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Trial registered on ANZCTR


Registration number
ACTRN12610000996066
Ethics application status
Approved
Date submitted
11/11/2010
Date registered
17/11/2010
Date last updated
18/11/2010
Type of registration
Retrospectively registered

Titles & IDs
Public title
Exercise-induced improvement in insulin levels is maintained in obese youth independently of changes in fat mass
Scientific title
Structured exercise can improve insulin levels in obese youth and can be maintained without changes in fat mass
Secondary ID [1] 253076 0
non applicable
Universal Trial Number (UTN)
U1111-1117-9183
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Obesity 258637 0
Insulin resistance 258638 0
Condition category
Condition code
Metabolic and Endocrine 258778 258778 0 0
Other metabolic disorders
Diet and Nutrition 258796 258796 0 0
Obesity

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Participants were enrolled in an exercise program that involved one hour of supervised mixed aerobic and resistance training three times a week.
Each training session consisted of individually prescribed cycle ergometer and resistance training, the latter performed at low intensity on weight-stack machines (Pulsestar, UK). Cycle ergometry was initially maintained at 65% of maximum heart rate (HR), with progression to 85% by week 2/3. Resistance training (12 repetitions/minute) was initially maintained at 55% of pre-training maximum voluntary contraction, and progressed to 70% by week 2/3. Subjects completed 2 sets of this circuit at each of the three weekly visits to the gymnasium for 8 weeks. Inclusive of the 10 min warm-up and cool down periods, each exercise training session lasted approximately 60 minutes. All group exercise sessions were supervised by the same experienced Exercise Physiologists, with a maximum subject to staff ratio of 6:1. Exercise training intensity (HR and weights lifted) was maintained within the target zones by intermittent checking undertaken in all subjects throughout each session.
Intervention code [1] 257595 0
Lifestyle
Intervention code [2] 257624 0
Prevention
Comparator / control treatment
We compared three 8 week periods: (1) normal activity before exercise (control period), (2) exercise training and (3) normal activity post exercise.
Subjects participated in the program for 16 weeks. They were randomised to either 8 weeks of normal activity, followed by 8 weeks of exercise, or alternatively, 8 weeks of exercise followed by 8 weeks of return to normal activity. For each subject outcome measures were assessed at 2 consecutive time points 8 weeks apart. This allowed us to obtain data at the following time points: start of the study (timepoint 1, 0 weeks), end of period of normal activity/start of exercise (timepoint 2, 8 weeks), end of exercise (timepoint 3, 16 weeks), end of normal activity post exercise (timepoint 4, 24 weeks). In each subject outcome measurements were restricted to two timepoints to minimise the number of invasive procedures in children.
The resulting periods for analysis were named as follows:
1. Control period: normal activity during study weeks 0 to 8
2. Exercise period: exercise training during study weeks 8 to 16
3. Post exercise period: normal activity during study weeks 16 to 24.
Control group
Active

Outcomes
Primary outcome [1] 259643 0
Oral glucose tolerance tests (OGTT) with insulin levels
Timepoint [1] 259643 0
Start and end of each 8 week period
Secondary outcome [1] 266305 0
cardiovascular and fitness measures
Timepoint [1] 266305 0
Start and end of each 8 week period, assessed by Multi-Stage Fitness test.
Secondary outcome [2] 266355 0
body composition (DXA)
Timepoint [2] 266355 0
Start and end of each 8 week period, assessed using a DXA scan.
Secondary outcome [3] 266356 0
height and weight.
Timepoint [3] 266356 0
Start and end of each 8 week period

Eligibility
Key inclusion criteria
Obese children and adolescents from the Endocrinology Clinic at Princess Margaret Hospital Perth, WA , Australia
Minimum age
6 Years
Maximum age
16 Years
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Not matching the weight criteria according to Cole et al. (Cole TJ, Bellizzi MC, Flegal KM, Dietz WH. Establishing a standard definition for child overweight and obesity worldwide: international survey. BMJ Clinical research ed 2000;320(7244):1240-3).

