Investigating the Acute Effect of Alternative Forms of Physical Activity in a Multi-ethnic Population
Condition: Type 2 Diabetes Mellitus
MeSH terms: Diabetes Mellitus, Type 2
Study type: Interventional

Summary: 
      The amount of people with diabetes has now reached over 4 million in the United Kingdom. Type
      2 Diabetes accounts for the majority of all cases of diabetes and increases the risk of many
      other diseases, such as heart disease.

      Research has shown that individuals from South Asian descent have elevated risk of certain
      chronic diseases, such as type 2 diabetes and cardiovascular disease. The risk of developing
      these diseases can be reduced by engaging in a healthy lifestyle. One component of a healthy
      lifestyle is engaging in physical activity. However, previous research has shown that South
      Asian individuals engage in less physical activity, compared to other ethnicities. It is not
      yet wholly understood why South Asians engage in less physical activity, but it is vitally
      important to try and find new ways to increase South Asian physical activity levels.
      Therefore, the investigators have worked with South Asian communities in identifying
      culturally appropriate forms of physical activity. From this, yoga and walking were
      identified as two forms of culturally appropriate physical activity. This study will test and
      compare whether yoga and light intensity walking can be effectively used in the prevention of
      type 2 diabetes. The results of this study will help the investigators and health policy
      makers understand how South Asians and other ethnicities respond to exercise, the therapeutic
      benefits of yoga and help inform future diabetes prevention programmes within multi-ethnic
      communities.
    

Detailed description: 
      Physical activity, commonly defined as any movement of skeletal muscle that requires low-mid
      level energy expenditure has long been associated with improving cardiometabolic health.
      Furthermore, increased PA has more recently been associated with decreased all-cause and
      chronic disease mortality. Evidence on lifestyle risk factors such as PA continues to grow
      and demonstrate associations with improved health. Interestingly, evidence has suggested type
      2 diabetes is a 'lifestyle disease', with 80-90% of the prevalence in any given ethnic group
      explained by lifestyle and environmental factors. This suggests lifestyle factors, such as PA
      and diet may play a pivotal role in the prevention and management of T2D. The number of
      individuals with diabetes has risen from 108 million in 1980 to 425 million in 2017, with
      global prevalence in over 18 year olds rising from 4.7% to 8.5% in the same time period. This
      illustrates the importance of PA in preventing and managing T2D.

      Diabetes is a disease characterised by chronic hyperglycaemia with disturbances to
      carbohydrate metabolism, resulting from the body's impaired ability to produce or respond to
      insulin. Diabetes can lead to a number of complications which can reduce a person's quality
      of life and life expectancy. The main cause of premature mortality with diabetes is
      cardiovascular disease. Insulin resistance is suggested to be the predominant factor in the
      aetiology of T2D. PA has been shown to be a stimulator of insulin sensitivity, both acutely
      and chronically. Epidemiological data on PA (and other lifestyle habits) and T2D is important
      as it provides associations between exposures and the disease. This research can give a sense
      of an association and where robust evidence reinforces these associations, it can be the
      starting point for initiating disease prevention programmes based on reducing/increasing
      exposure to the risk/preventative factor.

      A systematic review and network meta-analysis of lifestyle, pharmacological and surgical
      interventions stated that lifestyle interventions, which included exercise, are beneficial in
      reducing the risk of developing T2D, compared to standard care. When focusing on lifestyle
      interventions, diet plus exercise plus pedometer had the highest probability of being
      effective (HR 0.35 95% CI [0.11-1.14]). Exercise had the second highest probability of being
      the most effective lifestyle intervention (HR 0.51 95% CI [0.33-0.82]). The Indian Diabetes
      Prevention Programme found improved lifestyle significantly improved cardiometabolic health
      in a 42-month study. Improved lifestyle accounted for educational sessions revolving around
      improving diet and then engaging in PA. When comparing control, metformin, lifestyle and
      lifestyle + metformin groups it was found metformin, lifestyle and lifestyle & metformin
      groups significantly delayed time to diabetes, compared to control. The two groups that
      involved positive lifestyle changes delayed time to diabetes marginally longer than the
      metformin group. The solely lifestyle group delayed time to diabetes the longest over the
      entire 42-month period. Similarly, The Diabetes Prevention Program found that incorporating
      positive lifestyle changes significantly reduced the cumulative incidence of T2D, compared to
      metformin and placebo groups. The lifestyle group were instructed to engage in 150min.week-1
      of PA. There was a 58% reduction in incidence of T2D in the lifestyle group, compared to
      placebo, in a 4-year follow-up. When participants were split into their respective
      ethnicities, American Indians and Asians saw the greatest reductions in T2D incidence. At 10
      year post trial follow up, the lifestyle group still had significantly lower cumulative
      incidence of T2D.

