Metabolic Syndrome

What is metabolic syndrome?

An association between certain metabolic disorders and cardiovascular disease has been known since the 1940s. In the 1980s this association became more clearly defined and the term metabolic syndrome (also known as syndrome X or the dysmetabolic syndrome) was coined to designate a cluster of metabolic risk factors that come together in a single individual.

There are slight differences in the criteria of diagnosis - depending on which authority is quoted. Regardless, the concept of a clustering of risks factors leading to cardiovascular disease is well accepted.

he main features of metabolic syndrome include insulin resistance, hypertension (high blood pressure), cholesterol abnormalities, and an increased risk for clotting. Patients are most often overweight or obese.

Insulin resistance refers to the diminished ability of cells to respond to the action of insulin in promoting the transport of the sugar glucose, from blood into muscles and other tissues. Because of the central role that insulin resistance plays in the metabolic syndrome, a separate article is devoted to insulin resistance.

How is metabolic syndrome defined?

The definition of metabolic syndrome depends on which group of experts is doing the defining. Based on the guidelines from the 2001 National Cholesterol Education Program Adult Treatment Panel (ATP III), any three of the following traits in the same individual meet the criteria for the metabolic syndrome:

1. Abdominal obesity: a waist circumference over 102 cm (40 in) in men and over 88 cm (35 inches) in women.
   
2. Serum triglycerides 150 mg/dl or above.
   
3. HDL cholesterol 40mg/dl or lower in men and 50mg/dl or lower in women.
   
4. Blood pressure of 130/85 or more.
   
5. Fasting blood glucose of 110 mg/dl or above. (Some groups say 100mg/dl)

The World Health Organization (WHO) has slightly different criteria for the metabolic syndrome:

1. High insulin levels, an elevated fasting blood glucose or an elevated post meal glucose alone with at least 2 of the following criteria:
   
2. Abdominal obesity as defined by a waist to hip ratio of greater than 0.9, a body mass index of at least 30 kg/m2 or a waist measurement over 37 inches.
   
3. Cholesterol panel showing a triglyceride level of at least 150 mg/dl or an HDL cholesterol lower than 35 mg/dl.
   
4. Blood pressure of 140/90 or above (or on treatment for high blood pressure).

How common is metabolic syndrome?

Metabolic syndrome is quite common. Approximately 20%-30% of the population in industrialized countries have metabolic syndrome. By the year 2010, the metabolic syndrome is expected to affect 50-75 million people in the US alone.

What causes metabolic syndrome?

As is true with many medical conditions, genetics and the environment both play important roles in the development of the metabolic syndrome.

Metabolic syndrome is present in about 5% of people with normal body weight, 22% of those who are overweight and 60% of those considered obese. Adults who continue to gain five or more pounds per year raise their risk of developing metabolic syndrome by up to 45%.

Why should I know about metabolic syndrome?

Metabolic syndrome is worth caring about because it is a condition that can pave the way to both diabetes and heart disease, two of the most common and important chronic diseases today.

Metabolic syndrome increases the risk of type 2 diabetes (the common type of diabetes) anywhere from 9-30 times over the normal population. That's a huge increase. As to the risk of heart disease, studies vary, but the metabolic syndrome appears to increase the risk 2-4 times that of the normal population.

Other problems associated with metabolic syndrome include obstructive sleep apnea, polycystic ovary syndrome , increased risk of dementia with aging, and cognitive decline in the elderly.

How is metabolic syndrome treated?

The major goals are to treat both the underlying cause of the syndrome, and also to treat the cardiovascular risk factors if they persist. As has been discussed, the majority of people with metabolic syndrome are overweight and lead a sedentary lifestyle.

Lifestyle modification is the preferred treatment of metabolic syndrome. Weight reduction usually requires a specifically tailored multifaceted program that includes diet and exercise. Sometimes medications may be useful.

Diet

There is now a trend toward the use of a Mediterranean diet -- one that is rich in "good" fats (olive oil) and contains a reasonable amount of carbohydrates and proteins (such as from fish and chicken).

Exercise

30 minutes five days a week is reasonable to start, providing there is no medical contraindication. (If you have any special concerns in this regard, check with your doctor first.) There is a beneficial effect of exercise on blood pressure, cholesterol levels, and insulin sensitivity, regardless of whether weight loss is achieved or not. Thus, exercise in itself is a helpful tool in treating metabolic syndrome.

What if lifestyle changes are not enough to treat metabolic syndrome?

What if changes in lifestyle do not do the trick, what then? Drugs to control cholesterol levels, lipids, and high blood pressure may be considered.

Some blood pressure medications offer more than simply lowering blood pressure. For example, a class of blood pressure drugs called ACE inhibitors has been found to also reduce the levels of insulin resistance and actually deter the development of type 2 diabetes. This is an important consideration when discussing the choice blood pressure drugs in the metabolic syndrome.

Metformin (Glucophage), usually used to treat type 2 diabetes, also has been found to help prevent the onset of diabetes in people with metabolic syndrome. There are currently no established guidelines on treating metabolic syndrome patients with metformin if they do not have overt diabetes.