Diabetes

nicky Gilbert lead Research Dietitian, intervention Co-ordinator and Group instructor pRevieW study, university of nottingham

Dr moira taylor, associate professor of human nutrition (Dietetics), university of nottingham pRevieW team

Cheryl percival, Group instructor pRevieW study university of nottingham

laura helm, Research Dietitian pRevieW study university of nottingham

please see end of article for details of other contributors.

introduCinG the preView Study:

preVention of diabetes through lifestyle intervention and population studies in europe and around the world

preView: preVention of diabetes through lifestyle intervention and population studies in europe and around the world

PREVIEW is an acronym of PREVention of diabetes through lifestyle Intervention and population studies in Europe and around the World. This collaborative research project (led by Professor Anne Raben from the University of Copenhagen) is funded by the European Union in its 7th Framework Programme. Eight European (Bulgaria, Denmark, Finland, Germany, Great Britain, Netherlands, Spain, Switzerland) and three overseas countries (Australia, Canada, New Zealand) are involved in the project, which started in January 2013 and will run until December 2018.

baCKGRounD In the last century, Type 2 diabetes (T2D) was named ‘adult-onset diabetes’, because it was mainly older people who suffered from it. However, T2D is now affecting children and adolescents and having T2D not only means living life in a rigid manner (e.g. by having to watch what to eat), but also confers a higher risk of developing diseases such as high blood pressure, coronary heart diseases and chronic kidney failure, to name a few. Despite this global rise in T2D, it is a condition that may be prevented.

Type 2 diabetes accounts for about 90 percent of all cases of diabetes, primarily caused by the worldwide obesity epidemic (1). The relative risk of getting T2D rises exponentially with increasing body mass index (BMI); a BMI above 23kg/m² already doubles the risk of getting T2D (2). The increasing prevalence of obesity is caused by general food abundance together with increased sedentariness (sitting time in front of the TV, computer, etc) and decreased physical activity during work and leisure time (3). Recent studies have also indicated that stress and certain sleeping patterns may also promote overweight and obesity.

Indeed, short sleep appears to increase appetite and may be particularly pertinent in increasing obesity and its related diseases (4, 5).

Diabetes is a costly condition; according to WHO, the direct healthcare costs of diabetes range from two and a half percent to 15 percent of annual national healthcare budgets (6). This worrying trend calls for action and a need for a variety of innovative approaches to address the problem. One key to success is the prevention of overweight and obesity. Another is to help obese people lose weight and maintain a reduced body weight.

In order to successfully fight against T2D, there are two major questions that still need to be answered: “What type of diet is most effective?” and “How intense should physical activity be performed to be able to maintain weight loss?” Both questions are addressed in the PREVIEW study and the public health and socio-economic impact of PREVIEW is expected to be significant.

aims The primary goal of PREVIEW is to identify the most efficient lifestyle pattern for the prevention of Type 2 diabetes in a population of pre-diabetic,

overweight or obese individuals in Europe and overseas countries. The project comprises of two approaches: 1) A multicentre randomised lifestyle intervention trial of three-year duration, with a recruitment target of 2,500 pre-diabetic participants, including children and adolescents, adults and the elderly. 2) An epidemiological project, investigating the natural history of T2D and its cardiovascular consequences, according to specific dietary and exercise factors (i.e. protein and GI of diet as well as physical activity intensity), using a large database comprising information that covers the whole lifespan.

RanDomiseD ContRol tRial PREVIEW consists of six work packages, fig. 1 (see the PREVIEW website http://preview.ning. com/). At the University of Nottingham, led by Professor Ian Macdonald (Principal Investigator), we are focusing on Work package 1 (WP1) which is a randomised controlled and multicentre trial directed by Professor Mikael Fogelholm (Helsinki University).

participant recruitment In Nottingham we have recruited 265 adults between the ages of 25 and 70 years. Participants were selected by GPs from details held on their databases and were approached by letter inviting them to participate in an initial telephone screening. Using a scoring system (Diabetes Risk Questionnaire), suitable participants were then invited for diagnostic tests at the Medical School in the Queen’s Medical Centre. Those meeting the study inclusion criteria were invited to join the study.

Weight reduction phase For the first eight weeks of the intervention, participants attend fortnightly group meetings with a registered dietitian. The emphasis of these group meetings is to support and guide participants towards achieving a target weight loss of eight percent of their initial body weight by following a prescribed low energy diet (approximately 800kcal per day), with products supplied free of charge by the Cambridge Weight Plan Ltd. The content of each group meeting is carefully planned to develop and improve knowledge of T2D and lifestyle modification, whilst also introducing behavioural modification techniques and tools to support the required changes in lifestyle after this phase. Group dynamics are especially nurtured to promote a supportive and friendly environment that will continue throughout the

Several studies have indicated that protein promotes greater satiety and weight loss, but higher protein diets can be more expensive and there is a need to assess safety, acceptability and effectiveness in the longer term.

study. Exercise is not encouraged during this phase, but participants are prepared for increasing activity when this phase is finished.

the weight maintenance phase Those who achieve their eight percent weight loss target enter the 136-week weight maintenance phase of the intervention and are introduced to their randomisation group for diet and exercise.

DietaRy ReCommenDations There are two dietary approaches being compared in PREVIEW. One diet includes foods with a medium GI and a moderate protein intake of 15 percent of energy intake, whilst the alternative incorporates foods with a lower GI and modestly more protein (25 percent of energy).

