Patient Care Endocrinology & Cardiology - October 2007 - (Page 13)

Metabolic syndrome I nents. However, studies have shown that the pathophysiology of the syndrome comprises 5 major metabolic risk factors: atherogenic dyslipidemia, hypertension, insulin resistance, and proinflammatory and prothrombotic states. Factors increasing the risk of developing the metabolic syndrome are obesity, older age, genetic influence, ethnic background, low household income, decreased physical activity, marital dissatisfaction, no alcohol consumption, a high-fat diet, and high carbohydrate intake. The combination of increased waist circumference (WC) and elevated triglyceride levels—the so-called hypertriglyceridemic waist—is associated with higher apolipoprotein B, higher insulin levels, and a small, dense LDL-C pattern. This triad was found in 83% of subjects with an increased WC and elevated triglyceride levels and is also strongly associated with angiographic evidence of CAD.14 Atherogenic dyslipidemia This is one of the most important modifiable risk factors in the prevention of CV events. The metabolic syndrome is usually associated with elevated serum triglyceride and LDL-C levels and decreased HDL-C levels. There is an increased production of lipoprotein particles and formation of triglyceride-rich verylow-density-lipoproteins (VLDLs). Alcohol consumption and increased calorie and carbohydrate consumption also increase VLDL overproduction. Lipoprotein lipase (LPL) normally degrades these triglyceride-rich particles into smaller particles that can be cleared from the circulation. In the presence of insulin resistance, however, LPL function is impaired, and this results in further increases in serum triglyceride and VLDL levels.11 In a metaanalysis of 17 population-based prospective studies of 46,413 men and 10,864 women, after adjusting for HDL-C and other risk factors, every 100 mg/dL increase in triglyceride level was associated with an increase in CV events of 16% in men and 42% in women.12 In the Copenhagen Male Study, the combination of increased triglycerides and low HDL-C was associated with an 11.4% incidence of ischemic heart disease, compared with 8.2% in those with high LDL-C levels and 17.5% when all 3 lipid abnormalities were found.13 Abdominal obesity This type of obesity is associated with insulin resistance to the effects of insulin on peripheral glucose and fatty acid utilization, which in turn leads to prothrombotic, inflammatory, and dyslipidemic states. Hypertension In the STOP-NIDDM (Stop Non-Insulin-Dependent Diabetes Mellitus) study, the subjects who developed CV events had higher mean systolic and diastolic BP at baseline, compared with those without a CV event.15 Adequate control of hypertension was found to be responsible for the reduction of CV events.16 CVD risk A meta-analysis of 21 studies recently examined the association between the metabolic syndrome and the risk of CVD. Individuals with the metabolic syndrome, compared with those without, had increased mortality from all causes and from CVD, as well as an increased incidence of CVD and coronary heart disease (CHD).17 Ample data suggest that when more features of the metabolic syndrome are present, the CHD risk increases. The presence of 4 or 5 features in men was associated with a 3.7-fold increase in CHD risk and a 24.5-fold increase for incident DM, compared with men without the metabolic syndrome.18 Keep in mind, however, that the detection of the metabolic syndrome is only part of the overall risk assessment for CVD and that the syndrome by itself is not an adequate tool to estimate 10-year risk of CHD. To assess the overall risk of CHD, other factors such as age, sex, smoking status, and total cholesterol levels have to be considered and the severity of the risk factors has to be graded as in the Framingham Risk Score system.6 Insulin resistance and impaired glucose tolerance The metabolic syndrome has been shown to predict development of type 2 DM. In the Framingham Off- OCTOBER 2007 PATIENT CARE ENDOCRINOLOGY & CARDIOLOGY 13

Table of Contents Feed for the Digital Edition of Patient Care Endocrinology & Cardiology - October 2007

Patient Care - Endocrinology & Cardiology - October 2007 Research Digest Contents Medicine in the News Recognizing and Managing Patients with the Metabolic Syndrome and Prediabetes Using Troponins to Evaluate Cardiac Injury The 15-Minute Visit Classified Advertising Clinical Clips

Patient Care Endocrinology & Cardiology - October 2007

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.