Controlled Exposure of Healthy Nonsmokers to Secondhand and Thirdhand Cigarette Smoke

Pollution; Exposure Clinical Trial

— THS04  

Official title:

Controlled Human Exposure and THS Generation Core

Clinical Trial Details — Status: Suspended

Administrative data

• NCT number: NCT04013256
• Other study ID #: 28PT-0081
• Status: Suspended
• Phase: N/A
• Start date: January 20, 2020
• Est. completion date: October 31, 2024

Study information

• Verified date: August 2023
• Source: University of California, San Francisco
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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.

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.

Recruitment information / eligibility

• Status: Suspended
• Enrollment: 66
• Est. completion date: October 31, 2024
• Est. primary completion date: October 31, 2024
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 50 Years

Eligibility

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

Related Conditions & MeSH terms

• Exposure to Pollution
• Pollution; Exposure
• Smoke Inhalation
• Smoke Inhalation Injury

Intervention

Other:
• Cigarette Smoke
Cigarette smoke, generated by a smoking machine and aged is used to reproduce exposure to secondhand and thirdhand cigarette smoke.
• Clean Air and Clean Clothing/Sham exposure
Clean air, created by high-efficiency particulate air (HEPA) and charcoal filtration and temperature and humidity control. Clean cotton clothing.

Locations

Country	Name	City	State
United States	Zuckerberg San Francisco General Hospital	San Francisco	California

Sponsors (2)

Lead Sponsor	Collaborator
University of California, San Francisco	Tobacco Related Disease Research Program

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Changes in flow-mediated dilation (FMD) of the brachial artery, caused by pollution exposures, measured by ultrasound	High-resolution ultrasound of right brachial artery is performed 1 cm distal to antecubital fossa with a 10 megahertz (MHz) linear array probe coupled to a General Electric (GE) Vivid 7 Imaging System. To assess endothelium-dependent dilation, after recording baseline B-mode ultrasound images of the brachial artery and spectral Doppler images of flow velocity, a forearm cuff is inflated to 250 mmHg for 5 minutes to induce reactive hyperemia. Immediately after deflation, Doppler images are obtained to measure reactive hyperemia. FMD of brachial artery will be determined every 15 seconds between 30 and 120 seconds after cuff deflation to capture maximal dilation.The % FMD will be calculated as ratio between the maximum post cuff release brachial artery diameter and baseline diameter. By comparing changes in FMD before exposure, after exposure and next day, we will be able to assess effects of exposure on endothelial function and the potential recovery from these effects.	Baseline (before exposure) 30 minutes (after 30 minutes exposure) and 3 hours.
Secondary	Changes in trans-epidermal water loss caused by pollution exposures, comparing intact skin to tape-stripped skin	We will measure trans-epidermal water loss (TEWL) on the volar forearm using a dermal relative humidity monitor (model IP52, Delfin Technologies Inc.) on adjacent circles of intact skin and skin that has been tape stripped prior to exposure. By comparing changes in TEWL at these two sites, before and after exposure and at day 2 and day 5, we will be able to detect any effects of dermal cigarette smoke exposure on skin barrier function and the rate of barrier function recovery.	Baseline, 30 minutes, 3 hours, 2 days, 5 days