Study on Lifestyle Intervention and Impaired Glucose Tolerance Maastricht (SLIM): preliminary results after one year

Effects of dietary quality, physical activity and weight loss on glucose homeostasis in persons with and without prediabetes in the PREMIER trial

AIMS

We examined the contribution of changes in diet quality, physical activity and weight loss to improvements in insulin resistance (HOMA-IR index) and fasting glucose concentrations in a long-term behavioural trial. Furthermore, we compared the effects of lifestyle changes on glycaemic markers for individuals with and without prediabetes.

MATERIALS AND METHODS

The PREMIER trial was an 18-month parallel randomized trial of the impact of behavioural lifestyle interventions implementing lifestyle recommendations (dietary changes, physical activity, moderate weight loss) in adults with prehypertension or stage 1 hypertension. We analysed data on 685 men and women without diabetes. Data on body weight, fitness (treadmill test), dietary intake (24-h recalls) and glycaemic outcomes were collected at baseline and at 6 and 18 months. We used general linear models to assess the association between the exposure variables and glycaemic markers.

RESULTS

The mean (SD) age was 49.9 (8.8) years, the mean (SD) body mass index was 32.9 (5.7) kg/m² , and 35% had prediabetes at baseline. Weight loss and improvements in fitness and diet quality were each significantly associated with lower HOMA-IR and fasting glucose concentrations at 6 and 18 months. Mediation analysis indicated that the effects of fitness and diet quality were partly mediated by weight loss, but significant direct effects of diet and fitness (independent of weight changes) were also observed. Furthermore, insulin sensitivity and fasting glucose improved significantly in participants with and without prediabetes.

CONCLUSIONS

Our findings indicate that behavioural lifestyle interventions can substantially improve glucose metabolism in persons with and without prediabetes and that the effects of diet quality and physical activity are partly independent of weight loss.

Racial/ethnic and socioeconomic disparities in weight outcomes, cardiovascular events, and mortality in the look AHEAD trial

BACKGROUND

Intensive lifestyle interventions (ILI) for type 2 diabetes (T2D) improve health outcomes, but participants from different races/ethnicities or socioeconomic status may not benefit equally.

METHODS

Within the Look AHEAD trial, we examined achievement of the 7% weight loss goal, as well as secondary weight, cardiovascular, and mortality outcomes, by race/ethnicity and educational attainment (EA).

RESULTS

Among 4,640 participants (31 % Black or Hispanic, 13 % with less than a high school degree), Black and Hispanic participants were less likely than White participants to achieve 7 % weight loss in both the ILI (45.8 % v. 60.7 %, p < 0.001 and 53.0 % v. 60.7 %, p = 0.01, respectively) and diabetes support and education (DSE) arms. Contrastingly, participants with less than a high school degree were more likely in the ILI but less likely in the DSE arm to achieve this goal, with a significant arm by EA interaction. Hispanic participants and those with lowest EA also experienced decreased mortality in the ILI versus the DSE arm.

CONCLUSIONS

All Look AHEAD participant subgroups achieved greater weight loss from ILI; however, Black and Hispanic participants lost less weight than White participants in both arms, while those with lowest EA benefited disproportionately from the ILI compared to participants with higher EA.

Differential Effects of Amount, Intensity, and Mode of Exercise Training on Insulin Sensitivity and Glucose Homeostasis: A Narrative Review

As type 2 diabetes remains a leading cause of morbidity and mortality, identifying the most appropriate preventive treatment early in the development of disease is an important public health matter. In general, lifestyle interventions incorporating exercise and weight loss via caloric restriction improve cardiometabolic risk by impacting several key markers of insulin sensitivity and glucose homeostasis. However, variations in the effects of specific types of exercise interventions on these markers have led to conflicting results surrounding the optimal amount, intensity, and mode of exercise for optimal effects. Moreover, the addition of weight loss via caloric restriction to exercise interventions appears to differentially impact changes in body composition, metabolism, and insulin sensitivity compared to exercise alone. Determining the optimal amount, intensity, and mode of exercise having the most beneficial impact on glycemic status is both: (1) clinically important to provide guidelines for appropriate exercise prescription; and (2) physiologically important to understand the pathways by which exercise-with and without weight loss-impacts glycemic status to enhance precision lifestyle medicine. Thus, the purposes of this narrative review are to: (1) summarize findings from the three Studies of a Targeted Risk Reduction Intervention through Defined Exercise (STRRIDE) randomized trials regarding the differential effects of exercise amount, intensity, and mode on insulin action and glucose homeostasis markers; and (2) compare the STRRIDE findings to other published dose-response exercise trials in order to piece together the various physiologic pathways by which specific exercise interventions-with or without weight loss-impact glycemic status.

The effectiveness of goal setting on glycaemic control for people with type 2 diabetes and prediabetes: A systematic review and meta-analysis

AIM

This review assessed the effectiveness of interventions using a goal-setting approach on glycaemic control for people diagnosed with prediabetes or type 2 diabetes.

DESIGN

A systematic review guided by the Joanna Briggs Institute methodology for conducting systematic reviews of primary research studies was conducted.

DATA SOURCES

Randomized controlled trials and experimental studies with a minimum follow-up period of 6 months were considered for inclusion. The primary outcome was change in glycaemic control as measured by glycated haemoglobin (%) and/or fasting plasma glucose (mg/dl). A systematic search of seven electronic databases was completed in October 2020.

REVIEW METHODS

Papers meeting the inclusion criteria were critically appraised using the Joanna Briggs Institute tools for critical appraisal followed by data extraction. A Grading of Recommendations Assessment, Development and Evaluation assessment was conducted to assess the overall certainty of the evidence. Fixed-effect meta-analyses were completed to demonstrate the mean effect for each outcome of interest.

RESULTS

Twenty one studies were included in this review. Goal setting was more effective than usual care for glycaemic control in prediabetes at 6 months and at 12 months for fasting plasma glucose (mg/dl) and glycated haemoglobin (%). Goal setting was more effective than usual care for glycaemic control in type 2 diabetes for fasting plasma glucose (mg/dl) at 6 months, fasting plasma glucose (mg/dl) at 12 months, glycated haemoglobin (%) at 6 months and glycated haemoglobin (%) at 12 months.

CONCLUSION

The evidence suggests goal setting is effective in supporting people to achieve glycaemic targets in prediabetes and type 2 diabetes.

Barriers and Strategies to Lifestyle and Dietary Pattern Interventions for Prevention and Management of TYPE-2 Diabetes in Africa, Systematic Review

BACKGROUND

Diabetes mellitus is a major chronic illness in Africa that requires lifelong lifestyle interventions and pharmacological therapy. Lifestyle change is the most important aspect of diabetes care and includes diabetes self-management education and support, medical nutrition therapy, physical activity, smoking cessation counseling, and psychosocial care.

PURPOSE

The purpose of this project was to review published articles that investigate lifestyle and dietary pattern interventions for diabetes prevention and management in Africa. Barriers to lifestyle interventions and strategies to overcome the barriers are also reviewed in this study.

METHODS

The article search was conducted in an electronic database search of PubMed, Google Scholar, and Cochrane Library. Studies were included if they were published between 2011 and 2019, if they were conducted in an African country, and were written in the English language.

RESULTS

Articles reviewed included several that examined the basic lifestyle and dietary pattern changes for all patients diagnosed with type 2 diabetes, on self-care behavior of type 2 diabetes patients, on the cost of diabetes in Africa, and on barriers for adherence to lifestyle and dietary changes in Africa, with strategies to address those barriers.

CONCLUSION

Lifestyle interventions including regular physical exercise, weight management, and adherence to health care professionals' recommendations on a healthy diet are the cornerstone in the prevention and management of diabetes in Africa. The main barriers to adherence were both systemic (population changes, poor access, western cultural influences, and low-quality healthcare) and personal (poverty and cost, educational status, and perceptions about the disease) in nature. The strategies for the barriers include health education programs, advocacy, and capacity building.

Diet, physical activity or both for prevention or delay of type 2 diabetes mellitus and its associated complications in people at increased risk of developing type 2 diabetes mellitus

BACKGROUND

The projected rise in the incidence of type 2 diabetes mellitus (T2DM) could develop into a substantial health problem worldwide. Whether diet, physical activity or both can prevent or delay T2DM and its associated complications in at-risk people is unknown.

OBJECTIVES

To assess the effects of diet, physical activity or both on the prevention or delay of T2DM and its associated complications in people at increased risk of developing T2DM.

SEARCH METHODS

This is an update of the Cochrane Review published in 2008. We searched the CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, ICTRP Search Portal and reference lists of systematic reviews, articles and health technology assessment reports. The date of the last search of all databases was January 2017. We continuously used a MEDLINE email alert service to identify newly published studies using the same search strategy as described for MEDLINE up to September 2017.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) with a duration of two years or more.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology for data collection and analysis. We assessed the overall quality of the evidence using GRADE.

