Habitual physical activity, aerobic capacity and metabolic control in patients with newly-diagnosed type 2 (non-insulin-dependent) diabetes mellitus: effect of 1-year diet and exercise intervention

Effects of combined aerobic exercise and diet on cardiometabolic health in patients with obesity and type 2 diabetes: a systematic review and meta-analysis

BACKGROUND

Lifestyle modifications involving diet and exercise are recommended for patients diagnosed with obesity and type 2 diabetes mellitus (T2DM). The purpose of this review was to systematically evaluate the effects of combined aerobic exercise and diet (AEDT) on various cardiometabolic health-related indicators among individuals with obesity and T2DM.

METHODOLOGY

A comprehensive search of the PubMed/Medline, Web of Science, Scopus, Science Direct, Cochrane, and Google Scholar databases was conducted for this meta-analysis. The Cochrane risk of bias tool was used to evaluate eligible studies, and the GRADE tool was used to rate the certainty of evidence. A random-effects model for continuous variables was used, and the results were presented as mean differences or standardised mean differences with 95% confidence intervals.

RESULTS

A total of 16,129 studies were retrieved; 20 studies were included, and data were extracted from 1,192 participants. The findings revealed significant improvements in body mass index, body weight, waist circumference, systolic blood pressure, diastolic blood pressure, total cholesterol, triglycerides, fasting blood glucose, fasting plasma insulin, glycated hemoglobin, leptin, interleukin-6, C-reactive protein, and adiponectin (p < 0.05) compared to the standard treatment (ST) group. No significant differences were observed between the AEDT and ST groups in fat mass, hip circumference, waist-to-hip ratio, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and tumor necrosis factor-alpha. The present findings are based on low- to moderate-quality evidence.

CONCLUSIONS

AEDT may be a critical behavior for holistic cardiometabolic health-related benefits as a contemporary anti-obesity medication due to its significant positive impact on patients with obesity and T2DM. Nevertheless, further robust evidence is necessary to determine whether AEDT is an effective intervention for lowering cardiovascular and metabolic risk factors among individuals with obesity and T2DM.

Effects of Exercise On Coronary Flow Reserve And Biochemical Parameters in Patients With Type 2 Diabetes Mellitus

The most important mortality and morbidity causes in diabetic patients are coronary, peripheral and cerebral diseases. The aim of our study was to noninvasively determine dysfunction in epicardial coronary arteries and microvascular circulation with measurement of coronary flow reserve using transthoracic echocardiography in patients with type 2 diabetes despite absence of ischemic symptoms, and to demonstrate the amelioration in endothelial functions, glycemic control and insulin resistance along with increase in coronary flow reserve after 8 weeks of regular exercise. 40 patients diagnosed with type 2 diabetes in Istanbul Facuty of Medicine, Department of Diabetes, who were on follow-up for at least three years due to diabetes, without ischemic symptoms and 20 healthy subjects took part in study. Basal values before exercise of diabetic patients who were included in the exercise program were compared with basal values of diabetic patients who did not exercise regularly. To summarize, regular exercise and physical activity are highly important in diabetic patients for primary and secondary protection against cardiovascular incidents. Physical activity increases insulin sensitivity in diabetic patients, and has many positive effects on glucose metabolism. It is the important way to decrease obesity and visceral fat tissue. There is evidence pointing out that regular exercise can defer or even prevent initiation of diabetes.

The Impact of Exercise Training Intensity on Physiological Adaptations and Insulin Resistance in Women with Abdominal Obesity

Abdominal obesity has emerged globally as a major public health issue due to its high prevalence and morbidity. The benefits of physical exercise among the obese population are well documented. However, the optimal exercise intensity for reducing body fat and preventing insulin resistance and metabolic disorders is still under debate. This study aimed to examine the effects of three different intensities of combined endurance and strength training programs on anthropometric variables, physiological and muscular adaptations, and insulin sensitivity. Forty-three obese young women (age 26.4 ± 4.7 years, BMI 33.1 ± 2.5 kg/m2) were randomly assigned to one of four groups: a control group (G0), a moderate-intensity training group (G50, exercising brisk walking at 50% heart rate reserve HRR), a high-intensity training group (G75, exercise jogging at 75% HRR), and an alternated-intensity training group (G50/75, exercise brisk-walking/jogging at 50−75% HRR) with additional strength training once a week for each group. Body composition, waist circumference (WC), fasting blood glucose, insulin sensitivity and resistance (Homa-IR), resting heart rate (RHR), 6-min walk distance (6MWD), 1-repetition maximum (1-RM), and time to exhaustion (TTE) at 45% and 75% maximal voluntary contraction (MVC) for both the flexor and extensor muscle groups of the knees, were recorded before and after three months of exercise training. All training groups showed significant decreases in body mass, BMI, total body fat, body fat percentage, WC, abdominal and visceral mass (p < 0.001), with a greater reduction of body mass and BMI in G75 (p < 0.05). Lean mass increased significantly only in G50/75 (p < 0.05). The insulin sensitivity and Homa-IR decreased in the three training groups (p < 0.01), with greater enhanced resistance in G50 compared to G75 and G50/75 (p < 0.05). In contrast, there were no pre-post changes in all groups for fasting blood glucose (p > 0.05). 1-RM and TTE of the knee flexor and extensor muscles were improved in the three groups (p < 0.01), with greater improvement in G50/75 for 1RM and G75 in most of the TTE parameters (p < 0.05). RHR decreased and 6MWD increased significantly in the three training groups (p < 0.01), with greater 6MWD improvement in G75 (p < 0.05). In conclusion, the three training intensities seem to generate benefits in terms of body composition, physiological and muscular adaptations, and insulin resistance. High training intensity resulted in greater improvements in body mass, BMI, and endurance and strength, whereas moderate training intensity resulted in greater improvements of insulin resistance and homo-IR. Following alternate-intensity training, greater improvements were observed in lean mass and maximal strength performance.

Effect of Exercise Instructions With Ambulatory Accelerometer in Japanese Patients With Type 2 Diabetes: a Randomized Control Trial

This study aimed to investigate the effects of physical therapists' exercise instructions in Japanese patients with type 2 diabetes. Thirty-six participants were recruited from the outpatient clinic at Matsushita Memorial Hospital, Osaka, Japan from June 2020 to September 2020 and were randomly assigned to either the non-intervention or intervention group. The intervention group received exercise instructions from physical therapists for 30 min at baseline (week 0) and at week 4 by referring to ambulatory accelerometer records. Laboratory parameters, physical activity, body composition, motor skill, and transtheoretical model were assessed in both the groups at baseline (week 0) and week 8. In week 8, patients in the intervention group had a statistically significant reduction in HbA1c levels compared with those in the non-intervention group (7.3% [6.8-%-7.9%] vs. 7.4% [7.3%-7.7%], P = 0.04). The number of steps per day (P = 0.001), energy expenditure (P = 0.01), lower extremity muscle strength (P = 0.002), and 6-min walk test results (P = 0.04) were significantly increased in the intervention group compared with those in the non-intervention group in week 8. The transtheoretical model varied between baseline (week 0) and week 8 only in the intervention group (P < 0.001). Thus, outpatient exercise instructions from physical therapists could improve glycemic control owing to physical activity by improving motor skills and changing the transtheoretical model in Japanese patients with type 2 diabetes.

Exercise Intensities as Factors of Metabolic Outcomes in Type 2 Diabetes: A Systematic Review

Exercise is effective to prevent and treat type 2 diabetes, although currently underutilized. This review analyzes the metabolic response to exercise performance at various intensities in individuals with type 2 diabetes. These findings provide insight into the development of safe and efficacious exercise prescriptions and education. We conducted a systemic review of the literature to examine the association of various exercise protocols with metabolic outcomes in type 2 diabetes. Between 1984 and 2018, 29 studies were categorized per exercise mode and intensity levels according to the American College of Sports Medicine standards. The most consistent improvement was found in HbA1c following moderate- to high-intensity exercise—post-exercise fasting glucose improved to a lesser extent. Low-intensity exercise improved HOMA-IR (homeostasis model assessment for insulin resistance) levels. Glucose and HbA1c improved most following interval compared with continuous exercise, irrespective of intensity. A comparison of high-intensity exercise with moderate-intensity exercise demonstrated few differences in HbA1c, fasting glucose, fasting insulin, and HOMA-IR. Irrespective of exercise intensity, HbA1c improvements were observed, suggesting a delayed progression to diabetes-related complications. Initial low-intensity exercise, with increased quantities when feasible, will contribute to metabolic improvements. The variability in methodology and measurement contributed to inconsistent outcomes; additional research with larger samples sizes is warranted.

