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| ID | Type | Description | Link |
|---|---|---|---|
| R01ES026980 | U.S. NIH Grant/Contract | View source |
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| Name | Class |
|---|---|
| National Institute of Environmental Health Sciences (NIEHS) | NIH |
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This randomized trial assessed the effect of modifying building envelop and level of air filtration on blood pressure over two hour exposure sessions.
Living close to major roadways is associated with elevated blood pressure (BP) amongst other adverse health effects. There is growing evidence that ultrafine particles (UFP, <100 nm in diameter), which are elevated near major roads and highways, contribute to such risks. We assessed the efficacy of high efficiency particulate arrestance (HEPA) filtration and building envelope adjustment at reducing exposure to and health effects of air pollution next to major highways.
We used a randomized three-period crossover trial design to assign 77 participants (aged 40-75 and without diagnosis of hypertension) to three two-hour exposure sessions. Sessions were conducted in one of two rooms immediately adjacent to highways. High, medium and low exposures were attained by varying the degree of air exchange and amount of HEPA filtration in the room. During high exposure sessions, the room was ventilated with outdoor air and no filtration was used. During low exposure sessions, leakage of outdoor air into the room was minimized and HEPA filtration was maximized. During medium exposure sessions, a moderate amount of HEPA filtration was used (less than half of that used in low sessions). Indoor particle number and black carbon (BC) concentrations (i.e., markers of traffic-related air pollution) were monitored continuously.
During each session participants sat quietly and wore noise-cancelling headphones, while their BP was monitored every ten minutes using an ambulatory BP monitor. We monitored pulse and oxygen saturation continuously.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| High exposure | Experimental | Ambient air was allowed freely into the room. |
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| Medium exposure | Experimental | Limited air filtration was used to partially reduce levels of pollution in the room relative to outside. |
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| Low exposure | Experimental | Doors and windows were closed and sealed and full filtration was used to maximally reduce pollution in the room. |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Air filtration and building envelop modifications | Other | Air filters and closing and sealing of windows and doors was used to reduce infiltration of air pollution from outdoors in rooms next to major highways at rush hour. |
| Measure | Description | Time Frame |
|---|---|---|
| Systolic Blood Pressure (SBP) | Systolic blood pressure measured with ambulatory blood pressure monitors in mmHg. | Over 2 hour exposure period, we measured SBP after 20 minutes with the objective to assess change in SBP in a time series of measurements over that time period. |
| Measure | Description | Time Frame |
|---|---|---|
| Diastolic Blood Pressure (DBP) | The unit of measurement, mmHg for the diastolic blood pressure. | Over a 2 hour exposure period with the objective to assess change in DBP measured after 10 minutes in a time series of measurements over that time period. |
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Inclusion Criteria:
Exclusion Criteria:
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| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| University of Connecticut | Farmington | Connecticut | 06030 | United States |
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Using a 3-period crossover design, 77 participants were randomized to attend. Three 2-hour-long exposure sessions separated by 1-week washout periods.
None was excluded.
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| ID | Title | Description |
|---|---|---|
| FG000 | High Exposure (First Session) Low, Medium | Ambient air was allowed freely into the room. |
| FG001 | Medium Exposure (First Session) High, Low Exposure | Limited air filtration was used to partially reduce levels of pollution in the room relative to outside. Air filtration and building envelop modifications: Air filters and closing and sealing of windows and doors was used to reduce infiltration of air pollution from outdoors in rooms next to major highways at rush hour. |
| FG002 | Low Exposure (First Session) Medium, High Exposure | Doors and windows were closed and sealed and full filtration was used to maximally reduce pollution in the room. Air filtration and building envelop modifications: Air filters and closing and sealing of windows and doors was used to reduce infiltration of air pollution from outdoors in rooms next to major highways at rush hour. |
| Title | Milestones | Reasons Not Completed | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| First Intervention (2 Hours) |
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| Wash Out (1 Week) |
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| Third Intervention (2 Hours) |
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A linear mixed model will be used to analyze the 3-exposure, 3-period crossover design. The primary outcome measure is the change in systolic blood pressure from the beginning of each exposure session. Before calculating change scores in each exposure session, each participant's systolic blood pressure measurements will be smoothed using a 3-time-period, centered moving average.
