Human Perception of Odors and Odor Blockers

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.

Study Overview

• Status: Recruiting
• Conditions: Tobacco Smoking; Smoking Behaviors
• Intervention / Treatment: Other: Odorants

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 Type: Interventional
• Enrollment (Estimated): 40
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Timothy McClintock, PhD; Phone Number: 8593231083; Email: mcclint@uky.edu

Study Locations

• United States
  • Kentucky
    • Lexington, Kentucky, United States, 40536
      • Recruiting
      • University of Kentucky
      • Contact: Timothy S McClintock; Phone Number: 859-940-3364; Email: mcclint@uky.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Smoker

Exclusion Criteria:

• Non Smoker
• Self reported inability to smell or taste

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Participants that Smoke; 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.	Other: Odorants; Each smoker is assigned a CPAP nose mask. Odor sample bags are attached to the mask. Smokers open the valve, inhale once through the nose, close the valve, remove the bag from the mask and report on the odor.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cigarette Purchase Task	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.	3 hours (total for all outcome measures)
Desire to Smoke	A rating of participant's desire to smoke on a scale of 0 - 100, where a higher score indicates increased desire.	3 hours (total for all outcome measures)

Secondary Outcome Measures

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

Collaborators and Investigators

• Sponsor: Tim McClintock
• Collaborators: National Institute on Deafness and Other Communication Disorders (NIDCD)
• Investigators: Principal Investigator: Timothy McClintock, PhD, University of Kentucky

Study record dates

Study Major Dates

• Study Start (Actual): April 5, 2024
• Primary Completion (Estimated): December 1, 2024
• Study Completion (Estimated): March 1, 2025

Study Registration Dates

• First Submitted: December 20, 2023
• First Submitted That Met QC Criteria: December 20, 2023
• First Posted (Actual): January 5, 2024

Study Record Updates

• Last Update Posted (Actual): April 8, 2024
• Last Update Submitted That Met QC Criteria: April 5, 2024
• Last Verified: April 1, 2024

More Information

Terms related to this study

• Keywords: Motivation; Nicotine addiction; Odors; Sensory perception
• Other Study ID Numbers: 43123; 1K18DC020155 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No