The ESTxENDS Trial- Substudy on Effects of Using Electronic Nicotine Delivery Systems (ENDS) on Olfactory Function

Summary

--\> This is a substudy of the main ESTxENDS trial (NCT03589989). Olfactory function outcomes should be considered secondary outcomes of the main smoking cessation outcome formulated in NCT03589989.

Up to one in five people have suffered loss or impairment of their sense of smell, limiting their available information about the environment, including possible hazards (e.g. gas or smoke). An impaired sense of smell is strongly associated with smoking, but its prevalence in smokers has yet to be established. Since only a few prospective cohort studies among smokers have compared change in olfactory function in smokers, it is not known how much or how fast smoking may impair olfactory function. Some studies describe improvement in olfactory function among quitters, supporting anecdotal evidence from ex-smokers who say they regained their sense of smell over time. As far as the investigators know, no randomized controlled trial has tested the effects of a smoking cessation intervention on olfactory function.

A reliable and validated olfactory function test is the Burghart Sniffin' Sticks 16-item Identification-test, which is quick and easy to administer. 16 familiar odours will be presented to the participants, each for 3-4 seconds. After each odour the participant is asked to select the correct answer from 4 possible answers.

With increasing popularity of e-cigarettes, their effect on the olfactory function also needs to be assessed. It is known, that e-cigarettes produce toxic compounds such as carbonyl and aldehydes, what could impair the sense of smell - especially if the liquid-level is too low or the temperature on the coil is too hot. This is the source of a phenomenon called "dry-hit", which is said to leave a burnt taste or smell to be recognized by users. However, it is unclear if e-cigarettes users with an olfactory dysfunction can adequately recognize a "dry-hit". Therefore, the goal is to investigate the effects of smoking cessation and use of ENDS on olfactory function and the recognition of a "dry-hit" from a test e-cigarette.

For the main ESTxENDS trial (NCT03589989), cigarette smokers motivated to quit smoking cigarettes will be included. Participants in the intervention group will receive an ENDS and nicotine-containing e-liquids, which they will be allowed to use ad libitum. Additionally, they will receive smoking cessation counseling. Participants in the control group will receive smoking cessation counseling only. All participants will be followed over a 24-month period. The primary objective is to assess changes in olfactory function from baseline to 6 months post target quit date (TQD) in cigarette smokers randomized to the intervention group compared to the control group.

Conditions

• Smoking Cessation
• Olfactory Disorder

Interventions

OTHER

ENDS (vaporizer/e-cig) and smoking cessation counseling

Participants in the intervention group will receive an ENDS and nicotine-containing e-liquids, which they will be allowed to use ad libitum. Additionally, they will receive smoking cessation counseling. Participants will be allowed to additionally use nicotine replacement therapy. All participants will be followed over a 24-month period. Smoking cessation counseling will be provided in person at the first clinical visit and then over the phone at the target quit date one week later and again at week 2, 4 and 8 after the target quit date. After 6, 12 and 24 months, participants will be asked to come to a clinical visit.

OTHER

Smoking cessation counseling

Participants in the control group will receive smoking cessation counseling only. Participants will be allowed to additionally use nicotine replacement therapy. All participants will be followed over a 24-month period. Smoking cessation counseling will be provided in person at the first clinical visit and then over the phone at the target quit date one week later and again at week 2, 4 and 8 after the target quit date. After 6, 12 and 24 months, participants will be asked to come to a clinical visit.

Sponsors & Collaborators

• University of Lausanne

  collaborator OTHER

• University of Geneva, Switzerland

  collaborator OTHER

• University of Zurich

  collaborator OTHER

• State Hospital, St. Gallen

  collaborator OTHER_GOV

• Swiss National Science Foundation

  collaborator OTHER

• Krebsforschung Schweiz, Bern, Switzerland

  collaborator OTHER

• Federal Office of Public Health, Switzerland

  collaborator OTHER_GOV

• University of Bern

  lead OTHER

Principal Investigators

• Reto Auer, Prof.Dr.med · Berner Institut für Hausarztmedizin (BIHAM)

Study Design

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2020-09-07

Primary Completion

2023-08-31

Completion

2023-08-31

Countries

• Switzerland

Study Locations