City air and nighttime asthma: a new clue?
NCT ID NCT03406351
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study looks at how air pollution and the body's internal clock (circadian rhythm) interact to worsen asthma, especially at night. Researchers will measure tiny molecules called microRNAs in the sputum of 20 adults with and without asthma over 48 hours. The goal is to understand why asthma symptoms often spike at night and how pollution plays a role.
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Study facts
What this study's own registry entry says, in plain language.
- Participants
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About 20 people
The number the study aims to enrol. It can still change while the study runs.
- Started
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Jan 2018
- Expected to finish
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Jan 2028
An estimate. End dates often move.
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
Who is studied
Cohort 1: asthmatic patients (case); Cohort 2: matched healthy volunteers (control).
- Ages
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18 to 70 years
- Sex
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Anyone
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: 1. \>18 years of age, 2. Physician's diagnosis of asthma, 3. Prescribed an inhaled-steroid-containing medication for asthma (ensuring the patient is believed to have at least moderate reversible airways obstruction by their physician), 4. severe persistent asthma according to the NHLBI Guidelines, 5. evidence of reversible airflow obstruction: (a) forced expiratory volume in 1 second (FEV1) \<80% predicted at the time of or within 3 years of screening, and (b) improvement with bronchodilator: either (i) an increase of ≥15% and 200mL in FEV1 with asthma treatment over the previous 3 years or (ii) after 4 puffs of albuterol by MDI (or 2.5 mg by nebulizer), an increase in FEV1 or FVC ≥12% and 200 mL in FEV1 within 30 min at screening, 6. Own a smartphone. Exclusion Criteria: 1. Severe psychiatric or cognitive problems (obvious mania, schizophrenia, significant mental retardation) making study conduct impossible. Formal psychiatric evaluations are outside of the scope; however, research coordinators will be trained to identify such cases followed by review of the PI. Patients can be referred to mental health facilities. 2. Past diagnosis of gastroesophageal reflux disease or obstructive sleep apnea, 3. Transmeridian travel across ≥2 time zones in the past month, 4. Planned transmeridian travel across more than ≥2 time zones during the planned study activities; 5. Use of oral or intravenous antibiotics in the past 6 months, 6. Episodes of bronchospasm in response to ultrasonic nebulizer treatment (to induce sputum collection non-invasively), 7. Any contraindication listed below in the separate paragraph "Contraindications for the use of CorTemp® Disposable Temperature Sensors"; 8. Subjects, who have received an experimental drug, used an experimental medical device within 30 days prior to screening, or who gave a blood donation of ≥ one pint within 8 weeks prior to screening; 9. \> 2 drinks of alcohol per day; 10. Use of illicit drugs; 11. Smoking; 12. Pregnant or nursing; 13. Avoid over-the-counter NSAID use 2 weeks prior to 48 hour session \& during 48 hour session (Visit 3, Visit 4 \& Visit 5); 14. Avoid Alcohol use 2 weeks prior to the 48 hour session and during the 3 day session (Visit 3, Visit 4 \& Visit 5); 15. Vitamins use 1 week prior to and during the 48 hour session. 16. BMI \> 30.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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University of Pennsylvania School of Medicine
Philadelphia, Pennsylvania, 19104, United States
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Other studies related to the condition(s) this trial covers.
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