Physical Activity/Exercise and Type 2 Diabetes Effect of communicating genetic and phenotypic risk for type 2 diabetes in combination with lifestyle advice on objectively measured physical activity: protocol of a randomised controlled trial Lifestyle intervention according to general recommendations improves glucose tolerance. Prevention of type 2 diabetes - where is the evidence? The Diabetes Prevention Program. Design and methods for a clinical trial in the prevention of type 2 diabetes. Study on lifestyle-intervention and impaired glucose tolerance Maastricht (SLIM): design and screening results. Effects of a Mediterranean-Style Diet on the Need for Antihyperglycemic Drug Therapy in Patients With Newly Diagnosed Type 2 Diabetes Improved lifestyle and decreased diabetes risk over 13 years: long-term follow-up of the randomised Finnish Diabetes Prevention Study (DPS) Do simple questions about diet and physical activity help to identify those at risk of Type 2 diabetes? Living Well with Diabetes: a randomized controlled trial of a telephone-delivered intervention for maintenance of weight loss, physical activity and glycaemic control in adults with type 2 diabetes
For decades , exercise has been considered a cornerstone of diabetes management , along with diet and medication . However , high- quality evidence on the importance of exercise and fitness in diabetes was lacking until recent years . The present document summarizes the most clinical ly relevant recent advances related to people with type 2 diabetes and the recommendations that follow from these . Our recently published technical review on physical activity/exercise and type 2 diabetes ( 1 ) includes greater detail on individual studies , on prevention of diabetes , and on the physiology of exercise . The present statement focuses on type 2 diabetes . Issues primarily germane to type 1 diabetes will be covered in a subsequent technical review and ADA Statement . The levels of evidence used are defined by the ADA in ref . 2 . Two r and omized trials each found that lifestyle interventions including ∼150 min/week of physical activity and  diet-induced weight loss of 5–7 % reduced the risk of progression from impaired glucose tolerance ( IGT ) to type 2 diabetes by 58 % ( 3,4 ) . A cluster-r and omized trial found that diet alone , exercise alone , and combined diet and exercise were equally effective in reducting the progression from IGT to diabetes ( 5 ) . Therefore , there is firm and consistent evidence that programs of increased physical activity  and modest weight loss reduce the incidence of type 2 diabetes in individuals with IGT . Boule et al. ( 6 ) undertook a systematic review and meta- analysis on the effects of structured exercise interventions in clinical trials of ≥8 weeks duration on HbA1c ( A1C ) and body mass in people with type 2 diabetes . Postintervention A1C was significantly lower in exercise than control groups ( 7.65 vs. 8.31 % , weighted mean difference −0.66 % ; P < 0.001 ) . In contrast , postintervention body weight did not differ between the exercise and control groups . Meta-regression confirmed that the beneficial effect of exercise on A1C Type 2 diabetes ( T2D ) is associated with increased risk of morbidity and premature mortality . Among those at high risk , incidence can be halved through healthy changes in behaviour . Information about genetic and phenotypic risk of T2D is now widely available . Whether such information motivates behaviour change is unknown . We aim to assess the effects of communicating genetic and phenotypic risk of T2D on risk-reducing health behaviours , anxiety , and other cognitive and emotional theory-based antecedents of behaviour change . In a parallel group , open r and omised controlled trial , approximately 580 adults born between 1950 and 1975 will be recruited from the on-going population -based , observational Fenl and Study ( Cambridgeshire , UK ) . Eligible participants will have undergone clinical , anthropometric , and psychosocial measurements , been genotyped for 23 single-nucleotide polymorphisms associated with T2D , and worn a combined heart rate monitor and accelerometer ( Actiheart ® ) continuously for six days and nights to assess physical activity .  