Impact of Flavors on Nicotine Perception and Self-Administration Via E-cigarettes

August 1, 2024 updated by: Yale University
The goal of this application is to test whether menthol and fruit flavors impact e-cigarette use through dissociable mechanisms and exert their effects differentially across nicotine doses.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

This study examines the impact of menthol and fruit flavors on self-administration of e-cigarette solutions containing varying amounts of nicotine. This is a randomized, double-blind study with a within-subject cross-over design, using e-liquids with 5 different flavors and 4 different levels of nicotine for a total of 20 different e-liquid formulations. Each subject will participate in 4 test sessions. The order of flavor and nicotine delivery will be randomized. At each test session, they will undergo directed self-administration, in a randomized order, then an ad libitum self-administration session where they can choose among all of the e-cigarettes used during the directed session. The primary aims assess the impacts of nicotine and flavor (and their interactions) on participants' subjective ratings of the e-liquids during the 'directed' self-administration component, and self-administered puffs during the ad libitum self-administration component. In addition, the study will explore the impact of sex/gender and sensitivity to nicotine aversiveness or bitterness (as operationalized by genetic variations in the alpha-5 subunit of nicotinic acetylcholine receptor that influences the aversive effects of nicotine, or a taste receptor number 38 ( TAS2R38) important for bitterness perception) on study outcomes.

Study Type

Interventional

Enrollment (Actual)

54

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Connecticut
      • New Haven, Connecticut, United States, 06511
        • Yale University School of Medicine

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

14 years to 26 years (Adult)

Accepts Healthy Volunteers

Yes

Description

INCLUSION CRITERIA

  • Aged 18 to 30;
  • Past month daily nicotine-containing e-cigarette, cigarette, and/or cigar/little cigar/cigarillo use;
  • Urine cotinine levels consistent with regular nicotine use (e.g., NicAlert urine cotinine dipstick ≥3 or Accutest Positive for Cotinine);
  • For females, using acceptable birth control methods;
  • Able to provide written informed consent;
  • Able to read and write in English;
  • Stated willingness to comply with all study procedures (including self-administration of all e-liquid conditions; attend in-person sessions; comply with COVID guidelines of the research facilities) and lifestyle considerations (including overnight nicotine abstinence) and availability for the duration of the study;
  • Cardiovascular measures in normal/ non-hypertensive range for adults, including resting heart rate (HR) of 60-100 bpm; blood pressure (BP) of equal to or less than 129 mmHg (systolic)/80 mmHg (diastolic)); and oximeter (i.e., blood oxygenation) readings of 95-100 SpO2;
  • Resident of the State of Connecticut.

Exclusion Criteria:

  • Any allergy or known hypersensitivity to propylene glycol, vegetable glycerin, menthol, mint, green apple or watermelon flavorants or history of allergic or hypersensitive reaction to use of an e-cigarette/vaping device;
  • Has not used e-cigarettes at least 10 times in the last 6 months;
  • For females, pregnant (as determined by pregnancy screening) or breast feeding;
  • Seeking (or undergoing) treatment for nicotine dependence or tobacco product use (smoking or vaping) or has current plans to quit tobacco product use;
  • Meet current criteria for psychiatric disorder (according to the MINI);
  • Current or history of respiratory illnesses including pneumonia with COVID-19 , other medical illness, and/or psychotropic medication use that a clinician investigator deems a contraindication for study participation.
  • History of environmental - bronchospastic allergies, multiple chemical sensitivities, or other airway sensitivities that require the use of an epi pen or that in the investigators view would make it risky for participation;
  • Not fully vaccinated for COVID-19

