The Effects of Reducing Prolonged Sitting Bouts in Individuals at High Risk of or With Type 2 Diabetes
Condition: Type 2 Diabetes Mellitus
MeSH terms: Diabetes Mellitus; Diabetes Mellitus, Type 2
Study type: Interventional

Summary: 
      Over 3 million in the United Kingdom are now diagnosed with type 2 diabetes, with current
      estimates suggesting this will rise to over 5 million by 2025. Type 2 diabetes increases the
      risk of developing cardiovascular disease, kidney disease, depression, neuropathy and
      dementia, along with being a leading cause of amputation and adult blindness.

      Sedentary behaviour, defined as any waking moment spend sitting or reclining with energy
      expenditure equal to or less than 1.5 METs, has emerged as a risk factor in the development
      of type 2 diabetes. Recent evidence has shown that breaking up prolonged sitting with regular
      short bouts of activity or standing lower postprandial glucose and insulin. However, the
      effectiveness of breaking prolonged sitting on glucose metabolism over a longer period of
      time is unknown. Therefore, the aim of this study is to investigate whether the reduction in
      postprandial plasma glucose in response to breaking prolonged sitting time is maintained
      following an intervention to reduce and break up prolonged sitting over a four to five week
      period.

      The study will be a single group intervention with pre and post randomised measurement
      conditions (prolonged sitting and light upright breaks) at both time points. A sample of 43
      people (34 to complete), aged 50-75, identified as at risk of or with (drug naive) type 2
      diabetes will be sought. The intervention will last approximately 5 weeks. Experimental
      conditions will be conducted before and after the intervention to assess whether reducing and
      breaking up prolonged sitting in free living effects glucose metabolism.
    

Detailed description: 
      Study Design

      This study consists of an intervention lasting approximately 5 weeks (depending on follow-up
      measurement timings), with a before and after 'two-arm' randomised crossover design, one
      prior to the intervention and one at the end of the intervention used as measurement periods.
      Screening will require one laboratory visit, with the study commencing one week following
      baseline. The intervention will last a minimum of four weeks, while the measurement
      conditions will each involve two laboratory days separated by a minimum of five days. The
      duration from screening through to study end will be an estimated 9 weeks. This trial will
      evaluate the effectiveness of regular light upright movement breaks at reducing glucose iAUC
      by examining if acute adaptations to sitting time are maintained or improved following the
      behavioural intervention.

      Study Setting

      The study will be co-ordinated within the Leicester Biomedical Research Centre (Leicester
      Diabetes Centre) at the Leicester General Hospital. Clinical measurement sessions will be
      carried out by the appointed research team. Participants will be asked to visit the study
      centre on seven occasions.

      Measurement conditions

      Measurement condition A will consist of seven and a half hours of prolonged sitting, where
      participants will be restricted from walking or standing for the duration. Lavatory breaks
      will be carried out using a wheelchair to transport the participant to minimise time spent
      upright. The condition will be conducted in the laboratory at the Leicester Diabetes Centre.
      Participants will have access to a computer with internet services, books and magazines for
      the duration of the measurement day.

      Upon arrival, the participant will have a cannula inserted into an accessible vein by a
      trained member of the study team, which will be used to collect blood samples throughout the
      measurement day. Blood pressure will be taken prior to each blood sample, while visual
      analogue scales for hunger, energy, fullness, satiety, desire to eat and fatigue will be
      completed following each blood sample. The first blood sample will be taken at the start of
      the 'steady state' following anthropometric measurements. The next sample will be taken one
      hour after the first sample. Following this, participants will be given a standardized meal
      consumed over a maximum of 15 minutes. Blood samples will be then be taken at 30, 60, 120 and
      180 minutes after commencing eating. Another standardized meal and the same schedule of blood
      sampling will take place following the blood sample taken 180 minutes postprandial to the
      first meal. Meals will be based on body weight, with eight kcals per kg of body weight, made
      up of 52% carbohydrate, 35% fats and 13% protein.

      Measurement condition B will follow the same procedures as condition A in terms of
      standardised meals, blood sampling, blood pressure, visual analogue scales and meal
      consumption. Similarly, participants will be allowed access to a lavatory in the same way as
      condition A, as well as have access to a computer, books, magazines and other typical
      sedentary pursuits. The only difference in this measurement condition to condition A, is that
      participants will regularly break their sitting time, for five minutes every 30 minutes with
      upright light movement after sitting quietly for one hour upon arrival and following
      cannulation (steady state). This will involve the participant walking and moving around
      slowly and freely in the testing room and surrounding laboratory. This is to maximise the
      ecological validity of the study, particularly in comparison to studies using a treadmill for
      light walking breaks. Five minute breaks every 30 minutes was chosen as this has previously
      shown positive effects on both glucose metabolism and insulin in postmenopausal women (19).
      Light breaks will accumulate 60 minutes of light upright movement across the measurement day.

      Intervention

      The participants will be encouraged to reduce prolonged sitting by at least 60 minutes per
      day by introducing light upright movement breaks spread throughout their day. The frequency
      and duration of these breaks will be tailored to each participant to suit their individual
      circumstances. A 60 minute reduction is judged to be clinically meaningful. For example, a
      modelling study found that replacing 60 minutes of sedentary time with light movement was
      associated with around 20% better insulin sensitivity in those with dysglycemia.

      The intervention will involve one participant face-to-face session, lasting approximately two
      hours. It will also involve personalised feedback which will review progress and goals based
      on the baseline data. The visit will involve personalised education and goal setting, based
      on objective measures of sitting time taken at baseline. These data will be explained to the
      participant, which will then form the basis of a plan to reduce prolonged bouts of sitting
      with light movement. This session will also explain what is meant by light movement, as well
      as identifying a number of different ways to break prolonged bouts effectively. Participants
      will be encouraged to self-monitor their sitting time, with specific examples of how his can
      be achieved depending on the needs of the participant. They will be given an accelerometer to
      be worn for the duration of the four week intervention.

      The participant will receive feedback from a member of the study team on at least a weekly
      basis (more frequently feedback expected in the early weeks) in regards to current sedentary
      behavior and movement time. Data received from the accelerometer or self-monitoring device
      will be used to discuss the positives and negatives of the previous days or week's behaviour.
      These will be talked through and adjustments made to the goals if needed. The feedback
      sessions will take place primarily over the telephone, however if the participant would like
      to visit the Leicester Diabetes Centre for these sessions that will be made available to
      them. All feedback is personalised meaning it will be different for each participant in terms
      of the data fed back as well as the timings of each feedback session
    

Intervention name(s): Reducing/breaking prolonged sitting
Intervention type(s): Behavioral
Intervention description(s): The participants will be encouraged to reduce prolonged sitting by at least 60 minutes per day by introducing light upright movement breaks spread throughout their day. The frequency and duration of these breaks will be tailored to each participant to suit their individual circumstances.
The intervention will involve education regarding the health implications of prolonged sitting, personalised goal setting, behavioural feedback and self-monitoring of behaviour.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Sedentary Behaviour; Prevention