Exercise training with dietary counselling increases mitochondrial chaperone expression in middle-aged subjects with impaired glucose tolerance.

BACKGROUND: Insulin resistance and diabetes are associated with increased oxidative stress and impairment of cellular defence systems. Our purpose was to investigate the interaction between glucose metabolism, antioxidative capacity and heat shock protein (HSP) defence in different skeletal muscle phenotypes among middle-aged obese subjects during a long-term exercise and dietary intervention. As a sub-study of the Finnish Diabetes Prevention Study (DPS), 22 persons with impaired glucose tolerance (IGT) taking part in the intervention volunteered to give samples from the vastus lateralis muscle. Subjects were divided into two sub-groups (IGTslow and IGTfast) on the basis of their baseline myosin heavy chain profile. Glucose metabolism, oxidative stress and HSP expressions were measured before and after the 2-year intervention. RESULTS: Exercise training, combined with dietary counselling, increased the expression of mitochondrial chaperones HSP60 and glucose-regulated protein 75 (GRP75) in the vastus lateralis muscle in the IGTslow group and that of HSP60 in the IGTfast group. In cytoplasmic chaperones HSP72 or HSP90 no changes took place. In the IGTslow group, a significant positive correlation between the increased muscle content of HSP60 and the oxygen radical absorbing capacity values and, in the IGTfast group, between the improved VO2max value and the increased protein expression of GRP75 were found. Serum uric acid concentrations decreased in both sub-groups and serum protein carbonyl concentrations decreased in the IGTfast group. CONCLUSION: The 2-year intervention up-regulated mitochondrial HSP expressions in middle-aged subjects with impaired glucose tolerance. These improvements, however, were not correlated directly with enhanced glucose tolerance.

Physical activity in the prevention of type 2 diabetes: the Finnish diabetes prevention study.

Clinical trials have demonstrated that lifestyle changes can prevent type 2 diabetes, but the importance of leisure-time physical activity (LTPA) is still unclear. We carried out post hoc analyses on the role of LTPA in preventing type 2 diabetes in 487 men and women with impaired glucose tolerance who had completed 12-month LTPA questionnaires. The subjects were participants in the Finnish Diabetes Prevention Study, a randomized controlled trial of lifestyle changes including diet, weight loss, and LTPA. There were 107 new cases of diabetes during the 4.1-year follow-up period. Individuals who increased moderate-to-vigorous LTPA or strenuous, structured LTPA the most were 63-65% less likely to develop diabetes. Adjustment for changes in diet and body weight during the study attenuated the association somewhat (upper versus lower third: moderate-to-vigorous LTPA, relative risk 0.51, 95% CI 0.26-0.97; strenuous, structured LTPA, 0.63, 0.35-1.13). Low-intensity and lifestyle LTPA and walking also conferred benefits, consistent with the finding that the change in total LTPA (upper versus lower third: 0.34, 0.19-0.62) was the most strongly associated with incident diabetes. Thus increasing physical activity may substantially reduce the incidence of type 2 diabetes in high-risk individuals.

Prevalence of the metabolic syndrome and its components: findings from a Finnish general population sample and the Diabetes Prevention Study cohort.

OBJECTIVE: To assess the prevalence of the metabolic syndrome (MetS) in two independent Finnish study cohorts. RESEARCH DESIGN AND METHODS: The prevalence of the MetS by modified World Health Organization criteria was analyzed in different categories of glucose tolerance in a cross-sectional, population-based sample of 2,049 individuals (FINRISK) aged 45-64 years and in 522 participants of the Finnish Diabetes Prevention Study (DPS) with impaired glucose tolerance (IGT). RESULTS: In the FINRISK cohort, the MetS was present in 38.8% of the men and 22.2% of the women. The prevalence was 14.4 and 10.1% in subjects with normal glucose tolerance, 74.0 and 52.2% in subjects with impaired fasting glucose, 84.8 and 65.4% in subjects with IGT, and 91.5 and 82.7% in subjects with type 2 diabetes in men and women, respectively. Among women, the prevalence of the MetS increased with increasing age. In the DPS cohort, the MetS was present in 78.4% of the men and 72.2% of the women with IGT. CONCLUSIONS: The MetS was extremely common in middle-aged subjects The high prevalence in men was mostly due to their high waist-to-hip ratio. The prevalence of the MetS increased in both sexes with deterioration in glucose regulation. Approximately 75% of the subjects with IGT had the MetS. Because the syndrome includes the major risk factors for atherosclerotic vascular diseases and is the major antecedent for type 2 diabetes, concerted preventive action should be targeted to control all the features of the MetS.

The Finnish Diabetes Prevention Study (DPS): Lifestyle intervention and 3-year results on diet and physical activity.

OBJECTIVE: To describe the 1) lifestyle intervention used in the Finnish Diabetes Prevention Study, 2) short- and long-term changes in diet and exercise behavior, and 3) effect of the intervention on glucose and lipid metabolism. RESEARCH DESIGN AND METHODS: There were 522 middle-aged, overweight subjects with impaired glucose tolerance who were randomized to either a usual care control group or an intensive lifestyle intervention group. The control group received general dietary and exercise advice at baseline and had an annual physician's examination. The subjects in the intervention group received additional individualized dietary counseling from a nutritionist. They were also offered circuit-type resistance training sessions and advised to increase overall physical activity. The intervention was the most intensive during the first year, followed by a maintenance period. The intervention goals were to reduce body weight, reduce dietary and saturated fat, and increase physical activity and dietary fiber. RESULTS: The intervention group showed significantly greater improvement in each intervention goal. After 1 and 3 years, weight reductions were 4.5 and 3.5 kg in the intervention group and 1.0 and 0.9 kg in the control group, respectively. Measures of glycemia and lipemia improved more in the intervention group. CONCLUSIONS: The intensive lifestyle intervention produced long-term beneficial changes in diet, physical activity, and clinical and biochemical parameters and reduced diabetes risk. This type of intervention is a feasible option to prevent type 2 diabetes and should be implemented in the primary health care system.

Prevention of diabetes mellitus in subjects with impaired glucose tolerance in the Finnish Diabetes Prevention Study: results from a randomized clinical trial.

Type 2 diabetes mellitus is increasing worldwide largely as a result from increasing obesity and sedentary lifestyle. The Finnish Diabetes Prevention Study (DPS) is the first individually randomized controlled clinical trial to test the feasibility and efficacy of lifestyle modification in high-risk subjects. We randomly assigned 522 (172 men, 350 women) middle-aged (mean age 55 yr), overweight (mean body mass index 31 kg/m(2)) subjects with impaired glucose tolerance either to the lifestyle intervention or control group. Each subject in the intervention group received individualized counseling aimed at reducing weight and intake of total and saturated fat, and increasing intake of fiber and physical activity. An oral glucose tolerance test was performed annually to detect incident cases of diabetes and to measure changes in metabolic parameters. The mean (+/- SD) weight reduction from baseline to year 1 and to year 2, respectively, was 4.2 +/- 5.1 kg and 3.5 +/- 5.5 in the intervention group and 0.8 +/- 3.7 kg and 0.8 +/- 4.4 in the control group (P < 0.001 between the groups). At the time of first analysis of the outcome data the mean duration of follow-up was 3.2 yr. The risk of diabetes was reduced by 58% (P < 0.001) in the intervention group compared with the control group. The reduction in the incidence of diabetes was directly associated with number and magnitude of lifestyle changes made. In conclusion, the DPS is the first controlled trial demonstrating that type 2 diabetes can be prevented by changes in lifestyle in high-risk subjects.

Effects of diet and simvastatin on serum lipids, insulin, and antioxidants in hypercholesterolemic men: a randomized controlled trial.

CONTEXT: Limited information exists on the interaction between diet and 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) and the interaction's effect on serum lipid and lipoprotein levels, insulin sensitivity, and circulating antioxidant vitamin and provitamin levels. OBJECTIVE: To evaluate the separate and combined effects of diet and simvastatin therapy on serum levels of lipids, lipoproteins, antioxidants, and insulin. DESIGN, SETTING, AND PARTICIPANTS: Randomized, controlled crossover trial conducted from August 1997 to June 1998 in 120 previously untreated hypercholesterolemic men aged 35 to 64 years who were recruited from the community in Turku, southwestern Finland. INTERVENTIONS: After a 4- to 6-week placebo run-in period, participants were randomly allocated to a habitual diet (n = 60) or dietary treatment group (n = 60), and each of these groups was further randomized in a double-blind crossover fashion to receive simvastatin (20 mg/d) or placebo, each for 12 weeks (n = 30 in each group). The main goals of the dietary treatment were to reduce energy intake from saturated plus trans-unsaturated fats to no more than 10% by replacing them partly with monounsaturated and polyunsaturated fats rich in omega-3 fatty acids and to increase intake of fruits, vegetables, and dietary fiber. MAIN OUTCOME MEASURES: Changes in levels of total, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol; triglycerides; apolipoprotein B; insulin; glucose; and antioxidants at week 12 of each treatment period, compared among the 4 groups. RESULTS: Dietary treatment decreased levels of total cholesterol by 7.6% (P<.001), LDL cholesterol by 10.8% (P<.001), HDL cholesterol by 4.9% (P =.01), apolipoprotein B by 5.7% (P =.003), serum insulin by 14.0% (P =.02), and alpha-tocopherol by 3.5% (P =.04). Simvastatin decreased levels of total cholesterol by 20.8%, LDL cholesterol by 29.7%, triglycerides by 13.6%, apolipoprotein B by 22.4%, alpha-tocopherol by 16.2%, beta-carotene by 19.5%, and ubiquinol-10 by 22.0% (P<.001 for all) and increased levels of HDL cholesterol by 7.0% (P<.001) and serum insulin by 13.2% (P =.005). Glucose levels remained unchanged in all groups. The effects of dietary treatment and simvastatin were independent and additive. CONCLUSIONS: A modified Mediterranean-type diet rich in omega-3 fatty acids efficiently potentiated the cholesterol-lowering effect of simvastatin, counteracted the fasting insulin-elevating effect of simvastatin, and, unlike simvastatin, did not decrease serum levels of beta-carotene and ubiquinol-10.