MAIN RESULTS

We included 12 RCTs randomising 5238 people. One trial contributed 41% of all participants. The duration of the interventions varied from two to six years. We judged none of the included trials at low risk of bias for all 'Risk of bias' domains.Eleven trials compared diet plus physical activity with standard or no treatment. Nine RCTs included participants with impaired glucose tolerance (IGT), one RCT included participants with IGT, impaired fasting blood glucose (IFG) or both, and one RCT included people with fasting glucose levels between 5.3 to 6.9 mmol/L. A total of 12 deaths occurred in 2049 participants in the diet plus physical activity groups compared with 10 in 2050 participants in the comparator groups (RR 1.12, 95% CI 0.50 to 2.50; 95% prediction interval 0.44 to 2.88; 4099 participants, 10 trials; very low-quality evidence). The definition of T2DM incidence varied among the included trials. Altogether 315 of 2122 diet plus physical activity participants (14.8%) developed T2DM compared with 614 of 2389 comparator participants (25.7%) (RR 0.57, 95% CI 0.50 to 0.64; 95% prediction interval 0.50 to 0.65; 4511 participants, 11 trials; moderate-quality evidence). Two trials reported serious adverse events. In one trial no adverse events occurred. In the other trial one of 51 diet plus physical activity participants compared with none of 51 comparator participants experienced a serious adverse event (low-quality evidence). Cardiovascular mortality was rarely reported (four of 1626 diet plus physical activity participants and four of 1637 comparator participants (the RR ranged between 0.94 and 3.16; 3263 participants, 7 trials; very low-quality evidence). Only one trial reported that no non-fatal myocardial infarction or non-fatal stroke had occurred (low-quality evidence). Two trials reported that none of the participants had experienced hypoglycaemia. One trial investigated health-related quality of life in 2144 participants and noted that a minimal important difference between intervention groups was not reached (very low-quality evidence). Three trials evaluated costs of the interventions in 2755 participants. The largest trial of these reported an analysis of costs from the health system perspective and society perspective reflecting USD 31,500 and USD 51,600 per quality-adjusted life year (QALY) with diet plus physical activity, respectively (low-quality evidence). There were no data on blindness or end-stage renal disease.One trial compared a diet-only intervention with a physical-activity intervention or standard treatment. The participants had IGT. Three of 130 participants in the diet group compared with none of the 141 participants in the physical activity group died (very low-quality evidence). None of the participants died because of cardiovascular disease (very low-quality evidence). Altogether 57 of 130 diet participants (43.8%) compared with 58 of 141 physical activity participants (41.1%) group developed T2DM (very low-quality evidence). No adverse events were recorded (very low-quality evidence). There were no data on non-fatal myocardial infarction, non-fatal stroke, blindness, end-stage renal disease, health-related quality of life or socioeconomic effects.Two trials compared physical activity with standard treatment in 397 participants. One trial included participants with IGT, the other trial included participants with IGT, IFG or both. One trial reported that none of the 141 physical activity participants compared with three of 133 control participants died. The other trial reported that three of 84 physical activity participants and one of 39 control participants died (very low-quality evidence). In one trial T2DM developed in 58 of 141 physical activity participants (41.1%) compared with 90 of 133 control participants (67.7%). In the other trial 10 of 84 physical activity participants (11.9%) compared with seven of 39 control participants (18%) developed T2DM (very low-quality evidence). Serious adverse events were rarely reported (one trial noted no events, one trial described events in three of 66 physical activity participants compared with one of 39 control participants - very low-quality evidence). Only one trial reported on cardiovascular mortality (none of 274 participants died - very low-quality evidence). Non-fatal myocardial infarction or stroke were rarely observed in the one trial randomising 123 participants (very low-quality evidence). One trial reported that none of the participants in the trial experienced hypoglycaemia. One trial investigating health-related quality of life in 123 participants showed no substantial differences between intervention groups (very low-quality evidence). There were no data on blindness or socioeconomic effects.

AUTHORS' CONCLUSIONS

There is no firm evidence that diet alone or physical activity alone compared to standard treatment influences the risk of T2DM and especially its associated complications in people at increased risk of developing T2DM. However, diet plus physical activity reduces or delays the incidence of T2DM in people with IGT. Data are lacking for the effect of diet plus physical activity for people with intermediate hyperglycaemia defined by other glycaemic variables. Most RCTs did not investigate patient-important outcomes.

The cost-effectiveness of interventions targeting lifestyle change for the prevention of diabetes in a Swedish primary care and community based prevention program

BACKGROUND

Policymakers need to know the cost-effectiveness of interventions to prevent type 2 diabetes (T2D). The objective of this study was to estimate the cost-effectiveness of a T2D prevention initiative targeting weight reduction, increased physical activity and healthier diet in persons in pre-diabetic states by comparing a hypothetical intervention versus no intervention in a Swedish setting.

METHODS

A Markov model was used to study the cost-effectiveness of a T2D prevention program based on lifestyle change versus a control group where no prevention was applied. Analyses were done deterministically and probabilistically based on Monte Carlo simulation for six different scenarios defined by sex and age groups (30, 50, 70 years). Cost and quality adjusted life year (QALY) differences between no intervention and intervention and incremental cost-effectiveness ratios (ICERs) were estimated and visualized in cost-effectiveness planes (CE planes) and cost-effectiveness acceptability curves (CEA curves).

RESULTS

All ICERs were cost-effective and ranged from 3833 €/QALY gained (women, 30 years) to 9215 €/QALY gained (men, 70 years). The CEA curves showed that the probability of the intervention being cost-effective at the threshold value of 50,000 € per QALY gained was very high for all scenarios ranging from 85.0 to 91.1%.

DISCUSSION/CONCLUSION

The prevention or the delay of the onset of T2D is feasible and cost-effective. A small investment in healthy lifestyle with change in physical activity and diet together with weight loss are very likely to be cost-effective.

A lifestyle intervention study targeting individuals with low socioeconomic status of different ethnic origins: important aspects for successful implementation

Background

Evaluation of the implementation process of trials is important, because the way a study is implemented modifies its outcomes. Furthermore, lessons learned during implementation can inform other researchers on factors that play a role when implementing interventions described in research. This study evaluates the implementation of the MetSLIM study, targeting individuals with low socioeconomic status of different ethnic origins. The MetSLIM study was set up to evaluate the effectiveness of a lifestyle programme on waist circumference and other cardio-metabolic risk factors. The objective of this evaluation was to identify components that were essential for the implementation of the MetSLIM study and to inform other researchers on methodological aspects when working with inadequately reached populations in health research.

Methods

In this evaluation study the experiences of health professionals, study assistants, a community worker and regional research coordinators involved in the MetSLIM study were explored using semi-structured interviews. Questionnaires were used to evaluate participants’ satisfaction with the lifestyle intervention.

Results

Our analyses show that a flexible recruitment protocol eventually leads to recruitment of sufficient participants; that trust in the recruiter is an important factor in the recruitment of individuals with low socioeconomic status of different ethnic origins; and that health professionals will unavoidably shape the form of intervention activities. Furthermore, our evaluation shows that daily practice and research mutually influence each other and that the results of an intervention are a product of this interaction.

Conclusions

Health promotion research would benefit from a perspective that sees intervention activities not as fixed entities but rather as social interaction that can take on numerous forms. Analysing and reporting the implementation process of studies, like in this evaluation, will allow readers to get a detailed view on the appropriateness of the (intended) study design and intervention for the targeted population. Evaluation studies that shed light on the reasons for adaptations, rather than describing them as deviation from the original plan, would point out methodological aspects important for a study’s replication. Furthermore, they would show how various factors can influence the implementation, and therewith initiate a learning cycle for the development of future intervention studies.

Trial registration

Netherlands Trial Register NTR3721 (since November 27, 2012).

Effectiveness of the MetSLIM lifestyle intervention targeting individuals of low socio-economic status and different ethnic origins with elevated waist-to-height ratio

Objective

To evaluate whether the lifestyle intervention MetSLIM targeting individuals of low socio-economic status of Turkish, Moroccan and Dutch origin was successful in improving waist circumference and other cardiometabolic risk factors, lifestyle behaviour and quality of life.

Design

A quasi-experimental intervention study (Netherlands Trial Register NTR3721). The intervention group participated in a 12-month combined dietary and physical activity programme. Examinations were performed at baseline and after 12 months. Participants underwent anthropometric measurements and blood withdrawal, and completed questionnaires on dietary intake, physical activity and quality of life.

Setting

Socio-economically deprived neighbourhoods in two Dutch cities, involving non-blinded ethnicity-matched and gender-matched research assistants, dietitians and sports instructors.

Subjects

Mainly Turkish (49 %) and Dutch (36 %) subjects, aged 30–70 years, with a waist-to-height ratio of &gt;0·5 (intervention,n117; control,n103). Dropout was 31 %.

Results

At 12 months, the intervention group showed greater improvements than the control group in waist circumference (β=−3·3 cm, 95 % CI −4·7, −1·8,P&lt;0·001) and other obesity measures. Additionally, greater reductions were observed for total cholesterol (β=−0·33 mmol/l, 95 % CI −0·56, −0·10,P=0·005) and LDL cholesterol (β=−0·35 mmol/l, 95 % CI −0·56, −0·14,P=0·001). Dietary changes were significant for fibre intake (β=1·5 g/4184 kJ (1000 kcal), 95 % CI 0·3, 2·7,P=0·016). Compared with the control group, the intervention group reported a decrease in total minutes of physical activity (β=−573 min/week, 95 % CI −1126, −21,P=0·042) and showed improvements in the quality-of-life domains ‘health transition’ and ‘general health’.

Conclusions

MetSLIM was shown to be effective in improving waist circumference, total and LDL cholesterol, and quality of life among Dutch and Turkish individuals living in deprived neighbourhoods.

Role of lifestyle factors in the epidemic of diabetes: lessons learnt from India

The prevalence of type 2 diabetes (T2D) is increasing steadily globally with the largest increases occurring in developing countries like India. This is attributed to the changes in the lifestyle factors, including physical inactivity and unhealthy diet, both of which are modifiable. Existing evidence suggests that increasing physical activity reduces the risk of T2D. Improving the built environment can make it more conducive to people to increase physical activity. There is also a rapid nutrition transition with consumption of diets with higher intake of refined grains, higher fat, increased consumption of sugar and sweetened beverages, and lower intake of fruits and vegetables. A multisectoral approach promoting healthier diets and increasing physical activity can help in slowing down the diabetic epidemic. However, this requires political will to make necessary policy changes, as well as empowerment of the community, if the preventive measures are to be sustainable and scalable.

