Different definitions of metabolic syndrome The International Diabetes Association defines abdominal obesity strictly, with different cut-off points for different races. The International Diabetes Association emphasizes abdominal obesity as the initiating factor for the metabolic syndrome. Because of the linear role of metabolic syndrome risk factor aggregation and cardiovascular risk factor impairment, the different definitions of metabolic syndrome make little difference in prognostic value.
Some consider component 5 to be only a borderline cardiovascular risk factor. However, if considered together, the risk is significantly increased. The linear relationship between risk factors and myocardial infarction has been confirmed by a large number of international cardiac interconnection studies. Specifically, the linear cardiovascular risk factors are: 1. degree of abdominal obesity; 2. fasting or two-hour postprandial glucose levels; 3. elevated mean blood pressure; 4. reduced circulating HDL and 5. high triglyceride levels. Metabolic syndrome increases the risk of coronary heart disease by 2-3 times, a similar risk for future ischemic stroke and a greater risk of diabetes mellitus. The more features of the metabolic syndrome a patient meets, the greater the risk, and the worse if there are also elevated LDL cholesterol levels.
Mechanism of metabolic syndrome The syndrome views abdominal adipose tissue as an endocrine organ that releases excess harmful free fatty acids (FFA) into the circulation, angiotensin II and adipokines into the circulation. First, increased blood FFA prevents muscle uptake of glucose. Excess FFA and angiotensin II damage the pancreas. Although the pancreas makes extra insulin, it cannot reverse hyperglycemia, which would explain the paradoxical phenomenon of increased fasting glucose levels and increased plasma insulin levels, so-called insulin resistance.
Angiotensin II raises blood pressure through vasoconstriction. Tumor necrosis factor alpha and other cytokines (interleukins) promote an inflammatory response, which reduces the effect of insulin and promotes hypertension. High blood glucose and increased circulating FFA provide the substrate for increased triglyceride production by the liver. Circulating triglycerides increase lipoprotein transport of more triglycerides and less HDL (note the complex reciprocal relationship between circulating triglycerides and HDL).
Treatment Lifestyle Regular exercise is the first step in the treatment of metabolic syndrome because it increases glucose metabolism through muscle and contributes to weight loss. Dietary treatment lies in two areas: weight loss (sustained negative calorie balance); and a Mediterranean diet, rich in olive oil and nuts. This Mediterranean-rich food lowers blood pressure, fasting glucose and insulin. This approach moderately raised HDL while lowering triglyceride levels (while one study showed that a low-fat diet lasted only 3 months). When the Mediterranean diet was applied to patients with metabolic syndrome for more than two years, it lowered body weight and reduced inflammatory factors. In an observational study, those Greek subjects who adhered to the Mediterranean diet showed a 20% reduction in the risk of metabolic syndrome. Healthy food choices, regular exercise and non-smoking reduced the risk of coronary heart disease, partly through anti-inflammatory mechanisms. Thus, the Mediterranean diet seems to be a good and palatable food choice and easy for patients to accept, while its main drawback is that it does not reduce body weight (which requires exercise and low calorie intake).
Reducing the risk of future diabetes In a study by Tuomilehto et al, in the intervention group of those patients with pre-diabetes with metabolic syndrome, the mean waist circumference was 102 cm, fasting glucose was 109 mg/dL, HDL levels were 46 mg/dL, triglyceride levels were 154 mg/dL and blood pressure values were 140/86 mm Hg. The goal of the study was to reduce weight loss by 5%, reduce fat intake, increase fiber intake, and increase exercise to 4 weekly hours. The exercise goal was met at a high rate (86%), followed by fat intake (47%), weight loss (43%), reduced fat intake (26%), and increased fiber intake (25%). The relative risk of diabetes in the intervention group was 0.4 (60% reduction). In another similar study, metformin also reduced new-onset diabetes but not as much as lifestyle changes. The glitazones (rosiglitazone and pioglitazone) were particularly effective in reducing triglyceride levels with minimal increased risk of weight gain and heart failure. However, they lower FFA levels, reduce insulin resistance and lower triglycerides, and increase HDL. Antihypertensive therapy The risk of future diabetes needs to be considered. The combination of diuretics and beta-blockers should be avoided. Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers reduce the risk of new-onset diabetes, although with a small absolute cardiovascular benefit.
Low HDL and high triglycerides This one is trickier to manage. HDL-elevating substances such as tolcherep, a cholesteryl ester transfer protein, can potentially increase HDL protein by 50%. Preliminary trials will be terminated due to increased mortality. Existing drugs that increase HDL and lower triglycerides include niacin and gliadin. Clofibrate is less effective on HDL and more effective on triglycerides. In significantly obese individuals, high doses of rimonabant increase HDL by 19% and lower triglycerides by 16%, accompanied by moderate weight loss. Moderate alcohol consumption increased HDL moderately, and genetically low hepatic alcohol dehydrogenase slowed ethanol catabolism, which increased HDL levels and reduced the incidence of myocardial infarction. Almonds lower the LDL:HDL ratio.
How is the treatment chosen for our patients?
In addition to candesartan as an anti-hypertensive drug, regular exercise and a Mediterranean diet are advocated for the patients in front. Using high quality olive oil and eating plenty of almonds, emphasizing vegetables and fruits, and drinking 1-2 glasses of wine with meals. After this arrangement, his fasting blood sugar dropped to 96 mg/dL, while HDL rose to 40 mg/dL (1.1 mmol/L). He did not stop smoking, but the amount was halved, thus halving the linear risk. Despite treatment and lifestyle recommendations to reverse all the abnormal components of metabolic syndrome, regular morning exercise and evening dietary adjustments are difficult to maintain for a businessman. Therefore, he should be given metformin when hyperglycemia rebound and worsen. If the response to metformin is not adequate, it should be adjusted to rosiglitazone.
Conclusion Individuals with untreated metabolic syndrome are at risk of developing diabetes and cardiovascular disease. Of the 5 features of the metabolic syndrome, abdominal circumference, high triglycerides, and moderately elevated glucose were not included in the initial Framingham risk factor score or in the Framingham prognostic factors for future diabetes mellitus and ischemic stroke. Thus, the diagnosis of metabolic syndrome expands our concept of cardiovascular risk.