Asthma (Diagnosis)NCT07261774
The Impact of Extreme Heat Waves and Air Pollution on the Prognosis of Chronic Airway Diseases
An observational study of Asthma (Diagnosis) and COPD (Chronic Obstructive Pulmonary Disease), run by Mersin University at 1 site in Turkey (Türkiye).
Trial summary
Extreme heat waves (EHW) and air pollution exacerbate chronic airway diseases, but little is known about how these environmental stressors affect quality of life, airway inflammation, symptom control, and pulmonary function. This study was designed to determine the impact of EHW and air pollution on asthma and COPD. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Asthma (Diagnosis), COPD (Chronic Obstructive Pulmonary Disease)
- How many people
- 96 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 6 Mar 2024to 1 Dec 2024
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: The study population will consist of adult patients (≥18 years) diagnosed with asthma according to the GINA 2024 guidelines or COPD according to the GOLD 2024 guidelines, who are in a stable phase for at least four weeks. Participants must provide written informed consent and reside within the central district of Mersin. Patients with other chronic lung diseases, history of lung surgery, recent respiratory infections, active tuberculosis, significant comorbidities affecting lung function, pregnancy, active smoking within the past year, cancer history within the past five years, or those living outside Mersin city center will be excluded.
Who may be able to join
- Age ≥ 18 years
- Provision of written informed consent
- For the asthma group:
- Diagnosis of asthma for at least 6 months according to the GINA 2024 guidelines
- Variable respiratory symptoms together with documented variable expiratory airflow limitation, demonstrated by at least one of the following:
- Positive bronchodilator reversibility test (>12% and >200 mL increase in FEV1 10-15 minutes after 400 μg salbutamol)
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- Peak expiratory flow (PEF) variability (>10% average daily PEF variability over 2 weeks)
- Positive delayed reversibility (improvement in lung function after 4 weeks of anti-inflammatory treatment with >12% and >200 mL increase in FEV1 or >20% increase in PEF)
- Positive bronchial provocation test (≥20% fall in FEV1 with standard doses of methacholine or histamine)
- Stable disease for at least 4 weeks prior to enrollment
- For the COPD group:
- Diagnosis of COPD for at least 6 months according to the GOLD 2024 guidelines (post-bronchodilator FEV1/FVC <70% in the presence of compatible clinical findings)
- Stable disease for at least 4 weeks prior to enrollment
Who cannot join
- Presence of other pulmonary diseases apart from asthma or COPD (e.g., interstitial lung diseases, pleural diseases, pulmonary vascular diseases)
- Pregnant women
- History of cancer within the past 5 years
- Previous lung surgery
- Active pulmonary tuberculosis
- Respiratory tract infection within the last 4 weeks
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- Presence of significant extrapulmonary disease that may affect lung function (e.g., cerebrovascular disease, acute myocardial infarction)
- Active smoking within the past year
- Residence outside the central district of Mersin
Trial locations and contacts
1 site in 1 country.
Turkey (Türkiye)1 site
Mersin University Faculty of Medicin
Mersin, Mersin
About this study
Extreme heat waves (EHW) and air pollution exacerbate chronic airway diseases, but little is known about how these environmental stressors affect quality of life, airway inflammation, symptom control, and pulmonary function. This study was designed to determine the impact of EHW and air pollution on asthma and COPD.
This was a prospective cohort study conducted among individuals with asthma and COPD in Mersin, Türkiye, between February 14 and December 1, 2024. Meteorological and air quality index (AQI) data were obtained from official sources. Participants underwent pulmonary function tests (PFTs) and fractional exhaled nitric oxide (FeNO) measurements during periods of normal weather conditions and repeated assessments during documented EHW periods. Patient-reported outcomes included the Asthma Control Test (ACT) and Asthma Quality of Life Questionnaire (AQLQ) for asthma, and the Modified Medical Research Council (mMRC) scale and COPD Assessment Test (CAT) for COPD. Exacerbation episodes requiring systemic corticosteroid use or hospitalization were also recorded.
The study aimed to evaluate the effects of EHW and air pollution on disease control, quality of life, lung function, airway inflammation, and exacerbation burden in patients with asthma and COPD.
Read the detailed description
Climate change has led to a global increase in temperatures, and according to NASA, 2024 was the hottest year on record since 1850. Extreme heatwaves (EHW) represent one of the most significant manifestations of this crisis. While the adverse effects of air pollution on chronic respiratory diseases are well documented, the impact of extreme heatwaves on asthma and chronic obstructive pulmonary disease (COPD) has received less attention.