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: E-liquid Order 'A'
Order 'A' for E-liquid Self-Administration: All participants will be given all e-liquids (i.e., all 20 nicotine*flavor combinations (4 nicotine* 5 flavor combinations)) in this within-subject, cross-over design study. Participants will be randomized the order in which they self-administer the 20 nicotine*flavor combinations of e-liquid (across and within the 4 visits). The specific order cannot be described here without disrupting the double-blind nature of the study design.
Drug: Nicotine 0 mg/mL
E-liquid containing no nicotine (0 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
Other Names:
  • nicotine
Drug: Nicotine 6 mg/mL
E-liquid containing low nicotine (6 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
Other Names:
  • nicotine
Drug: Nicotine 12 mg/mL
E-liquid containing medium nicotine ( 12 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
Other Names:
  • nicotine
Drug: Nicotine 24 mg/mL
E-liquid containing high nicotine ( 24 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
Other Names:
  • nicotine
Other: 'Menthol' flavor
E-liquid containing 'menthol' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • menthol
Other: 'Menthol/Mint' flavor
E-liquid containing 'menthol/mint' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • menthol
Other: 'Green Apple' flavor
E-liquid containing 'green apple' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • fruit
Other: 'Watermelon' flavor
E-liquid containing 'watermelon' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • fruit
Other: 'Unflavored'
E-liquid containing no additional flavor (i.e., 'unflavored') will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • unflavored
Experimental: E-liquid Order 'B'
Order 'B' for E-liquid Self-Administration: All participants will be given all e-liquids (i.e., all 20 nicotine*flavor combinations (4 nicotine* 5 flavor combinations)) in this within-subject, cross-over design study. Participants will be randomized the order in which they self-administer the 20 nicotine*flavor combinations of e-liquid (across and within the 4 visits). The specific order cannot be described here without disrupting the double-blind nature of the study design.
Drug: Nicotine 0 mg/mL
E-liquid containing no nicotine (0 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
Other Names:
  • nicotine
Drug: Nicotine 6 mg/mL
E-liquid containing low nicotine (6 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
Other Names:
  • nicotine
Drug: Nicotine 12 mg/mL
E-liquid containing medium nicotine ( 12 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
Other Names:
  • nicotine
Drug: Nicotine 24 mg/mL
E-liquid containing high nicotine ( 24 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
Other Names:
  • nicotine
Other: 'Menthol' flavor
E-liquid containing 'menthol' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • menthol
Other: 'Menthol/Mint' flavor
E-liquid containing 'menthol/mint' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • menthol
Other: 'Green Apple' flavor
E-liquid containing 'green apple' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • fruit
Other: 'Watermelon' flavor
E-liquid containing 'watermelon' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • fruit
Other: 'Unflavored'
E-liquid containing no additional flavor (i.e., 'unflavored') will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • unflavored
Experimental: E-liquid Order 'C'
One nicotine level condition is a medium nicotine e-liquid (12 mg/mL nicotine). All participants will be given all e-liquids (i.e., all 20 nicotine*flavor combinations (4 nicotine* 5 flavor combinations)) in this within-subject, cross-over design study. Participants will be randomized the order in which they self-administer the 20 nicotine*flavor combinations of e-liquid (across and within the 4 visits). The specific order cannot be described here without disrupting the double-blind nature of the study design.
Drug: Nicotine 0 mg/mL
E-liquid containing no nicotine (0 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
Other Names:
  • nicotine
Drug: Nicotine 6 mg/mL
E-liquid containing low nicotine (6 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
Other Names:
  • nicotine
Drug: Nicotine 12 mg/mL
E-liquid containing medium nicotine ( 12 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
Other Names:
  • nicotine
Drug: Nicotine 24 mg/mL
E-liquid containing high nicotine ( 24 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
Other Names:
  • nicotine
Other: 'Menthol' flavor
E-liquid containing 'menthol' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • menthol
Other: 'Menthol/Mint' flavor
E-liquid containing 'menthol/mint' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • menthol
Other: 'Green Apple' flavor
E-liquid containing 'green apple' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • fruit
Other: 'Watermelon' flavor
E-liquid containing 'watermelon' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • fruit
Other: 'Unflavored'
E-liquid containing no additional flavor (i.e., 'unflavored') will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • unflavored
Experimental: E-liquid Order 'D'
One nicotine level condition is a high nicotine e-liquid (24 mg/mL nicotine). All participants will be given all e-liquids (i.e., all 20 nicotine*flavor combinations (4 nicotine* 5 flavor combinations)) in this within-subject, cross-over design study. Participants will be randomized the order in which they self-administer the 20 nicotine*flavor combinations of e-liquid (across and within the 4 visits). The specific order cannot be described here without disrupting the double-blind nature of the study design.
Drug: Nicotine 0 mg/mL
E-liquid containing no nicotine (0 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
Other Names:
  • nicotine
Drug: Nicotine 6 mg/mL
E-liquid containing low nicotine (6 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
Other Names:
  • nicotine
Drug: Nicotine 12 mg/mL
E-liquid containing medium nicotine ( 12 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
Other Names:
  • nicotine
Drug: Nicotine 24 mg/mL
E-liquid containing high nicotine ( 24 mg/mL nicotine) will be self-administered via e-cigarettes. This will be administered in 5 flavor conditions (1 unflavored, 2 menthol, and 2 fruit conditions).
Other Names:
  • nicotine
Other: 'Menthol' flavor
E-liquid containing 'menthol' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • menthol
Other: 'Menthol/Mint' flavor
E-liquid containing 'menthol/mint' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • menthol
Other: 'Green Apple' flavor
E-liquid containing 'green apple' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • fruit
Other: 'Watermelon' flavor
E-liquid containing 'watermelon' flavor will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • fruit
Other: 'Unflavored'
E-liquid containing no additional flavor (i.e., 'unflavored') will be self-administered via e-cigarettes. This will be administered in 4 nicotine conditions (0, 6, 12, 24 mg/mL nicotine).
Other Names:
  • unflavored

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Subjective drug ratings
Time Frame: immediately after intervention
Subjective ratings of e-liquids delivered via e-cigarette will be assessed during the 'directed' self-administration component of each test day, using visual analogue scales (VAS). VAS scores range from 0=not at all to 100=extremely. Separate VAS scales will be collected for subjective ratings of aversive properties (higher scores reflect more aversiveness) and rewarding properties (higher scores reflect more rewarding properties) of the e-cigarettes, in each nicotine*flavor condition. Subjective drug ratings for each nicotine*flavor condition will be tested at one test day only and the order of nicotine*flavor conditions will be randomized across the test days (and order within test days will be randomized).
immediately after intervention
E-cigarette use
Time Frame: immediately after intervention
Number of puffs from each e-cigarette (containing different e-liquids) will be measured during the ad libitum self-administration component of each test day. E-cigarette use (ad libitum puffs) for each nicotine*flavor condition will be tested at one test day only and the order of nicotine*flavor conditions will be randomized across the test days (and order within test days will be randomized).
immediately after intervention

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Yale University

Collaborators

National Institute on Drug Abuse (NIDA)

Investigators

  • Principal Investigator: Elise DeVito, PhD, Yale University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 27, 2022

Primary Completion (Actual)

June 3, 2024

Study Completion (Actual)

June 3, 2024

Study Registration Dates

First Submitted

July 24, 2019

First Submitted That Met QC Criteria

July 29, 2019

First Posted (Actual)

July 30, 2019

Study Record Updates

Last Update Posted (Actual)

August 5, 2024

Last Update Submitted That Met QC Criteria

August 1, 2024

Last Verified

August 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2000029704
  • R01DA046360 (U.S. NIH Grant/Contract)
  • 2000025408 (Other Identifier: Original IRB #)

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

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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