A community-based primary prevention programme for type 2 diabetes mellitus integrating identification and lifestyle intervention for prevention: a cluster randomised controlled trial

Background

Prevention of type 2 diabetes mellitus (T2DM) is a global priority; however, there is a lack of evidence investigating how to effectively translate prevention research into a primary care setting.

Objectives

(1) To develop and validate a risk score to identify individuals at high risk of T2DM in the UK; and (2) to establish whether or not a structured education programme targeting lifestyle and behaviour change was clinically effective and cost-effective at preventing progression to T2DM in people with prediabetes mellitus (PDM), identified through a risk score screening programme in primary care.

Design

A targeted screening study followed by a cluster randomised controlled trial (RCT), with randomisation at practice level. Participants were followed up for 3 years.

Setting

A total of 44 general practices across Leicestershire, UK. The intervention took place in the community.

Participants

A total of 17,972 individuals from 44 practices identified through the risk score as being at high risk of T2DM were invited for screening; of these, 3449 (19.2%) individuals attended. All received an oral glucose tolerance test. PDM was detected in 880 (25.5%) of those screened. Those with PDM were included in the trial; of these, 36% were female, the average age was 64 years and 16% were from an ethnic minority group.

Intervention

Practices were randomised to receive either standard care or the intervention. The intervention consisted of a 6-hour group structured education programme, with an annual refresher and regular telephone contact.

Main outcome measures

The primary outcome was progression to T2DM. The main secondary outcomes were changes in glycated haemoglobin concentrations, blood glucose levels, cardiovascular risk, the presence of metabolic syndrome, step count and the cost-effectiveness of the intervention.

Results

A total of 22.6% of the intervention group did not attend the education and 29.1% attended all sessions. A total of 131 participants developed T2DM (standard care,n = 67; intervention,n = 64). There was a 26% reduced risk of T2DM in the intervention arm compared with standard care, but this did not reach statistical significance (hazard ratio 0.74, 95% confidence interval 0.48 to 1.14;p = 0.18). There were statistically significant improvements in glycated haemoglobin concentrations, low-density lipoprotein cholesterol levels, psychosocial well-being, sedentary time and step count in the intervention group. The intervention was found to result in a net gain of 0.046 quality-adjusted life-years over 3 years at a cost of £168 per patient, with an incremental cost-effectiveness ratio of £3643 and a probability of 0.86 of being cost-effective at a willingness-to-pay threshold of £20,000.

Conclusions

We developed and validated a risk score for detecting those at high risk of undiagnosed PDM/T2DM. We screened > 3400 people using a two-stage screening programme. The RCT showed that a relatively low-resource pragmatic programme may lead to a reduction in T2DM and improved biomedical and psychosocial outcomes, and is cost-effective.

Limitations

Only 19% of those invited to screening attended, which may limit generalisability. The variation in cluster size in the RCT may have limited the power of the study.

Future work

Future work should focus on increasing attendance to both screening and prevention programmes and offering the programme in different modalities, such as web-based modalities. A longer-term follow-up of the RCT participants would be valuable.

Trial registration

Current Controlled Trials ISRCTN80605705.

Funding

The National Institute for Health Research Programme Grants for Applied Research programme.

Metabolic effects of a 13-weeks lifestyle intervention in older adults: The Growing Old Together Study

For people in their 40s and 50s, lifestyle programs have been shown to improve metabolic health. For older adults, however, it is not clear whether these programs are equally healthy. In the Growing Old Together study, we applied a 13-weeks lifestyle program, with a target of 12.5% caloric restriction and 12.5% increase in energy expenditure through an increase in physical activity, in 164 older adults (mean age=63.2 years; BMI=23-35 kg/m²). Mean weight loss was 4.2% (SE=2.8%) of baseline weight, which is comparable to a previous study in younger adults. Fasting insulin levels, however, showed a much smaller decrease (0.30 mU/L (SE=3.21)) and a more heterogeneous response (range=2.0-29.6 mU/L). Many other parameters of metabolic health, such as blood pressure, and thyroid, glucose and lipid metabolism improved significantly. Many ¹H-NMR metabolites changed in a direction previously associated with a low risk of type 2 diabetes and cardiovascular disease and partially independently of weight loss. In conclusion, 25% reduction in energy balance for 13 weeks induced a metabolic health benefit in older adults, monitored by traditional and novel metabolic markers.

A systematic review of real-world diabetes prevention programs: learnings from the last 15 years

Background

The evidence base for the prevention of type 2 diabetes mellitus (T2DM) has progressed rapidly from efficacy trials to real-world translational studies and practical implementation trials over the last 15 years. However, evidence for the effective implementation and translation of diabetes programs and their population impact needs to be established in ways that are different from measuring program effectiveness. We report the findings of a systematic review that focuses on identifying the critical success factors for implementing diabetes prevention programs in real-world settings.

Methods

A systematic review of programs aimed at diabetes prevention was undertaken in order to evaluate their outcomes using the penetration, implementation, participation, and effectiveness (PIPE) impact metric. A search for relevant articles was carried out using PubMed (March 2015) and Web of Science, MEDLINE, CENTRAL, and EMBASE. A quality coding system was developed and included studies were rated independently by three researchers.

Results

Thirty eight studies were included in the review. Almost all (92 %) provided details on participation; however, only 18 % reported the coverage of their target population (penetration). Program intensity or implementation—as measured by frequency of contacts during first year and intervention duration—was identified in all of the reported studies, and 84 % of the studies also reported implementation fidelity; however, only 18 % of studies employed quality assurance measures to assess the extent to which the program was delivered as planned. Sixteen and 26 % of studies reported ‘highly’ or ‘moderately’ positive changes (effectiveness) respectively, based on weight loss. Six (16 %) studies reported ‘high’ diabetes risk reduction but ‘low’ to ‘moderate’ weight loss only.

Conclusion

Our findings identify that program intensity plays a major role in weight loss outcomes. However, programs that have high uptake—both in terms of good coverage of invitees and their willingness to accept the invitation—can still have considerable impact in lowering diabetes risk in a population, even with a low intensity intervention that only leads to low or moderate weight loss. From a public health perspective, this is an important finding, especially for resource constrained settings. More use of the PIPE framework components will facilitate increased uptake of T2DM prevention programs around the world.

Electronic supplementary material

The online version of this article (doi:10.1186/s13012-015-0354-6) contains supplementary material, which is available to authorized users.

Prevention of type 2 diabetes through lifestyle modification: is there a role for higher-protein diets?

Type 2 diabetes (T2D) incidence is increasing worldwide, driven by a rapidly changing environment and lifestyle and increasing rates of overweight and obesity. Prevention of diabetes is key and is most likely achieved through prevention of weight gain and/or successful long-term weight loss maintenance. Weight loss is readily achievable but there is considerable challenge in maintaining that weight loss over the long term. Lower-fat carbohydrate-based diets are widely used for T2D prevention. This is supported primarily by 3 successful long-term interventions, the US Diabetes Prevention Program, the Finnish Diabetes Prevention Study, and the Chinese Da Qing Study, but evidence is building in support of novel higher-protein (>20% of energy) diets for successful weight loss maintenance and prevention of T2D. Higher-protein diets have the advantage of having relatively low energy density, aiding longer-term appetite suppression, and preserving lean body mass, all central to successful weight loss and prevention of weight regain. Here, we review the carbohydrate-based intervention trials and present mechanistic evidence in support of increased dietary protein for weight loss maintenance and a possible novel role in prevention of dysglycemia and T2D.

Adapting an effective lifestyle intervention towards individuals with low socioeconomic status of different ethnic origins: the design of the MetSLIM study

Background

People with low socioeconomic status (SES) and some ethnic minorities are often underrepresented in lifestyle programmes. Therefore, a lifestyle programme was developed especially targeting these groups. Developing this lifestyle programme and designing an intervention study to test the effectiveness of this programme was an informative process in which several obstacles were encountered and choices had to be made. Study protocols, however, rarely describe these obstacles encountered in the protocol design process, and it is not always clear why researchers made certain choices. Therefore, the aim of this article is to describe both the final MetSLIM study protocol and the considerations and choices made in designing this study protocol.

Methods/Design

The developed MetSLIM study has a quasi-experimental design, targeting 30- to 70-year-old adults with an elevated waist circumference, living in deprived neighbourhoods, of Dutch, Turkish or Moroccan descent. The intervention group participates in a 12-month lifestyle programme consisting of individual dietary advice, four group sessions and weekly sports lessons. The control group receives written information about a healthy lifestyle and one group session provided by a dietician. The study contains an elaborate effect, process and economic evaluation. Outcome measures are, among other things, change in waist circumference and the other components of the metabolic syndrome.

Discussion

Matching the preferences of the target group, such as their preferred setting, has implications for the entire study protocol. The process evaluation of the MetSLIM study will provide insight into the consequences of the choices made in the MetSLIM study protocol in terms of reach, acceptability and delivery of the programme, and the effect and economic evaluation will provide insight into the (cost)effectiveness of the lifestyle programme in order to reduce waist circumference among individuals with low SES of different ethnic origins.

Trial registration

Netherlands Trial Register NTR3721 (since November 27, 2012).

Effects of diet and exercise interventions on diabetes risk factors in adults without diabetes: meta-analyses of controlled trials

BACKGROUND AND AIMS

Fasting insulin (FI), fasting glucose (FG), systolic blood pressure (SBP), high density lipoproteins (HDL), triacylglycerides (TAG), and body mass index (BMI) are well-known risk factors for type 2 diabetes. Reliable estimates of lifestyle intervention effects on these factors allow diabetes risk to be predicted accurately. The present meta-analyses were conducted to quantitatively summarize effects of diet and exercise intervention programs on FI, FG, SBP, HDL, TAG and BMI in adults without diabetes.

MATERIALS AND METHODS

MEDLINE and EMBASE were searched to find studies involving diet plus exercise interventions. Studies were required to use adults not diagnosed with type 2 diabetes, involve both dietary and exercise counseling, and include changes in diabetes risk factors as outcome measures. Data from 18, 24, 23, 30, 29 and 29 studies were used for the analyses of FI, FG, SBP, HDL, TAG and BMI, respectively. About 60% of the studies included exclusively overweight or obese adults. Mean age and BMI of participants at baseline were 48 years and 30.1 kg/m(2). Heterogeneity of intervention effects was first estimated using random-effect models and explained further with mixed-effects models.

RESULTS

Adults receiving diet and exercise education for approximately one year experienced significant (P <0.001) reductions in FI (-2.56 ± 0.58 mU/L), FG (-0.18 ± 0.04 mmol/L), SBP (-2.77 ± 0.56 mm Hg), TAG (-0.258 ± 0.037 mmol/L) and BMI (-1.61 ± 0.13 kg/m(2)). These risk factor changes were related to a mean calorie intake reduction of 273 kcal/d, a mean total fat intake reduction of 6.3%, and 40 minutes of moderate intensity aerobic exercise four times a week. Lifestyle intervention did not have an impact on HDL. More than 99% of total variability in the intervention effects was due to heterogeneity. Variability in calorie and fat intake restrictions, exercise type and duration, length of the intervention period, and the presence or absence of glucose, insulin, or lipid abnormalities explained 23-63% of the heterogeneity.

CONCLUSIONS

Calorie and total fat intake restrictions coupled with moderate intensity aerobic exercises significantly improved diabetes risk factors in healthy normoglycemic adults although normoglycemic adults with glucose, insulin, and lipid abnormalities appear to benefit more.

Feasibility and potential impact of the adapted SLIM diabetes prevention intervention in a Dutch real-life setting: the SLIMMER pilot study

OBJECTIVE

Pilot-testing of the adapted Study on Lifestyle intervention and Impaired glucose tolerance Maastricht (SLIM) and to determine its feasibility and likelihood of achieving desired impact.

METHODS

Pilot intervention study (a 10-month combined lifestyle intervention) using a one group pre-test post-test design with on-going process measures (i.e. reach, acceptability, implementation integrity, and applicability) and several health outcomes (e.g. body weight).

RESULTS

In total, 31 subjects participated in the SLIMMER (SLIM iMplementation Experience Region Noord- en Oost-Gelderland) intervention. Participant weight loss was -3.5 kg (p=0.005). Both participants and health care professionals (i.e. practice nurses, dieticians, and physiotherapists) were satisfied with the intervention. The intervention was implemented as planned and appeared to be suitable for application in practice. Refinements have been identified and will be made prior to further implementation and evaluation.

CONCLUSION

Implementation of the SLIMMER intervention is feasible in a Dutch real-life setting and it is likely to achieve desired impact. Practising and optimising the intervention creates local support for SLIMMER among stakeholders.

PRACTICE IMPLICATIONS

Performing a pilot study on the basis of a structured approach is a meaningful step in the process of optimising the feasibility and potential impact of an evidence-based intervention in a real-life setting.

SLIMMER: a randomised controlled trial of diabetes prevention in Dutch primary health care: design and methods for process, effect, and economic evaluation

BACKGROUND

Implementation of interventions in real-life settings requires a comprehensive evaluation approach. The aim of this article is to describe the evaluation design of the SLIMMER diabetes prevention intervention in a Dutch real-life setting.

METHODS/DESIGN

The SLIMMER study is a randomised, controlled intervention study including subjects aged 40 through 70 years with impaired fasting glucose or high risk of diabetes. The 10-month SLIMMER intervention involves a dietary and physical activity intervention, including case management and a maintenance programme. The control group receives usual health care and written information about a healthy lifestyle. A logic model of change is composed to link intervention activities with intervention outcomes in a logical order. Primary outcome is fasting insulin. Measurements are performed at baseline and after 12 and 18 months and cover quality of life, cardio-metabolic risk factors (e.g. glucose tolerance, serum lipids, body fatness, and blood pressure), eating and physical activity behaviour, and behavioural determinants. A process evaluation gives insight in how the intervention was delivered and received by participants and health care professionals. The economic evaluation consists of a cost-effectiveness analysis and a cost-utility analysis. Costs are assessed from both a societal and health care perspective.

DISCUSSION

This study is expected to provide insight in the effectiveness, including its cost-effectiveness, and delivery of the SLIMMER diabetes prevention intervention conducted in Dutch primary health care. Results of this study provide valuable information for primary health care professionals, researchers, and policy makers.

TRIAL REGISTRATION

The SLIMMER study is registered with ClinicalTrials.gov (NCT02094911) since March 19, 2014.

Diabetes prevention in the real world: effectiveness of pragmatic lifestyle interventions for the prevention of type 2 diabetes and of the impact of adherence to guideline recommendations: a systematic review and meta-analysis

OBJECTIVE To summarize the evidence on effectiveness of translational diabetes prevention programs, based on promoting lifestyle change to prevent type 2 diabetes in real-world settings and to examine whether adherence to international guideline recommendations is associated with effectiveness. RESEARCH DESIGN AND METHODS Bibliographic databases were searched up to July 2012. Included studies had a follow-up of ≥12 months and outcomes comparing change in body composition, glycemic control, or progression to diabetes. Lifestyle interventions aimed to translate evidence from previous efficacy trials of diabetes prevention into real-world intervention programs. Data were combined using random-effects meta-analysis and meta-regression considering the relationship between intervention effectiveness and adherence to guidelines. RESULTS Twenty-five studies met the inclusion criteria. The primary meta-analysis included 22 studies (24 study groups) with outcome data for weight loss at 12 months. The pooled result of the direct pairwise meta-analysis shows that lifestyle interventions resulted in a mean weight loss of 2.12 kg (95% CI -2.61 to -1.63; I(2) = 91.4%). Adherence to guidelines was significantly associated with a greater weight loss (an increase of 0.3 kg per point increase on a 12-point guideline-adherence scale). CONCLUSIONS Evidence suggests that pragmatic diabetes prevention programs are effective. Effectiveness varies substantially between programs but can be improved by maximizing guideline adherence. However, more research is needed to establish optimal strategies for maximizing both cost-effectiveness and longer-term maintenance of weight loss and diabetes prevention effects.

A cluster-randomized controlled trial to study the effectiveness of a protocol-based lifestyle program to prevent type 2 diabetes in people with impaired fasting glucose

BACKGROUND

Effective diabetes prevention strategies that can be implemented in daily practice, without huge amounts of money and a lot of personnel are needed. The Dutch Diabetes Federation developed a protocol for coaching people with impaired fasting glucose (IFG; according to WHO criteria: 6.1 to 6.9 mmol/l) to a sustainable healthy lifestyle change: 'the road map towards diabetes prevention' (abbreviated: Road Map: RM). This protocol is applied within a primary health care setting by a general practitioner and a practice nurse. The feasibility and (cost-) effectiveness of care provided according to the RM protocol will be evaluated.

METHODS/DESIGN

A cluster randomised clinical trial is performed, with randomisation at the level of the general practices. Both opportunistic screening and active case finding took place among clients with high risk factors for diabetes. After IFG is diagnosed, motivated people in the intervention practices receive 3-4 consultations by the practice nurse within one year. During these consultations they are coached to increase the level of physical activity and healthy dietary habits. If necessary, participants are referred to a dietician, physiotherapist, lifestyle programs and/or local sports activities. The control group receives care as usual. The primary outcome measure in this study is change in Body Mass Index (BMI). Secondary outcome measures are waist circumference, physical activity, total and saturated fat intake, systolic blood pressure, blood glucose, total cholesterol, HDL cholesterol, triglycerides and behaviour determinants like risk perception, perceived knowledge and motivation. Based on a sample size calculation 120 people in each group are needed. Measurements are performed at baseline, and after one (post-intervention) and two years follow up. Anthropometrics and biochemical parameters are assessed in the practices and physical activity, food intake and their determinants by a validated questionnaire. The cost-effectiveness is estimated by using the Chronic Disease Model (CDM). Feasibility will be tested by interviews among health care professionals.

DISCUSSION

The results of the study will provide valuable information for both health care professionals and policy makers. If this study shows the RM to be both effective and cost-effective the protocol can be implemented on a large scale.

TRIAL REGISTRATION

ISRCTN41209683. Ethical approval number: NL31342.075.10.

Prevention of the metabolic syndrome in IGT subjects in a lifestyle intervention: results from the SLIM study

BACKGROUND AND AIMS

The Study on Lifestyle intervention and Impaired glucose tolerance Maastricht (SLIM), a randomized controlled trial, directed at diet and physical activity in impaired glucose tolerant subjects was effective to improve glucose tolerance and prevent type 2 diabetes. The aim of this study was to determine the effects of the SLIM lifestyle intervention on the incidence and prevalence of the metabolic syndrome (MetS) during the active intervention and four years thereafter.

METHODS AND RESULTS

MetS was diagnosed according to the NCEP ATP III criteria. At baseline, 66.4% of all participants (n = 146, age 57 ± 7 years, BMI 29.7 ± 3.6, 51.3% female) fulfilled the criteria for MetS. No significant difference in MetS prevalence was observed between the intervention (63.9%) and control group (68.9%). At the end of active intervention (average duration 4.2 ± 2.0 years), prevalence of MetS was significantly lower in the intervention group (52.6%, n = 57) compared to the control group (74.6%, n = 59) (p = 0.014). Furthermore, in participants without MetS at baseline, cumulative incidence of MetS was 18.2% in the intervention group at the end of active intervention, compared to 73.7% in the control group (Log-rank test, p = 0.011). Four years after stopping active intervention, the reduced incidence of MetS was maintained (Log-rank test, p = 0.002).

CONCLUSION

In conclusion, a combined diet-and-exercise intervention to improve glucose tolerance, not only prevented type 2 diabetes, but also reduced the prevalence of MetS and prevented MetS development, showing the long-term impact of lifestyle intervention on cardiovascular risk reduction.

Factors influencing participation in a vascular disease prevention lifestyle program among participants in a cluster randomized trial

Background

Previous research suggests that lifestyle intervention for the prevention of diabetes and cardiovascular disease (CVD) are effective, however little is known about factors affecting participation in such programs. This study aims to explore factors influencing levels of participation in a lifestyle modification program conducted as part of a cluster randomized controlled trial of CVD prevention in primary care.

Methods

This concurrent mixed methods study used data from the intervention arm of a cluster RCT which recruited 30 practices through two rural and three urban primary care organizations. Practices were randomly allocated to intervention (n = 16) and control (n = 14) groups. In each practice up to 160 eligible patients aged between 40 and 64 years old, were invited to participate. Intervention practice staff were trained in lifestyle assessment and counseling and referred high risk patients to a lifestyle modification program (LMP) consisting of two individual and six group sessions over a nine month period. Data included a patient survey, clinical audit, practice survey on capacity for preventive care, referral and attendance records at the LMP and qualitative interviews with Intervention Officers facilitating the LMP. Multi-level logistic regression modelling was used to examine independent predictors of attendance at the LMP, supplemented with qualitative data from interviews with Intervention Officers facilitating the program.

Results

A total of 197 individuals were referred to the LMP (63% of those eligible). Over a third of patients (36.5%) referred to the LMP did not attend any sessions, with 59.4% attending at least half of the planned sessions. The only independent predictors of attendance at the program were employment status - not working (OR: 2.39 95% CI 1.15-4.94) and having high psychological distress (OR: 2.17 95% CI: 1.10-4.30). Qualitative data revealed that physical access to the program was a barrier, while GP/practice endorsement of the program and flexibility in program delivery facilitated attendance.

Conclusion

Barriers to attendance at a LMP for CVD prevention related mainly to external factors including work commitments and poor physical access to the programs rather than an individuals’ health risk profile or readiness to change. Improving physical access and offering flexibility in program delivery may enhance future attendance. Finally, associations between psychological distress and attendance rates warrant further investigation.

Trial registration

ACTRN12607000423415

Baseline predictors of maintenance of intervention-induced changes in physical activity and sitting time among diabetic and pre-diabetic patients: a descriptive case series

Background

The aim of this study was to explore the predictive value of baseline characteristics in relation to changes in physical activity (PA) and sedentary behaviour among diabetic and pre-diabetic patients participating in a primary care based exercise intervention. We used a descriptive case series among diabetic and pre-diabetic patients (n = 119, 50.8% male, mean age 65.5 (SD = 7.8)). Measurements took place with questionnaires at baseline and two years after the start of the intervention. Predictor variables included demographic factors, Body Mass Index, baseline PA and sitting time, and baseline socio-cognitive profile.

Results

At follow-up, respondents spent more time being physically active than at baseline. For the total group, the average sitting time remained almost unchanged between the two measurements. Further exploration showed that respondents who had relatively high levels of PA at the start of the intervention, increased their total sitting time, while respondents with relatively low levels of PA at the start decreased their sitting time. The socio-cognitive profile did not predict behaviour change. The intervention appeared to be suitable for people with a low-education level, but the results should be interpreted in view of the limitations of the study such as the non-controlled design, self-reported outcomes and selective drop-out of participants.

Conclusions

Interventions for this specific target group may need to put more emphasis on the prevention of increased sitting time. The finding that the socio-cognitive profile did not predict behaviour change may underline the proposition that decisions to initiate and maintain PA behaviour change are to a large extend non-linear events. Acknowledging the possible non-linearity of the relationship between socio-cognitive determinants and behaviour change will help our understanding of this complex and dynamic process.

Lifestyle intervention, glucose tolerance, and risk of developing type 2 diabetes mellitus

Diabetes mellitus is rapidly becoming one of the main health issues in the 21st century. Environmental factors such as lifestyle habits (i.e., physical inactivity and dietary intake) and obesity may act as initiating factors or progression factors for type 2 diabetes. Therefore, changes in lifestyle (i.e., diet and physical activity) should have the potential to postpone or prevent the development of type 2 diabetes mellitus in subjects at high risk (for example, those with impaired glucose tolerance [IGT]). Several independent and well-controlled randomized studies have shown the beneficial impact of a lifestyle intervention program on glucose tolerance, insulin resistance, and diabetes risk in populations at risk for developing type 2 diabetes mellitus. After 2 years of a combined diet and physical activity intervention program, according to general public health guidelines, the Study on Lifestyle-intervention and IGT Maastricht (SLIM) revealed an improved glucose tolerance in the intervention group compared to a further deterioration in the control group. The Finnish Diabetes Prevention Study (DPS) and the US Diabetes Prevention Program (DPP) both observed a 58% reduction in diabetes risk after 3 years of intervention in a high-risk population. Although other intervention strategies can reduce the incidence of diabetes, lifestyle changes are the most effective mean of delaying or preventing the development of type 2 diabetes mellitus. For a successful implementation of a diabetes prevention program in a primary healthcare setting, both patients and healthcare professionals should be aware of the (clinical) significance of impaired glucose tolerance and the effectiveness of lifestyle interventions to prevent or postpone type 2 diabetes mellitus and its complications.

Factors influencing participant enrolment in a diabetes prevention program in general practice: lessons from the Sydney diabetes prevention program

BACKGROUND

The effectiveness of lifestyle interventions in reducing diabetes incidence has been well established. Little is known, however, about factors influencing the reach of diabetes prevention programs. This study examines the predictors of enrolment in the Sydney Diabetes Prevention Program (SDPP), a community-based diabetes prevention program conducted in general practice, New South Wales, Australia from 2008-2011.

METHODS

SDPP was an effectiveness trial. Participating general practitioners (GPs) from three Divisions of General Practice invited individuals aged 50-65 years without known diabetes to complete the Australian Type 2 Diabetes Risk Assessment tool. Individuals at high risk of diabetes were invited to participate in a lifestyle modification program. A multivariate model using generalized estimating equations to control for clustering of enrolment outcomes by GPs was used to examine independent predictors of enrolment in the program. Predictors included age, gender, indigenous status, region of birth, socio-economic status, family history of diabetes, history of high glucose, use of anti-hypertensive medication, smoking status, fruit and vegetable intake, physical activity level and waist measurement.

RESULTS

Of the 1821 eligible people identified as high risk, one third chose not to enrol in the lifestyle program. In multivariant analysis, physically inactive individuals (OR: 1.48, P = 0.004) and those with a family history of diabetes (OR: 1.67, P = 0.000) and history of high blood glucose levels (OR: 1.48, P = 0.001) were significantly more likely to enrol in the program. However, high risk individuals who smoked (OR: 0.52, P = 0.000), were born in a country with high diabetes risk (OR: 0.52, P = 0.000), were taking blood pressure lowering medications (OR: 0.80, P = 0.040) and consumed little fruit and vegetables (OR: 0.76, P = 0.047) were significantly less likely to take up the program.

CONCLUSIONS

Targeted strategies are likely to be needed to engage groups such as smokers and high risk ethnic groups. Further research is required to better understand factors influencing enrolment in diabetes prevention programs in the primary health care setting, both at the GP and individual level.

Lifestyle Intervention and Fatty Acid Metabolism in Glucose-Intolerant Subjects

OBJECTIVE

Free fatty acid (FFA) oxidation is reduced in subjects with type 2 diabetes mellitus and impaired glucose tolerance (IGT). Weight reduction does not improve these impairments. Because exercise training is known to increase fatty acid (FA) oxidation, we investigated whether a combined diet and physical activity intervention program can improve FA oxidation in subjects with IGT.

RESEARCH METHODS AND PROCEDURES

Sixteen subjects with IGT were studied before and after 1 year of a lifestyle intervention program [nine intervention (INT) subjects, seven controls (CON)]. INT subjects received regular (i.e., every 3 months) dietary advice and were stimulated to increase their level of physical activity. Glucose tolerance, anthropometric characteristics, and substrate use at rest and during exercise were evaluated before and after 1 year. Substrate oxidation was measured at rest and during moderate intensity exercise using indirect calorimetry in combination with stable isotope infusion ([U-(13)C]palmitate and [6,6-(2)H(2)-]glucose).

RESULTS

After 1 year, no differences were seen in substrate use at rest. During exercise, total fat and plasma FFA oxidation were slightly increased in the INT group and decreased in the CON group, with the change being significantly different (change after 1 year: INT, +2.0 +/- 1.4 and +1.9 +/- 0.9 micromol/kg per minute; CON, -3.5 +/- 1.6 and -1.8 +/- 0.5 micromol/kg per minute for total and plasma FFA, respectively; p < 0.05).