Participants are r and omised to receive either st and ard lifestyle advice alone ( control group ) , or in combination with a genetic or a phenotypic risk estimate for T2D ( intervention groups ) . The primary outcome is objective ly measured physical activity . Secondary outcomes include self-reported diet , self-reported weight , intention to be physically active and to engage in a healthy diet , anxiety , diabetes-related worry , self-rated health , and other cognitive and emotional outcomes . Follow-up occurs eight weeks post-intervention . Values at follow-up , adjusted for baseline , will be compared between r and omised groups . This study will provide much needed evidence on the effects of providing information about the genetic and phenotypic risk of T2D . Importantly , it will be among the first to examine the impact of genetic risk information using a r and omised controlled trial design , a population -based sample , and an objective ly measured behavioural outcome . Results of this trial , along with recent evidence syntheses of similar studies , should inform policy concerning the availability and use of genetic risk information . Current Controlled Trials IS RCT OBJECTIVE Changing dietary and physical activity habits has the potential to postpone or prevent the development of type 2 diabetes . However , it needs to be assessed whether moderate interventions , in agreement with current guidelines for the general population , are effective . We evaluated the impact of a 2-year combined diet and physical activity intervention program on glucose tolerance in Dutch subjects at increased risk for developing diabetes . RESEARCH METHODS AND PROCEDURES Subjects with glucose intolerance were r and omly assigned to either the lifestyle intervention group ( INT ) or control group ( CON ) . The INT received regular dietary advice and was stimulated to increase their physical activity . The CON received a brief leaflet about healthy diet and increased physical activity . Primary outcome measure was the change in glucose tolerance . RESULTS In total , 88 subjects completed 2 years of intervention ( 40 subjects in the INT , 48 subjects in the CON , mean BMI 29.4 kg/m2 ) . Subjects in the INT reduced their body weight , waist circumference , and ( saturated ) fat intake and improved their aerobic capacity . Two-hour plasma glucose concentration declined from 8.7 to 8.0 mM in the INT and rose from 8.6 to 9.4 mM in the CON ( p < 0.01 ) . Subjects adherent to both the diet and exercise intervention showed the largest reduction in 2-hour glucose levels . DISCUSSION Our results showed that a lifestyle intervention program according to general recommendations improves glucose tolerance , even in a less obese and more physical active population . Furthermore , our results underscore the importance of combining diet and physical activity to improve glucose tolerance and insulin resistance Diabetes is an “ old disease ” . The first description of diabetes written on papyrus about 3500 years ago is found in the Ebers papyrus  , which was discovered in Egypt in 1873 by the German archeologist Georg Ebers . Humans , like most mammals , may develop diabetes , if sufficient environmental exposure to physical inactivity , unhealthy diet and obesity are present . Genetic effects are important for the individual risk of type 2 diabetes ( T2D ) but twin studies have shown that the genetic effects combined explain less than 50 % of the risk of T2D ( 1 ) . Today we know almost 100 susceptibility genes associated with T2D but the relative importance of each of these genes is low ( 2 ) , and together they explain only a small part of the disease risk . Thus , genetic screening can not be used for the prediction of T2D for individuals . On the other h and , healthy lifestyle can also prevent T2D in people who are genetically at high risk , e.g. those with positive family history ( 3 ) . Thus , the importance of lifestyle factors for the development and prevention of T2D is overwhelming . The strongest evidence in medicine is considered to come from r and omized controlled trials ( RCTs ) . They are also important in providing the link to causal inference that in most observational studies can not be derived . At the same time , observational studies are necessary for the identification of factors associated with an increased or decreased risk of a disease , and for generation of hypotheses on potential means for prevention based on modifiable risk factors . Observational studies have by now identified a large number of factors that are associated with the development of T2D or with the protection against it . Most of them are related to physical activity , diet and obesity . It has also been shown unequivocally that exposures ( poor nutrition , infections , smoking , etc . ) during fetal life and early infancy result ing in insufficient development ( often shown as low birth weight ) also predict T2D later in life ( 4 ) . Traditionally , T2D has been considered to be a disease of the elderly . However , with increasing obesity and sedentary lifestyle in children , there are increasing numbers of cases of T2D already