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Air Pollution, Asthma and Circadian Clocks

NCT03406351 · Status: ACTIVE_NOT_RECRUITING · Type: OBSERVATIONAL · Enrollment: 20

Last updated 2026-01-23

No results posted yet for this study

Summary

Societies become increasingly urban - more than half the world's population now lives in cities. Urbanization elevates anthropogenic (man-made) exposure to air pollutants. A clear association exists between exposure to air pollutants and exacerbations (worsening) of pre-existing asthma, incidence of nighttime asthma, difficulties with asthma control and increased disease risk. In 2012, the Public Health Management Corporation's Community Health Data Base estimated that 19.4% of adults in Philadelphia had asthma compared to a national prevalence of 7%.

Asthma has a clear temporal signal. A majority of asthma patients, up to 75%, reports nighttime awakenings due to worsened cough, wheeze and dyspnea. This time-of-day-dependent exacerbation of symptoms, coined nocturnal asthma, is associated with poorer disease control, more frequent medication, and higher asthma-related morbidity and mortality. Consequently, several pathophysiological mechanisms proposed for nocturnal asthma relate to circadian clock biology.

Lung function oscillates over the course of 24 hours, peaking around noon and reaching its nadir during early morning hours. Concentrations of air pollutants show oscillating patterns in urban settings.

In this clinical research study, the investigators start to address how spatiotemporal fluctuations in air pollutants relate to asthma. Mechanistically, the investigators wish to address the hypothesis that microRNAs (miRs) act as interface between asthma phenotypes, circadian clocks and environmental exposure.

Conditions

Interventions

OTHER

Observational

Observational deep phenotyping physiological readouts

Sponsors & Collaborators

Principal Investigators

  • Garret FitzGerald, MD · University of Pennsylvania

Eligibility

Min Age
18 Years
Max Age
70 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2018-01-15
Primary Completion
2027-01-31
Completion
2028-01-31

Countries

  • United States

Study Locations

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Entities

Diseases
Companies

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT03406351 on ClinicalTrials.gov