DISCUSSION

A combined diet and physical activity intervention program can prevent further deterioration of impaired FA oxidation during exercise in subjects with IGT.

Measuring Free-Living Energy Expenditure and Physical Activity with Triaxial Accelerometry

OBJECTIVE

To investigate the ability of a newly developed triaxial accelerometer to predict total energy expenditure (EE) (TEE) and activity-related EE (AEE) in free-living conditions.

RESEARCH METHODS AND PROCEDURES

Subjects were 29 healthy subjects between the ages of 18 and 40. The Triaxial Accelerometer for Movement Registration (Tracmor) was worn for 15 consecutive days. Tracmor output was defined as activity counts per day (ACD) for the sum of all three axes or each axis separately (ACD-X, ACD-Y, ACD-Z). TEE was measured with the doubly labeled water technique. Sleeping metabolic rate (SMR) was measured during an overnight stay in a respiration chamber. The physical activity level was calculated as TEE x SMR(-1), and AEE was calculated as [(0.9 x TEE) - SMR]. Body composition was calculated from body weight, body volume, and total body water using Siri's three-compartment model.

RESULTS

Age, height, body mass, and ACD explained 83% of the variation in TEE [standard error of estimate (SEE) = 1.00 MJ/d] and 81% of the variation in AEE (SEE = 0.70 MJ/d). The partial correlations for ACD were 0.73 (p < 0.001) and 0.79 (p < 0.001) with TEE and AEE, respectively. When data on SMR or body composition were used with ACD, the explained variation in TEE was 90% (SEE = 0.74 and 0.77 MJ/d, respectively). The increase in the explained variation using three axes instead of one axis (vertical) was 5% (p < 0.05).

DISCUSSION

The correlations between Tracmor output and EE measures are the highest reported so far. To measure daily life activities, the use of triaxial accelerometry seems beneficial to uniaxial.

Effectiveness of diet versus exercise intervention on weight reduction in local Japanese residents

OBJECTIVE

To evaluate the effect of diet versus exercise intervention on weight reduction.

METHODS

Participants were randomly divided by gender, age, and living area into four groups: group DE (diet and exercise, n = 16), group D (diet only, n = 15), group E (exercise only, n = 15), and group C (control, n = 16). This study ultimately aimed to help participants reduce their body mass index (BMI) by 7% of baseline value. Subjects were 62 residents (men and women ranging in age from 40 to 69 years) of two residential areas in Nara Prefecture, Japan, who participated in annual health checkups in 2006. BMI of the participants was ≥24 and <28 kg/m² at baseline examination. All participants agreed to undergo a 6-month intervention between January 2007 and September 2007.

RESULTS

In our intention-to-treat analysis, mean change in BMI from baseline to final examination was as follows: group DE mean BMI decreased 6.6%, group D mean BMI decreased 5.3%, group E mean BMI decreased 2.3%, and group C mean BMI decreased 2.2%. The reduction in BMI from baseline to final examination was significant in all groups (DE, p < 0.001; D, p < 0.001; E, p = 0.009; C, p = 0.019). Further, mean abdominal circumference was significantly reduced in all groups. Blood glucose levels were significantly reduced only in group DE (p = 0.047).

CONCLUSION

Combined intervention with diet and exercise proved to be effective in weight reduction, whereas exercise intervention alone was not found to be effective.

Efficacy of multifactorial lifestyle interventions in patients with established cardiovascular diseases and high risk groups

BACKGROUND

Lifestyle modification is recommended for patients with established cardiovascular diseases (CVD) or at high risk of CVD. In recent years, risk factor interventions in which multiple risk factors are addressed simultaneously are increasingly conducted.

AIM

To determine, and if possible quantify, the efficacy of multifactorial lifestyle interventions (without drug therapy) in patients with established CVD or in high risk groups.

METHODS

A literature search was conducted using 'Pubmed', to identify articles of randomized controlled trials (RCTs) or reviews of RCTs, published between 1990 and 2007.

RESULTS

In patients with established CVD, multifactorial lifestyle interventions can reduce the occurrence of cardiovascular diseases and/or mortality, even many years after the end of the intervention. Further, in both patients and high risk groups, multifactorial lifestyle interventions have favorable effects on biological risk factors and lifestyle and are able to reduce the incidence of diabetes. In the long-term, in particular lifestyle changes seem to persist, such as improved dietary habits and increased physical activity, while the favorable effects on biological risk factors, such as body weight and blood pressure, are no longer different from the control group. Regular contact with the participants seems to be part of the "success factor".

CONCLUSION

It can be recommended to offer patients with established CVD as well as individuals at high risk of CVD a comprehensive lifestyle advice, as part of their medical treatment, combined with intensive counseling.

Factors determining the motivation of primary health care professionals to implement and continue the 'Beweegkuur' lifestyle intervention programme

AIM

To examine factors explaining motivation among health care professionals to implement and continue a multidisciplinary primary care-based lifestyle intervention, called BeweegKuur, to support prevention and treatment of type 2 diabetes mellitus.

METHODS

Questionnaire research with two measurements among Dutch general practitioners, practice nurses and physiotherapists participating in a pilot study. At baseline, professionals were generally preparing to start the implementation. At second measurement, all practices were implementing BeweegKuur.

RESULTS

The results reveal a positive motivation among professionals to implement and continue the intervention. The motivation of practice nurses to continue implementation was lower compared with other professionals. Social support by colleagues, compatibility and perceived relative advantage of the intervention for the professionals were associates of the baseline motivation to implement it. High-baseline self-efficacy and profession (i.e. not being practice nurse) positively predicted the motivation to continue the intervention at second measurement.

CONCLUSIONS

Professionals in our study can be characterized as innovators or early adopters, and inclusion of BeweegKuur in the basic health insurance package may persuade other adoption categories to implement the intervention. An intensified focus on skills building (e.g. motivational interviewing skills, general lifestyle counselling skills) is expected to contribute to sustained high-quality implementation of the intervention.

Feasibility and effectiveness of a targeted diabetes prevention program for 18 to 60-year-old South Asian migrants: design and methods of the DH!AAN study

BACKGROUND

South Asian migrants are at particularly high risk of type 2 diabetes. Previous studies have shown that intensive lifestyle interventions may prevent the onset of diabetes. Such interventions have not been culturally adapted and evaluated among South Asians in industrialized countries. Therefore, we have set up a randomized controlled trial to study the effectiveness of a targeted lifestyle intervention for the risk of type 2 diabetes and cardiovascular risk factors among 18 to 60-year-old Hindustani Surinamese (South Asians) in The Hague, the Netherlands. Here we present the study design and describe the characteristics of those recruited.

METHODS

Between May 18, 2009 and October 11, 2010, we screened 2307 Hindustani Surinamese (18-60 years old) living in The Hague. We sent invitations to participate to those who had an impaired fasting glucose of 5.6-6.9 mmol/l, an impaired glucose tolerance of 7.8-11.0 mmol/L, a glycated hemoglobin level of 6.0% or more and/or a value of 2.39 or more for the homeostasis model assessment of estimated insulin resistance. In total, 536 people (56.1% of those eligible) participated. People with a higher level of education and a family history of type 2 diabetes were more likely to participate. The control and intervention groups were similar with regard to important background characteristics. The intervention group will receive a culturally targeted intervention consisting of dietary counseling using motivational interviewing and a supervised physical activity program. The control group will receive generic lifestyle advice. To determine the effectiveness, a physical examination (anthropometrics, cardiorespiratory test, lipid profile, and measures of oral glucose tolerance, glycated hemoglobin, and insulin) and interview (physical activity, diet, quality of life, and intermediate outcomes) were carried out at baseline and will be repeated at 1 year and 2 years. The process and the costs will be evaluated.

DISCUSSION

This trial will provide insight into the feasibility and effectiveness of a targeted, intensive, lifestyle intervention for the risk of type 2 diabetes and cardiovascular risk factors among 18 to 60-year-old South Asians.

TRIAL REGISTRATION

Dutch Trial Register: NTR1499.

Effectiveness and cost-effectiveness of 'BeweegKuur', a combined lifestyle intervention in the Netherlands: rationale, design and methods of a randomized controlled trial

Background

Improving the lifestyle of overweight and obese adults is of increasing interest in view of its role in several chronic diseases. Interventions aiming at overweight or weight-related chronic diseases suffer from high drop-out rates. It has been suggested that Motivational Interviewing and more frequent and more patient-specific coaching could decrease the drop-out rate. 'BeweegKuur' is a multidisciplinary lifestyle intervention which offers three programmes for overweight persons. The effectiveness and the cost-effectiveness of intensively guided programmes, such as the 'supervised exercise programme' of 'BeweegKuur', for patients with high weight-related health risk, remain to be assessed. Our randomized controlled trial compares the expenses and effects of the 'supervised exercise programme' with those of the less intensively supervised 'start-up exercise programme'.

Methods/Design

The one-year intervention period involves coaching by a lifestyle advisor, a physiotherapist and a dietician, coordinated by general practitioners (GPs). The participating GP practices have been allocated to the interventions, which differ only in terms of the amount of coaching offered by the physiotherapist. Whereas the 'start-up exercise programme' includes several consultations with physiotherapists to identify barriers hampering independent exercising, the 'supervised exercise programme' includes more sessions with a physiotherapist, involving exercise under supervision. The main goal is transfer to local exercise facilities. The main outcome of the study will be the participants' physical activity at the end of the one-year intervention period and after one year of follow-up. Secondary outcomes are dietary habits, health risk, physical fitness and functional capacity. The economic evaluation will consist of a cost-effectiveness analysis and a cost-utility analysis. The primary outcome measures for the economic evaluation will be the physical activity and the number of quality-adjusted life years. Costs will be assessed from a societal perspective with a time horizon of two years. Additionally, a process evaluation will be used to evaluate the performance of the intervention and the participants' evaluation of the intervention.