This study was designed to prospectively evaluate the effects of extreme heatwaves and air pollution on patients with asthma and COPD. The study was conducted in Mersin, Türkiye, between February and December 2024. Individuals with physician-diagnosed asthma or COPD who attended the outpatient clinic were enrolled.
Baseline assessments were performed on days with normal seasonal weather. Lung function was measured using spirometry, and airway inflammation was assessed using fractional exhaled nitric oxide (FeNO). Symptom control and quality of life were measured using validated questionnaires: the Asthma Control Test (ACT) and Asthma Quality of Life Questionnaire (AQLQ) for patients with asthma, and the Modified Medical Research Council (mMRC) scale and COPD Assessment Test (CAT) for patients with COPD.
Meteorological variables, including temperature, humidity, and wind, as well as daily air pollution levels, were obtained from official sources. On documented extreme heatwave days, participants were recalled for follow-up visits. At these visits, spirometry, FeNO, and questionnaire assessments were repeated. Information regarding exacerbation episodes requiring systemic corticosteroid use or hospitalization during the study period was also collected.
The study was designed to compare patient-level outcomes between normal weather days and extreme heatwave days. The overall objective was to investigate how environmental stressors such as heat and air pollution influence disease control, quality of life, symptoms, lung function, and airway inflammation in patients with asthma and COPD.
- Keywords
- Asthma, COPD, Extreme Heatwave, Air Pollution, Climate Change
- Medical subject headings
- Asthma, Disease, Pulmonary Disease, Chronic Obstructive
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Asthma Group | Patients with physician-diagnosed asthma who met the inclusion criteria and were followed during periods of extreme heat waves and normal seasonal weather. | |
| COPD Group | Patients with physician-diagnosed chronic obstructive pulmonary disease (COPD) who met the inclusion criteria and were followed during periods of extreme heat waves and normal seasonal weather. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in FeNO levels during extreme heat waves vs seasonal normal conditions
Fractional exhaled nitric oxide (FeNO) (parts per billion (ppb)) measured using the Bedfont® NObreath device.
Measured: Participants were evaluated twice over a 292-day period, from February 14, 2024, to December 1, 2024 (once during seasonal normal conditions and once during extreme heat waves).
Secondary outcomes (1)
Exacerbation frequency in asthma and COPD patients during extreme heat waves vs seasonal normal conditions
Exacerbations (number of events per participant) defined as events requiring systemic corticosteroid use or hospitalization.
Measured: Participants were evaluated twice over a 292-day period, from February 14, 2024, to December 1, 2024 (once during seasonal normal conditions and once during extreme heat waves).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Dec 2025
- Study start6 Mar 2024
- Primary completion7 Nov 2024
- Study completion1 Dec 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Asthma (Diagnosis)Studies of the same condition, open and under way.
- More trials run by Mersin UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 96 participants (actual)
Sponsor and investigators
- Lead sponsor
- Mersin University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Sibel Naycı, Mersin University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07261774
- Sponsor's protocol ID
- MU-2024/097
- Status last verified
- Sep 2025
- First submitted
- 29 Aug 2025
- Last updated
- 3 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 3 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Impact of Extreme Heat Waves and Air Pollution on the Prognosis of Chronic Airway Diseases
- ClinicalTrials.gov ID
- NCT07261774
- Acronym / sponsor ID
- MU-2024/097
- Keywords
- Asthma, COPD, Extreme Heatwave, Air Pollution, Climate Change
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 96 participants (actual)
- Lead sponsor
- Mersin UniversityUniversity, hospital or other
- Study start
- 6 Mar 2024 (actual)
- Primary completion
- 7 Nov 2024 (actual)
- Study completion
- 1 Dec 2024 (actual)
- First posted
- 3 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Extreme heat waves (EHW) and air pollution exacerbate chronic airway diseases, but little is known about how these environmental stressors affect quality of life, airway inflammation, symptom control, and pulmonary function. This study was designed to determine the impact of EHW and air pollution on asthma and COPD.
This was a prospective cohort study conducted among individuals with asthma and COPD in Mersin, Türkiye, between February 14 and December 1, 2024. Meteorological and air quality index (AQI) data were obtained from official sources. Participants underwent pulmonary function tests (PFTs) and fractional exhaled nitric oxide (FeNO) measurements during periods of normal weather conditions and repeated assessments during documented EHW periods. Patient-reported outcomes included the Asthma Control Test (ACT) and Asthma Quality of Life Questionnaire (AQLQ) for asthma, and the Modified Medical Research Council (mMRC) scale and COPD Assessment Test (CAT) for COPD. Exacerbation episodes requiring systemic corticosteroid use or hospitalization were also recorded.
