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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Office-based Program To Improve Metabolic control In Sedentary Employees with type 2 diabetes: The ‘OPTIMISE Your Health' study
Scientific title
Reducing sitting time on glycaemic control in middle-aged and older office workers with type 2 diabetes
Secondary ID [1] 295399 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
type 2 diabetes 308628 0
Condition category
Condition code
Metabolic and Endocrine 307577 307577 0 0

Study type
Description of intervention(s) / exposure
This is an 18-month, controlled-trial design, in which middle-aged and older office workers with T2D (n=250) will be randomly assigned to one of two conditions: 1) a multi-component intervention to reduce sitting time; 2) a usual-care control condition.
Those randomised to the multi-component intervention will receive the following:
• Health coaching: Trained-researchers in motivational training will deliver the health coaching sessions. The health coaching sessions will consist of two in-person meetings and eight telephone-delivered sessions over six months, to support initiation and maintenance of the sitting-time reduction changes. Both the face to face and telephone health coaching sessions will focus on delivering two key messages: Sit less and move more, both at work and outside of work. the following 6-months will consist of text message support via the propelo system.

The in-person meetings will occur at baseline (at the participant’s workplace) and at the three month assessment (at Baker Institute) and will include the following: provision of feedback on baseline levels of sitting time, assessment and strategies to enhance motivation, and identify/set goals related to reducing and breaking-up sitting time in both the home and work environment. A participant workbook will also be provided to participants to help with goal setting and progress. The telephone calls will be brief (~10min) and used to check on progress on reducing sitting at home and at work, address problems, revise goals as needed and reinforce goal attainment. The telephone calls will be once a week for the first three weeks and then every three weeks until the end of the intervention.

• Sit–stand desktop workstations: A manually adjustable sit–stand workstation will be provided for the duration of the study to use at the participant’s workplace. All participants will be required to provide written approval from their employer to use the workstation in the workplace. During the intervention, participants will be encourage to use the sit-stand workstation throughout their whole work day by regularly alternating between sitting and standing throughout the work day. After the intervention, participants will retain the sit-stand workstation.

• Smartphone-based monitoring and behavioural prompting: A wrist-worn activity monitor (Fitbit) and Fitbit mobile app will be provided to each participant to continuously self-monitor their daily movement patterns in real-time over the 18 month intervention. On the smartphone app, participants can set prompts to interrupt their idle states and also receive reinforcing feedback in real-time on interruptions to prolonged periods of sedentary behaviour. Research staff will set up the Fitbit watch and the app during the initial face-to-face intervention session and encourage participants to use the device.

The intervention group’s outcomes will be compared at three, six, twelve and eighteen months to those of the control condition.
Intervention code [1] 301709 0
Intervention code [2] 301786 0
Comparator / control treatment
Those randomised to the usual-care control condition will receive a monthly generic newsletter (12 in total) containing non-tailored information on diabetes education and various health behaviours. The newsletters will contain diabetes fact sheets designed by the National Diabetes Service Scheme (NDSS). These fact sheets are written for people with diabetes and contain the following topics: physical activity, healthy snacks, understanding food labels, the glycaemic index, food choices for people with diabetes, hints for healthy cooking, eating out, alternative sweeteners and alcohol intake.

A modified (6 month) version of the intervention, including the use of a sit-stand workstation will be offered to the control participants after the 12 month assessment.

Control group

Primary outcome [1] 306552 0
Overall daily sitting time assessed using activpal inclinometer and actigraph accelerometer
Timepoint [1] 306552 0
Baseline (0 months), Mid-intervention (3 months, 6 months, 12 months) and Post-intervention (18 months) [primary end point]
Primary outcome [2] 306553 0
Glycosylated haemoglobin (HbA1c)
Timepoint [2] 306553 0
Baseline (0 months), Mid-intervention (3 months, 6 months, 12 months) and Post-intervention (18 months) [primary end point]
Secondary outcome [1] 348851 0
Sitting time accumulated in prolonged bouts (greater than 30 min) assessed using activpal inclinometer and actigraph accelerometer
Timepoint [1] 348851 0
Baseline (0 months), Mid-intervention (3 months, 6 months, 12 months) and Post-intervention (18 months)
Secondary outcome [2] 348852 0
Plasma glucose incremental area under the curve (iAUC). Plasma glucose (fluoride/oxalate) will be measured by a NATA-/RCPA-accredited laboratory using a hexokinase method.
Timepoint [2] 348852 0
Five time points during the 2-hour oral glucose test (e.g. 0 h, 0.5 h, 1.0 h, 1.5 h & 2.0 h) on the following five time points: - Baseline (0 months), Mid-intervention (3 months, 6 months, 12 months) and Post-intervention (18 months)
Secondary outcome [3] 348853 0
Serum insulin measured using a chemiluminescent microparticle immunoassay and calculated as incremental area under the curve (iAUC)
Timepoint [3] 348853 0
Five time points during the 2-hour oral glucose test (e.g. 0 h, 0.5 h, 1.0 h, 1.5 h & 2.0 h) on the following five time points: - Baseline (0 months), Mid-intervention (3 months, 6 months, 12 months) and Post-intervention (18 months)
Secondary outcome [4] 348854 0
Total body and regional lean tissue mass, fat mass and percentage of body fat will be measured using GE Lunar iDXA scanner.
Timepoint [4] 348854 0
Baseline (0 months), Mid-intervention (3 months, 6 months, 12 months) and Post-intervention (18 months)
Secondary outcome [5] 348855 0
Blood pressure measured via an OMRON HEM-907 automatic digital BP machine
Timepoint [5] 348855 0
Baseline (0 months), Mid-intervention (3 months, 6 months, 12 months) and Post-intervention (18 months)
Secondary outcome [6] 348856 0
Fasting plasma lipids (from EDTA tubes) will be analysed using a COBAS Integra 400+ analyzer (Roche Diagnostics, Indianapolis, IN).
Timepoint [6] 348856 0
Baseline (0 months)
Mid-intervention (3 months)
Post-intervention (6 months)
Secondary outcome [7] 348857 0
Flow-mediated dilatation (FMD) will be assessed using high-resolution duplex ultrasound (Terason, USA) to image changes in arterial diameter, according to accepted international guidelines. Post hoc bespoke software will be used to determine the resultant FMD (%) of the artery.
Timepoint [7] 348857 0
FMD will be measured twice during the 2-hr oral glucose test at baseline (0 h) and 1 h on the following five time points: - Baseline (0 months), Mid-intervention (3 months, 6 months, 12 months) and Post-intervention (18 months)
Secondary outcome [8] 348858 0
Economic evaluation. Both a ‘trial-based evaluation’ (analysing costs and outcomes exactly as per the trial) and a ‘modelled evaluation’ (extending the time horizon, population and the decision context and using best-available information from the literature) will be undertaken, including the incorporation of adjustments for real-life recruitment, participation and attrition rates. A societal perspective will incorporate cost impacts on government as the provider of healthcare services, healthcare costs to individuals and costs to workplace organisations. Pathway analysis will fully specify all activities in both intervention and control arms, to measure costs of associated resource use. Unit costs will be drawn from best available sources for the 2017 reference year. In addition to incremental costs of the intervention (measured against the control), incremental cost offsets attributable to disease prevention will be reported. The results will be reported as incremental cost effectiveness ratios, across both primary and secondary outcomes, including cost per unit change in postprandial glucose metabolism, cost per unit reduction in sitting time, and cost per quality-adjusted life year (QALY) gained (using the validated AQoL-8D tool suitable for cost-utility analysis), allowing consideration of value-for-money against a reference threshold ($50,000 per QALY in Australia). The health-economic modelling from our outcomes will use a Markov approach to estimate the health impacts of changes in biomarkers and behavioural outcomes over the lifetime of participants. Modelling the maintenance of intervention effect beyond the 6-month observed trial horizon will be critical; besides the conservative base case assumptions, maintenance of effect assumptions will be varied under sensitivity testing. Standard discounting will be applied to both costs and outcomes. Simulation modelling using the @RISK software package will be employed to calculate 95% uncertainty intervals around the epidemiological probabilities and cost estimates.
Timepoint [8] 348858 0
Baseline, 6 months and 18 months post-intervention commencement.
Secondary outcome [9] 368835 0
Cognitive function will be assessed via: 1) 'written assessment' where the participant completes the addenbrooke's cognitive examination (researcher led, interview style) in a private room; 2) 'practical assessment' where the participant completes a set of CANTAB assessments on an iPad. The assessments include 'PAL Paired Associated Learning' (to assess visual memory); RTI Reaction Time (to assess Attention & Psychomotor control); MOT Motor Screening Task (to assess Attention & Psychomotor control); Delayed Matching to Sample (DMS) (to assess Short term visual recognition memory) and SWM Spatial Working Memory (to assess Memory & Executive function).

Timepoint [9] 368835 0
Cognitive assessments performed 0, 6, 12 and 18 months

Key inclusion criteria
• Aged between 35-65 years;
• Have a body mass index (BMI) between 25-50 kg/m2;
• Be medically diagnosed with T2D for at least three months
• T2D to be treated by diet alone or with oral hypoglycaemic agents or GLP1 agonists and be on stable treatment regimen for > 3 months
• Stable body weight (+/-5 kg) for > 3 months prior to beginning the intervention
• Working at least 0.8 full-time equivalent in a desk-based occupation for > 6 months with the same employer and able to obtain employer permission to install the provided sit–stand workstation on their work surface.
• Working in the Melbourne metropolitan area within a 40km radius from Baker Clinic
Minimum age
35 Years
Maximum age
65 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
• Using insulin to treat T2D
• HbA1c less than 6.5% (indicative of good control) or greater than 10% (reflects uncontrolled);
• Pregnant
• Women of childbearing potential not currently using adequate contraception
• Non-Smartphone user
• Currently using a height adjustable workstation at their workplace
• Regularly engaged in moderate-vigorous intensity exercise more than 30 min/day for more than 3 months
• Regularly engaged in more than 30 minutes/week of structured strength/resistance training (i.e. involving machine or free weights) for more than 3 months
• Regularly sits for less than 7 hours per day for more than 3 months
• Major illness/physical problems (acute or chronic) that may limit participation in the intervention.
• Significant cardiovascular disease (unstable angina, cardiac failure) or recent myocardial infarction, coronary artery bypass graft, ischaemic or haemorrhagic stroke in the previous 3 months
• Cancer diagnosis in the previous 12 months
• A medically diagnosed and untreated severe sleeping disorder
• Planning to move from the current employer in the next 6 months
• Intending to have an extended vacation (greater than 4 weeks) in the next 6 months
• Unable to communicate in English
• Unable to provide written informed consent

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
central randomisation by phone/fax/computer
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Participants will be randomised, in random blocks of sizes 4–8 using the NHMRC Clinical Trials Centre randomisation service
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

The people analysing the results/data
Intervention assignment
Other design features
Not Applicable
Type of endpoint/s
Statistical methods / analysis
Differences between groups in primary and secondary outcomes during (3 months), and at the end of the intervention (6 months) will be tested using mixed models accounting for repeated measures, and adjusting for baseline values and potential confounders. Outcomes are all continuous and expected to be either normal or log-normal, in which case log-transformation will be used. Possible confounders will be narrowed down to a number that can be modelled without overfitting, based on an objective criterion not open to manipulation (backwards elimination, p<0.2 association with the outcome). Analyses will follow intention-to-treat principles. Sensitivity to missing data handling will be evaluated by comparing results for completers’ analyses and alternative methods that are appropriate for different missing data scenarios (eg selection-covariate adjusted completers’ analysis and multiple imputation). Analyses will be performed in STATA version 13 or higher. Significance is set at p<0.05 two-tailed, with significance adjustment for the two primary outcomes.
added 16th August 2020:
Sample size
With an estimated 20% attrition based on our previous intervention trials, 2-tailed significance of 2.5% (correcting for 2 primary outcomes), 125 participants per group (250 total) are required for 80% power to detect minimum differences of interest in HbA1c and sitting of 0.5% and 0.5h/16h-day, assuming standard deviations (SD) of 1.6 and 1.3 and a pre-post correlation (r) of 0.7 and 0.6 respectively. A 0.5% HbA1c decrease is clinically meaningful (˜10% reduction in diabetes-related mortality) and about average for physical activity advice interventions that achieve behaviour change. The calculations assumed standard deviations and pre-post correlations (SD, r) of (1.6, r=0.7) for HbA1c and (1.3, r=0.6) for sitting. Assumptions concerning attrition, SD and r for primary and most secondary outcomes were based on Living Well with Diabetes (27) , AusDiab (28) and Stand Up Victoria (29) studies. With this sample size, the minimum detectable differences for secondary outcomes with 80-90% power, 5% significance are: 0.6–0.7 h/16h day prolonged sitting (1.8, r=0.6); 1.0–1.1 mmol/L fasting glucose (3, r=0.6); 23–26 pmol/L fasting insulin (70, r=0.6); 0.35–0.40 SD 2-h iAUC for post-load glucose and insulin (r=0.5); 0.5–0.6 mmol/L fasting triglycerides (1.5, r=0.6); 0.08–0.09 mmol/L fasting HDL (0.3, r=0.8); 0.26–0.30 mmol/L fasting LDL (0.9, r=0.7); 0.8–1.0 DXA-total % body fat (10, r=0.98); 0.4–0.5 DXA-leg lean mass (4.5kg, r=0.98); 0.05–0.06 DXA-abdominal body fat (0.6kg, r=0.98); 1.2–1.4 FMD(%) (4, r=0.7); 5.2–6.0 mmHg systolic and 3.1–3.6 mmHg diastolic BP (15 and 9, r=0.5). Recruitment projections prior to the study indicated 250 participants to be feasible. Recruitment will stop when the study reaches either the required sample size or the maximum number of participants who can be recruited in the study’s allotted recruitment timeframe while complying with the unforeseeable restrictions and conditions related to the COVID-19 pandemic.

