Olfactory Dysfunction in Aging Adults

June 16, 2026 updated by: Medical University of South Carolina
This prospective longitudinal cohort study will enroll adults aged 50 years and older to characterize olfactory dysfunction in aging. Participants will undergo comprehensive olfactory testing, cognitive assessment, biomarker collection, and imaging to identify clinically relevant phenotypes based on anatomic site of dysfunction. The study will also evaluate the impact of olfactory dysfunction on quality of life and identify baseline factors associated with changes in olfactory function over time.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Olfactory dysfunction is common in older adults and is associated with impaired quality of life and increased mortality, yet underlying mechanisms and clinically relevant classifications remain poorly defined. Prior studies have relied on limited screening methods and have not adequately characterized the anatomic sites or mechanisms contributing to olfactory loss.

This prospective longitudinal cohort study will enroll adults aged 50 years and older to comprehensively evaluate olfactory function and its determinants. Participants will undergo psychophysical olfactory testing using Sniffin' Sticks (threshold, discrimination, and identification), cognitive assessment, nasal endoscopy, and olfactory mucus collection for biomarker analysis. A subset of participants will also undergo magnetic resonance imaging to assess peripheral and central olfactory structures.

The primary objective is to establish clinically relevant phenotypes of olfactory dysfunction based on olfactory testing and cognitive function, corresponding to peripheral, sensorineural, or central mechanisms. Secondary objectives are to determine the impact of olfactory dysfunction on quality of life, depression, social isolation, and nutrition using validated patient-reported outcome measures, and to identify baseline factors that predict longitudinal changes in olfactory function.

Participants will be followed annually with repeat olfactory testing and outcome assessments to evaluate changes over time and identify predictors of olfactory decline. This study aims to improve understanding of olfactory dysfunction in aging and provide a foundation for future diagnostic and therapeutic strategies.

Study Type

Observational

Enrollment (Estimated)

500

Contacts and Locations

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

Study Contact

Study Locations

  • United States
    • South Carolina
      • Charleston, South Carolina, United States, 29425
        • MUSC
        • Contact:

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Community-dwelling adults aged 50 years and older recruited from the Medical University of South Carolina (MUSC) and surrounding community, including clinic patients and individuals responding to advertisements, who may have normal olfactory function or varying degrees of olfactory dysfunction.

Description

Inclusion Criteria:

  • Age: 50 years or older
  • Ability to follow instructions and understand consent process in English
  • Adequate visual, auditory, or motor functioning to complete items in the test battery or availability of assistance or assist devices to complete tasks

Exclusion Criteria:

- Vulnerable populations including prisoners or institutionalized individuals

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

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Older Adults With and Without Olfactory Dysfunction
Adults aged 50 years and older enrolled in a prospective cohort study assessing olfactory function, cognition, biomarkers, and quality of life, with annual follow-up. Participants will be classified post hoc into olfactory phenotypes based on testing results.
Other: Clinical and Biomarker Assessments
Participants undergo olfactory testing (Sniffin' Sticks), cognitive assessment, nasal endoscopy, olfactory mucus collection, MRI imaging (subset), and patient-reported outcome measures to evaluate olfactory function, biomarkers, and health outcomes over time.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Olfactory Function
Time Frame: Baseline
Olfactory Threshold, Discrimination, and Identification (TDI scores) using Sniffin' Sticks.
Baseline

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Olfactory Function Over Time
Time Frame: Year 1 and year 2
Longitudinal assessment of changes in olfactory function to identify decline over time.. Change in TDI scores (threshold, discrimination, identification)
Year 1 and year 2
Patient-Reported Outcomes
Time Frame: Baseline, Year 1 and year 2
Patient-reported measure assessing quality of life using QOD questionnaire.
Baseline, Year 1 and year 2

Collaborators and Investigators

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

Sponsor

Medical University of South Carolina

Collaborators

National Institute on Deafness and Other Communication Disorders (NIDCD)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 (Estimated)

April 1, 2027

Primary Completion (Estimated)

April 30, 2032

Study Completion (Estimated)

April 30, 2032

Study Registration Dates

First Submitted

May 27, 2026

First Submitted That Met QC Criteria

June 16, 2026

First Posted (Actual)

June 22, 2026

Study Record Updates

Last Update Posted (Actual)

June 22, 2026

Last Update Submitted That Met QC Criteria

June 16, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • Pro00150356
  • 5R01DC019078-05 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Protection of individual privacy

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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