy or other over-the-counter (OTC) medicines Occupational exposure to smoke, dusts and fumes Concurrent participation in another clinical trial Unable to communicate in English No social security number

Primary outcomes:
measure: Changes in flow-mediated dilation (FMD) of the brachial artery, caused by pollution exposures, measured by ultrasound
timeFrame: Baseline (before exposure) 30 minutes (after 30 minutes exposure) and 3 hours.
Secondary outcomes:
measure: Changes in trans-epidermal water loss caused by pollution exposures, comparing intact skin to tape-stripped skin
timeFrame: Baseline, 30 minutes, 3 hours, 2 days, 5 days
Other outcomes:
Locations:
city: San Francisco
country: United States
facility: Zuckerberg San Francisco General Hospital
state: California
Study officials:
affiliation: University of California, San Francisco
name: Suzaynn F Schick, PhD
role: PRINCIPAL_INVESTIGATOR
References: