Timo A. Lakka

Epidemiology and treatment of the metabolic syndrome.

Recent definitions of the metabolic syndrome from the World Health Organization (WHO) and National Cholesterol Education Program (NCEP) have given us a clearer picture of the prevalence of the metabolic syndrome and the risks it poses for cardiovascular disease and type 2 diabetes. Solid epidemiological and trial evidence support lifestyle changes as the main modifiable risk factors, including abdominal obesity, sedentary lifestyle and a diet rich in saturated fat and low in fiber content, in the treatment of individual components of the metabolic syndrome. Physical activity may prevent the metabolic syndrome as defined by the WHO and NCEP, but the evidence for lifestyle changes using these definitions is still sparse. No trials on the treatment of the metabolic syndrome to prevent diabetes have been published. However, both the Finnish Diabetes Prevention Study and the Diabetes Prevention Program found that moderate lifestyle interventions in persons with impaired glucose tolerance, a condition related to the metabolic syndrome, decreased the incidence of type 2 diabetes by 58%. Some drugs may also prevent diabetes. Further research on lifestyle modifications in the prevention and treatment of the metabolic syndrome, and on how best to promote lifestyle changes, is needed. In the meantime, efforts to curb obesity and overweight, increase physical activity and improve compliance with current dietary recommendations should continue.

Plasma Vitamin C Modifies the Association Between Hypertension and Risk of Stroke

Background and Purpose— There are no prospective studies to determine whether plasma vitamin C modifies the risk of stroke among hypertensive and overweight individuals. We sought to examine whether plasma vitamin C modifies the association between overweight and hypertension and the risk of stroke in middle-aged men from eastern Finland. Methods— We conducted a 10.4-year prospective population-based cohort study of 2419 randomly selected middle-aged men (42 to 60 years) with no history of stroke at baseline examination. A total of 120 men developed a stroke, of which 96 were ischemic and 24 hemorrhagic strokes. Results— Men with the lowest levels of plasma vitamin C (<28.4 &mgr;mol/L, lowest quarter) had a 2.4-fold (95% CI, 1.4 to 4.3;P =0.002) risk of any stroke compared with men with highest levels of plasma vitamin C (>64.96 &mgr;mol/L, highest quarter) after adjustment for age and examination months. An additional adjustment for body mass index, systolic blood pressure, smoking, alcohol consumption, serum total cholesterol, diabetes, and exercise-induced myocardial ischemia attenuated the association marginally (relative risk, 2.1; 95% CI, 1.2 to 3.8;P =0.01). Adjustment for prevalent coronary heart disease and atrial fibrillation did not attenuate the association any further. Furthermore, hypertensive men with the lowest vitamin C levels (<28.4 &mgr;mol/L) had a 2.6-fold risk (95% CI, 1.52 to 4.48;P <0.001), and overweight men (≥25 kg/m2) with low plasma vitamin C had a 2.7-fold risk (95% CI, 1.48 to 4.90;P =0.001) for any stroke after adjustment for age, examination months, and other risk factors. Conclusions— Low plasma vitamin C was associated with increased risk of stroke, especially among hypertensive and overweight men.

Physical Activity, Obesity and Cardiovascular Diseases

Sedentary lifestyle and overweight are major public health, clinical, and economical problems in modern societies. The worldwide epidemic of excess weight is due to imbalance between physical activity and dietary energy intake. Sedentary lifestyle, unhealthy diet, and consequent overweight and obesity markedly increase the risk of cardiovascular diseases. Regular physical activity 45-60 min per day prevents unhealthy weight gain and obesity, whereas sedentary behaviors such as watching television promote them. Regular exercise can markedly reduce body weight and fat mass without dietary caloric restriction in overweight individuals. An increase in total energy expenditure appears to be the most important determinant of successful exercise-induced weight loss. The best long-term results may be achieved when physical activity produces an energy expenditure of at least 2,500 kcal/week. Yet, the optimal approach in weight reduction programs appears to be a combination of regular physical activity and caloric restriction. A minimum of 60 min, but most likely 80-90 min of moderate-intensity physical activity per day may be needed to avoid or limit weight regain in formerly overweight or obese individuals. Regular moderate intensity physical activity, a healthy diet, and avoiding unhealthy weight gain are effective and safe ways to prevent and treat cardiovascular diseases and to reduce premature mortality in all population groups. Although the efforts to promote cardiovascular health concern the whole population, particular attention should be paid to individuals who are physically inactive, have unhealthy diets or are prone to weight gain. They have the highest risk for worsening of the cardiovascular risk factor profile and for cardiovascular disease. To combat the epidemic of overweight and to improve cardiovascular health at a population level, it is important to develop strategies to increase habitual physical activity and to prevent overweight and obesity in collaboration with communities, families, schools, work sites, health care professionals, media and policymakers.

Epidemiological studies of exercise in diabetes prevention

Type 2 diabetes is one of the fastest growing public health problems in both developed and developing countries. It is estimated that the number of people with diabetes in the world will double in coming years, from 171 million in 2000 to 366 million in 2030. Cardiovascular disease accounts for more than 70% of total mortality among patients with type 2 diabetes. The associations of physical activity, physical fitness, and changes in the lifestyle with the risk of type 2 diabetes have been assessed by a number of prospective studies and clinical trials in the past decade. Several studies have also evaluated the joint associations of physical activity, body mass index, and glucose levels with the risk of type 2 diabetes. Prospective studies and clinical trials have shown that moderate or high levels of physical activity or physical fitness and changes in the lifestyle (dietary modification and increase in physical activity) can prevent type 2 diabetes. Our review of the scientific evidence confirms that 30 min/d of moderate- or high-level physical activity is an effective and safe way to prevent type 2 diabetes in all populations.

Dietary factors and their associations with socioeconomic background in Finnish girls and boys 6-8 years of age: the PANIC Study.

Background/Objectives:To study nutrient intake, food consumption and meal pattern, and their associations with socioeconomic background in Finnish children.Subjects/Methods:The subjects were a population sample of 424 children (211 girls, 213 boys) 6–8 years of age. Nutrient intake and meal pattern were measured by food records, and food intake and socioeconomic characteristics were assessed by questionnaires.Results:Intakes of saturated fat, sucrose and salt were higher, and intakes of vitamin D, iron and fibre and unsaturated-to-saturated fat ratio lower than recommended. Less than 5% of children consumed vegetables, fruit and berries as recommended. Children with highest parental education more likely ate fish (odds ratio (OR) 2.20, 95% confidence interval (CI) 1.06–4.54), fibre-rich bread (OR 5.06, 95% CI 1.80–14.29) and main meals (OR 2.54, 95% CI 1.34–4.83), but less likely used soft margarine (OR 0.43, 95% CI 0.20–0.94) as recommended than children with lowest parental education. Children with highest household income more likely consumed skimmed milk (OR 2.43, 95% CI 1.21–4.88) and fish (OR 2.21, 95% CI 1.12–4.36) as recommended than children with lowest household income. Only 34% of girls and 45% of boys ate all main meals daily. Snacks provided as much as 42% of total energy intake.Conclusions:Children do not meet recommendations in all important nutrients. Children from lowest socioeconomic position least likely consumed fish, skimmed milk and fibre-rich bread and ate main meals, but most likely used soft margarine as recommended. Less than half of children ate all main meals daily.

Association of Exercise-Induced, Silent ST-Segment Depression With the Risk of Stroke and Cardiovascular Diseases in Men

Background and Purpose— There are few if any data on the prognostic importance of silent myocardial ischemia during exercise with regard to the risk of stroke and cardiovascular diseases (CVDs) among asymptomatic men. In this prospective study, we investigated the relation of silent myocardial ischemia and the risk of stroke and CVD death in men with and without conventional risk factors. Methods— The study sample included 1726 middle-aged men with no history of stroke, coronary heart disease, or atrial fibrillation at baseline. Silent myocardial ischemia was defined as a horizontal or downsloping ST-segment depression (⪖1 mm) during exercise electrocardiography. A total of 86 CVD-related deaths and 78 strokes occurred during an average follow-up of 10 years. Results— Men with silent ischemia during exercise had a 3.5-fold increased risk of CVD death and a 2.2-fold increased risk of stroke compared with men without silent ischemia, after adjusting for conventional risk factors. Silent ischemia during exercise was associated with a 3.8-fold (95% confidence interval [CI], 1.5 to 9.5) increased risk for CVD in smokers, a 3.9-fold (95% CI, 2.1 to 7.3) increased risk in hypercholesterolemic subjects, a 3.6-fold (95% CI, 1.9 to 6.8) increased risk in the hypertensives, and 3.8-fold (95% CI, 2.0 to 7.1) increased risk in overweight men. The respective relative risks for stroke were 3.8 (95% CI, 1.1 to 12.5), 3.5 (95% CI, 1.7 to 7.4), 3.4 (95% CI, 1.6 to 7.1), and 2.9 (95% CI, 1.4 to 6.1). Conclusions— Exercise-induced silent myocardial ischemia is an important indicator of increased risk of stroke and CVD in men with other risk factors, such as smoking, hypercholesterolemia, hypertension, and being overweight.

Cardiorespiratory fitness modifies the association between dietary fat intake and plasma fatty acids

Objectives: To investigate the relation between (1) cardiorespiratory fitness and plasma saturated, monounsaturated and polyunsaturated fatty acids and (2) the interactions between cardiorespiratory fitness, dietary fat intake and plasma fatty acid composition.Design: Cross-sectional analysis.Setting and subjects: The subjects were randomly selected, 127 middle-aged Finnish men participating in the DNASCO exercise intervention study.Interventions: Cardiorespiratory fitness was determined spiroergometrically, dietary intake of macro- and micronutrients by 4-day food records and plasma fatty acids by gas chromatography. The subjects were divided into tertiles of aerobic fitness.Results: Differences between fitness tertiles were not observed for dietary intake of total fat, and saturated, monounsaturated or polyunsaturated fatty acids (percent of total energy). In contrast, plasma saturated fatty acids were significantly lower (P<0.01) and polyunsaturated fatty acids significantly higher (P<0.05) in the highest fitness tertile compared to the lowest tertile. Dietary saturated fat intake was positively associated with plasma saturated fatty acids (r=0.342; P<0.05) and inversely with plasma polyunsaturated fatty acids (r=−0.453; P<0.01) only in the lowest fitness tertile. In addition, a positive correlation between body mass index and plasma saturated fatty acids (r=0.516; P<0.01) as well as a negative correlation between body mass index and plasma polyunsaturated fatty acids (r=−0.516; P<0.01) was observed in the lowest tertile solely.Conclusion: Different levels in cardiorespiratory fitness are associated with different levels in plasma saturated and polyunsaturated fatty acids and lead to modifications in the association between dietary and plasma fatty acids. These findings can perhaps be explained by a reduced hepatic fatty acid and lipoprotein synthesis as well as by an enhanced muscular lipid utilization, which are commonly seen in those who are physically active and who exhibit a higher level of fitness.