Metabolic Syndrome

Metabolic syndrome is considered to be a risk factor for cardiovascular disease and type 2 diabetes.

Metabolic syndrome is a cluster of metabolic risk factors that come together in a single individual. These metabolic factors include insulin resistance, hypertension (high blood pressure), cholesterol abnormalities, and an increased risk for blood clotting. Affected individuals are most often overweight or obese. An association between certain metabolic disorders and cardiovascular disease has been known since the 1940s.

Metabolic syndrome is considered to be a risk factor for cardiovascular diseases and type 2 diabetes. Insulin resistance refers to the diminished ability of cells to respond to the action of insulin in promoting the transport of sugar glucose, from the blood into muscles and other tissues. Type 2 diabetes is caused by insulin resistance.

Metabolic syndrome is also known as syndrome X, insulin resistance syndrome, or dysmetabolic syndrome.

Metabolic syndrome is quite common.

• Approximately 32% of the population in the U.S. has metabolic syndrome, and
  • about 85% of those with type 2 diabetes have metabolic syndrome.
• Around 25% of adults in Europe and Latin America are estimated to have the condition, and rates are rising in developing East Asian countries.
• Within the US, Mexican Americans have the highest prevalence of metabolic syndrome.
• The prevalence of metabolic syndrome increases with age, and about 40% of people over 60 are affected.

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

Genetic factors influence each individual component of the syndrome, and the syndrome itself. A family history that includes type 2 diabetes, hypertension, and early heart disease greatly increases the chance that an individual will develop metabolic syndrome.

Environmental issues such as low activity levels, sedentary lifestyles, and progressive weight gain also contribute significantly to the risk of developing metabolic syndrome.

Metabolic syndrome is present in about 9% 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%.

While obesity itself is likely the greatest risk factor, other factors of concern include:

• Post-menopausal women
• Smoking
• Eating an excessively high carbohydrate diet
• Sedentary lifestyle

Based on the guidelines from the National Heart, Lung, and Blood Institute (NHLBI) and the American Heart Association (AHA), any three of the following traits in the same individual meet the five criteria for metabolic syndrome:

1. Abdominal obesity: a waist circumference of 102 cm (40 in) or more in men and 88 cm (35 inches) or more in women. For Asian Americans, the cutoff values are ≥90 cm (35 in) in men or ≥80 cm (32 in) in women.
2. Serum triglycerides: 150 mg/dl or above.
3. HDL cholesterol: 40 mg/dl or lower in men and 50mg/dl or lower in women.
4. Blood pressure: 130/85 or more.
5. Fasting blood glucose: 100 mg/dl or above.

Metabolic syndrome is a condition that in general, has no symptoms. If a person has risk factors for metabolic syndrome (particularly a large waist circumference), your doctor can help evaluate your risk.

The major goals are to treat both the underlying cause of the syndrome, to prevent the development of type 2 diabetes, and also to treat the cardiovascular risk factors if they persist. As has been discussed, a majority of people with metabolic syndrome are overweight and live a sedentary lifestyle.

• Lifestyle modification is the preferred treatment for metabolic syndrome
• Weight reduction usually requires a specifically tailored multifaceted program that includes:
  • Diet
  • Exercise
• Smoking cessation is an important component of treatment
• Sometimes medications may be useful

A detailed discussion of diet therapies, the pros, and cons of various diets, etc. is beyond the scope of this article. However, 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 fish and chicken).

The Mediterranean diet is palatable and easily sustained. In addition, recent studies have shown that when compared to a low-fat diet, people on the Mediterranean diet have a greater decrease in body weight, and also had greater improvements in blood pressure, cholesterol levels, and other markers of heart disease -- all of which are important in evaluating and treating metabolic syndrome.

Other nutritional plans that may be recommended for people with metabolic syndrome include the American Dietary Association (ADA) diet and the Dietary Approaches to Stop Hypertension (DASH) diet.

A sustainable exercise program, for example, 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.

Some people may ask: Why not just have liposuction of the abdomen and remove the large amount of abdominal fat that is a big part of the problem? Data thus far shows no benefit of liposuction on insulin sensitivity, blood pressure, or cholesterol. As the saying goes, "If it's too good to be true, it probably is." Diet and exercise are still the preferred primary treatment for metabolic syndrome.

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

If someone has already had a heart attack, their LDL ("bad") cholesterol should be reduced below 70mg/dl. A person who has diabetes has a heart attack risk equivalent to that of someone who has already one and so should be treated in the same way. If you have metabolic syndrome, a detailed discussion about lipid therapy is needed between you and your doctor, as each individual is unique.

Blood pressure goals are generally set lower than 130/80. Some blood pressure medications offer more benefits 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 deter the development of type 2 diabetes. This is an important consideration when discussing the choice of blood pressure drugs for metabolic syndrome.

The discovery that a drug is prescribed for one condition, and has other beneficial effects is not new. Drugs used to treat high blood sugar and insulin resistance may have beneficial effects on blood pressure and cholesterol profiles.

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. However, there are currently no established guidelines on treating metabolic syndrome patients with metformin if they do not have overt diabetes.