Partitioning of radiological, stress and biochemical changes in pre-diabetic women subjected to Diabetic Yoga Protocol

BACKGROUND

Yoga is an ancient system of wellness with Asana and Pranayama as its most popular and propagated modules for management of lifestyle disorders.

OBJECTIVES

The aim of the study was to characterise the liver abnormalities, biochemical changes, and stress levels after Yoga intervention in prediabetic females.

MATERIALS AND METHODS

37 females were randomly divided into Yoga practising and non-practising control groups. The Yoga practising group performed Diabetic Yoga Protocol (DYP) for 3 months. Parameters including size of liver, fatty infiltration, and grade of severity were measured using ultrasonography along with biochemical parameters and stress levels at baseline and after Yoga practice.

RESULTS

The glycosylated hemoglobin (HbA1c) and glucose levels were found significantly reduced in prediabetic (p = 0.015) women after practising DYP, although cholesterol levels increased in menopausal women. No escalation of fatty liver was noted among women practising DYP.

CONCLUSION

DYP reduced the HbA1c and stress levels and therefore, could be a cost-effective tool for preventing prediabetes to diabetes progression.

Behaviour change techniques targeting both diet and physical activity in type 2 diabetes: A systematic review and meta-analysis

BACKGROUND

Changing diet and physical activity behaviour is one of the cornerstones of type 2 diabetes treatment, but changing behaviour is challenging. The objective of this study was to identify behaviour change techniques (BCTs) and intervention features of dietary and physical activity interventions for patients with type 2 diabetes that are associated with changes in HbA1c and body weight.

METHODS

We performed a systematic review of papers published between 1975-2015 describing randomised controlled trials (RCTs) that focused exclusively on both diet and physical activity. The constituent BCTs, intervention features and methodological rigour of these interventions were evaluated. Changes in HbA1c and body weight were meta-analysed and examined in relation to use of BCTs.

RESULTS

Thirteen RCTs were identified. Meta-analyses revealed reductions in HbA1c at 3, 6, 12 and 24 months of -1.11 % (12 mmol/mol), -0.67 % (7 mmol/mol), -0.28 % (3 mmol/mol) and -0.26 % (2 mmol/mol) with an overall reduction of -0.53 % (6 mmol/mol [95 % CI -0.74 to -0.32, P < 0.00001]) in intervention groups compared to control groups. Meta-analyses also showed a reduction in body weight of -2.7 kg, -3.64 kg, -3.77 kg and -3.18 kg at 3, 6, 12 and 24 months, overall reduction was -3.73 kg (95 % CI -6.09 to -1.37 kg, P = 0.002). Four of 46 BCTs identified were associated with >0.3 % reduction in HbA1c: 'instruction on how to perform a behaviour', 'behavioural practice/rehearsal', 'demonstration of the behaviour' and 'action planning', as were intervention features 'supervised physical activity', 'group sessions', 'contact with an exercise physiologist', 'contact with an exercise physiologist and a dietitian', 'baseline HbA1c >8 %' and interventions of greater frequency and intensity.

CONCLUSIONS

Diet and physical activity interventions achieved clinically significant reductions in HbA1c at three and six months, but not at 12 and 24 months. Specific BCTs and intervention features identified may inform more effective structured lifestyle intervention treatment strategies for type 2 diabetes.

Exercise as medicine - evidence for prescribing exercise as therapy in 26 different chronic diseases

This review provides the reader with the up-to-date evidence-based basis for prescribing exercise as medicine in the treatment of 26 different diseases: psychiatric diseases (depression, anxiety, stress, schizophrenia); neurological diseases (dementia, Parkinson's disease, multiple sclerosis); metabolic diseases (obesity, hyperlipidemia, metabolic syndrome, polycystic ovarian syndrome, type 2 diabetes, type 1 diabetes); cardiovascular diseases (hypertension, coronary heart disease, heart failure, cerebral apoplexy, and claudication intermittent); pulmonary diseases (chronic obstructive pulmonary disease, asthma, cystic fibrosis); musculo-skeletal disorders (osteoarthritis, osteoporosis, back pain, rheumatoid arthritis); and cancer. The effect of exercise therapy on disease pathogenesis and symptoms are given and the possible mechanisms of action are discussed. We have interpreted the scientific literature and for each disease, we provide the reader with our best advice regarding the optimal type and dose for prescription of exercise.

WITHDRAWN: Group based diabetes self-management education compared to routine treatment, waiting list control or no intervention for people with type 2 diabetes mellitus

The review authors of this review update are unable to continue with their work. The Cochrane Metabolic and Endocrine Disorders Review Group is seeking very experienced new authors to perform an update on this complex intervention review.

At June 2015, this review has been withdrawn. This review is out of date although it is correct as the date of publication. The latest version is available in the 'Other versions' tab on the Cochrane Library, and may still be useful to readers.

The editorial group responsible for this previously published document have withdrawn it from publication.

Impact of diabetes and diastolic dysfunction on exercise capacity in normotensive patients without coronary artery disease

OBJECTIVE

The aim of this study was to determine the impact of diabetes and diastolic dysfunction on exercise capacity in asymptomatic, normotensive patients with type 2 diabetes without coronary artery disease.

METHODS

A total of 43 type 2 diabetes patients (age: 50 ± 5 years) and 20 healthy controls (age: 48 ± 4 years) were enrolled. Diastolic function was investigated by conventional pulsed-wave (PW) Doppler and tissue Doppler imaging (TDI). Exercise capacity was evaluated with cardiopulmonary exercise testing (CPET).

RESULTS

In patients with type 2 diabetes, increase in resting heart rate (HR-rest) (p = 0.013), decrease in maximum heart rate during exercise (HR-max) (p < 0.001) and exercise time (p < 0.001) compared with controls were significant. Patients had significantly increased minute ventilation volume (VE)/maximum carbon dioxide discharge (VCO2) ratio (p < 0.001), decreased maximum oxygen consumption (VO2-max) (p < 0.001), oxygen consumption at anaerobic threshold (VO2-an) (p < 0.001) and maximum carbon dioxide discharge (VCO2) (p < 0.001) compared to controls indicating significantly reduced exercise capacity. HbA1c was inversely correlated with VO2-max (r = -0.456, p < 0.01) independent of the absence or presence of mild diastolic dysfunction.

CONCLUSION

Exercise capacity was found to be significantly decreased in normotensive patients with type 2 diabetes without coronary artery disease, and this decrease was independent of diastolic dysfunction.

When it comes to lifestyle recommendations, more is sometimes less: a meta-analysis of theoretical assumptions underlying the effectiveness of interventions promoting multiple behavior domain change

A meta-analysis of 150 research reports summarizing the results of multiple behavior domain interventions examined theoretical predictions about the effects of the included number of recommendations on behavioral and clinical change in the domains of smoking, diet, and physical activity. The meta-analysis yielded 3 main conclusions. First, there is a curvilinear relation between the number of behavioral recommendations and improvements in behavioral and clinical measures, with a moderate number of recommendations producing the highest level of change. A moderate number of recommendations is likely to be associated with stronger effects because the intervention ensures the necessary level of motivation to implement the recommended changes, thereby increasing compliance with the goals set by the intervention, without making the intervention excessively demanding. Second, this curve was more pronounced when samples were likely to have low motivation to change, such as when interventions were delivered to nonpatient (vs. patient) populations, were implemented in nonclinic (vs. clinic) settings, used lay community (vs. expert) facilitators, and involved group (vs. individual) delivery formats. Finally, change in behavioral outcomes mediated the effects of number of recommended behaviors on clinical change. These findings provide important insights that can help guide the design of effective multiple behavior domain interventions.

Yoga: As an adjunct therapy to trim down the Ayurvedic drug requirement in non insulin-dependent diabetes mellitus

Introduction:

In spite of a large number of drugs showing anti-hyperglycemic activities, none of them have been successful in complete management of diabetes mellitus (DM). Yoga and Ayurveda are the two schools of thought in India, which have a history of curing diseases since thousands of years. Yogic techniques and Ayurvedic herbs have proven their anti-diabetic potential without inducing untoward effects. The present study combines Ayurvedic medication with Yoga techniques as a new approach toward healing DM.

Aims and Objectives:

To assess the effect of Yoga therapy in the management of non insulin-dependent DM (NIDDM) and to decrease the oral drug dose requirement of guḍūcī ghana Tablet.

Materials and Methods:

Thirty known NIDDM patients of both genders, who were on guḍūcī ghana (solidified aqueous extract of Tinospora cordifolia (Willd.) Miers.) tablets from past 2 months as Ayurvedic remedy for DM were selected. Along with guḍūcī ghana administration, the subjects were instructed to follow Yogic procedures including Āsanas, prāṇāyāma, and śuddhi kriyās. The study was conducted for 8 weeks, wherein fasting blood sugar (FBS) and postprandial blood sugar (PPBS) levels along with relief in sign and symptoms were assessed at every 2 weeks intervals, and according to relief in sign and symptoms, tapering of drug dosage was carried out. The obtained data were analyzed statistically by applying paired t-test.

Results and Conclusion:

The results obtained were promising as the relief in diabetic symptomatology was highly significant in terms of P value. 80.83% reduction in dose of guḍūcī ghana tablets and 7.85% and 8.78% fall in FBS and PPBS levels, respectively, after the complete course of treatment. The obtained P value showed highly significant results.

Effect of Aerobic Exercise Training on MDA and TNF- α Levels in Patients with Type 2 Diabetes Mellitus

Objective. Diabetes mellitus (DM) is associated with low-grade inflammation. The benefits of regular exercise for the DM are well established, whereas less is known about the impact of aerobic exercise on malondialdehyde (MDA) and tumor necrosis factor-alpha (TNF-α) in the DM. Methods. We randomised 64 participants, who do not exercise regularly, without any diabetic chronic complications in parallel to 12 weeks of aerobic exercise (three times per week, n = 31) and no exercise (control; n = 33). Plasma levels of soluble TNF-α and MDA levels were measured before-after physical training programme and control group. Results. Sixty-four patients with type 2 diabetes mellitus were analysed. When comparing the two groups of patients with age, gender, hemoglobin A1c (HbA1c) levels, lipid profile, waist circumference, body mass index (BMI) and class of treatment for diabetes were not different between groups. While soluble TNF-α remained essentially unaffected by physical training, plasma concentrations of MDA markedly decreased (P < 0.05); physical training also decreased body weight, waist circumference, and blood pressure (P < 0.05). Conclusion. Exercise training favorably affected body weight, waist circumference, and blood pressure. A three-weekly, 12-week, aerobic-training programme, without a concomitant weight loss diet, was associated with significant decrease in MDA levels in type 2 diabetic individuals.

The acute effects of interval- Vs continuous-walking exercise on glycemic control in subjects with type 2 diabetes: a crossover, controlled study

CONTEXT

Glycemic control improves with physical activity, but the optimal exercise mode is unknown.

OBJECTIVE

The objective of the study was to determine whether interval-based exercise improves postprandial glucose tolerance and free-living glycemia more than oxygen consumption- and time duration-matched continuous exercise.

DESIGN

This was a crossover, controlled study with trials performed in randomized order.

SETTING

The study was conducted in hospitalized and ambulatory care.

PATIENTS

PATIENTS diagnosed with type 2 diabetes mellitus (n=10, no withdrawals) participated in the study.

INTERVENTIONS

Subjects performed three 1-hour interventions: 1) interval walking (IW; repeated cycles of 3 min of slow and fast walking); 2) continuous walking (CW); and 3) control (CON). Oxygen consumption (VO2) was measured continuously to match mean VO2 between exercise sessions (∼75% VO2peak).

MAIN OUTCOME MEASURES

A mixed-meal tolerance test (MMTT; 450 kcal, 55% carbohydrate) with stable glucose isotopic tracers was provided after each intervention, and glucose kinetics were measured during the following 4 hours. Free-living glycemic control was assessed for approximately 32 hours after the MMTT using continuous glucose monitoring.

RESULTS

VO2 was well matched between the exercise interventions. IW decreased the mean and maximal incremental plasma glucose during the MMTT when compared with the CON (mean 1.2 ± 0.4 vs 2.0 ± 0.5 mmol/L, P < .001; maximal 3.7 ± 0.6 vs 4.6 ± 0.7 mmol/L, P = .005) and mean when compared with CW (1.7 ± 0.4 mmol/L, P = .02). No differences in the mean or maximal incremental plasma glucose values were seen between the CW and CON. The metabolic clearance rate of glucose during the MMTT was increased in the IW compared with CW (P = .049) and CON (P < .001). Continuous glucose monitoring mean glucose was reduced in IW compared with CW for the rest of the intervention day (8.2 ± 0.4 vs 9.3 ± 0.7 mmol/L, P = .03), whereas no differences were found between IW and CW the following day.

CONCLUSIONS

One interval-based exercise session improves glycemic control in type 2 diabetes mellitus subjects when compared with an oxygen consumption- and time duration-matched continuous exercise session.

Type 1 diabetes, cardiovascular complications and sesame ( zhī má)

Diabetes is a major concern among medical practitioners, with the annual mortality rate increasing up to 26.9% in a person aged 65 years or older and 11.3% in the adult. There are many serious complications associated with diabetes, particularly cardiovascular complications due to microvascular diseases. A prerequisite to reduce the risk of microvascular and neurologic complications of type 1 diabetes is normoglycemia. Insulin therapy is the most common treatment used nowadays in type 1 diabetes. However, this method still has many disadvantages such as increased episode of severe hypoglycemia, hypoglycemia unawareness, increased weight gain, transient exacerbation of pre-existing retinopathy, etc. Using insulin pump (the insulin pump is a medical device used for continuous subcutaneous insulin infusion to manage the insulin level in the treatment of diabetes mellitus), is associated with known disadvantages including increased ketoacidosis, infection at the infusion site, and the treatment being less suitable in young children (less than 7 years of age). Therefore, alternative treatment for diabetes is still in great demand. We took the approach of traditional Chinese medicine to discuss this matter. Sesame (芝麻 Zhī Má), a herb, has been used medicinally for thousands of years in almost all the countries in the world. The beneficial effects of sesame in remediating diabetes, such as hypoglycemic effects, antioxidant, anti-inflammatory, and hypolipidemic effects, improving fat metabolism, and reducing cholesterol, have been demonstrated in many studies,. However, reports on the effects of sesame in remediating cardiovascular complications in diabetic patients are limited, which necessitates further studies on the effects of sesame on cardiovascular complications.

The diabetic lung--a new target organ?

Several abnormalities of the respiratory function have been reported in patients with type 1 and type 2 diabetes. These abnormalities concern lung volume, pulmonary diffusing capacity, control of ventilation, bronchomotor tone, and neuroadrenergic bronchial innervation. Many hypotheses have emerged, and characteristic histological changes have been described in the "diabetic lung", which could explain this abnormal respiratory function. Given the specific abnormalities in diabetic patients, the lung could thus be considered as a target organ in diabetes. Although the practical implications of these functional changes are mild, the presence of an associated acute or chronic pulmonary and/or cardiac disease could determine severe respiratory derangements in diabetic patients. Another clinical consequence of the pulmonary involvement in diabetes is the accelerated decline in respiratory function. The rate of decline in respiratory function in diabetics has been found to be two-to-three times faster than in normal non-smoking subjects, as reported in longitudinal studies. This finding, together with the presence of anatomical and biological changes similar to those described in the aging lung, indicates that the "diabetic lung" could even be considered a model of accelerated aging. This review describes and analyses the current insight into the relationship of diabetes and lung disease, and suggests intensifying research into the lung as a possible target organ in diabetes.

The DASH diet and insulin sensitivity

Lifestyle modifications, including adoption of the Dietary Approaches to Stop Hypertension (DASH) dietary pattern, weight loss in individuals who are overweight or obese, and physical activity, are effective in the prevention and treatment of hypertension. A healthy lifestyle may also have beneficial effects on metabolic abnormalities, such as insulin resistance, that are associated with high blood pressure. This review examines the independent and combined effects of the DASH diet and weight loss plus exercise on blood pressure and insulin sensitivity, with a focus on recently published results from the ENCORE study. Our data suggest that the DASH eating plan alone lowers blood pressure in overweight individuals with higher than optimal blood pressure, but significant improvements in insulin sensitivity are observed only when the DASH diet is implemented as part of a more comprehensive lifestyle modification program that includes exercise and weight loss.

Multiple risk factor interventions for primary prevention of coronary heart disease

BACKGROUND

Multiple risk factor interventions using counselling and educational methods assumed to be efficacious and cost-effective in reducing coronary heart disease (CHD) mortality and morbidity and that they should be expanded. Trials examining risk factor changes have cast doubt on the effectiveness of these interventions.

OBJECTIVES

To assess the effects of multiple risk factor interventions for reducing total mortality, fatal and non-fatal events from CHD and cardiovascular risk factors among adults assumed to be without prior clinical evidence CHD..

SEARCH STRATEGY

We updated the original search BY SEARCHING CENTRAL (2006, Issue 2), MEDLINE (2000 to June 2006) and EMBASE (1998 to June 2006), and checking bibliographies.

SELECTION CRITERIA

Randomised controlled trials of more than six months duration using counselling or education to modify more than one cardiovascular risk factor in adults from general populations, occupational groups or specific risk factors (i.e. diabetes, hypertension, hyperlipidaemia, obesity).

DATA COLLECTION AND ANALYSIS

Two authors extracted data independently. We expressed categorical variables as odds ratios (OR) with 95% confidence intervals (CI). Where studies published subsequent follow-up data on mortality and event rates, we updated these data.

MAIN RESULTS

We found 55 trials (163,471 participants) with a median duration of 12 month follow up. Fourteen trials (139,256 participants) with reported clinical event endpoints, the pooled ORs for total and CHD mortality were 1.00 (95% CI 0.96 to 1.05) and 0.99 (95% CI 0.92 to 1.07), respectively. Total mortality and combined fatal and non-fatal cardiovascular events showed benefits from intervention when confined to trials involving people with hypertension (16 trials) and diabetes (5 trials): OR 0.78 (95% CI 0.68 to 0.89) and OR 0.71 (95% CI 0.61 to 0.83), respectively. Net changes (weighted mean differences) in systolic and diastolic blood pressure (53 trials) and blood cholesterol (50 trials) were -2.71 mmHg (95% CI -3.49 to -1.93), -2.13 mmHg (95% CI -2.67 to -1.58 ) and -0.24 mmol/l (95% CI -0.32 to -0.16), respectively. The OR for reduction in smoking prevalence (20 trials) was 0.87 (95% CI 0.75 to 1.00). Marked heterogeneity (I(2) > 85%) for all risk factor analyses was not explained by co-morbidities, allocation concealment, use of antihypertensive or cholesterol-lowering drugs, or by age of trial.

AUTHORS' CONCLUSIONS

Interventions using counselling and education aimed at behaviour change do not reduce total or CHD mortality or clinical events in general populations but may be effective in reducing mortality in high-risk hypertensive and diabetic populations. Risk factor declines were modest but owing to marked unexplained heterogeneity between trials, the pooled estimates are of dubious validity. Evidence suggests that health promotion interventions have limited use in general populations.

Associations between physical fitness and HbA₁(c) in type 2 diabetes mellitus

AIM/HYPOTHESIS

In people with type 2 diabetes, exercise improves glucose control (as reflected in HbA₁(c)) and physical fitness, but it is not clear to what extent these exercise-induced improvements are correlated with one another. We hypothesised that reductions in HbA₁(c) would be related: (1) to increases in aerobic fitness and strength respectively in patients performing aerobic training or resistance training; and (2) to changes in strength and aerobic fitness in patients performing aerobic and resistance training.

METHODS

We randomly allocated 251 type 2 diabetes patients to aerobic, resistance, or aerobic plus resistance training, or to a sedentary control group. Peak oxygen consumption VO₂(peak), workload, treadmill time and ventilatory threshold measurements from maximal treadmill exercise testing were measured at baseline and 6 months. Muscular strength was measured as the maximum weight that could be lifted eight times on the leg press, bench press and seated row exercises.

RESULTS

With aerobic training, significant associations were found between changes in both VO₂(peak) (p = 0.040) and workload (p = 0.022), and changes in HbA₁(c.) With combined training, improvements in VO₂(peak) (p = 0.008), workload (p = 0.034) and ventilatory threshold (p = 0.003) were significantly associated with changes in HbA₁(c.) Increases in strength on the seated row (p = 0.006) and in mid-thigh muscle cross-sectional area (p = 0.030) were significantly associated with changes in HbA₁(c) after resistance exercise, whereas the association between increases in muscle cross-sectional area and HbA₁(c) in participants doing aerobic plus resistance exercise (p = 0.059) was of borderline significance.

CONCLUSIONS/INTERPRETATION

There appears to be a link between changes in fitness and HbA₁(c). The improvements in cardiorespiratory fitness with aerobic training may be a better predictor of changes in HbA₁(c) than improvements in strength.

Effect of exercise training on physical fitness in type II diabetes mellitus

Few studies have compared changes in cardiorespiratory fitness between aerobic training only or in combination with resistance training. In addition, no study to date has compared strength gains between resistance training and combined exercise training in type II diabetes mellitus (T2DM).

PURPOSE

We evaluated the effects of aerobic exercise training (A group), resistance exercise training (R group), combined aerobic and resistance training (A + R group), and sedentary lifestyle (C group) on cardiorespiratory fitness and muscular strength in individuals with T2DM.

METHODS

Two hundred and fifty-one participants in the Diabetes Aerobic and Resistance Exercise trial were randomly allocated to A, R, A + R, or C. Peak oxygen consumption (V O(2peak)), workload, and treadmill time were determined after maximal exercise testing at 0 and 6 months. Muscular strength was measured as the eight-repetition maximum on the leg press, bench press, and seated row. Responses were compared between younger (aged 39-54 yr) and older (aged 55-70 yr) adults and between sexes.

RESULTS

VO(2peak) improved by 1.73 and 1.93 mL O(2)*kg(-1)*min(-1) with A and A + R, respectively, compared with C (P < 0.05). Strength improvements were significant after A + R and R on the leg press (A + R: 48%, R: 65%), bench press (A + R: 38%, R: 57%), and seated row (A + R: 33%, R: 41%; P < 0.05). There was no main effect of age or sex on training performance outcomes. There was, however, a tendency for older participants to increase VO(2peak) more with A + R (+1.5 mL O(2)*kg(-1)*min(-1)) than with A only (+0.7 mL O(2)*kg(-1)*min(-1)).

CONCLUSIONS

Combined training did not provide additional benefits nor did it mitigate improvements in fitness in younger subjects compared with aerobic and resistance training alone. In older subjects, there was a trend to greater aerobic fitness gains with A + R versus A alone.

Long-term effects of a lifestyle intervention on weight and cardiovascular risk factors in individuals with type 2 diabetes mellitus: four-year results of the Look AHEAD trial

BACKGROUND

Lifestyle interventions produce short-term improvements in glycemia and cardiovascular disease (CVD) risk factors in individuals with type 2 diabetes mellitus, but no long-term data are available. We examined the effects of lifestyle intervention on changes in weight, fitness, and CVD risk factors during a 4-year study.

METHODS

The Look AHEAD (Action for Health in Diabetes) trial is a multicenter randomized clinical trial comparing the effects of an intensive lifestyle intervention (ILI) and diabetes support and education (DSE; the control group) on the incidence of major CVD events in 5145 overweight or obese individuals (59.5% female; mean age, 58.7 years) with type 2 diabetes mellitus. More than 93% of participants provided outcomes data at each annual assessment.

RESULTS

Averaged across 4 years, ILI participants had a greater percentage of weight loss than DSE participants (-6.15% vs -0.88%; P < .001) and greater improvements in treadmill fitness (12.74% vs 1.96%; P < .001), hemoglobin A(1c) level (-0.36% vs -0.09%; P < .001), systolic (-5.33 vs -2.97 mm Hg; P < .001) and diastolic (-2.92 vs -2.48 mm Hg; P = .01) blood pressure, and levels of high-density lipoprotein cholesterol (3.67 vs 1.97 mg/dL; P < .001) and triglycerides (-25.56 vs -19.75 mg/dL; P < .001). Reductions in low-density lipoprotein cholesterol levels were greater in DSE than ILI participants (-11.27 vs -12.84 mg/dL; P = .009) owing to greater use of medications to lower lipid levels in the DSE group. At 4 years, ILI participants maintained greater improvements than DSE participants in weight, fitness, hemoglobin A(1c) levels, systolic blood pressure, and high-density lipoprotein cholesterol levels.

CONCLUSIONS

Intensive lifestyle intervention can produce sustained weight loss and improvements in fitness, glycemic control, and CVD risk factors in individuals with type 2 diabetes. Whether these differences in risk factors translate to reduction in CVD events will ultimately be addressed by the Look AHEAD trial.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00017953.

Impact of exercise intensity and duration on insulin sensitivity in women with T2D

BACKGROUND

Clinical guidelines seldom provide in depth information about the most suitable type and intensity of exercise to obtain optimal benefit in different subgroups of T2D individuals. The aim of this study was to examine the effect of group exercise training on exercise capacity, insulin sensitivity and HbA1c in women with diabetes.

METHODS

Twenty-two women with T2D participated in a supervised group exercise program for six months. The program combined endurance and resistance exercise. The duration and intensity of exercise for each subject was recorded. The volume of exercise was calculated as the product of exercise duration and intensity. Exercise capacity, insulin sensitivity and HbA1c were measured at baseline and after six months of training. The subjects were dichotomized with respect to training volume in a high training volume group and a low training volume group.

RESULTS

Exercise capacity did not change significantly during the training period. Insulin sensitivity increased significantly and HbA1c decreased significantly from baseline in the high volume group but not in the low volume group. The increase in insulin sensitivity was explained with the intensity of exercise by 30%. The reduction in HbA1c was explained with exercise by 25%.

CONCLUSION

Improvement in insulin sensitivity after six months combined supervised group training in female diabetic subjects is related to exercise intensity, whereas the reduction in HbA1c is related mainly to training volume. Metabolic effects of training may be seen in the absence of improved exercise capacity.

Effects of the dietary approaches to stop hypertension diet alone and in combination with exercise and caloric restriction on insulin sensitivity and lipids

This study examined the effects of the Dietary Approaches to Stop Hypertension (DASH) diet on insulin sensitivity and lipids. In a randomized control trial, 144 overweight (body mass index: 25 to 40) men (n=47) and women (n=97) with high blood pressure (130 to 159/85 to 99 mm Hg) were randomly assigned to one of the following groups: (1) DASH diet alone; (2) DASH diet with aerobic exercise and caloric restriction; or (3) usual diet controls (UC). Body composition, fitness, insulin sensitivity, and fasting lipids were measured before and after 4 months of treatment. Insulin sensitivity was estimated on the basis of glucose and insulin levels in the fasting state and after an oral glucose load. Participants in the DASH diet with aerobic exercise and caloric restriction condition lost weight (-8.7 kg [95% CI: -2.0 to -9.7 kg]) and exhibited a significant increase in aerobic capacity, whereas the DASH diet alone and UC participants maintained their weight (-0.3 kg [95% CI: -1.2 to 0.5 kg] and +0.9 kg [95% CI: 0.0 to 1.7 kg], respectively) and had no improvement in exercise capacity. DASH diet with aerobic exercise and caloric restriction demonstrated lower glucose levels after the oral glucose load, improved insulin sensitivity, and lower total cholesterol and triglycerides compared with both DASH diet alone and UC, as well as lower fasting glucose and low-density lipoprotein cholesterol compared with UC. DASH diet alone participants generally did not differ from UC in these measures. Combining the DASH diet with exercise and weight loss resulted in significant improvements in insulin sensitivity and lipids. Despite clinically significant reductions in blood pressure, the DASH diet alone, without caloric restriction or exercise, resulted in minimal improvements in insulin sensitivity or lipids.

Aerobic exercise in obese diabetic patients with chronic kidney disease: a randomized and controlled pilot study

Background

Patients with obesity, diabetes, and chronic kidney disease (CKD) are generally physically inactive, have a high mortality rate, and may benefit from an exercise program.

Methods

We performed a 24-week randomized controlled feasibility study comparing aerobic exercise plus optimal medical management to medical management alone in patients with type 2 diabetes, obesity (body mass index [BMI] > 30 kg/m²), and stage 2-4 CKD (estimated glomerular filtration rate [eGFR] 15-90 mL/min/1.73 m² with persistent proteinuria). Subjects randomized to exercise underwent thrice weekly aerobic training for 6 followed by 18 weeks of supervised home exercise. The primary outcome variable was change in proteinuria.

Results

Seven subjects randomized to exercise and 4 control subjects completed the study. Exercise training resulted in an increase in exercise duration during treadmill testing, which was accompanied by slight but insignificant decreases in resting systolic blood pressure and 24-hour proteinuria. Exercise did not alter GFR, hemoglobin, glycated hemoglobin, serum lipids, or C-reactive protein (CRP). Caloric intake and body weight and composition also did not change with exercise training.

Conclusion

Exercise training in obese diabetic patients with CKD is feasible and may have clinical benefits. A large-scale randomized controlled trial to determine the effects of exercise on renal functions, cardiovascular fitness, inflammation, and oxidative stress in diabetic patients with CKD is planned.

Exercise therapy in type 2 diabetes

Structured exercise is considered an important cornerstone to achieve good glycemic control and improve cardiovascular risk profile in Type 2 diabetes. Current clinical guidelines acknowledge the therapeutic strength of exercise intervention. This paper reviews the wide pathophysiological problems associated with Type 2 diabetes and discusses the benefits of exercise therapy on phenotype characteristics, glycemic control and cardiovascular risk profile in Type 2 diabetes patients. Based on the currently available literature, it is concluded that Type 2 diabetes patients should be stimulated to participate in specifically designed exercise intervention programs. More attention should be paid to cardiovascular and musculoskeletal deconditioning as well as motivational factors to improve long-term treatment adherence and clinical efficacy. More clinical research is warranted to establish the efficacy of exercise intervention in a more differentiated approach for Type 2 diabetes subpopulations within different stages of the disease and various levels of co-morbidity.

Continuous, non-invasive measurement of the haemodynamic response to submaximal exercise in patients with diabetes mellitus: evidence of impaired cardiac reserve and peripheral vascular response

BACKGROUND

Reduced exercise capacity in diabetics has been attributed to limitations in cardiac function and microvascular dysfunction leading to impaired oxygen supply and nutritive perfusion to exercising muscles.

OBJECTIVE

To study changes in cardiac function and microvascular utilisation during exercise in diabetic individuals compared to age-matched controls.

METHODS

Diabetics with glycosylated haemoglobin (HbA(1c)) < 8 (n = 31), diabetics with HbA(1c) > or = 8 (n = 38) and age-matched non-diabetic controls (n = 32) performed exercise at 50 W for 10 minutes followed by recovery, with continuous monitoring of cardiac function by impedance cardiography and regional flow and oxygen saturation by laser Doppler and white light spectroscopy.

RESULTS

In the diabetics, cardiac reserve during exercise and cardiac overshoot during recovery are significantly reduced because of reduction in capacity to increase stroke volume. Regional flow to the exercising muscle is reduced and there is also disproportionately greater desaturation of the regional flow. Abnormalities in cardiac function and regional perfusion are related to the severity of diabetes.

CONCLUSION

Cardiac response to exercise is attenuated significantly in diabetic individuals. Simultaneously, there is impairment in the regional distribution. These changes could be the harbinger of reduced exercise capacity in diabetics.

The effect of weight reduction interventions for persons with type 2 diabetes: a meta-analysis from a self-regulation perspective

PURPOSE

The main purpose of this article was to investigate the value of a self-regulation approach for weight reduction interventions in patients with type 2 diabetes. In addition, the potentially moderating effect of other intervention characteristics was explored.

METHODS

In a meta-analysis of 34 studies, overall effect sizes were calculated for weight and A1C. The focus of the analysis was, however, on the moderating effect of intervention characteristics, especially whether interventions that score high on self-regulation produce stronger effects.

RESULTS

The overall effect sizes (d) for weight loss in the short term (<6 months) were low and even lower in the longer term (>6 months). The overall effect sizes for A1C outcomes were higher and remained stable in the longer term. Interventions that scored high on self-regulation characteristics produced significantly better effects on both weight and A1C outcomes. Furthermore, "goal reformulation" increased the effect on weight outcomes whereas "emotion regulation" increased the effect on A1C. With respect to the other intervention characteristics, only the "inclusion of a patient's partner or relative" increased the effect on weight loss.

CONCLUSIONS

This meta-analysis underlines the importance of a self-regulation approach for weight reduction interventions in diabetes patients, in particular, for A1C outcomes. However, more research is needed to fully understand the relationship among self-regulation, weight, and A1C.

Evaluation of the effects of exercise on insulin sensitivity in Arabian and Swedish women with type 2 diabetes

AIMS

The purpose of this study was to evaluate the effects of exercise on cardio-respiratory fitness and insulin sensitivity in sedentary, overweight Arabian and Swedish women with type 2 diabetes.

METHODS

Eighteen Arabian and 14 Swedish women participated in a supervised 6-month resistance training and aerobic program of moderate intensity. Insulin sensitivity and VO(2max) were measured at entry to the study and after 3 and 6 months training.

RESULTS

After 6 months exercise, insulin sensitivity (M-value) increased (2.7+/-1.4 mg kg(-1) min(-1) vs. 3.4+/-2 mg kg(-1) min(-1), p<0.05) in all patients and accounted for by an increase in non-oxidative glucose metabolism (0.3+/-1.1 mg kg(-1) min(-1) vs. 1.5+/-1.5 mg kg(-1) min(-1), p<0.005) with no significant difference between the ethnic groups. Notably, significant improvement in HbA1c was only seen in the Swedish patients who achieved greater exercise intensity (73.3+/-4.8% vs. 63.3+/-5.2% of maximum heart rate, p<0.005). No changes were observed regarding VO(2max) or lipid profile in either group.

CONCLUSIONS

Although a 6-month exercise intervention of moderate intensity in Arabian and Swedish patients with type 2 diabetes can improve insulin sensitivity it is hampered by the metabolic inflexibility of switching between oxidation of glucose or fat.

Lipoprotein profile, glycemic control and physical fitness after strength and aerobic training in post-menopausal women with type 2 diabetes

We studied the effects on blood lipids and physical fitness after a training program that combined strength and aerobic exercise in postmenopausal women with type 2 diabetes. Ten patients (55.0 +/- 5.2 years) followed four exercise sessions per week, two strength and two aerobic, and ten (59.4 +/- 3.2 years) served as a control group. Lipid profile, glycated hemoglobin (HbA(1c)), HOMA2 index, exercise stress and muscular testing were assessed at the beginning and after 16 weeks of training program. Exercise training increased significantly HDL-C (17.2%; P < 0.001) and decreased triglycerides (18.9%), HbA(1c) (15.0%), fasting plasma glucose (5.4%), insulin resistance (HOMA2 25.2%) and resting blood pressure (P < 0.01). After 16 weeks of training, exercise time (17.8%) and muscular strength increased significantly (P < 0.001). The results indicated that a combined strength and aerobic training program could induce positive adaptations on lipid profile, glycemic control, insulin resistance, cardiovascular function, and physical fitness in post-menopausal women with type 2 diabetes.

Efeito do exercício físico aeróbio sobre o perfil lipídico de pacientes idosas, portadoras de Diabetes Mellitus tipo 2, atendidas em Unidade Básica de Saúde, Maringá, Estado do Paraná

RESUMO Este estudo tem por objetivo verificar a influência de um programa de exercícios físicos aeróbios sobre o perfil lipídico de pacientes idosas, portadoras de Diabetes Mellitus (DM) tipo 2. Foram selecionados 40 pacientes do gênero feminino com idade maior ou igual a 60 anos. A amostra foi distribuída em dois grupos de 20 pacientes cada: Grupo Treinado, que recebeu orientação nutricional e participou das sessões supervisionadas de exercício físico aeróbio, e Grupo Controle, que recebeu somente orientação nutricional. A intervenção teve a duração de 12 semanas. O protocolo de exercício foi aplicado três vezes por semana, tendo cada sessão 1 h de duração. Os dados obtidos mostraram que o protocolo desenvolvido promoveu redução significativa nos triglicerídeos séricos (pré-teste= 190 ± 76,67 e pós-teste= 125,33 ± 45,82 mg/dL, p<0,05) e no LDL-colesterol (pré-teste= 147,98 ± 29,98 e pós-teste= 122,24 ± 17,61 mg/dL, p<0,05) no Grupo Treinado. Os resultados permitiram concluir que o programa de exercícios adotado promoveu melhora no perfil lipídico de pacientes idosas portadoras de DM tipo 2, demonstrando a importância da prática de atividade física orientada em Unidades Básicas de Saúde.

Effect of aerobic exercise training on oxidative stress in patients with type 2 diabetes mellitus

The purpose of this study was to determine whether moderate-intensity exercise training reduces oxidative stress in patients with type 2 diabetes mellitus over 12 months. The patients were divided into 3 groups: aerobic training combined with the use of a fitness center (group A, n = 43), aerobic training only (group B, n = 44), or controls (group C, n = 16). The subjects in groups A and B were instructed to exercise at 50% of peak oxygen uptake for more than 30 minutes on at least 3 days per week over a 12 month period. In addition, the subjects in group A were instructed to use a fitness center and were taught how to perform aerobic training in the indicated manner by certified fitness instructors. We measured the levels of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a parameter of oxidative stress. Serum glycated albumin levels were reduced significantly after 6 and 12 months in groups A and B and after 12 months in group C. Urinary 8-OHdG levels decreased after 12 months in groups A and B, but remained unchanged in group C. There was a significant positive linear association between percentage changes in urinary 8-OHdG and glycated albumin levels over the 12 months. In conclusion, aerobic exercise training improved glycemic control and reduced oxidative stress in patients with type 2 diabetes mellitus. Furthermore, improvement in glycemic control was associated with a reduction in oxidative stress.

Optimizing the therapeutic benefits of exercise in Type 2 diabetes

Other than diet and medication, exercise is considered one of the three cornerstones of good diabetes treatment. Nevertheless, current clinical guidelines on Type 2 diabetes provide no detailed information on the modalities of effective exercise intervention in the treatment of Type 2 diabetes. Based on a review of currently available literature, exercise modalities are being identified to maximize the benefits of exercise intervention in the treatment of different Type 2 diabetes subpopulations. Both endurance and resistance types of exercise have equal therapeutic strength to improve metabolic control in patients with Type 2 diabetes. When applying endurance-type exercise, energy expenditure should be equivalent to approximately 1.7-2.1 MJ/exercise bout on 3 but preferably 5 days/wk. In sarcopenic or severely deconditioned patients with Type 2 diabetes, focus should lie on the implementation of resistance-type exercise to attenuate and/or reverse the decline in skeletal muscle mass and strength. Before choosing the most appropriate exercise modalities, the patient's disease stage should be well characterized, and an ECG-stress test should be considered. Based on baseline aerobic fitness, level of co-morbidities, body composition, and muscle strength, patients should be provided with an individually tailored exercise intervention program to optimize therapeutic value. A multidisciplinary individualized approach and continued exercise training under personal supervision is essential to enhance compliance and allow long-term health benefits of an exercise intervention program.

Dietary advice for treatment of type 2 diabetes mellitus in adults

BACKGROUND

While initial dietary management immediately after formal diagnosis is an 'accepted' cornerstone of treatment of type 2 diabetes mellitus, a formal and systematic overview of its efficacy and method of delivery is not currently available.

OBJECTIVES

To assess the effects of type and frequency of different types of dietary advice for adults with type 2 diabetes.

SEARCH STRATEGY

We carried out a comprehensive search of The Cochrane Library, MEDLINE, EMBASE, CINAHL, AMED, bibliographies and contacted relevant experts.

SELECTION CRITERIA

All randomised controlled trials, of six months or longer, in which dietary advice was the main intervention.

DATA COLLECTION AND ANALYSIS

The lead investigator performed all data extraction and quality scoring with duplication being carried out by one of the other six investigators independently with discrepancies resolved by discussion and consensus. Authors were contacted for missing data.

MAIN RESULTS

Thirty-six articles reporting a total of eighteen trials following 1467 participants were included. Dietary approaches assessed in this review were low-fat/high-carbohydrate diets, high-fat/low-carbohydrate diets, low-calorie (1000 kcal per day) and very-low-calorie (500 kcal per day) diets and modified fat diets. Two trials compared the American Diabetes Association exchange diet with a standard reduced fat diet and five studies assessed low-fat diets versus moderate fat or low-carbohydrate diets. Two studies assessed the effect of a very-low-calorie diet versus a low-calorie diet. Six studies compared dietary advice with dietary advice plus exercise and three other studies assessed dietary advice versus dietary advice plus behavioural approaches. The studies all measured weight and measures of glycaemic control although not all studies reported these in the articles published. Other outcomes which were measured in these studies included mortality, blood pressure, serum cholesterol (including LDL and HDL cholesterol), serum triglycerides, maximal exercise capacity and compliance. The results suggest that adoption of regular exercise is a good way to promote better glycaemic control in type 2 diabetic patients, however all of these studies were at high risk of bias.

AUTHORS' CONCLUSIONS

There are no high quality data on the efficacy of the dietary treatment of type 2 diabetes, however the data available indicate that the adoption of exercise appears to improve glycated haemoglobin at six and twelve months in people with type 2 diabetes. There is an urgent need for well-designed studies which examine a range of interventions, at various points during follow-up, although there is a promising study currently underway.

Effect of psychological intervention on exercise adherence in type 2 diabetic subjects

Previous research has pointed to the efficacy of physical activity in individuals suffering from type 2 diabetes mellitus (type 2 DM). However, as with other populations, adherence to exercise programs is often problematic. This study assessed the effectiveness of a combination of exercise and psychological interventions in type 2 diabetics in terms of disease management and exercise adherence. Forty newly diagnosed type 2 diabetic subjects (54 +/- 6.5 years) took part in the study. Subjects were allocated to an exercise-only intervention (EO) or a combined exercise and psychological adherence intervention (EP) group. Adherence to the program was also monitored at a 6-month follow-up. The results confirmed a significant improvement in physiological parameters (total mass, fat mass, grip strength, peak flow, flexibility, and VO2 max) after the 12-week program in both groups (P < 0.001). The EP group had significant changes in body fat, grip strength, and peak flow (P < 0.05) in comparison to the EO group. Components of the visual analog mood scale (VAMS) were positively influenced in both groups from the therapy program (P < 0.001). The directed psychological intervention had a significant influence on attendance to the 12-week program (P < 0.001). This also resulted in significantly better adherence 6 months later (P < 0.05). In conclusion, the results have demonstrated that psychological intervention is of paramount importance for ensuring high adherence rates during exercise therapy for type 2 diabetic subjects.

Effects of different modes of exercise training on glucose control and risk factors for complications in type 2 diabetic patients: a meta-analysis

OBJECTIVE

We sought to meta-analyze the effects of different modes of exercise training on measures of glucose control and other risk factors for complications of diabetes.

RESEARCH DESIGN AND METHODS

The 27 qualifying studies were controlled trials providing, for each measure, 4-18 estimates for the effect of aerobic training, 2-7 for resistance training, and 1-5 for combined training, with 1,003 type 2 diabetic patients (age 55 +/- 7 years [mean +/- between-study SD]) over 5-104 weeks. The meta-analytic mixed model included main-effect covariates to control for between-study differences in disease severity, sex, total training time, training intensity, and dietary cointervention (13 studies). To interpret magnitudes, effects were standardized after meta-analysis using composite baseline between-subject SD.

RESULTS

Differences among the effects of aerobic, resistance, and combined training on HbA(1c) (A1C) were trivial; for training lasting >/=12 weeks, the overall effect was a small beneficial reduction (A1C 0.8 +/- 0.3% [mean +/- 90% confidence limit]). There were generally small to moderate benefits for other measures of glucose control. For other risk factors, there were either small benefits or effects were trivial or unclear, although combined training was generally superior to aerobic and resistance training. Effects of covariates were generally trivial or unclear, but there were small additional benefits of exercise on glucose control with increased disease severity.

CONCLUSIONS

All forms of exercise training produce small benefits in the main measure of glucose control: A1C. The effects are similar to those of dietary, drug, and insulin treatments. The clinical importance of combining these treatments needs further research.

Meta-analysis of the effect of exercise interventions on fitness outcomes among adults with type 1 and type 2 diabetes

This review applied meta-analytic procedures to integrate primary research that examined exercise fitness outcomes among adults with type 1 or type 2 diabetes. We used extensive literature searching strategies to locate published and unpublished intervention studies that tested exercise interventions. We conducted meta-analytic procedures using both fixed- and random-effects models. Analyses were conducted separately for type 1 and type 2 diabetes and separately for two-group and single-group data under two assumptions about pre-post fitness outcomes association: no association and a strong positive association (0.80). Codable data were extracted from 35 reports with 1074 subjects. The type 1 diabetes overall weighted mean effect size for two-group comparisons was 0.65. For treatment group pretest versus post-test, the effect was 0.62. The effect size among adults with type 2 diabetes for two-group comparisons was 0.35. The treatment group pretest versus post-test comparison effect was 0.37. Effect sizes among control group participants were not statistically different from 0. For type 2 diabetes two-group comparisons, larger effect sizes were associated with exercise prescription, fitness testing, supervised exercise, group sessions, and recommendations for longer duration exercise sessions. HbA1c, age, body mass index, and gender distribution were unrelated to fitness outcomes.

A randomized controlled trial to prevent glycemic relapse in longitudinal diabetes care: study protocol (NCT00362193)

Background

Diabetes is a common disease with self-management a key aspect of care. Large prospective trials have shown that maintaining glycated hemoglobin less than 7% greatly reduces complications but translating this level of control into everyday clinical practice can be difficult. Intensive improvement programs are successful in attaining control in patients with type 2 diabetes, however, many patients experience glycemic relapse once returned to routine care. This early relapse is, in part, due to decreased adherence in self-management behaviors.

Objective

This paper describes the design of the Glycemic Relapse Prevention study. The purpose of this study is to determine the optimal frequency of maintenance intervention needed to prevent glycemic relapse. The primary endpoint is glycemic relapse, which is defined as glycated hemoglobin greater than 8% and an increase of 1% from baseline.

Methods

The intervention consists of telephonic contact by a nurse practitioner with a referral to a dietitian if indicated. This intervention was designed to provide early identification of self-care problems, understanding the rationale behind the self-care lapse and problem solve to find a negotiated solution. A total of 164 patients were randomized to routine care (least intensive), routine care with phone contact every three months (moderate intensity) or routine care with phone contact every month (most intensive).

Conclusion

The baseline patient characteristics are similar across the treatment arms. Intervention fidelity analysis showed excellent reproducibility. This study will provide insight into the important but poorly understood area of glycemic relapse prevention.

Multiple risk factor interventions for primary prevention of coronary heart disease

BACKGROUND

Primary prevention programmes in many countries attempt to reduce mortality and morbidity due to coronary heart disease (CHD) through risk factor modification. It is widely believed that multiple risk factor intervention using counselling and educational methods is efficacious and cost-effective and should be expanded. Recent trials examining risk factor changes have cast considerable doubt on the effectiveness of these multiple risk factor interventions.

OBJECTIVES

To assess the effects of multiple risk factor intervention for reducing cardiovascular risk factors, total mortality, and mortality from CHD among adults without clinical evidence of established cardiovascular disease.

SEARCH STRATEGY

MEDLINE was searched for the original review to 1995. This was updated by searching the Cochrane Central Register of Controlled Trials on The Cochrane Library Issue 3 2001, MEDLINE (2000 to September 2001) and EMBASE (1998 to September 2001).

SELECTION CRITERIA

Intervention studies using counselling or education to modify more than one cardiovascular risk factor in adults from general populations, occupational groups, or high risk groups. Trials of less than 6 months duration were excluded.

DATA COLLECTION AND ANALYSIS

Data were extracted by two reviewers independently. Investigators were contacted to obtain missing information.

MAIN RESULTS

A total of 39 trials were found of which ten reported clinical event data. In the ten trials with clinical event end-points, the pooled odds ratios for total and CHD mortality were 0.96 (95% confidence intervals (CI) 0.92 to 1.01) and 0.96 (95% CI 0.89 to 1.04) respectively. Net changes in systolic and diastolic blood pressure, and blood cholesterol were (weighted mean differences) -3.6 mmHg (95% CI -3.9 to -3.3 mmHg), -2.8 mmHg (95% CI -2.9 to -2.6 mmHg) and -0.07 mMol/l (95% CI -0.8 to -0.06 mMol/l) respectively. Odds of reduction in smoking prevalence was 20% (95% CI 8% to 31%). Statistical heterogeneity between the studies with respect to mortality and risk factor changes was due to trials focusing on hypertensive participants and those using considerable amounts of drug treatment.

AUTHORS' CONCLUSIONS

The pooled effects suggest multiple risk factor intervention has no effect on mortality. However, a small, but potentially important, benefit of treatment (about a 10% reduction in CHD mortality) may have been missed. Risk factor changes were relatively modest, were related to the amount of pharmacological treatment used, and in some cases may have been over-estimated because of regression to the mean effects, lack of intention to treat analyses, habituation to blood pressure measurement, and use of self-reports of smoking. Interventions using personal or family counselling and education with or without pharmacological treatments appear to be more effective at achieving risk factor reduction and consequent reductions in mortality in high risk hypertensive populations. The evidence suggests that such interventions have limited utility in the general population.

Six months of aerobic exercise does not improve microvascular function in type 2 diabetes mellitus

AIMS/HYPOTHESIS

Adults with type 2 diabetes mellitus have impaired microvascular function. It has been hypothesised that microvascular function may be restored through regular exercise. The aim of this study was to investigate whether 6 months of regular aerobic exercise would improve microvascular function in adults with type 2 diabetes.

MATERIALS AND METHODS

Fifty-nine patients with type 2 diabetes (32 males, age 62.9+/-7.6 years, HbA(1c) 6.8+/-0.9%) were randomised to either a 6-month aerobic exercise programme (30 min, three times a week, 70-80% of maximal heart rate) or a 'standard care' control group. Before and after the intervention period, microvascular function was assessed as the maximum skin hyperaemia to local heating and endothelial and non-endothelial responsiveness following the iontophoretic application of acetylcholine and sodium nitroprusside. Maximal oxygen uptake, as an index of aerobic fitness, was assessed using a maximal exercise test.

RESULTS

No significant improvement was seen in the exercise group compared with the control group for any of the variables measured: maximal oxygen uptake (control pre: 1.73+/-0.53 [means+/-SD] vs post: 1.67+/-0.40; exercise pre: 1.75+/-0.56 vs post: 1.87+/-0.62 l/min, p=0.10); insulin sensitivity (insulin tolerance test) (control pre: -0.17+/-0.06 vs post: -0.17+/-0.06; exercise pre: -0.16+/-0.1 vs post: -0.17+/-0.07 mmol l(-1) min(-1), p=0.97); maximal hyperaemia (control pre: 1.49+/-0.43 vs post: 1.52+/-0.57; exercise pre: 1.42+/-0.36 vs post: 1.47+/-0.33 V, p=0.85); peak response to acetylcholine (control pre: 1.37+/-0.47 vs post: 1.28+/-0.37; exercise pre: 1.27+/-0.44 vs post: 1.44+/-0.23 V, p=0.19) or to sodium nitroprusside (control pre: 1.09+/-0.50 vs post: 1.10+/-0.39; exercise pre: 1.12+/-0.28 vs post: 1.13+/-0.40 V, p=0.98).

CONCLUSIONS/INTERPRETATION

In this group of type 2 diabetic patients with good glycaemic control a 6-month aerobic exercise programme did not improve microvascular function or aerobic fitness.

Evidence for prescribing exercise as therapy in chronic disease

Considerable knowledge has accumulated in recent decades concerning the significance of physical activity in the treatment of a number of diseases, including diseases that do not primarily manifest as disorders of the locomotive apparatus. In this review we present the evidence for prescribing exercise therapy in the treatment of metabolic syndrome-related disorders (insulin resistance, type 2 diabetes, dyslipidemia, hypertension, obesity), heart and pulmonary diseases (chronic obstructive pulmonary disease, coronary heart disease, chronic heart failure, intermittent claudication), muscle, bone and joint diseases (osteoarthritis, rheumatoid arthritis, osteoporosis, fibromyalgia, chronic fatigue syndrome) and cancer, depression, asthma and type 1 diabetes. For each disease, we review the effect of exercise therapy on disease pathogenesis, on symptoms specific to the diagnosis, on physical fitness or strength and on quality of life. The possible mechanisms of action are briefly examined and the principles for prescribing exercise therapy are discussed, focusing on the type and amount of exercise and possible contraindications.

Exercise for type 2 diabetes mellitus

BACKGROUND

Exercise is generally recommended for people with type 2 diabetes mellitus. However, some studies evaluate an exercise intervention including diet or behaviour modification or both, and the effects of diet and exercise are not differentiated. Some exercise studies involve low participant numbers, lacking power to show significant differences which may appear in larger trials.

OBJECTIVES

To assess the effects of exercise in type 2 diabetes mellitus.

SEARCH STRATEGY

Trials were identified through the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and manual searches of bibliographies. Date of last search was March 3, 2005.

SELECTION CRITERIA

All randomised controlled trials comparing any type of well-documented aerobic, fitness or progressive resistance training exercise with no exercise in people with type 2 diabetes mellitus.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials, assessed trial quality and extracted data. Study authors were contacted for additional information. Any information on adverse effects was collected from the trials.

MAIN RESULTS

Fourteen randomised controlled trials comparing exercise against no exercise in type 2 diabetes were identified involving 377 participants. Trials ranged from eight weeks to twelve months duration. Compared with the control, the exercise intervention significantly improved glycaemic control as indicated by a decrease in glycated haemoglobin levels of 0.6% (-0.6 % HbA(1c), 95% confidence interval (CI) -0.9 to -0.3; P < 0.05). This result is both statistically and clinically significant. There was no significant difference between groups in whole body mass, probably due to an increase in fat free mass (muscle) with exercise, as reported in one trial (6.3 kg, 95% CI 0.0 to 12.6). There was a reduction in visceral adipose tissue with exercise (-45.5 cm(2), 95% CI -63.8 to -27.3), and subcutaneous adipose tissue also decreased. No study reported adverse effects in the exercise group or diabetic complications. The exercise intervention significantly increased insulin response (131 AUC, 95% CI 20 to 242) (one trial), and decreased plasma triglycerides (-0.25 mmol/L, 95% CI -0.48 to -0.02). No significant difference was found between groups in quality of life (one trial), plasma cholesterol or blood pressure.

AUTHORS' CONCLUSIONS

The meta-analysis shows that exercise significantly improves glycaemic control and reduces visceral adipose tissue and plasma triglycerides, but not plasma cholesterol, in people with type 2 diabetes, even without weight loss.

The diabetes educator: trying hard, but must concentrate more on behaviour

Current guidelines state that education is fundamental to help people with diabetes modify their lifestyle and prevent ill health and early death. However, many people with diabetes are not receiving adequate education. There is a widespread assumption that transferring knowledge will improve health outcomes but there is little empirical support for this assertion. Indeed, knowledge and behaviour are poorly correlated. Knowledge may be a necessary condition but is rarely a sufficient condition for behaviour change. Single interventions, cognitive or behavioural, have had disappointing results, unsurprisingly given the complexity of human behaviour. The most effective interventions are multifaceted and include education, behavioural and psychosocial elements, and target lifestyle change and factors such as self-efficacy and empowerment. We advocate that educational interventions should have multiple components. They should aim to improve patients' sense of self-efficacy and empowerment, and build attitudes towards diabetes that will support the lifestyle changes needed for successful self-management. These conclusions have implications for future research and clinical practice.

Should we quantify insulin resistance in patients with renal disease?

Cardiovascular disease is a major cause of morbidity and mortality in dialysis patients. Vascular disease develops before the initiation of dialysis, and it is now recognized that chronic kidney disease (CKD) is an independent risk factor for cardiovascular disease. Death from cardiovascular disease is a more common endpoint of CKD than progression to dialysis. There are multiple mechanisms that contribute to the increased vascular risk of CKD, one of which is the presence of insulin resistance (IR). CKD is characterised by many features of the metabolic syndrome, and features of IR are also observed in dialysis and transplant patients. IR may be quantified by several different methods. One such method is homeostatic model assessment (HOMA) technique, which derives a measurement of IR from fasting plasma glucose and insulin concentrations. The HOMA index has been demonstrated to be an independent predictor of survival in dialysis patients. CKD is characterised by a chronic inflammatory response and abnormalities in the production and regulation of adipose tissue derived proteins, which may contribute to the development of IR. There are a range of interventions including diet and exercise programmes or medications that may influence IR; however, the impact of these interventions in the context of CKD has not been systematically evaluated.

Determinants of exercise capacity in patients with type 2 diabetes

OBJECTIVE

Type 2 diabetes is associated with reduced exercise capacity, but the cause of this association is unclear. We sought the associations of impaired exercise capacity in type 2 diabetes.

RESEARCH DESIGN AND METHODS

Subclinical left ventricular (LV) dysfunction was sought from myocardial strain rate and the basal segmental diastolic velocity (Em) of each wall in 170 patients with type 2 diabetes (aged 56 +/- 10 years, 91 men), good quality echocardiographic images, and negative exercise echocardiograms. The same measurements were made in 56 control subjects (aged 53 +/- 10 years, 29 men). Exercise capacity was calculated in metabolic equivalents, and heart rate recovery (HRR) was measured as the heart rate difference between peak and 1 min after exercise. In subjects with type 2 diabetes, exercise capacity was correlated with clinical, therapeutic, biochemical, and echocardiographic variables, and significant independent associations were sought using a multiple linear regression model.

RESULTS

Exercise capacity, strain rate, Em, and HRR were significantly reduced in type 2 diabetes. Exercise capacity was associated with age (r = -0.37, P < 0.001), male sex (r = 0.26, P = 0.001), BMI (r = -0.19, P = 0.012), HbA(1c) (A1C; r = -0.22, P = 0.009), Em (r = 0.43, P < 0.001), HRR (r = 0.42, P < 0.001), diabetes duration (r = -0.18, P = 0.021), and hypertension history (r = -0.28, P < 0.001). Age (P < 0.001), male sex (P = 0.007), BMI (P = 0.001), Em (P = 0.032), HRR (P = 0.013), and A1C (P = 0.0007) were independent predictors of exercise capacity.

CONCLUSIONS

Reduced exercise capacity in patients with type 2 diabetes is associated with diabetes control, subclinical LV dysfunction, and impaired HRR.