Blood Pressure
Conditions
Keywords
PM2.5, air purification, randomized controlled trial, metabolomics, Metabolites, exhaled nitric oxide
Brief summary
This study aims to detect serum metabolite changes, as well as other health indicators with the intervention of air purifiers on a randomized, crossover, double-blind trial.
Detailed description
The investigators conducted a randomized double-blind crossover trial among 60 healthy college students in Shanghai, China from November to December, 2015. These students lived in dormitories that were randomized into two groups and alternated the use of true or sham air purifiers for 9 consecutive days with a 2-week wash-out interval. All participants and research staffs were blinded to the group assignment. All participants were required to stay in their dormitory with the windows/doors closed for at least 50% of the time on weekdays and for 80% on weekends throughout the 9-day intervention period. All interventions started at 7 a.m. to avoid issues related to diurnal variation. Health endpoints, including blood pressure, fractional exhaled nitric oxide were evaluated and biological samples such as morning urine, fast blood and buccal cells were collected at baseline and immediately after the completion of each intervention period.
Interventions
BEHAVIORALAir Purifiers
The 17 dormitory rooms and their residents were randomized into two groups: the intervention and control group. The intervention group went through a 9-day intervention with an air purifier placed in the center of the room. All rooms in this group used the same qualified air purifiers (model KJEA200e, 3M), and all participants were required to stay in their dormitory rooms with the windows/doors closed throughout intervention period. All participants and research staffs were blinded to the group assignment.
BEHAVIORALSham Air Purifiers
The control group went through a 9-day intervention with a sham air purifier (with its filter gauze removed) placed in the center of the room. All rooms used the same air purifiers (model KJEA200e, 3M) as the intervention group, except the filter gauze was removed. During the study period all participants were required to stay in their dormitory rooms with the windows/doors closed. All participants and research staffs were blinded to the group assignment.
Sponsors
Fudan University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
ALL
Age
18 Years to 30 Years
Healthy volunteers
Yes
Inclusion criteria
* Healthy university students in Jiangwan Campus, Fudan university * Non-smoking, no history of alcohol or drug abuse * Free of chronic cardiovascular, respiratory, liver and kidney disease * Spend at least 50% (weekdays) or 80% (weekends) of time indoors
Exclusion criteria
* Current or ever smokers * History of asthma, chronic bronchitis，cough, hypertension or other chronic inflammatory disease * acute infections * medication use in recent one month
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Changes of Serum Cortisol Levels | at the end of each 9-day intervention period | Using metabolomic methods to screen and quantify all the serum metabolites, and calculate changes in main metabolites in sham purification compared to real purification. Relative intensity was calculated by dividing the peak intensity of cortisol with the peak intensity of internal standard (2-chloro-D-phenylalanine methanol solution, 0.014mg/mL) |
| Changes of Serum Cortisone Concentration | at the end of each 9-day intervention period | Use metabolomic methods to screen and quantify all the serum metabolites, and calculate changes in main metabolites in sham purification compared to real purification. Relative intensity was calculated by dividing the peak intensity of cortisone with the peak intensity of internal standard (2-chloro-D-phenylalanine methanol solution, 0.014mg/mL) |
| Changes of Serum Epinephrine Concentrations | at the end of each 9-day intervention | Use metabolomic methods to screen and quantify all the serum metabolites, and calculate changes in main metabolites in sham purification compared to real purification. Relative intensity was calculated by dividing the peak intensity of epinephrine with the peak intensity of internal standard (2-chloro-D-phenylalanine methanol solution, 0.014mg/mL) |
| Changes of Serum Norepinephrine Concentration | at the end of each 9-day intervention | Use metabolomic methods to screen and quantify all the serum metabolites, and calculate changes in main metabolites in sham purification compared to real purification. Relative intensity was calculated by dividing the peak intensity of cortisol with the peak intensity of internal standard (2-chloro-D-phenylalanine methanol solution, 0.014mg/mL) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Diastolic Blood Pressure | at the end of each 9-day intervention | To eliminate possible error, blood pressure for each participant were conducted by the same working staff using the same instrument. Average levels were calculated by treatments (intervention or control). |
| Pulse Pressure | at the end of each 9-day intervention | To eliminate possible error, blood pressure for each participant were conducted by the same working staff using the same instrument. Average levels were calculated by treatments (intervention or control). |
| Systolic Blood Pressure | at the end of each 9-day intervention period | To eliminate possible error, blood pressure for each participant were conducted by the same working staff using the same instrument. Average levels were calculated by treatments (intervention or control). |
Countries
China
Participant flow
Recruitment details
Recruitment was conducted on November, 2015 in Jiangwan Campus, Fudan University. A total of 65 participants were assessed for eligibility and 60 of them were finally recruited
Participants by arm
| Arm | Count |
|---|---|
| Group1-air Purification First, Then Sham Air Purification Participants in this group received a treatment of true air purification first, and then switched to the sham purification treatment the second stage.
