The metabolic syndrome is a cluster of metabolic disorders that are likely caused by the insulin resistance that characterises the condition. These metabolic disorders include, but are not limited to, changes to plasma lipoproteins, raised levels of fasting blood glucose, raised levels of fasting insulin, systemic inflammation, oxidative stress, immune dysfunction, the development of nonalcoholic fatty liver, high blood pressure and weight gain, particularly around the waist. The changes to plasma lipoproteins that occur with development of the metabolic syndrome include increases in plasma triglycerides (also called very low density lipoprotein (VLDL)), increases in the small dense low density lipoprotein (LDL) particle, and decreases in the high density lipoprotein (LDL) particle. While developing one or two of these disorders in no way confirms the metabolic syndrome, they can be used as a guide to determine if the disorder is present. This is because there is no defined medical definition for the metabolic syndrome.
Diagnosing the metabolic syndrome can therefore be very difficult without a detailed clinical examination and careful analysis of blood tests. However, there are a number of easy ways to determine if the metabolic syndrome is likely present without detailed biochemical tests. A simple oral glucose tolerance test is one of the best ways to determine the health of the insulin system. Following an overnight fast, a glucose drink is consumed and then periodically blood glucose measurements are taken using a finger prick lancet and a simple blood glucose measuring device. Under normal circumstances, following ingestion of glucose, there will be a rapid increase in blood glucose, and then as insulin is released, that blood glucose will fall to baseline over the course of around 90 minutes. Blood glucose falls because the insulin facilitates the transport the glucose into the cells. If insulin resistance in present, the glucose stays in the blood for longer and blood sugar may not return to baseline for some hours.
Another of the classic signs of insulin resistance that strongly suggests that the metabolic syndrome might be present is a large amount of deep abdominal fat. This gives the individual a rotund appearance, and this characteristic body shape is described as android or apple shaped. Measuring the waist to hip ratio of an individual is a good indicator if they have such a body composition. This can be done by dividing the waist measurement in cm by the hip measurement is cm. A waist to hip ratio of above 1.00 or 0.85 strongly suggests that insulin resistance is present in men and women, respectively. Abdominal fat is associated with insulin resistance, but the cause and effects are not fully understood. The storage of fat preferentially in the viscera of the abdomen may relate to changes in hormones that occurs during the development of the metabolic syndrome. Much of the metabolic damage that occurs from the presence of the metabolic syndrome results from the accumulation of visceral fat in and around the liver.