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Trial registered on ANZCTR


Registration number
ACTRN12616000525482
Ethics application status
Approved
Date submitted
19/04/2016
Date registered
22/04/2016
Date last updated
20/02/2017
Type of registration
Prospectively registered

Titles & IDs
Public title
A preliminary investigation on the effects of intermittent exposure to hypoxia on glucose homeostasis
Scientific title
A preliminary investigation on the effects of intermittent exposure to hypoxia on glucose homeostasis in overweight adults with impaired fasting blood glucose
Secondary ID [1] 289031 0
Nil known
Universal Trial Number (UTN)
U1111-1182-0446
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Impaired fasting blood glucose 298445 0
Pre-diabetes 298446 0
Overweight 298492 0
Type 2 diabetes 302155 0
Condition category
Condition code
Metabolic and Endocrine 298545 298545 0 0
Diabetes

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Participants with impaired fasting blood glucose will be given intermittent exposure to hypoxic air from a hypoxicator via a breathing mask. The biofeedback mode of the hypoxicator will be used with the target hypoxia level set as blood oxygen saturation at 90% (corresponding oxygen level in the air at approximately 15%). The blood oxygen saturation is monitored by a pulse oximeter. Each intervention session is for 1 hour that includes four cycles of breathing hypoxic air for 10 minutes followed by normal air for 5 minutes. The intervention will be administered by research scientists and accredited exercise physiologists. Each intervention session will be delivered individually at the research laboratory in School of Health and Human Sciences, Lismore Campus of Southern Cross University.
The research has two phases. The first phase is a pilot investigation that will use a single system research design to examine the acute effects of 1 hour hypoxia or normoxia exposure on blood glucose. Each participant will be randomly allocated into two hypoxia and two normoxia sessions each is separated by one week. The phase two of the research will be a randomised controlled trial that uses a single-blind crossover design to investigate the effects of four weeks (three 1 hour sessions per week in non-consecutive days) hypoxia or placebo intervention on blood glucose homeostasis and insulin sensitivity. A 4-week wash-out period will be inserted between the two 4-week hypoxia or normoxia (placebo) intervention periods).
Intervention code [1] 294513 0
Treatment: Other
Comparator / control treatment
Hypoxia group will be given normobaric hypoxic air and control group will be given normal air during the intervention sessions.
Control group
Placebo

Outcomes
Primary outcome [1] 298032 0
Phase 1: Acute changes in blood glucose (skin-puncture samples), assessed by a hand-hold glucometer..

Timepoint [1] 298032 0
Phase 1: Pre, 30 min and 60 min during, and 30 min, 1 hour and 24 hour post an intervention trial.

Primary outcome [2] 298073 0
Phase 2: Changes in fasting blood glucose (veni-puncture samples), assessed by serum assay at an accredited pathology lab..
Timepoint [2] 298073 0
Pre and post four weeks hypoxia and four weeks placebo intervention periods.
Primary outcome [3] 298074 0
Phase 2: Changes in glucose tolerance (veni-puncture samples), assessed by serum assay at an accredited pathology lab..
Timepoint [3] 298074 0
Pre and post four weeks hypoxia and four weeks placebo intervention periods.
Secondary outcome [1] 322974 0
Phase 2: Changes in blood insulin (veni-puncture samples), assessed by serum assay at an accredited pathology lab.
Timepoint [1] 322974 0
Phase 2: Pre and post four weeks hypoxia and four weeks placebo intervention periods.
Secondary outcome [2] 323104 0
Phase 2: Changes in HbA1c, assessed by ion-exchange high-performance liquid chromatography at an accredited pathology lab.
Timepoint [2] 323104 0
Pre and post four weeks hypoxia and four weeks placebo intervention periods.
Secondary outcome [3] 323105 0
Blood oxygen saturation (SpO2), monitored by a pulse oximeter in all intervention sessions.
Timepoint [3] 323105 0
Monitored continuously during each intervention session to provide biofeedback to the hypoxicator.
Secondary outcome [4] 323106 0
Heart rate, monitored by a pulse oximeter.
Timepoint [4] 323106 0
Monitored continuously and recorded every 5 minutes during each intervention session.
Secondary outcome [5] 323107 0
Blood pressure, monitored using a sphygmomanometer.
Timepoint [5] 323107 0
Every 15 minutes during each intervention session.