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| ID | Title | Description |
|---|---|---|
| BG000 | High Exposure (First Session), Low, Medium Exposure | Ambient air was allowed freely into the room. Participants first received a 2-hour-long High exposure session. After a washout period of 1 week, they then received a 2-hour-long Low exposure session. After a washout period of 1 week, they then received a 2-hour-long Medium exposure session. All sessions occurred on the same day of the week. |
| Units | Counts |
|---|---|
| Participants |
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| Title | Description | Population Description | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Denominator Units Selected | Denominators | Classes |
|---|---|---|---|---|---|---|---|---|---|
| Age, Continuous | Mean |
| Type | Title | Description | Population Description | Reporting Status | Anticipated Posting Date | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Time Frame | Units Analyzed | Denominator Units Selected | Arm/Group Information | Denominators | Classes | Analyses | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Primary | Systolic Blood Pressure (SBP) | Systolic blood pressure measured with ambulatory blood pressure monitors in mmHg. | Posted | Mean | Standard Error | mmHg | Over 2 hour exposure period, we measured SBP after 20 minutes with the objective to assess change in SBP in a time series of measurements over that time period. |
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3 weeks.
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| ID | Title | Description | Deaths (Affected) | Deaths (At Risk) | Serious Events (Affected) | Serious Events (At Risk) | Other Events (Affected) | Other Events (At Risk) |
|---|---|---|---|---|---|---|---|---|
| EG000 | High Exposure | Ambient air was allowed freely into the room. | 0 |
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| Title | Organization | Phone | Extension | |
|---|---|---|---|---|
| Dr. Douglas Brugge | UConnHealth | 860-679-8814 | brugge@uchc.edu |
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| Type | Includes Protocol | Includes SAP | Includes ICF | Document Label | Document Date | Document Uploaded Date | Document File Name |
|---|---|---|---|---|---|---|---|
| Prot_SAP | Yes | Yes | No | Study Protocol and Statistical Analysis Plan | Jul 26, 2023 | Aug 10, 2023 | Prot_SAP_000.pdf |
| ICF | No | No | Yes | Informed Consent Form | Jul 26, 2023 | Aug 14, 2023 | ICF_001.pdf |
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Randomized cross over trial
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Participants were not told the high, medium and low exposure context, however, some aspects of the sessions might have been apparent to them since filters were running during high, but not low exposure sessions.
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| BG001 | Medium Exposure(First Session), High, Low Exposure | Limited air filtration was used to partially reduce levels of pollution in the room relative to outside. Air filtration and building envelop modifications: Air filters and closing and sealing of windows and doors was used to reduce infiltration of air pollution from outdoors in rooms next to major highways at rush hour. Participants first received a 2-hour-long Medium exposure session. After a washout period of 1 week, they then received a 2-hour-long High exposure session. After a washout period of 1 week, they then received a 2-hour-long Low exposure session. All sessions occurred on the same day of the week. |
| BG002 | Low Exposure (First Session), Medium, High Exposure | Doors and windows were closed and sealed and full filtration was used to maximally reduce pollution in the room. Air filtration and building envelop modifications: Air filters and closing and sealing of windows and doors was used to reduce infiltration of air pollution from outdoors in rooms next to major highways at rush hour. Participants first received a 2-hour-long Low exposure session. After a washout period of 1 week, they then received a 2-hour-long Medium exposure session. After a washout period of 1 week, they then received a 2-hour-long High exposure session. All sessions occurred on the same day of the week. |
| BG003 | Total | Total of all reporting groups |
| years |
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| Sex: Female, Male | Count of Participants | Participants |
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| Ethnicity (NIH/OMB) | Count of Participants | Participants |
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| Race (NIH/OMB) | Count of Participants | Participants |
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| Region of Enrollment | Count of Participants | Participants |
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| Systolic Blood Pressure | Mean | Standard Deviation | mmHg |
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| OG002 | Low Exposure | Doors and windows were closed and sealed and full filtration was used to maximally reduce pollution in the room. Air filtration and building envelop modifications: Air filters and closing and sealing of windows and doors was used to reduce infiltration of air pollution from outdoors in rooms next to major highways at rush hour. |
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| Secondary | Diastolic Blood Pressure (DBP) | The unit of measurement, mmHg for the diastolic blood pressure. | Posted | Mean | Standard Error | mmHg | Over a 2 hour exposure period with the objective to assess change in DBP measured after 10 minutes in a time series of measurements over that time period. |
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| 30 |
| 0 |
| 30 |
| 0 |
| 30 |
| EG001 | Medium Exposure | Limited air filtration was used to partially reduce levels of pollution in the room relative to outside. Air filtration and building envelop modifications: Air filters and closing and sealing of windows and doors was used to reduce infiltration of air pollution from outdoors in rooms next to major highways at rush hour. | 0 | 28 | 0 | 28 | 0 | 28 |
| EG002 | Low Exposure | Doors and windows were closed and sealed and full filtration was used to maximally reduce pollution in the room. Air filtration and building envelop modifications: Air filters and closing and sealing of windows and doors was used to reduce infiltration of air pollution from outdoors in rooms next to major highways at rush hour. | 0 | 19 | 0 | 19 | 0 | 19 |
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