occurring at a young age in many population s ( 5 ) . In the past two decades several innovative RCTs have repeatedly shown that interventions on modifiable risk factors can reduce the incidence of diabetes in high-risk groups . The evidence has been summarized in several systematic review s and meta-analyses ( 6,7 ) . There is compelling scientific evidence from RCTs that T2D can be prevented or its onset delayed . The key for prevention is a multimodal package of lifestyle changes that is a sum outcome of dietary and physical activity behaviours . The power of lifestyle was dramatically illustrated by the Finnish Diabetes Prevention Study ( DPS ) that explicitly showed that when the study participants with impaired glucose tolerance reached all five modest lifestyle intervention targets , none of them progressed to T2D ( 8) . Importantly , lifestyle intervention lasting for 3–6 years has been shown to have a carry-over effect on T2D incidence that lasts for several years ; up to 15 in the Finnish Diabetes Prevention Study ( 9 ) and 20 years in the China Da Qing Diabetes Prevention Study ( 10 ) . The observed sustained risk reduction seems to be a result of sustained lifestyle changes , but the legacy effect of improved glycaemia during the early intervention may also have contributed to the long-term effect . The follow-up data from the Chinese study indicate moreover that vascular risks are also reduced by lifestyle management . Several prognostic question naires exist for detecting people at risk of T2D ( 11 ) . One of the screening tools with an adequately high sensitivity and specificity is the Finnish Diabetes Risk Score ( FINDRISC ) developed in Finl and ( 12 ) . The FINDRISC has been successfully implemented in the Finnish primary health care system and used also in many other countries . The FINDRISC was also tested in the Omani population and as a result a slightly modified Omani Diabetes Risk Score was developed ( 13 ) which may be a suitable screening tool for the Arab population s in the Middle East . Lifestyle interventions aim ing at translating evidence from efficacy RCTs on T2D prevention into “ real world ” intervention programmes have also been carried out in various population s. Such data were recently combined in a meta- analysis considering the relationship between intervention effectiveness and adherence to guidelines ( 14 ) . The primary meta- analysis included 22 studies with outcome data for weight loss at 12 months . The pooled result of the direct pairwise meta- analysis shows that The Diabetes Prevention Program is a r and omized clinical trial testing strategies to prevent or delay the development of type 2 diabetes in high-risk individuals with elevated fasting plasma glucose concentrations and impaired glucose tolerance . The 27 clinical centers in the U.S. are recruiting at least 3,000 participants of both sexes , approximately 50 % of whom are minority patients and 20 % of whom are > or = 65 years old , to be assigned at r and om to one of three intervention groups : an intensive lifestyle intervention focusing on a healthy diet and exercise and two masked medication treatment groups -- metformin or placebo -- combined with st and ard diet and exercise recommendations .  Participants are being recruited during a 2 2/3-year period , and all will be followed for an additional 3 1/3 to 5 years after the close of recruitment to a common closing date in 2002 . The primary outcome is the development of diabetes , diagnosed by fasting or post-challenge plasma glucose concentrations meeting the 1997 American Diabetes Association criteria . The 3,000 participants will provide 90 % power to detect a 33 % reduction in an expected diabetes incidence rate of at least 6.5 % per year in the placebo group . Secondary outcomes include cardiovascular disease and its risk factors ; changes in glycemia , beta-cell function , insulin sensitivity , obesity , diet , physical activity , and health-related quality of life ; and occurrence of adverse events . A fourth treatment group -- troglitazone combined with st and ard diet and exercise recommendations --was included initially but discontinued because of the liver toxicity of the drug . This r and omized clinical trial will test the possibility of preventing or delaying the onset of type 2 diabetes in individuals at high risk The study on lifestyle-intervention and impaired glucose tolerance Maastricht ( SLIM ) is a 3 years r and omised clinical trial design ed to evaluate the effect of a combined diet and physical activity intervention program on glucose tolerance in a Dutch population at increased risk for developing type 2 diabetes . Here the design of the lifestyle-intervention