For real air purification, we used high efficient air purifiers (model KJEA200e, 3M), and all participants were required to stay in their dormitory rooms with the windows/doors closed throughout intervention period. For sham air purification, we placed a sham air purifier (with HEPA filters removed) while keeping the rest of the experiment conditions and requirements for the participants unchanged. All participants and research staffs were blinded to the group assignment. | 31 |
| Group2-sham Air Purification First, Then Real Air Purification Participants in this group received a treatment of sham air purification first, and then switched to the real purification treatment the second stage.
For real air purification, we used high efficient air purifiers (model KJEA200e, 3M), and all participants were required to stay in their dormitory rooms with the windows/doors closed throughout intervention period. For sham air purification, we placed a sham air purifier (with HEPA filters removed) while keeping the rest of the experiment conditions and requirements for the participants unchanged. All participants and research staffs were blinded to the group assignment. | 24 |
| Total | 55 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| First Period | Withdrawal by Subject | 3 | 2 |
Baseline characteristics
| Characteristic | Group1-air Purification First, Then Sham Air Purification | Group2-sham Air Purification First, Then Real Air Purification | Total |
|---|---|---|---|
| Age, Continuous | 20.0 years STANDARD_DEVIATION 1.3 | 20.6 years STANDARD_DEVIATION 1.4 | 20.2 years STANDARD_DEVIATION 1.3 |
| Body mass index | 21.6 kg/m^2 STANDARD_DEVIATION 2.9 | 20.6 kg/m^2 STANDARD_DEVIATION 2.5 | 21.1 kg/m^2 STANDARD_DEVIATION 2.6 |
| Sex: Female, Male Female | 17 Participants | 11 Participants | 28 Participants |
| Sex: Female, Male Male | 14 Participants | 13 Participants | 27 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 0 / 55 | 0 / 55 |
| serious Total, serious adverse events | 0 / 55 | 0 / 55 |
Outcome results
Primary
Changes of Serum Cortisol Levels
Using metabolomic methods to screen and quantify all the serum metabolites, and calculate changes in main metabolites in sham purification compared to real purification. Relative intensity was calculated by dividing the peak intensity of cortisol with the peak intensity of internal standard (2-chloro-D-phenylalanine methanol solution, 0.014mg/mL)
Time frame: at the end of each 9-day intervention period
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Real Purification | Changes of Serum Cortisol Levels | 0.012835 relative intensity | Standard Deviation 0.00371 |
| Sham Purification | Changes of Serum Cortisol Levels | 0.016206 relative intensity | Standard Deviation 0.00474 |
Comparison: we analyzed the serum cortisol levels (presented as relative intensities in high perfomance liquid chromatography-mass spectrum) by treatments (intervention group vs control group)p-value: <0.0595% CI: [4.65, 10.41]Mixed Models Analysis
p-value: <0.01t-test, 2 sided
Primary
Changes of Serum Cortisone Concentration
Use metabolomic methods to screen and quantify all the serum metabolites, and calculate changes in main metabolites in sham purification compared to real purification. Relative intensity was calculated by dividing the peak intensity of cortisone with the peak intensity of internal standard (2-chloro-D-phenylalanine methanol solution, 0.014mg/mL)
Time frame: at the end of each 9-day intervention period
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Real Purification | Changes of Serum Cortisone Concentration | 0.021076 relative intensity | Standard Error 0.004375 |
| Sham Purification | Changes of Serum Cortisone Concentration | 0.024338 relative intensity | Standard Error 0.004625 |
Comparison: we analyzed the serum cortisone levels by treatment (intervention group vs control group)p-value: <0.0195% CI: [1.85, 5.54]Mixed Models Analysis