Discussion

This study is expected to provide information regarding the additional costs and effects of the 'supervised exercise programme' in adults with very high weight-related health risk.

Trial registration number

ISRCTN: ISRCTN46574304

Sitting time and Body Mass Index in diabetics and pre-diabetics willing to participate in a lifestyle intervention

This cross-sectional study examined the relationship between Body Mass Index (BMI), total sitting time and total physical activity time in a generally overweight or obese population of type 2 diabetics or pre-diabetics willing to participate in a lifestyle intervention [n = 221, 55.1% male, mean age (SD) 62.0 (9.9), mean BMI (SD) 31.4 (5.0)]. In addition, we aimed to identify demographic and psychosocial associates of the motivation to become more physically active. The measurement instrument was a self-report questionnaire. Results showed that total sitting time was more closely related to BMI than total physical activity time. Subjects with a higher weight status were more sedentary, but they were also more motivated to be physically active. On the other hand, their self-efficacy to be physically active was lower than subjects with a lower weight status. Lifestyle interventions to decrease the risk of obesity and type 2 diabetes should aim not only at increasing total physical activity time, but also at reducing the total sitting time. Despite generally high levels of motivation among these obese participants, intervention designers and intermediaries should be aware of their low level of self-efficacy towards being physically active.

Qi-gong mind-body therapy and diabetes control. A randomized controlled trial

BACKGROUND

Previous studies have shown that qi-gong, a form of mind-body movement therapy, may be beneficial for people with type 2 diabetes; however, no controlled studies have been conducted to examine the predictors and mediators of qi-gong effects on indicators of diabetes control. This study examined the effects of qi-gong on diabetes control and identified the predictors and mediators of these effects.

DESIGN

RCT.

SETTING/PARTICIPANTS

The study included forty-one participants (16 men and 25 women; aged 41-71 years) with elevated blood glucose levels.

INTERVENTIONS

Participants were randomized to qi-gong intervention or a usual medical care control group. Physical and hematologic measures were assessed at baseline and after 12 weeks.

MAIN OUTCOME MEASURES

The outcomes were indicators of diabetes control (HbA1c, insulin resistance, fasting blood glucose and insulin, and 2-hour blood glucose and insulin) and potential mediators of these (body weight, waist circumference, and leg strength). Data were collected in 2006 and analyzed in 2007 to 2009.

RESULTS

Linear regression analyses showed significant between-group differences in favor of the intervention group in weight (p<0.01); waist circumference (p<0.01); leg strength (p<0.01); HbA1c (p<0.05); insulin resistance (p<0.01); and fasting blood insulin (p<0.01) at 12 weeks. Logistic regression analyses showed that the qi-gong intervention was a significant predictor of reduced weight (odds for decreasing by -2 kg=11.14, p<0.01); waist circumference (by -5 cm=22.50, p<0.01); insulin resistance (by -0.2 unit=3.75, p<0.05); and improved leg strength (odds for increasing by 4 stands in 30 seconds=7.00, p<0.01). The effect of the qi-gong intervention on improved insulin resistance was mediated by reduced weight.

CONCLUSIONS

The qi-gong intervention was associated with improvements in weight, waist circumference, leg strength, and insulin resistance. The mediation analyses highlight the importance of weight reduction in the control of diabetes. TRIAL REGISTRATION #: Australian New Zealand Clinical Trials Registry: ACTRN12607000528459.

Outcome of intensive integrated intervention in participants with impaired glucose regulation in China

INTRODUCTION

This study investigated the outcomes and identified influencing factors of intensive integrated intervention over 2 years in Chinese patients with impaired glucose regulation (IGR).

METHODS

Adults in Beijing, China, were screened for IGR using the 75 g oral glucose tolerance test. Participants with IGR received lifestyle and health education; those who still had IGR after 1 year were randomly assigned to either a routine care group or to an intensive integrated intervention group.

RESULTS

Of 2344 adults screened, 463 had IGR. Of these, 210 adults had IGR after 1 year and were therefore recruited and randomized to an intensive integrated intervention group (n=106) or a control group (n=104). The percentage of patients who reached the set targets of plasma glucose, blood pressure, body mass index, or triglycerides was significantly higher in the intensive integrated intervention group. None of the patients within the intensive integrated intervention group progressed to diabetes, whereas eight (9.3%) cases of the control group developed type 2 diabetes mellitus (T2DM). Logistic regression analysis showed that both an increase in waist circumference and systolic blood pressure (SBP) were positively correlated with the development of T2DM, whereas improvement in islet beta cell function was negatively correlated with the development of T2DM.

CONCLUSIONS

Intensive integrated intervention may significantly decrease the conversion rate of IGR to T2DM, and increase the conversion ratio to normal glucose tolerance. The increase of waist circumference or SBP and the deterioration of islet beta cell function may be important risk factors for progression from prediabetes to diabetes.

Reduction of diabetes risk in routine clinical practice: are physical activity and nutrition interventions feasible and are the outcomes from reference trials replicable? A systematic review and meta-analysis

Background

The clinical effectiveness of intensive lifestyle interventions in preventing or delaying diabetes in people at high risk has been established from randomised trials of structured, intensive interventions conducted in several countries over the past two decades. The challenge is to translate them into routine clinical settings. The objective of this review is to determine whether lifestyle interventions delivered to high-risk adult patients in routine clinical care settings are feasible and effective in achieving reductions in risk factors for diabetes.

Methods

Data sources: MEDLINE (PubMed), EMBASE, CINAHL, The Cochrane Library, Google Scholar, and grey literature were searched for English-language articles published from January 1990 to August 2009. The reference lists of all articles collected were checked to ensure that no relevant suitable studies were missed. Study selection: We included RCTs, before/after evaluations, cohort studies with or without a control group and interrupted time series analyses of lifestyle interventions with the stated aim of diabetes risk reduction or diabetes prevention, conducted in routine clinical settings and delivered by healthcare providers such as family physicians, practice nurses, allied health personnel, or other healthcare staff associated with a health service. Outcomes of interest were weight loss, reduction in waist circumference, improvement of impaired fasting glucose or oral glucose tolerance test (OGTT) results, improvements in fat and fibre intakes, increased level of engagement in physical activity and reduction in diabetes incidence.

Results

Twelve from 41 potentially relevant studies were included in the review. Four studies were suitable for meta-analysis. A significant positive effect of the interventions on weight was reported by all study types. The meta-analysis showed that lifestyle interventions achieved weight and waist circumference reductions after one year. However, no clear effects on biochemical or clinical parameters were observed, possibly due to short follow-up periods or lack of power of the studies meta-analysed. Changes in dietary parameters or physical activity were generally not reported. Most studies assessing feasibility were supportive of implementation of lifestyle interventions in routine clinical care.

Conclusion

Lifestyle interventions for patients at high risk of diabetes, delivered by a variety of healthcare providers in routine clinical settings, are feasible but appear to be of limited clinical benefit one year after intervention. Despite convincing evidence from structured intensive trials, this systematic review showed that translation into routine practice has less effect on diabetes risk reduction.

Effect of a continuous diabetes lifestyle intervention program on male workers in Korea

AIMS

This study was conducted to compare the effects of two years of lifestyle intervention to no intervention or one year of intervention on diabetes risk factors in male workers with impaired fasting glucose (IFG) or diabetes.

METHODS

We conducted a randomized lifestyle intervention trial designed to alter personal lifestyles among 123 industrial male workers (CG; control group, n=75; OIG; one-year intervention group, n=23; TIG; two-year intervention group, n=25). The intervention consisted of two parts, the main program (face-to-face counseling five times/12 weeks) and a follow-up program (e-mail counseling ten times/30 weeks). Assessments included biochemical characteristics, anthropometry and nutrient intake at baseline and after two years.

RESULTS

After two years, systolic blood pressure, HOMA-IR, HDL cholesterol and total energy intake (p<0.05) were reduced in the OIG group, while weight, body mass index, waist circumference, blood pressure, fasting plasma glucose (FPG), HbA1c and nutrient intake (total energy, carbohydrate, protein and sodium) were significantly decreased (p<0.05, respectively) in the TIG group. When compared to the CG, subjects in OIG and TIG showed significant improvements in the level of FPG and HbA1c (p<0.05).

CONCLUSIONS

Continuous lifestyle intervention for two years is more effective at improving diabetes risk factors than OIG.

Economic evaluation of lifestyle interventions for preventing diabetes and cardiovascular diseases

Lifestyle interventions (i.e., diet and/or physical activity) are effective in delaying or preventing the onset of diabetes and cardiovascular disease. However, policymakers must know the cost-effectiveness of such interventions before implementing them at the large-scale population level. This review discusses various issues (e.g., characteristics, modeling, and long-term effectiveness) in the economic evaluation of lifestyle interventions for the primary and secondary prevention of diabetes and cardiovascular disease. The diverse nature of lifestyle interventions, i.e., type of intervention, means of provision, target groups, setting, and methodology, are the main obstacles to comparing evaluation results. However, most lifestyle interventions are among the intervention options usually regarded as cost-effective. Diabetes prevention programs, such as interventions starting with targeted or universal screening, childhood obesity prevention, and community-based interventions, have reported favorable cost-effectiveness ratios.

Development and implementation of a lifestyle intervention to promote physical activity and healthy diet in the Dutch general practice setting: the BeweegKuur programme

BACKGROUND

The number of patients with diabetes is increasing. BeweegKuur (Dutch for 'Exercise Therapy') is a Dutch lifestyle intervention which aims to effectively and feasibly promote physical activity and better dietary behaviour in primary health care to prevent diabetes.

METHODS

The goal of this paper is to present the development process and the contents of the intervention, using a model of systematic health promotion planning. The intervention consists of a 1-year programme for diabetic and prediabetic patients. Patients are referred by their general practitioner (GP) to a lifestyle advisor (LSA), usually the practice nurse or a physiotherapist. Based on specific inclusion criteria and in close collaboration with the patient, an individual exercise programme is designed and supervised by the LSA. This programme can be attended at existing local exercise facilities or (temporarily) under the supervision of a specialized exercise coach or physiotherapist. All participants are also referred to a dietician and receive diet-related group education. In the first pilot year (2008), the BeweegKuur programme was implemented in 7 regions in the Netherlands (19 GP practices and health centres), while 14 regions (41 GP practices and health centres) participated during the second year. The aim is to implement BeweegKuur in all regions of the Netherlands by 2012.

DISCUSSION

The BeweegKuur programme was systematically developed in an evidence- and practice-based process. Formative monitoring studies and (controlled) effectiveness studies are needed to examine the diffusion process and the effectiveness and cost-effectiveness of the intervention.

Weight control behaviors in overweight/obese U.S. adults with diagnosed hypertension and diabetes

Background

Obesity is a major risk factor for development and progression of hypertension and diabetes, which often coexist in obese patients. Losing weight by means of energy restriction and physical activity has been effective in preventing and managing these diseases. However, weight control behaviors among overweight/obese adults with these conditions are poorly understood.

Methods

Using self-reported data from 143,386 overweight/obese participants (aged ≥ 18 years) in the 2003 Behavioral Risk Factor Surveillance System, we examined the proportion of overweight/obese adults who tried to lose weight and their weight control strategies by hypertension and/or diabetes status.

Results

Among all participants, 58% of those with hypertension, 60% of those with diabetes, and 72% of those with both diseases tried to lose weight, significantly higher than the 50% of those with neither condition (Bonferroni corrected P < 0.017 for all comparisons). The multivariate-adjusted odds ratio (AOR) for trying to lose weight was 1.11 (95% confidence interval [CI]: 1.05–1.17) in participants with hypertension, 1.02 (95% CI: 0.90–1.15) in participants with diabetes, and 1.18 (95% CI: 1.07–1.29) in participants with both diseases (participants with neither condition as the referent). Among 78,446 participants who tried to lose weight, 23% of those with hypertension only and 28% of those with both hypertension and diabetes reported adopting a low fat/low calorie (LF/LC) diet in controlling their weight, significantly higher than 19% of those with neither disease (Bonferroni corrected P < 0.017 for all comparisons). Participants with both diseases had a significantly lower percentage of adopting physical activity in controlling their weight than those with neither condition (6% versus 12%, P < 0.01). After multivariate adjustment, the AOR for adopting a LF/LC diet plus physical activity to lose weight was 1.46 (95% CI: 1.15–1.84) in participants with both diseases. The AOR for adopting a LF/LC diet only to lose weight was 1.72 (95% CI: 1.35–2.20) in participants with both diseases and was 1.21 (95% CI: 1.03–1.40) in participants with hypertension only.

Conclusion

The proportion of overweight/obese patients with diagnosed hypertension and/or diabetes who attempted to lose weight remains suboptimal and the weight control strategies varied significantly among these patients.

Upregulation of mitochondrial uncoupling protein-2 by the AMP-activated protein kinase in endothelial cells attenuates oxidative stress in diabetes

OBJECTIVE

Recent evidence suggests that the AMP-activated protein kinase (AMPK) is an important therapeutic target for diabetes. The present study was conducted to determine how AMPK activation suppressed tyrosine nitration of prostacyclin synthase in diabetes.

RESEARCH DESIGN AND METHODS

Confluent human umbilical vein endothelial cells (HUVECs) or mice were treated with 5-amino-4-imidazole carboxamide riboside (AICAR) for the detection of AMPK phosphorylation and the expression of mitochondrial uncoupling protein (UCP)-2.

RESULTS

Exposure of HUVECs to high glucose (30 mmol/l) increased superoxide anions (O(2).(-)) and prostacyclin synthase nitration. In addition, overexpression of constitutively active AMPK (Ad-CA-AMPK) or the addition of AICAR reduced both O(2).(-) and prostacyclin synthase nitration caused by high glucose, whereas adenoviral overexpression of dominant-negative AMPK mutants (Ad-DN-AMPK) enhanced the latter effects of high glucose. Exposure of HUVECs to either AICAR or metformin caused AMPK-dependent upregulation of both UCP-2 mRNA and UCP-2 protein. Furthermore, overexpression of UCP-2 significantly ablated both O(2).(-) and prostacyclin synthase nitration triggered by high glucose. Furthermore, overexpression of Ad-CA-AMPK increased, whereas overexpression of Ad-DN-AMPK inhibited AICAR-induced phosphorylation of p38 kinase at Thr180/Tyr182. Inhibition of p38 kinase with SB239063, which had no effect on AICAR-induced AMPK-Thr172 phosphorylation, dose dependently suppressed AICAR-induced upregulation of UCP-2, suggesting that AMPK lies upstream of p38 kinase. Finally, AICAR markedly increased UCP-2 expression and reduced both O(2).(-) and prostacyclin synthase nitration in diabetic wild-type mice but not in their AMPKalpha2-deficient counterparts in vivo.

CONCLUSIONS

We conclude that AMPK activation increases UCP-2, resulting in the inhibition of both O(2).(-) and prostacyclin synthase nitration in diabetes.

An integrative literature review of lifestyle interventions for the prevention of type II diabetes mellitus

AIMS AND OBJECTIVES

An integrative literature review was undertaken to determine what type II diabetes prevention programmes have been evaluated, what type of programme is the most effective and how adherent to lifestyle changes adults are after participating in a prevention programme.

BACKGROUND

Type II diabetes is important because the disease is affecting millions of people worldwide. Obesity and sedentary lifestyles are preventable risk factors for type II diabetes, leading many researchers from around the world to examine different programmes that are focussed on prevention of the disease.

DESIGN

Integrative literature review.

METHOD

Search of electronic databases.

RESULTS

Diet, exercise, counselling and diet plus exercise were the types of prevention programmes, with the diet plus exercise being the most efficacious. Although many studies demonstrated excellent results initially, maintaining the effects of the lifestyle behaviour change proved to be difficult for participants, with only one study demonstrating the persistence of results after six years.

CONCLUSION

Future research should focus on long-term maintenance programmes, rather than just short-term prevention programmes to determine the need for booster interventions or other means to ultimately decrease the incidence of type II diabetes.

RELEVANCE TO CLINICAL PRACTICE

As front-line healthcare providers working across a broad array of settings, nurses are particularly well-suited to play an integral part in future applications of diabetes prevention programmes. Lifestyle interventions are being delivered in a variety of settings and venues such as the workplace, the Internet and places of worship. In addition, at-risk populations also can be targeted, particularly overweight and obese persons, with at least one parent having type II diabetes or persons with gestational diabetes.

Exercise or exercise and diet for preventing type 2 diabetes mellitus

BACKGROUND

The incidence of type 2 diabetes is associated with the 'Westernised lifestyle', mainly in terms of dietary habits and physical activity. Thus an intensive diet and exercise intervention might prevent or delay the appearance of diabetes in persons at high risk.

OBJECTIVES

To assess the effects of exercise or exercise and diet for preventing type 2 diabetes mellitus.

SEARCH STRATEGY

We searched The Cochrane Library, MEDLINE, EMBASE, CINAHL, LILACS, SocioFile, databases of ongoing trials and reference lists of relevant reviews.

SELECTION CRITERIA

Studies were included if they were randomised controlled trials of exercise and diet interventions of at least six month duration and reported diabetes incidence in people at risk for type 2 diabetes.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. Study authors were contacted to obtain missing data. Data on diabetes incidence and secondary outcomes were analysed by means of random-effects meta-analysis.

MAIN RESULTS

We included eight trials that had an exercise plus diet (2241 participants) and a standard recommendation arm (2509 participants). Two studies had a diet only (167 participants) and exercise only arm (178 participants). Study duration ranged from one to six years. Overall, exercise plus diet interventions reduced the risk of diabetes compared with standard recommendations (RR 0.63, 95% CI 0.49 to 0.79). This had also favourable effects on weight and body mass index reduction, waist-to-hip ratio and waist circumference. However, statistical heterogeneity was very high for these outcomes. Exercise and diet interventions had a very modest effect on blood lipids. However, this intervention improved systolic and diastolic blood pressure levels (weighted mean difference -4 mmHg, 95% CI -5 to -2 and -2 mmHg, 95% CI -3 to -1, respectively). No statistical significant effects on diabetes incidence were observed when comparing exercise only interventions either with standard recommendations or with diet only interventions. No study reported relevant data on diabetes and cardiovascular related morbidity, mortality and quality of life.

AUTHORS' CONCLUSIONS

Interventions aimed at increasing exercise combined with diet are able to decrease the incidence of type 2 diabetes mellitus in high risk groups (people with impaired glucose tolerance or the metabolic syndrome). There is a need for studies exploring exercise only interventions and studies exploring the effect of exercise and diet on quality of life, morbidity and mortality, with special focus on cardiovascular outcomes.