The sample size for the cognitive function outcomes are dictated by the original sample size calculations described above Out of a sample size of 250, we anticipate 160 participants (80 in each arm) will complete the 12-month assessment. This sample size of 80 per group provides >80% power (5% 2-tailed significance) to detect our minimum difference of interest in the primary outcome of visual memory at 12 months (1/3 SD, d=0.33) assuming r=0.7, based on a previous trial. The sample size is sufficient to detect small effects (d=0.2–0.5) in the secondary cognitive neurotropic and inflammatory biomarker outcomes, based on assumptions informed by the literature and our previous RESCUE and Living Well after Breast Cancer studies (cognitive outcomes, IL-6, C-Reactive Protein). The minimum detectable differences (standardised effect sizes (d)) with 80-90% power (5% 2-tailed significance) are: 0.32-0.37 for attention and psychomotor control, short term visual recognition memory z-scores (r=0.7, SD=1) ; 0.39-0.45 memory and executive function z-score (r=0.5, SD=1); 2.0-2.3 ng/ml BDNF (SD=10, r=0.9); 8.0-9.3 ng/ml IGF-1 (SD=30, r=0.8); 6.0-6.9 pg/ml IL-6 (SD=15, r=0.45); 0.38-0.44 mg/dl C-Reactive Protein (SD=1.2, r=0.7), 2.0-2.3 pg/ml TNF-a, 2.0-2.3 pg/ml (SD=10, r=0.9); 0.67-0.77 µg/ml adiponectin (SD=2.5, r=0.8); 2.9-3.4 ng/ml Leptin (SD=15, r=0.9); 0.49 - 0.56 Leptin-Adiopnectin ng/µg ratio (SD=2.5 r=0.9). Minimum detectable differences will be recalculated if the actual sample size is lower than projected due to the potential impact of the COVID-19 pandemic.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment postcode(s) [1] 23196 0
3004 - Melbourne

Funding & Sponsors
Funding source category [1] 299989 0
Government body
Name [1] 299989 0
National Health and Medical Research Council
Country [1] 299989 0
Primary sponsor type
Baker Heart and Diabetes Institute
Baker Heart and Diabetes Institute
Level 4, 99 Commercial Road,
Melbourne Vic 3004 Australia
Secondary sponsor category [1] 299370 0
Name [1] 299370 0
Address [1] 299370 0
Country [1] 299370 0

Ethics approval
Ethics application status
Ethics committee name [1] 300844 0
'Alfred Hospital Ethics Committee
Ethics committee address [1] 300844 0
55 Commercial Rd,
Melbourne VIC 3004
Ethics committee country [1] 300844 0
Date submitted for ethics approval [1] 300844 0
Approval date [1] 300844 0
Ethics approval number [1] 300844 0

Brief summary
Approximately 250 volunteers will be required for this study. The study will test whether a 6-month multicomponent intervention (involving health coaching, sit-stand workstations at work, and a smartphone behavioural promoting tool) can reduce daily sitting time and improve blood glucose control as well as risk markers for cardiovascular disease (blood pressure and blood vessel health). The results of this trial will build on our understanding of the cardiometabolic consequences (i.e. high risk of developing heart disease) of too much sitting in individuals with type 2 diabetes and will help design intervention strategies in the community to reduce the risk of developing complications associated with diabetes.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 85006 0
Prof David Dunstan
Address 85006 0
Baker Heart and Diabetes Institute
Level 4, 99 Commercial Road,
Melbourne Vic 3004
Country 85006 0
Phone 85006 0
Fax 85006 0
Email 85006 0
Contact person for public queries
Name 85007 0
Ms Ruth Grigg
Address 85007 0
Baker Heart and Diabetes Institute
Level 4, 99 Commercial Road,
Melbourne Vic 3004
Country 85007 0
Phone 85007 0
+61 385321845
Fax 85007 0
Email 85007 0
Contact person for scientific queries
Name 85008 0
Ms Ruth Grigg
Address 85008 0
Baker Heart and Diabetes Institute
Level 4, 99 Commercial Road,
Melbourne Vic 3004
Country 85008 0
Phone 85008 0
+61 385321845
Fax 85008 0
Email 85008 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment

What supporting documents are/will be available?

No Supporting Document Provided

Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.