NCT07237958

Brief Summary

The goal of this study is to study the effect exposure to air pollution and its effect on development of dementia. Does the diesel exhaust change the function of the olfactory system? Have the exposures measurable effects on the sense of smell and cognitive ability? Forty people are exposed to diesel exhaust exhaust and filtered air. The exposures are blinded and in a randomized order. Both groups undergo biopsies of the olfactory epithelium in the nose under local anesthesia after the exposures and after performing cognitive test.

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
40

participants targeted

Target at P25-P50 for not_applicable

Timeline
Completed

Started Feb 2019

Longer than P75 for not_applicable

Geographic Reach
1 country

1 active site

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

Study Start

First participant enrolled

February 1, 2019

Completed
4.3 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

May 12, 2023

Completed
7 days until next milestone

Study Completion

Last participant's last visit for all outcomes

May 19, 2023

Completed
2.1 years until next milestone

First Submitted

Initial submission to the registry

July 4, 2025

Completed
5 months until next milestone

First Posted

Study publicly available on registry

November 20, 2025

Completed
Last Updated

November 20, 2025

Status Verified

November 1, 2025

Enrollment Period

4.3 years

First QC Date

July 4, 2025

Last Update Submit

November 14, 2025

Conditions

Alzheimer Disease (AD)Dementia Alzheimer TypeAir Pollution Exposure

Keywords

cognitive functionAlzheimer DiseaseDiesel ExhaustOlfactory nerve

Outcome Measures

Primary Outcomes (1)

  • Diesel exhaust causes cellular dysfunction of the olfactory system

    RNA sequencing and DNA methylation will be conducted to identify biomarkers for acute exposure to diesel exhaust.

    3 years.

Secondary Outcomes (1)

  • Cognitive test

    3 years

Study Arms (2)

Exposure to diesel exhaust

ACTIVE COMPARATOR

The participants will be exposed in an exposure chamber for diesel exhaust in a concentration of 300 µg/m³ for one hour.

Other: Diesel Exhaust Particles

Exposure to filtered air

PLACEBO COMPARATOR

The participants will be exposed in an exposure chamber to filtered air for one hour.

Other: Filtered air

Interventions

Diesel Exhaust ParticlesOTHER

During exposure to diesel exhaust, participants alternate between 15-minute periods of rest and exercise on an ergometer cycle with a workload that results in a minute ventilation of 20L/min/m² body surface area. Symptom recording is done every 30 minutes, following a routine based on a modified Borg scale.

Exposure to diesel exhaust
Filtered airOTHER

During exposure to filtered air, participants alternate between 15-minute periods of rest and exercise on an ergometer cycle with a workload that results in a minute ventilation of 20L/min/m² body surface area. Symptom recording is done every 30 minutes, following a routine based on a modified Borg scale

Exposure to filtered air

Eligibility Criteria

Age20 Years - 70 Years
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • Healthy
  • non-smoker

You may not qualify if:

  • Allergic rhinitis
  • Asthma
  • Diabetes mellitus
  • Kidney or liver failure
  • Angina pectoris or previous ventricular arrhythmia
  • Systolic blood pressure \>190 mmHg or \<100 mmHg
  • Previous blood disease
  • Blood donation in the last three months prior to study start
  • Previous or ongoing tobacco smoking and exposure to air pollution in the workplace
  • Absence of informed consent

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Umeå Univeristy

Umeå, 90185, Sweden

Location

Related Publications (1)

  • Martikainen MV, Aakko-Saksa P, van den Broek L, Cassee FR, Carare RO, Chew S, Dinnyes A, Giugno R, Kanninen KM, Malm T, Muala A, Nedergaard M, Oudin A, Oyola P, Pfeiffer TV, Ronkko T, Saarikoski S, Sandstrom T, Schins RPF, Topinka J, Yang M, Zeng X, Westerink RHS, Jalava PI. TUBE Project: Transport-Derived Ultrafines and the Brain Effects. Int J Environ Res Public Health. 2021 Dec 28;19(1):311. doi: 10.3390/ijerph19010311.

    PMID: 35010571BACKGROUND

Related Links

MeSH Terms

Conditions

Alzheimer Disease

Condition Hierarchy (Ancestors)

DementiaBrain DiseasesCentral Nervous System DiseasesNervous System DiseasesTauopathiesNeurodegenerative DiseasesNeurocognitive DisordersMental Disorders

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
QUADRUPLE
Who Masked
PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
Purpose
DIAGNOSTIC
Intervention Model
CROSSOVER
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
MD, PhD

Study Record Dates

First Submitted

July 4, 2025

First Posted

November 20, 2025

Study Start

February 1, 2019

Primary Completion

May 12, 2023

Study Completion

May 19, 2023

Last Updated

November 20, 2025

Record last verified: 2025-11

Data Sharing

IPD Sharing
Will not share

Locations

SE(1)