Human Perception of Odors and Odor Blockers

Not Applicable

Recruiting

• Conditions: Tobacco Smoking; Smoking Behaviors
• Interventions: Other: Odorants

• Registration Number: NCT06191419
• Lead Sponsor: Tim McClintock

Brief Summary

The goal of this clinical trial is to determine whether blockers of perception of key odorants in cigarette smoke have any utility in smoking cessation. The main question it aims to answer is:

• Can odor blockers be used to suppress perception of the intensity of cigarette smoke in ways that reduce the ability of the odor of cigarette smoke to increase the urge to smoke.

Participants will be asked to smell up to 20 odor samples per session and report on odor pleasantness and desire to smoke.

Detailed Description

The experimental treatments include controls (clean air, irrelevant odor), blocking odors, cigarette smoke odor, and cigarette smoke odor mixed with blocking odors or irrelevant odor. To obtain cigarette smoke odor a 1 inch length of a 1R6F research cigarette is burned to completion in a sealed 5 gallon chamber fitted with septa. Using a syringe fit with a needle and filter, 60 mL aliquots of smoke odor are obtained. These smoke odor aliquots, along with blocking odors, are injected into odor sample bags fit with a septum and a valve that can be attached to the CPAP nose mask worn by each participating smoker. Participants open the valve, inhale once through the nose, close the valve, and then remove the bag from the mask before reporting odor pleasantness and the desire to smoke. A 2 - 3 min wait period is enforced between each odor presentation to prevent odor adaptation and to allow acute motivational effects to subside.

In a testing session a participant sniffs 4 concentrations of a mixture of 2 blocking odors, along with control odor samples. Presentation order is randomized. Each participant is assigned their own CPAP nose mask, and masks are disinfected after use. Participants also provide demographic (age, sex, ethnic and racial background) and smoking history information (cigarettes per day, preferred brand, age at onset, and time since last cigarette).

Study Timeline

• Study First Submitted: 2023-12-20
• Study First Submitted QC: 2023-12-20
• Study First Posted: 2024-01-05
• Study Start: 2024-04-05
• Status Verified: 2024-12
• Last Update Submitted: 2024-12-03
• Last Update Posted: 2024-12-06
• Primary Completion: 2025-12
• Study Completion: 2025-12

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 40

Inclusion Criteria

• Smoker

Exclusion Criteria

• Non Smoker
• Self reported inability to smell or taste

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Participants that Smoke	Odorants	Each smoker is asked to smell up to 20 samples per session. Samples include controls (clean air, irrelevant odor), blocking odors, cigarette smoke, and cigarette smoke mixed with blocking odors or irrelevant odors.

Primary Outcome Measures

Name	Time	Method
Desire to Smoke	3 hours (total for all outcome measures)	A rating of participant's desire to smoke on a scale of 0 - 100, where a higher score indicates increased desire.
Cigarette Purchase Task	3 hours (total for all outcome measures)	The Cigarette Purchase Task (Strickland et al., 2016) requires selecting how much the smoker is willing to spend for a single cigarette (their preferred brand) from a list of 19 amounts ranging from $0.00 (free) to $1,120.

Secondary Outcome Measures

Name	Time	Method
Odor pleasantness score	3 hours (total for all outcome measures)	Participants complete a forced choice test by scoring whether the odor is pleasant or unpleasant

Trial Locations

Locations (1)

University of Kentucky; 🇺🇸 Lexington, Kentucky, United States