study is described and results are presented from the preliminary population screening , conducted between March 1999 and June 2000 . In total , 2,820 subjects with an increased risk of having disturbances in glucose homeostasis ( i.e. age > 40 years and BMI > 25 kg/m(2 ) or a family history of diabetes ) underwent a first oral glucose tolerance test ( OGTT ) . Abnormal glucose homeostasis was detected in 826 subjects ( 30.4 % ) : 226 type 2 diabetes ( type 2DM , 8.3 % ) , 215 impaired fasting glucose ( IFG , 7.9 % ) and 385 impaired glucose tolerance ( IGT , 14.2 % ) . Both increasing age and BMI were strongly related to the prevalence of IGT and diabetes . After a second OGTT , 114 subjects with glucose intolerance and in otherwise good health were eligible for participation in the intervention study ( SLIM ) . The high prevalence of disturbances in glucose homeostasis observed in the preliminary screening underscore the importance of early ( lifestyle ) interventions in those at risk for developing diabetes . SLIM will address this topic in the Dutch population Context Mediterranean-style diets improve control of coronary risk factors and hyperglycemia , but few direct comparisons of the diet with other st and ard diets have been done . Contribution In this r and omized clinical trial , patients with newly diagnosed type 2 diabetes who were assigned to a low-carbohydrate , Mediterranean-style diet had better glycemic control and were less likely to need oral antihyperglycemic therapy than patients assigned to a low-fat diet . Caution The trial was unblinded , and dietary intake was self-reported . Implication A low-carbohydrate , Mediterranean-style diet seems to be preferable to a low-fat diet for glycemic control in patients with newly diagnosed type 2 diabetes . The Editors The p and emic of type 2 diabetes is an enormous public health problem , with 380 million cases worldwide projected by 2025 ( 1 , 2 ) . Lifestyle intervention studies ( 3 ) have demonstrated large reductions in risk for type 2 diabetes that remain after lifestyle counseling is stopped ( 4 , 5 ) . Despite this beneficial effect , the American Diabetes Association ( ADA ) recommends that patients with newly diagnosed type 2 diabetes be treated with pharmacotherapy as well as lifestyle changes ( 6 ) . The rationale for combination therapy is presumably that each form of treatment alone is imperfect . Lifestyle changes are often inadequate because patients do not lose weight or regain weight or their diabetes worsens independent of weight ( 6 ) . Pharmacotherapy also often fails with time ( 7 ) , and some drugs have associated cardiovascular and other risks ( 8 , 9 ) . For those reasons , lifestyle changes proven to be more effective than what is typically recommended would be welcome . For example , Mediterranean-style ( MED ) diets with a high proportion of monounsaturated fat provide cardiovascular benefits and increase insulin sensitivity ( 1012 ) , and the ADA recommends low-carbohydrate or low-fat , calorie-restricted diets for weight loss in overweight and obese patients with type 2 diabetes ( 13 ) . However , few direct , long-term comparisons of the 2 diets in patients with diabetes have been done ( 11 ) . We conducted a r and omized trial to compare the effectiveness , durability , and safety of a low-carbohydrate MED diet and a low-fat diet on glycemic control in patients with newly diagnosed type 2 diabetes . Methods We conducted the trial between January 2004 ( first patient enrolled ) and September 2008 ( end of follow-up of the last patient ) at the research center of the Diabetes Clinic of the Azienda Ospedaliera Universitaria , Second University of Naples , Naples , Italy , in accordance with the Declaration of Helsinki and with the institutional review board 's approval . Screening Phase We recruited men and women with newly diagnosed type 2 diabetes by ADA criteria who had never been treated with antihyperglycemic drugs from the clinical practice s of trial investigators and screened them for eligibility . Inclusion criteria were age 30 to 75 years , body mass index ( BMI ) greater than 25 kg/m2 , and hemoglobin A1c ( HbA1c ) level less than 11 % . Participants also had to be sedentary ( < 1 hour of physical activity per week ) with no evidence of participation in weight-reduction programs and with a stable weight ( 2 kg ) in the past 6 months . Exclusion criteria included pregnancy or breastfeeding , use of any investigational drug in the previous 3 months , use of agents affecting glycemic control ( such as systemic glucocorticoids and weight loss drugs ) , and any condition that might compromise adherence to diet regimens . To minimize the