The study aimed to evaluate the effects of EHW and air pollution on disease control, quality of life, lung function, airway inflammation, and exacerbation burden in patients with asthma and COPD.
Detailed description
Climate change has led to a global increase in temperatures, and according to NASA, 2024 was the hottest year on record since 1850. Extreme heatwaves (EHW) represent one of the most significant manifestations of this crisis. While the adverse effects of air pollution on chronic respiratory diseases are well documented, the impact of extreme heatwaves on asthma and chronic obstructive pulmonary disease (COPD) has received less attention.
This study was designed to prospectively evaluate the effects of extreme heatwaves and air pollution on patients with asthma and COPD. The study was conducted in Mersin, Türkiye, between February and December 2024. Individuals with physician-diagnosed asthma or COPD who attended the outpatient clinic were enrolled.
Baseline assessments were performed on days with normal seasonal weather. Lung function was measured using spirometry, and airway inflammation was assessed using fractional exhaled nitric oxide (FeNO). Symptom control and quality of life were measured using validated questionnaires: the Asthma Control Test (ACT) and Asthma Quality of Life Questionnaire (AQLQ) for patients with asthma, and the Modified Medical Research Council (mMRC) scale and COPD Assessment Test (CAT) for patients with COPD.
Meteorological variables, including temperature, humidity, and wind, as well as daily air pollution levels, were obtained from official sources. On documented extreme heatwave days, participants were recalled for follow-up visits. At these visits, spirometry, FeNO, and questionnaire assessments were repeated. Information regarding exacerbation episodes requiring systemic corticosteroid use or hospitalization during the study period was also collected.
The study was designed to compare patient-level outcomes between normal weather days and extreme heatwave days. The overall objective was to investigate how environmental stressors such as heat and air pollution influence disease control, quality of life, symptoms, lung function, and airway inflammation in patients with asthma and COPD.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Asthma Group | – | –Patients with physician-diagnosed asthma who met the inclusion criteria and were followed during periods of extreme heat waves and normal seasonal weather. |
| COPD Group | – | –Patients with physician-diagnosed chronic obstructive pulmonary disease (COPD) who met the inclusion criteria and were followed during periods of extreme heat waves and normal seasonal weather. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- The study population will consist of adult patients (≥18 years) diagnosed with asthma according to the GINA 2024 guidelines or COPD according to the GOLD 2024 guidelines, who are in a stable phase for at least four weeks. Participants must provide written informed consent and reside within the central district of Mersin. Patients with other chronic lung diseases, history of lung surgery, recent respiratory infections, active tuberculosis, significant comorbidities affecting lung function, pregnancy, active smoking within the past year, cancer history within the past five years, or those living outside Mersin city center will be excluded.
Key inclusion criteria (13 listed)
- Age ≥ 18 years
- Provision of written informed consent
- Diagnosis of asthma for at least 6 months according to the GINA 2024 guidelines
- Variable respiratory symptoms together with documented variable expiratory airflow limitation, demonstrated by at least one of the following:
- Positive bronchodilator reversibility test (>12% and >200 mL increase in FEV1 10-15 minutes after 400 μg salbutamol)
Key exclusion criteria (9 listed)
- Presence of other pulmonary diseases apart from asthma or COPD (e.g., interstitial lung diseases, pleural diseases, pulmonary vascular diseases)
- Pregnant women
- History of cancer within the past 5 years
- Previous lung surgery
- Active pulmonary tuberculosis
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Change in FeNO levels during extreme heat waves vs seasonal normal conditions
Time frame: Participants were evaluated twice over a 292-day period, from February 14, 2024, to December 1, 2024 (once during seasonal normal conditions and once during extreme heat waves).
Fractional exhaled nitric oxide (FeNO) (parts per billion (ppb)) measured using the Bedfont® NObreath device.
1 secondary outcome
Exacerbation frequency in asthma and COPD patients during extreme heat waves vs seasonal normal conditions
Time frame: Participants were evaluated twice over a 292-day period, from February 14, 2024, to December 1, 2024 (once during seasonal normal conditions and once during extreme heat waves).
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Dec 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Asthma (Diagnosis) and COPD (Chronic Obstructive Pulmonary Disease), run by Mersin University at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 13 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 3 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in FeNO levels during extreme heat waves vs seasonal normal conditions (time frame: Participants were evaluated twice over a 292-day period, from February 14, 2024, to December 1, 2024 (once during seasonal normal conditions and once during extreme heat waves).). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Dec 2025.