Several studies have indicated that protein promotes greater satiety and weight loss, but higher protein diets can be more expensive and there is a need to assess safety, acceptability and effectiveness in the longer term. Lower GI diets have been associated with greater body fat loss in some studies, but the evidence is not consistent. The GI concept has been criticised as ‘too complex’ for the average person to translate into practice. Therefore, the PREVIEW intervention compares two healthy diets with slightly different protein content and GI, to determine which is the most efficient at reducing the risk of developing T2D. Both diets are healthy and varied, high in fibre, low in total fat, saturated fat and added sugar. We hypothesise that one diet will be more satiating and help to maintain weight loss over a long period of time. If this is realised, this diet is also likely to reduce the risk of developing Type 2 diabetes. making the dietary changes Participants are initially supported in following their dietary prescription by using a structured two-week menu plan with recipes. A unit ‘swap’ system for each food group is then introduced, allowing participants control and flexibility to personalise their meal plans to suit their preferences, appetite and lifestyles. Mindful eating and related behaviour are fundamental to the dietary interventions. Participants are strongly encouraged to eat ‘ad libitum’ and to ‘eat to appetite’ and also to stop eating before they feel full.

physiCal aCtivity ReCommenDations There is good evidence that physical activity (PA) is a crucial behaviour to keep healthy and, in many cases, it is an efficient and inexpensive way to regain health. Despite persuasive evidence, PA seems to be very difficult to realise with the majority of adults and an increasing proportion of young people, failing to achieve sufficient volume of PA for health. Instead of being active, they have a sedentary and inactive lifestyle.

PA is any movement that involves the skeletal muscles and results in increased energy expenditure. Exercise is a subcategory of PA that is planned, structured, purposeful, and repetitive. Sedentary time is more difficult to define, but generally involves sitting or lying where energy expenditure drops to around one and a half times the resting level. The volume of PA is composed of intensity, duration and frequency. The question for PREVIEW is, how much and how intense should PA be, in order to prevent a severe disease like Type 2 diabetes? The World Health Organisation recommends 150 minutes moderate intensity activity and/or 75 minutes of high intensity PA per week. PREVIEW will investigate which of these two recommendations is more effective at preventing Type 2 diabetes.

After the weight reduction phase, participants meet with their group fitness instructor and are introduced to their physical activity recommendations; either high intensity (HI) or moderate intensity (MI). During the next few months of the intervention participants are supported by fitness instructors in group meetings to become fitter and more active, eventually achieving the required PA behaviours. Participants are encouraged to take up a variety of structured activities to suit their lifestyles, as well as becoming more active in everyday pursuits and less sedentary.

integration with behaviour modification Emphasis on behaviour modification strategies is a key feature of PREVIEW and all group instructors, dietitians and fitness instructors have been trained in the specific package of techniques, designed for PREVIEW by our partners at Stuttgart University, known as PREVIEW PREMIT (PREVIEW Behaviour Modification Intervention Toolbox). These techniques are utilised in group meetings through all aspects of the intervention.

The ‘phasing out’ approach of the intervention means that group meetings, which initially occur fortnightly, gradually stretch out to six monthly by year three. Participants are strategically guided to acquire skills which will promote maintenance of their PREVIEW lifestyle behaviours.

ouR expeRienCes so faR The two years that we have been working on PREVIEW have been nothing less than exciting, exhilarating and intensive for our team in Nottingham. Members of the team were involved from the start in shaping aspects of the dietary intervention programme. For example, how we would achieve specific individual protein and glycaemic index targets for participants across relatively diverse cultures, whilst ensuring that the intervention programme remains practical for application at a population level. We also contributed to the development of centrally produced documents and resources and the refining of inclusion and exclusion criteria.

Detailed lesson plans for use in Nottingham were developed for all group meetings, which integrated dietary targets and behavioural techniques at each stage in the intervention. Comprehensive materials were, and continue to be, developed to support and inspire participants to follow their diet and exercise programmes. Contributions and suggestions are also obtained from participants and these are published in a newsletter distributed to all participants bimonthly.

Group meetings are frequent and the timetable is busy; in the first six months of this year, we will have run nearly 70 group meetings across 16 cohorts of participants. In order to ensure consistency in delivering the intervention with our colleagues worldwide, we co-lead the Instructor’s Network which operates as an email-based discussion forum, with monthly teleconferences to share experiences and solve any problems which may arise.

Recruitment has finally finished, but has been a major logistical challenge; around 50, 000 letters have been sent out to potential participants, resulting in 980 screenings to recruit 265 participants. Our team have had many skills to develop, as well as frustrations and trials to overcome, to ensure smooth running of the study. On a daily basis, there are ongoing challenges to ensure participant motivation, interest and compliance prevails. However, the formation of a stable team of dedicated and enthusiastic individuals is making PREVIEW possible. We are ever grateful to all our participants and are motivated and encouraged by the strength, determination and successes of many, who have not only changed shape, size and body composition, but are enjoying improved health and embracing a better quality of life. We look forward to sharing further information and findings in due course.

Other contributors to the article: Liz Simpson, nottingham, Uk; Wolfgang Schlicht, Stuttgart, germany; Jennie Brand-Miller, Sydney, australia; gareth Stratton, Swansea, Uk

References 1 Wild S, Roglic G, Green a et al (2004). Global prevalence of diabetes. Diabetes care, 27: 1047-1053 2 Hu FB, Manson Je, Stampfer MJ et al. New eng J Med, 2001;345 (11): 790-7 3 Swinburn Ba, Sacks G, Hall KD et al. Lancet, 2011: 378:804-14 4 Kobayashi D, takahashi O, Deshpande Ga et al. Sleep Breath, 2012;16: p 829-33 5 Fogelholm M, Kronholm e, Kukkonen-Harjula K et al. Int J Obes (Lond), 2007: 31:1713-21 6 WHO (2015). Diabetes: the cost of diabetes fact sheet No 236