Eligibility
Key inclusion criteria
Fasting blood glucose greater than 6.0 mM
Body mass index >25 (i.e. overweight or obese);
No planned changes to medication regimen for hyperglycaemia (e.g. metformin, acarbose) or other metabolic diseases (e.g. lipid lowering drugs); and
No planned major lifestyle changes during the testing period (i.e. commencement/ceasing of exercise regimen, pregnancy, etc.)
Minimum age
18 Years
Maximum age
65 Years
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Cardiovascular diseases;
Anemia or blood donation within past 3 months;
Severe chronic obstructive pulmonary disease;
Smoking;
Alcohol consumption for more than 3 standard drinks per day;
Obstructive sleep apnea;
Uncontrolled asthma;
Inflammatory and/or infectious diseases;
Intolerance to oxygen insufficiency;
Disease with symptoms of decompensation;
Terminal illness;
Cancer;
Pregnant;
Neurological diseases; or
Mental illness.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation is not concealed.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
A restricted randomization (blocking) method will be used. Participants will be randomly given a code number among 1 to 4 in Phase 1, or 1 to 20 In Phase 2, then a random pick of odd (or even) number will determine whether those having an odd (or even) number will start with treatment A – hypoxia, or B - normoxia, then change over to the alternate treatment at the designed time point.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s


Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
Phase one of the trial is a pilot investigation that will use a single system research design. Each individual’s responses to 1 hour hypoxia or placebo treatment will be visually demonstrated and inspected. Four participants with impaired fasting blood glucose and one healthy participant will be recruited and are thought sufficient in validating intervention procedures.

The phase two of the trial is a randomised controlled trial that will use a single-blind crossover design to investigate the effects of four weeks (three 1 hour sessions per week) hypoxia or normoxia (as control) intervention. The number of participants is justified by a priori estimation. With assumptions of effect size of 0.4, power of 0.8, alpha level of 0.05, and two groups with three measures, the minimum number required is 12 (i.e. 6 in each group) for general linear model with repeated measures statistical analysis. Therefore, a total 20 participants (10 in each group) would be sufficient, with consideration of potential dropouts.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
NSW
Recruitment postcode(s) [1] 13091 0
2480 - Lismore
Recruitment postcode(s) [2] 13092 0
2478 - Ballina
Recruitment postcode(s) [3] 13093 0
2470 - Casino

Funding & Sponsors
Funding source category [1] 293396 0
University
Name [1] 293396 0
Southern Cross University
Address [1] 293396 0
Military Road
Lismore, NSW 2480
Country [1] 293396 0
Australia
Primary sponsor type
University
Name
Southern Cross University
Address
Military Road
Lismore, NSW 2480

Country
Australia
Secondary sponsor category [1] 292226 0
None
Name [1] 292226 0
Address [1] 292226 0
Country [1] 292226 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 294854 0
Southern Cross University Human Research Ethics Committee
Ethics committee address [1] 294854 0
Military Road
Lismore, NSW 2480
Ethics committee country [1] 294854 0
Australia
Date submitted for ethics approval [1] 294854 0
09/02/2016
Approval date [1] 294854 0
14/03/2016
Ethics approval number [1] 294854 0
ECN-16-025

Summary
Brief summary
Obesity and diabetes have become global epidemics. It is known that adequate physical activity and a healthy diet are among the key factors in weight control and management of type 2 diabetes. However, participation in regular exercise could be a challenge to some individuals with various capacities. There have been reports in the literature that hypoxia interventions, alone or combined with exercise, may have beneficial effects on weight control and blood glucose homeostasis in individuals with obesity and hyperglycaemia. With advancement of technology, hypoxia chambers and breathing devices (hypoxicators) have become available to provide air with various levels of oxygen. Whether hypoxia can be validated as an alternative or complementary intervention for obesity and diabetes requires further research.

The aim of this research is to conduct a preliminary investigation on the effect of four weeks intermittent exposure to mild hypoxia (with the target blood oxygen saturation level at approximately 90%) on blood glucose homeostasis and insulin sensitivity in individuals with impaired fasting blood glucose. The participants’ responses (including blood oxygen saturation level, heart rate, and blood pressure) during the intervention sessions will be closely monitored, and their blood glucose, insulin and HbA1c levels, and glucose tolerance will be assessed pre and post the intervention period to determine the effects.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 65238 0
Prof Shi Zhou
Address 65238 0
School of Health and Human Sciences
Southern Cross University
Military Road, Lismore NSW 2480
Country 65238 0
Australia
Phone 65238 0
+61 2 66203991
Fax 65238 0
Email 65238 0
shi.zhou@scu.edu.au
Contact person for public queries
Name 65239 0
Mr Charl Neuhoff
Address 65239 0
School of Health and Human Sciences
Southern Cross University
Military Road, Lismore NSW 2480
Country 65239 0
Australia
Phone 65239 0
+61 2 66203868
Fax 65239 0
Email 65239 0
g.neuhoff.10@student.scu.edu.au
Contact person for scientific queries
Name 65240 0
Prof Shi Zhou
Address 65240 0
School of Health and Human Sciences
Southern Cross University
Military Road, Lismore NSW 2480
Country 65240 0
Australia
Phone 65240 0
+61 2 66203991
Fax 65240 0
Email 65240 0
shi.zhou@scu.edu.au

No information has been provided regarding IPD availability
Summary results
No Results