p-value: <0.01t-test, 2 sided
Primary
Changes of Serum Epinephrine Concentrations
Use metabolomic methods to screen and quantify all the serum metabolites, and calculate changes in main metabolites in sham purification compared to real purification. Relative intensity was calculated by dividing the peak intensity of epinephrine with the peak intensity of internal standard (2-chloro-D-phenylalanine methanol solution, 0.014mg/mL)
Time frame: at the end of each 9-day intervention
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Real Purification | Changes of Serum Epinephrine Concentrations | 0.140609 relative intensity | Standard Error 0.027514 |
| Sham Purification | Changes of Serum Epinephrine Concentrations | 0.165321 relative intensity | Standard Error 0.036633 |
Comparison: we analyzed the serum epinephrine levels by treatment (intervention group vs control group)p-value: <0.0195% CI: [3.21, 7.14]Mixed Models Analysis
p-value: <0.01t-test, 2 sided
Primary
Changes of Serum Norepinephrine Concentration
Use metabolomic methods to screen and quantify all the serum metabolites, and calculate changes in main metabolites in sham purification compared to real purification. Relative intensity was calculated by dividing the peak intensity of cortisol with the peak intensity of internal standard (2-chloro-D-phenylalanine methanol solution, 0.014mg/mL)
Time frame: at the end of each 9-day intervention
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Real Purification | Changes of Serum Norepinephrine Concentration | 0.030752 relative intensity | Standard Deviation 0.024335 |
| Sham Purification | Changes of Serum Norepinephrine Concentration | 0.038695 relative intensity | Standard Deviation 0.024624 |
Comparison: we analyzed the serum norepinephrine levels by treatment (intervention group vs control group)p-value: <0.0195% CI: [7.37, 15.21]Mixed Models Analysis
p-value: <0.01t-test, 2 sided
Secondary
Diastolic Blood Pressure
To eliminate possible error, blood pressure for each participant were conducted by the same working staff using the same instrument. Average levels were calculated by treatments (intervention or control).
Time frame: at the end of each 9-day intervention
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Real Purification | Diastolic Blood Pressure | 64.5 mmHg | Standard Deviation 9.6 |
| Sham Purification | Diastolic Blood Pressure | 65.2 mmHg | Standard Deviation 8.8 |
Comparison: we analyzed the serum cortisol levels by treatment (intervention group vs control group)p-value: >0.0595% CI: [-1.59, 0.96]Mixed Models Analysis
Secondary
Pulse Pressure
To eliminate possible error, blood pressure for each participant were conducted by the same working staff using the same instrument. Average levels were calculated by treatments (intervention or control).
Time frame: at the end of each 9-day intervention
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Real Purification | Pulse Pressure | 37.7 mmHg | Standard Deviation 7.5 |
| Sham Purification | Pulse Pressure | 39.6 mmHg | Standard Deviation 8.3 |
Comparison: we analyzed the serum cortisol levels by treatment (intervention group vs control group)p-value: >0.0595% CI: [-1.14, 3.63]Mixed Models Analysis
Secondary
Systolic Blood Pressure
To eliminate possible error, blood pressure for each participant were conducted by the same working staff using the same instrument. Average levels were calculated by treatments (intervention or control).
Time frame: at the end of each 9-day intervention period
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Real Purification | Systolic Blood Pressure | 102.2 mmHg | Standard Deviation 13.4 |
| Sham Purification | Systolic Blood Pressure | 104.8 mmHg | Standard Deviation 12.8 |
Comparison: we analyzed the serum SBP levels by treatment (intervention group vs control group)p-value: <0.0195% CI: [0.09, 1.59]Mixed Models Analysis