likelihood of including participants with late-onset type 1 diabetes , we screened c and i date s by testing for antibodies to glutamate decarboxylase and measuring fasting plasma C-peptides . We excluded patients with positive antibodies or C-peptide levels less than 0.25 pmol/L ( < 0.76 ng/L ) . We also excluded patients with abnormal laboratory test results , including liver enzyme levels ( alanine aminotransferase , aspartate aminotransferase , and alkaline phosphatase ) greater than 3 times the upper limit of normal and serum creatinine levels greater than 123.8 mol/L ( > 1.4 mg/dL ) . We required that participants successfully self-monitor their diet and physical activity over a 2-week run-in period . We provided dietary education during that time that emphasized the importance of eating a healthy diet and being physically active for both weight loss and improvement of glycemic control . Participants were also taught to prepare their own meals at home . We encouraged all individuals who smoked to quit and provided self-help material s , referral to local programs , or both , as appropriate . R and omization and Blinding After obtaining informed consent , we r and omly assigned patients to 1 of the 2 study diets by using a computer-generated r and om-number sequence ( simple r and omization ) . Allocation was concealed in sealed study folders that were held in a central , secured location until after informed consent was obtained . The nurses who scheduled the study visits did not have access to the r and omization list , and laboratory staff did not know the participants ' group assignments . Staff members involved in the intervention were aware of group assignments , but those who assessed achievement of the primary outcome were blinded to the intervention . Participants received no financial compensation or gifts . Dietary Interventions We r and omly assigned patients to a low-carbohydrate MED diet or to a low-fat diet . The MED diet was rich in vegetables and whole grains and low in red meat , which was replaced with poultry and fish . We restricted energy intake to 1500 kcal/d for women and 1800 kcal/d for men , with the goal of no more than 50 % of calories from complex carbohydrates , based on evidence that , in the context of a MED diet , a carbohydrate content less than 50 % of daily energy is more beneficial than higher content for weight loss and cardiovascular risk reduction ( 14 ) . The diet had no less than 30 % calories from fat . The main source of added fat was 30 to 50 g of olive oil . The low-fat diet was based on American Heart Association guidelines ( 15 ) ; it was rich in whole grains and restricted additional fats , sweets , and high-fat snacks . We restricted energy intake to 1500 kcal/d for women and 1800 kcal/d for men , with the goal of no more than 30 % of calories from fat and no more than 10 % of calories from saturated fat . Nutritionists and dietitians gave dietary advice to participants in both groups in monthly sessions in the first year and bimonthly sessions thereafter . Participants kept diet diaries after being instructed how to record their intake using food models as examples of portion size and using actual weights or amounts in terms of common measures ( such as cups , teaspoons , and dessert spoons ) . We assessed adherence to the diets by session attendance and review of the diaries . Nondietary Interventions Patients in both groups also received guidance on increasing their level of physical activity , mainly walking for a minimum of 30 minutes per day , but also swimming or aerobic ball games . The physical activity program relied heavily on home-based exercise with gradual progression toward a goal of 175 minutes of moderate-intensity physical activity per week . Although walking was encouraged , participants were allowed to choose other types of moderate-intensity physical activity , and programs were tailored on the basis of the results of a baseline physical fitness test and safety concerns . We asked all patients to record occupational , household , and leisure time physical activity . Outcomes We followed patients for 4 years to assess trial outcomes . The primary outcome measure was time to introduction of antihyperglycemic drug therapy . Trial investigators were responsible for initiating drug therapy by the following protocol . As suggested by the ADA for clinical evaluation and management of diabetic patients ( 16 ) , we measured HbA1c at baseline and every 3 months thereafter . Participants who had a HbA1c level greater than 7 % were given an additional 3 months to reinforce dietary guidance and physical activity ; if the HbA1c level remained greater than 7 % , a drug regimen was