      The molecular mechanisms by which PA affects insulin have been heavily researched. In brief,
      after one bout of exercise there is an immediate increase in glucose uptake to the skeletal
      muscle, which is in response to muscle contraction. This increase is thought to be due to
      increased GLUT-4 translocation to the cell surface, which increases insulin sensitivity.
      Additionally, exercise may increase oxidative metabolism in mitochondria in the skeletal
      muscle. An increase in the size and number of mitochondria in the cells improves oxidative
      capacity, decreasing the amounts of TG and fatty acids. TG and fatty acids interfere with the
      insulin signalling process, which may cause insulin resistance. This reiterates the
      importance of PA in T2D prevention and management. Additionally, physical inactivity and
      sedentary behaviour have both been noted to disrupt normal metabolic state and chronically
      increase insulin resistance/decrease insulin sensitivity.

      Other mechanisms that PA may improve T2D by are improving lipoprotein profile, endothelial
      function (and subsequently hypertension), reducing obesity and increasing anti-inflammatory
      effects.

      Evidently, PA is vitally important in the prevention and management of T2D. However, rates of
      PA are worryingly low in the UK and globally. Globally, it is stated 1 in 4 adults are not
      active enough and more than 80% of world's adolescent population are insufficiently
      physically active (WHO). Within the UK, 39% (20 million) of adults do not meet recommended
      guidelines for PA. Importantly, PA levels in UK South Asian populations are reported to be
      lower, compared to White European populations. This trend is particularly evident among women
      and older individuals. Consequently, specific ethnicities may need culturally appropriate and
      alternative forms of PA to engage them. To date, public health guidelines have largely been
      based on results from studies in Caucasian populations. It is essential that governments and
      public health organisations engage individuals in more novel, appropriate and culturally
      specific practices.

      Therefore, researching culturally appropriate and alternative forms of exercise is important
      in understanding whether different types of exercise will engage individuals more and improve
      adherence, ultimately improving health. For example, SAs form the largest ethnic minority
      group in the UK and 1 in 5 individuals globally and while it is known PA can positively
      impact the health of SAs, it is not fully understood what types of PA can engage SA ethnic
      groups most effectively. This is of particular importance because the prevalence of T2D is 2
      to 4 times higher in SAs, compared to WEs. India is estimated to have a diabetes prevalence
      of 134.3 million by 2045, with Pakistan and Bangladesh estimated at 16.1 and 13.7 million,
      respectively.

      Accordingly, culturally appropriate forms of exercise are needed. Intervention trial data has
      suggested that yoga may yield similar health benefits to conventional exercise. Yoga is an
      ancient Indian tradition that embodies unity of body, mind, emotion and energy and has been
      part of traditional Indian spiritual practice for millennia. There are different forms of
      yoga that focus on slightly different aspects of one's self, with these respective
      philosophies varying focus on meditation (dhyana), body postures (asana) and breathing
      techniques (pranayama). Regardless of these different philosophies, yoga has over recent
      years become more prominent in improving physical and mental wellbeing worldwide.

      Two recent systematic reviews on yoga and T2D state yoga improves HbA1c, fasting blood
      glucose and postprandial blood glucose. Additionally, significant improvements were found in
      lipid profile, blood pressure and body composition. Overall, the metabolic benefits of yoga
      are not fully understood, particularly in those at high-risk of T2D. Further research is
      required on the metabolic benefits of yoga. Additionally, it is suggested that yoga may also
      have benefits to mental health, quality of life and emotional state. Data are needed to
      evaluate how individuals may respond psychologically to yoga, compared to traditional
      exercise, especially when used as a therapy to improve metabolic health in those at high
      diabetes and cardiovascular risk.

      There is a gap in the literature investigating the metabolic benefits of culturally
      appropriate and alternative forms of exercise in different ethnicities. Specifically, there
      is a lack of high-quality research investigating the health benefits of yoga in relation to
      T2D prevention, and comparing health benefits of yoga and traditional forms of PA. Therefore,
      this research will investigate the effects of yoga on glycaemic control in a multi-ethnic
      population at risk of type 2 diabetes and to compare these effects against matched
      traditional exercise and a non-exercise control.

      Statistical design Based on a previous study undertaken by the investigators group in a
      multi-ethnic population (https://clinicaltrials.gov/ct2/show/NCT02453204), 24 are needed to
      complete the trial. This is based on estimating a reduction in incremental area under the
      insulin curve from 76 to 53 mU/l x hr (30% reduction) in either exercise intervention group,
      a standard deviation of 38 mU/l x hr, a within person correlation of 0.05, a power of 80% and
      a significance of 0.05.

      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 six occasions.

      Study design This study is a three period crossover design. There are three experimental
      conditions (yoga, continuous exercise and control) and participants will be randomised to one
      of six sequences requiring them to complete all three conditions.
    

Intervention name(s): Physical activity
Intervention type(s): Behavioral
Intervention description(s): Light-moderate intensity physical activities
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: This study is a three period crossover design. There are three experimental conditions (yoga, continuous exercise and control) and participants will be randomised to one of six sequences requiring them to complete all three conditions.
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Type 2 diabetes; ethnicity; physical activity; yoga