Metabolic syndrome (also known as syndrome X, insulin resistance syndrome, and dysmetabolic syndrome) has been used to characterize a state of insulin resistance believed to be a major contributing factor to the development of a variety of significant health problems.
Pathophysiology and Etiology
- The central feature of this metabolic disorder is the diminished responsiveness of peripheral tissues to circulating insulin.
- The typical physiological response of the body to this condition is the increased production and secretion of insulin, leading to a state of compensatory hyperinsulinemia in order to maintain glucose homeostasis.
- While this response is beneficial from the standpoint of glucose metabolism, it is now believed that the state of hyperinsulinemia necessary to prevent glucose intolerance gives rise to other abnormalities that can also have significant health consequences.
- In addition to increased risk of type 2 diabetes associated with insulin resistance, hyperinsulinemia has also been associated with the development of hypertension, hyperlipidemia, atherosclerotic cardiovascular disease, cerebrovascular disease, polycystic ovary syndrome (PCOS), and acanthosis nigricans.
- While the pathogenesis of insulin resistance is not fully understood, genetic factors and environmental factors, such as obesity and physical inactivity, are believed to play an important role in the development and natural course of this condition.
Risk Factors
No specific diagnostic criteria have been formally established for identifying individuals who are insulin resistant; however, the presence of any of the risk factors associated with metabolic syndrome increase the likelihood that insulin resistance may be present.
Risk factors associated with metabolic syndrome include:
- Diagnosis of type 2 diabetes, cardiovascular disease, PCOS, hypertension, hyperlipidemia, or acanthosis nigricans
- Family history of type 2 diabetes, cardiovascular disease, or hypertension
- History of glucose intolerance or gestational diabetes
- Sedentary lifestyle
- Obesity
Management
- Treatment of metabolic syndrome involves measures directed at treating any diagnosed disease resulting from insulin resistance (diabetes, hypertension, hypercholesterolemia) as well as the underlying insulin resistance. This is accomplished by interventions that improve insulin sensitivity.
- Nonpharmacologic interventions effective in reducing insulin resistance include lifestyle changes that can have a direct impact on insulin sensitivity and include regular physical activity and nutritional management designed to reduce body weight.
- No pharmacologic agents have been approved for use in the treatment of metabolic syndrome. Agents currently available with known insulin-sensitizing effects (thiazolidinedione compounds, metformin) have shown effectiveness in treating individuals with PCOS and type 2 diabetes. The potential role of these agents in the management of metabolic syndrome is under investigation.