introduced . Participants with an HbA1c level greater than 7 % at baseline were counted as having experienced the primary outcome if they still had that level at first follow-up . Trial investigators were also responsible for initiating or titrating antihypertensive or lipid-lowering therapy . Secondary outcome measures were changes in weight ( including BMI and waist circumference ) , glycemic control ( HbA1c , glucose , serum insulin , and adiponectin levels and homeostasis model assessment of insulin sensitivity ) , coronary risk factors ( lipid levels and blood pressure ) , and medications and meeting ADA coronary risk factor goals ( HbA1c level < 7 % , blood pressure < 130/80 mm Hg , and low-density lipoprotein cholesterol level < 2.59 mmol/L [ < 100 mg/dL ] ) ( 16 ) . Participants were weighed without shoes and in lightweight clothing to the nearest 0.1 kg at baseline and every month . Height at baseline ( for calculation of BMI ) was measured to the nearest millimeter with the use of a wall-mounted stadiometer ( Seca , Hamburg , Germany ) . Waist circumference was measured halfway between the last rib and the iliac crest . We measured HbA1c levels with high-pressure liquid chromatography by using the fully automated Glycosylated Hemoglobin Analyzer System ( Bio-Rad , Hercules , California ) traceable to the Diabetes Control and Complications Trial reference method , with a reference range of 4.0 % to 6.0 % . Insulin sensitivity in the fasting state was assessed with homeostasis model assessment and calculated with the following formula , as described by Matthews and colleagues ( 17 ) : fasting plasma glucose (mmol/L)fasting serum insulin (U/mL)/25 . High scores indicate low insulin sensitivity ( insulin resistance ) . We assayed plasma insulin and adiponectin levels by radioimmunoassay , as described elsewhere ( 18 ) . We performed assays for serum Aims /hypothesisThis study aim ed to determine whether lifestyle intervention lasting for 4 years affected diabetes incidence , body weight , glycaemia or lifestyle over 13 years among individuals at high risk of type 2 diabetes . Methods Overweight , middle-aged men ( n = 172 ) and women ( n = 350 ) with impaired glucose tolerance were r and omised in 1993–1998 to an  intensive lifestyle intervention group ( n = 265 ) , aim ing at weight reduction , dietary modification and increased physical activity , or to a control group ( n  = 257  )  that received general lifestyle information . The primary outcome was a diagnosis of diabetes based on annual OGTTs . Secondary outcomes included changes in body weight , glycaemia , physical activity and diet . After active intervention ( median 4 years , range 1–6 years ) , participants still free of diabetes and willing to continue their participation ( 200 in the intervention group and 166 in the control group ) were further followed until diabetes diagnosis , dropout or the end of 2009 , with a median total follow-up of 9 years and a time span of 13 years from baseline . Results During the total follow-up the adjusted HR for diabetes ( intervention group vs control group ) was 0.614 ( 95 % CI 0.478 , 0.789 ; p < 0.001 ) . The corresponding HR during the post-intervention follow-up was 0.672 ( 95 % CI 0.477 , 0.947 ; p = 0.023 ) . The former intervention group participants sustained lower absolute levels of body weight , fasting and 2 h plasma glucose and a healthier diet . Adherence to lifestyle changes during the intervention period predicted greater risk reduction during the total follow-up . Conclusions /interpretationLifestyle intervention in people at high risk of type 2 diabetes induces sustaining lifestyle change and results in long-term prevention of progression to type 2 diabetes . Trial registration Clinical Trials.gov NCT00518167 Funding The DPS study has been financially supported by the Academy of Finl and ( 128315 , 129330 ) , Ministry of Education , Novo Nordisk Foundation , Yrjö Jahnsson Foundation , Juho Vainio Foundation , Finnish Diabetes Research Foundation , Finnish Foundation for Cardiovascular Research , Unilever , and Competitive Research Funding from Tampere , Kuopio and Oulu University Hospitals . The study sponsors had no role in the design and conduct of the study ; the collection , analysis and interpretation of the data ; or the preparation , review or approval of the manuscript AIMS Diet and physical activity interventions can prevent diabetes in those at high risk due to impaired glucose tolerance . We determined whether simple measures of physical activity and diet predicted incident diabetes and enhanced prediction by known risk factors including age , body mass index and family history . METHODS This was a population -based prospect i ve cohort study ( EPIC-Norfolk ) . Participants aged 40 - 79 years ( n = 25,633 ) attended a health check  between 1993 and 1998 and completed diet and activity question naires . We assessed the association between simple behavioural indices of physical activity and diet derived from the question naires as well as known risk score variables with incident diabetes at follow-up ( mean 4.6 years ) . We developed a new diabetes risk score incorporating simple behavioural indices in a r and omly selected half of the EPIC data set using forward step-wise multivariate logistic regression , and tested this score in the remaining half . We compared existing and new scores using receiver-operating characteristic ( ROC ) curves . RESULTS There were 417 incident cases of diabetes during 115,137 years of follow-up . A simple physical activity index independently predicted risk of diabetes . Eating one or more daily portion of vegetables , fresh fruit and wholemeal bread was associated with reduced risk ; whilst eating meat products was associated with increased risk . The area under the ROC curves for the new and original score was the same ( 76.3 % ) . CONCLUSIONS Simple indices of diet and activity  are feasible to collect , predict future diabetes risk and might enhance routine data collection in primary care . However , they do not improve the prediction of risk scores based on known risk factors Background By 2025 , it is estimated that approximately 1.8 million Australian adults ( approximately 8.4 % of the adult population ) will have diabetes , with the majority having type 2 diabetes . Weight management via improved physical activity and diet is the cornerstone of type 2 diabetes management . However , the majority of weight loss trials in diabetes have evaluated short-term , intensive clinic-based interventions that , while producing short-term outcomes , have failed to address issues of maintenance and broad population reach . Telephone-delivered interventions have the potential to address these gaps . Methods / Design Using a two-arm r and omised controlled design , this study will evaluate an 18-month , telephone-delivered , behavioural weight loss intervention focussing on physical activity , diet and behavioural therapy , versus usual care , with follow-up at 24 months . Three-hundred adult participants , aged 20 - 75 years , with type 2 diabetes , will be recruited from 10 general practice s via electronic medical records search . The Social-Cognitive Theory driven intervention involves a six-month intensive phase ( 4 weekly calls and 11 fortnightly calls ) and a 12-month maintenance phase ( one call per month ) . Primary outcomes , assessed at 6 , 18 and 24 months , are : weight loss , physical activity , and glycaemic control ( HbA1c ) , with weight loss and physical activity also measured at 12 months . Incremental cost-effectiveness will also be examined . Study recruitment began in February 2009 , with final data collection expected by February 2013 . Discussion This is the first study to evaluate the telephone as the primary method of delivering a behavioural weight loss intervention in type 2 diabetes . The evaluation of maintenance outcomes ( 6 months following the end of intervention ) , the use of accelerometers to objective ly measure physical activity , and the inclusion of a cost-effectiveness analysis will advance the science of broad reach approaches to weight control and health behaviour change , and will build the evidence base needed to advocate for the translation of this work into population health practice .Trial Registration
Small effect sizes and potentially transient effect were reported in some studies , and some review ers noted that durability of intervention impact was potentially sensitive to duration of intervention and adherence to behaviour change .
Behaviour change , vascular disease and mortality outcome data were infrequently reported , and evidence of the impact of intervention on these outcomes was minimal .
Relatively long- duration lifestyle interventions can limit or delay progression to diabetes under trial conditions .
However , outcomes from more time-limited interventions , and those applied in routine clinical setting s , appear more variable , in keeping with the findings of recent pragmatic trials .
There is little evidence of intervention impact on vascular outcomes or mortality end points in any context . '
Real-world ' implementation of lifestyle interventions for diabetes prevention may be expected to lead to modest outcomes
OBJECTIVES To review the clinical outcomes of combined diet and physical activity interventions for population s at high risk of type 2 diabetes .