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)
Subjects participated in the program for 16 weeks. They were randomised by taking numbers from a sealed opaque envelope. Groups either started with 8 weeks of normal activity, followed by 8 weeks of exercise, or alternatively, 8 weeks of exercise followed by 8 weeks of return to normal activity. For each subject outcome measures were assessed at 2 consecutive time points 8 weeks apart. This allowed us to obtain data at the following time points: start of the study (timepoint 1, 0 weeks), end of period of normal activity/start of exercise (timepoint 2, 8 weeks), end of exercise (timepoint 3, 16 weeks), end of normal activity post exercise (timepoint 4, 24 weeks). In each subject outcome measurements were restricted to two timepoints to minimise the number of invasive procedures in children.
The resulting periods for analysis were named as follows:
1. Control period: normal activity during study weeks 0 to 8
2. Exercise period: exercise training during study weeks 8 to 16
3. Post exercise period: normal activity during study weeks 16 to 24.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation by taking numbers from a sealed opaque envelope.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis

Recruitment
Recruitment status
Completed
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)

Funding & Sponsors
Funding source category [1] 258043 0
Hospital
Name [1] 258043 0
Princess Margaret Hospital for Children
Address [1] 258043 0
Department of Endocrinology and DiabetesRoberts Road
Subiaco, Perth, WA 6008
Western Australia
Country [1] 258043 0
Australia
Primary sponsor type
Hospital
Name
Princess Margaret Hospital for Children
Address
Department of Endocrinology and Diabetes
Roberts Road
Subiaco, Perth, WA 6008
Western Australia
Country
Australia
Secondary sponsor category [1] 257231 0
Charities/Societies/Foundations
Name [1] 257231 0
German Society for Endocrinology
Address [1] 257231 0
Geschaeftsstelle der DGE
c/o EndoScience Endokrinologie Service GmbH
Mozartstr. 23
93128 Regenstauf
Country [1] 257231 0
Germany

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 260040 0
Children and Adolescent Health Service - Ethics Committee
Ethics committee address [1] 260040 0
Princess Margaret Hospital for Children
Roberts Road
Subiaco, Perth, WA 6008
Western Australia
Ethics committee country [1] 260040 0
Australia
Date submitted for ethics approval [1] 260040 0
Approval date [1] 260040 0
17/05/2001
Ethics approval number [1] 260040 0
613EP

Summary
Brief summary
Being overweight is a major risk factor for diabetes. The main purpose of this study is to determine if exercise can reduce this risk for overweight children and adolescents.
At entry to the study, participants will be required to complete a 7 day activity record and a 3 day diet history diary. The participant will then be assigned to either an exercise training group, or a control (non-exercise) group. The 8-week exercise program involves attending a gymnasium three days per week for approximately 1 hour each time. The exercise training regime will be fully structured and supervised by experienced exercise physiologists. If a child is initially in the control group, they will be asked to continue with their normal routine for a period of 8 weeks.
At the beginning and at the end of each 8 week period subjects will have their blood pressure measured, and will have a test called a glucose tolerance test that involves the insertion of a small intravenous cannula for blood sampling. They will be asked to drink a sugary cola flavoured liquid and following this, blood samples for blood glucose levels, insulin and cardiovascular risk factors will be taken from the cannula. The test takes a total of 3 hours.
Other tests will include a special X-ray scan that determines body composition (fat mass and muscle mass) called a DXA scan. A DXA scan requires subjects to lie on their back on a scanning bed for 3-7 minutes and involves a low radiation dose (5% of a standard chest x-ray). This visit will take approximately 1 hour.
Following the series of tests outlined above participants will be allocated to the alternate training group for a further 8 week period followed by a series of repeat tests which are identical to the tests outlined above. By comparing the repeat and initial tests, the effect of the training program on fitness, insulin levels and body composition will be determined.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 31906 0
Address 31906 0
Country 31906 0
Phone 31906 0
Fax 31906 0
Email 31906 0
Contact person for public queries
Name 15153 0
A/Professor Aris Siafarikas
Address 15153 0
Princess Margaret Hospital
Department of Endocrinology and Diabetes
Roberts Road
Subiaco, Perth, WA 6008
Western Australia
Country 15153 0
Australia
Phone 15153 0
+61893408090
Fax 15153 0
+61893408605
Email 15153 0
Aris.Siafarikas@health.wa.gov.au
Contact person for scientific queries
Name 6081 0
A/Professor Aris Siafarikas
Address 6081 0
Princess Margaret Hospital
Department of Endocrinology and Diabetes
Roberts Road
Subiaco, Perth, WA 6008
Western Australia
Country 6081 0
Australia
Phone 6081 0
+61893408090
Fax 6081 0
+61893408605
Email 6081 0
Aris.Siafarikas@health.wa.gov.au

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary