Intense nonpharmacological intervention in subjects with multiple cardiovascular risk factors: decreased fasting insulin levels but only a minor effect on plasma plasminogen activator inhibitor activity

Novel risk factors of cardiovascular disease and their associations between obesity, physical activity and physical fitness

The prevalence of cardiovascular disease (CVD) is increasing around the globe and is the leading cause of death around the world. Though once thought of as an adult problem, it is now recognised that the early manifestations of disease may occur during childhood. Numerous risk factors have been linked to CVD with much of the research focusing on understanding the prevalence and relationship of traditional risk factors such as dyslipidemia, smoking, diabetes mellitus, hypertension, obesity, psychosocial stress, poor diet, physical inactivity and alcohol consumption to the early etiology of disease. While this line of investigation has greatly enhanced our understanding of the relationship between these risk factors and disease, they do not fully explain all cardiovascular events. To enhance our understanding and help with the management of CVD, investigations that involve the measurement of traditional as well as novel risk factors may be necessary. Public health strategies that aim to reduce the prevalence of obesity and overweight encourage youth to increase their physical activity levels as a means of protecting against poor cardiometabolic profiles. Interventions that increase physical activity levels and improve cardiorespiratory fitness cause a reduction in certain CVD risk factors but the lack of agreement between findings makes it impossible to give precise recommendations that will ensure CVD risk reduction. Yet it is important that research continues in order to establish the most appropriate means of improving the health and well-being of those at most risk of future CVD.

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.

Management of the metabolic syndrome and type 2 diabetes through lifestyle modification

Sustainable lifestyle modifications in diet and physical activity are the initial, and often the primary, component in the management of diabetes and the metabolic syndrome. An energy-prudent diet, coupled with moderate levels of physical activity, favorably affects several parameters of the metabolic syndrome and delays the onset of diabetic complications. Weight loss, albeit not an absolute prerequisite for improvement, is a major determinant and maximizes effectiveness. Adopting a healthy lifestyle pattern requires a series of long-term behavioral changes, but evidence to date indicates low long-term adherence to diet and physical activity recommendations. This calls for greater research and public health efforts focusing on strategies to facilitate behavior modification.

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.

Efficacy of a pedometer-based physical activity program on parameters of diabetes control in type 2 diabetes mellitus

The aim of the study was to determine whether a recommendation to walk 10000 steps per day would result in significant improvements in glycemic control, insulin sensitivity, and cardiovascular risk in patients with type 2 diabetes mellitus. The study was a 6-week randomized controlled trial that included 30 patients with type 2 diabetes mellitus. After 10 days of baseline activity, patients were randomized into 2 groups: control and active. The control group (n = 15) was instructed to continue with their baseline activity for 6 weeks. The active group (n = 15) was instructed to walk at least 10000 steps per day 5 or more days per week, for 6 weeks. Data relevant to glycemic control and other parameters of health were collected at study weeks 0 and 6. There were no differences in the baseline activity between groups (P = .36). Subjects in the active group significantly increased physical activity by 69% during the intervention phase of the study (P = .002), whereas there was no change in the physical activity of the control group (P > .05). High-density lipoprotein cholesterol and resting energy expenditure significantly increased in the active group (P < .05). Finally, plasminogen activator inhibitor 1 (PAI-1) activity was reduced by exercise relative to the control group (P = .03). There were no differences in any other study parameters during the 6-week study. In conclusion, short-term intervention with a pedometer increased physical activity and positively affected plasminogen activator inhibitor 1 activity in previously inactive patients with type 2 diabetes mellitus. The use of a pedometer may prove to be an effective tool for promoting healthy lifestyle changes that include daily physical activity and self-monitoring of therapeutic goals.

Plasminogen activator inhibitor activity, 4G5G polymorphism of the plasminogen activator inhibitor 1 gene, and first-trimester miscarriage in women with polycystic ovary syndrome

We assessed whether hypofibrinolytic plasminogen activator inhibitor 1 (PAI-1 activity) showed an independent association with first-trimester miscarriage in the 430 women with polycystic ovary syndrome (PCOS) who had previous pregnancies (from a cohort of 967 women with PCOS). Prospectively, we hypothesized that Glucophage (Bristol-Myers Squibb, Princeton, NJ) promotes successful live births in women with PCOS by lowering PAI-1 activity before conception and maintaining further reductions of PAI-1 activity during the first trimester of pregnancy. We also assessed whether PAI-1 activity levels were independently related to PAI-1 genotype and to modifiable risk factors body mass index (BMI), insulin, and triglyceride. By stepwise logistic regression, with the dependent variable being previous pregnancy outcomes at 3 levels (live birth pregnancies only [n = 208]; both > or =1 live birth and > or =1 first-trimester miscarriage [n = 111]; or first-trimester miscarriages only [n = 71]) and explanatory variables PAI-1 genotype, PAI-1 activity, insulin, homeostasis model assessment of insulin resistance, BMI, and triglyceride, PAI-1 activity was positively associated with first-trimester miscarriage (P = .004). For each 5 IU/mL increment in PAI-1 activity, the risk being in an adverse first-trimester miscarriage category increased (odds ratio, 1.12; 95% confidence interval, 1.04-1.20). Prospectively, from pretreatment to the last preconception visit on Glucophage, in 30 women who subsequently had live births, PAI-1 activity fell 44%, but rose 19% in 23 women with first-trimester miscarriage (P = .03). In the 30 women with live birth pregnancies, median PAI-1 activity fell continuously from pretreatment through the first trimester (from 16.8 to 6.7 IU/mL), whereas PAI-1 activity was either unchanged or rose in women with first-trimester miscarriage. Of the 921 women with PCOS who had 4G5G data, 718 (78%) had 4G4G-4G5G genotypes vs 87 (69%) of 126 normal female controls (chi(2) = 4.95, P = .026). The 4G allele frequency was 53% in women with PCOS vs 46% in controls (chi(2) = 4.3, P = .04). Of the 866 women with PCOS who had PAI-1 activity data, by stepwise regression, positive independent determinants of PAI-1 activity included BMI (partial R(2) = 10.6%, P < .0001), insulin (partial R(2) = 2.8%, P < .0001), triglyceride (partial R(2) = 1.1%, P = .0009), and the 4G4G-4G5G genotype (partial R(2) = 1%, P = .0011). The PAI-1 gene 4G polymorphism is more common in women with PCOS than in normal women and, in concert with obesity, hyperinsulinemia, and hypertriglyceridemia, contributes to treatable, hypofibrinolytic, miscarriage-promoting, high PAI-1 activity. Preconception and first-trimester decrements in PAI-1 activity on Glucophage are associated with live births, whereas increments or no change in PAI-1 activity despite Glucophage appears to be associated with first-trimester miscarriage.

Target value of intraabdominal fat area for improving coronary heart disease risk factors

OBJECTIVE

The goal of this study was to determine an intraabdominal fat (IF) area target value for improving coronary heart disease (CHD) risk factors in response to weight reduction.

RESEARCH METHODS AND PROCEDURES

Subjects were 279 obese Japanese women, 21 to 66 years old, who were divided into diet-alone and diet-plus-exercise groups and participated in a 14-week weight reduction program. The IF area was measured by computerized tomography scans. Systolic blood pressure > or = 140 mm Hg, diastolic blood pressure > or = 90 mm Hg, total cholesterol > or = 5.70 mM, triglycerides > or = 1.70 mM, and fasting plasma glucose > or = 6.99 mM were defined as CHD risk factors.

RESULTS

The best trade-off between sensitivity (probability of correctly detecting true positive) and specificity (probability of correctly detecting true negative) was found at 100 cm2 pretreatment in combined data of the two groups. At posttreatment, although a slight difference was found in the target value between the treatment groups (60 cm2 for diet alone and 50 cm2 for diet plus exercise), the combined data showed that the best trade-off occurred at 60 cm2 (sensitivity and specificity were 0.55 and 0.63, respectively). The percentage of subjects having no CHD risk factors was significantly lower in the group that had large IF areas (> or = 60 cm2) (46%) compared with the group that had normal IF areas (<60 cm2) (65%). However, the percentage of subjects having multiple CHD risk factors was significantly greater in the group that had large IF areas (16%) compared with the group with normal IF areas (7%) at posttreatment.

DISCUSSION

Our longitudinal data suggest that obese Japanese women should reduce their IF areas to < 60 cm2 through weight reduction to improve CHD risk factors independent of treatment.

Effects of short-term exercise training on plasminogen activator inhibitor (PAI-1)

PURPOSE

To observe the effects of exercise training on plasminogen activator inhibitor, type-1 (PAI-1), tissue plasminogen activator (tPA), and associated metabolic variables in sedentary men and women.

METHODS

A randomized, controlled experimental design was used to examine the influence of 10 d of moderate-intensity exercise training on measures of fibrinolysis. Sixteen men and 16 women between the ages of 50 and 70 yr were randomly assigned to exercise (EX) and control groups (CON) that were balanced for gender and hormone replacement therapy. Blood samples were collected on days 1, 2, 11, and 12 for measurement of plasma PAI-1, tPA, insulin, glucose, and triglyceride. Subjects in EX performed 50 min of treadmill walking at an intensity corresponding to 65% of heart rate reserve each day for 10 consecutive days.

RESULTS

There were no significant changes in PAI-1, tPA, or associated metabolic variables between EX and CON during the intervention period. Within EX subjects, those with higher body fatness had a significant decrease in insulin and triglyceride compared with those with lower body fatness. However, no changes in fibrinolytic measures were observed within these subgroups.

CONCLUSIONS

Short-term exercise training does not change PAI-1 levels in normal, asymptomatic men and women. In addition, modest decreases in insulin and triglyceride in individuals with elevated body fatness do not result in changes in PAI-1 after short-term training. It appears likely that decreases in PAI-1 with exercise training require decreases in adiposity and/or marked changes in metabolic variables.

Exercise-induced changes in coagulation and fibrinolysis in healthy populations and patients with cardiovascular disease

This review highlights the clinical significance of coagulation and fibrinolytic responses, and adaptations in healthy individuals and patients with cardiovascular disease (CVD). Much of the review focuses on indicators of the potential for coagulation and fibrinolysis. The terms 'coagulation potential' and 'fibrinolytic potential' are used frequently, as much of the literature in the area of exercise haemostasis evaluates factors that reflect an increased potential for coagulation, while coagulation per se, may or may not be occurring. Similarly, fibrinolysis is definitively the lysis of inappropriate or excessive blood clot, which may or may not be occurring when the enzymes that stimulate fibrinolysis are activated. Nevertheless, markers of coagulation and fibrinolytic potential are associated with CVD, ischaemic events, and cardiovascular mortality. Additionally, fibrinolytic potential is associated with other established CVD risk factors. Ischaemic events triggered by physical exertion are more likely to occur due to an occlusive thrombus, suggesting the exercise-induced responses related to haemostasis are of clinical significance. The magnitude of increase in coagulation potential, platelet aggregation and fibrinolysis appears to be primarily determined by exercise intensity. Patients with CVD may also have a larger increase in coagulation potential during acute exercise than healthy individuals. Additionally, the magnitude of the fibrinolytic response is largely related to the resting fibrinolytic profile of the individual. In particular, high resting plasminogen activator inhibitor-1 may diminish the magnitude of tissue plasminogen activator response during acute exercise. Therefore, acute responses to exercise may increase the risk of ischaemic event. However, chronic aerobic exercise training may decrease coagulation potential and increase fibrinolytic potential in both healthy individuals and CVD patients. Due to the aforementioned importance of resting fibrinolysis on the fibrinolytic response to exercise, chronic aerobic exercise training may cause favourable adaptations that could contribute to decreased risk for ischaemic event, both at rest and during physical exertion.

Association of the mitochondrial DNA 15497G/A polymorphism with obesity in a middle-aged and elderly Japanese population

Although polymorphism of the mitochondrial DNA 15497guanine/adenine (Mt15497G-->A) leads to the Gly251Ser amino acid replacement on human cytochrome b, it is unknown whether functional alteration of the mitochondrion is induced by the Gly251Ser replacement. To see if an association exists between the Mt15497G-->A polymorphism and obesity, we examined differences in body size, body composition, and regional body fat distribution between the two genotypes in middle-aged and elderly Japanese individuals (825 women and 906 men). The Mt15497 genotype was determined with an automated colorimetric allele-specific DNA probe assay system using the polymerase chain reaction (PCR) method. The Mt15497G-->A polymorphism was detected in 3.5% ( n=60) of all subjects: 2.8% ( n=23) among women and 4.1% ( n=37) among men. After adjusting for age and smoking, we found that body weight, body mass index, waist and hip circumferences, fat mass, fat-free mass, intra-abdominal fat and triglycerides were significantly greater in women with the A allele compared with the G allele ( p=0.001-0.025). For men, waist to hip ratio was significantly greater ( p=0.032), and waist circumference, intra-abdominal fat and triglycerides had a trend to be significantly greater ( p=0.062-0.087) in subjects with the A allele compared with the G allele. These data suggest that the Mt15497 polymorphism may be associated with obesity-related variables and lipid metabolism.

Reduction of risk factors following lifestyle modification programme in subjects with type 2 (non-insulin dependent) diabetes mellitus

Exercise and improved diet is known to be beneficial in the management of type 2 (non-insulin dependent) diabetes mellitus. In practice, however, it is difficult for patients to implement these changes unaided. We hypothesized that a lifestyle modification programme involving residential visits would result in beneficial effects on glycaemic control and lipid profile. Three hundred and four individuals with type 2 diabetes participated in a lifestyle modification programme, involving three residential visits (2 weeks, 1 week and one 3-day visit) spaced over 31 weeks. The subjects were all referred for treatment following repeated failure to achieve metabolic control in primary care settings. Participants received information and practical guidance regarding exercise training, nutrition, as well as stress management and psychological counselling. Clinical parameters were determined at each visit. After completion of the programme, subjects showed significant improvements in glycaemic control (P<0.0001). Oxygen uptake was significantly improved (P<0.0001) and blood pressure (P<0.0001), body mass index (P<0.0001) and serum cholesterol (P<0.001) was significantly reduced, while HDL cholesterol (P<0.05) was significantly increased. There were no changes in LDL cholesterol values. Subjects also reported increased well-being and reduced stress. In conclusion, a 31-week lifestyle modification programme results in marked improvements in glycaemic control, blood pressure and well-being in subjects with type 2 diabetes. Thus, this type of lifestyle modification programme is a powerful treatment option to reduce risk factors associated with diabetes and diabetic complications, even in patients who have not responded to conventional diabetic therapy.

Effects of obesity phenotype on coronary heart disease risk factors in response to weight loss

OBJECTIVE

To determine whether there is a difference in risk-factor improvement for coronary heart disease (CHD) between the intra-abdominal fat (IF) and subcutaneous fat (SF) obesity phenotypes after weight loss.

RESEARCH METHODS AND PROCEDURES

Subjects included 55 mildly obese women (body mass index, 25 to 36 kg/m(2); age range, 34 to 63 years) who had at least two of three CHD risk factors [systolic blood pressure (SBP), >140 mm Hg; total cholesterol (TC), >220 mg/dL; fasting plasma glucose, >110 mg/dL). Using computed tomography, IF obesity was classified as > or =110 cm(2) of the IF area measured; subjects with <110 cm(2) were classified as having SF obesity. The IF and SF obesity groups were divided into diet-only and diet-plus-exercise groups. Assays and measurements were performed before and after a 14-week (98-day) intervention.

RESULTS

Weight was reduced by 7 to 10 kg in each group. The IF and SF areas, SBP, diastolic blood pressure, TC, and low-density lipoprotein-cholesterol were significantly reduced in all groups (p < 0.01). Reduction in IF area was greater in IF obesity than in SF obesity, whereas no differences were observed in the improvement of CHD risk factors. Sample sizes needed for observing a significant difference for SBP, TC, triglycerides, and fasting plasma glucose were greater than the number of subjects in this study.

DISCUSSION

Our results suggest that the influence of the obesity phenotype on improving CHD risk factors is not apparent. A larger study is needed to prove the validity of this finding.

Dietary treatment of thrombogenic disorders related to the metabolic syndrome

The increased risk of coronary heart disease associated with the metabolic syndrome may be partially explained by prothrombotic deviations of the haemostatic system. Individuals with insulin resistance, dyslipidaemia and obesity are characterized by elevated plasma fibrinogen and factor VII coagulant activity levels and raised concentrations of plasminogen-activator inhibitor, the main inhibitor of endogenous fibrinolysis. These haemostatic abnormalities may be corrected with dietary treatment of the underlying clinical disorder. Dietary trials of diseased and healthy volunteers suggest that the optimal antithrombotic diet is a low-fat diet with a high content of foods rich in complex carbohydrates and dietary fibre. The dietary fatty acid composition has a profound effect on blood lipids, but seems of minor importance for the haemostatic system.

Improved fibrinolysis by intense lifestyle intervention. A randomized trial in subjects with impaired glucose tolerance

OBJECTIVE

To assess the effects of lifestyle intervention on cardiovascular risk factors in general and especially on fibrinolysis.

DESIGN

Randomized clinical study.

SUBJECTS

A total of 186 subjects with impaired glucose tolerance and obesity.

INTERVENTIONS

The intervention programme included a low-fat, high-fibre diet and regular physical exercise. Half of the participants (n = 93) took part in a one-month learning and training session using different behavioural modification techniques and conducted in a full-board wellness centre (intense intervention group). The other half (n = 93) was randomized a one-hour counselling session with a specially trained nurse (usual care group). Follow-up was carried out after 12 months.

MAIN OUTCOME MEASURES

Body weight, oxygen consumption, plasminogen activator inhibitor type 1 (PAI-1) activity, tissue plasminogen activator (tPA) antigen, fibrinogen and fasting plasma insulin measured at the start of the programme and at follow-up after 1 year.

RESULTS

The intense intervention group had a mean weight decline by 1 year of 5.4 kg compared to 0.5 kg in the usual care group. Oxygen consumption in the intense group increased 10% vs. a 1% decline in the usual care group. In the intense group, PAI-1 activity decreased 31% (-10.1 U mL(-1)), which was significantly more than in the usual care group (12%; -3.0 U mL(-1)). The corresponding reductions in tPA antigen were 14% (-1.65 microg L(-1)) and 6% (-0.69 microg L(-1)).

CONCLUSIONS

The present randomized study shows that an intense lifestyle programme has sustained beneficial effects on fibrinolysis.