Metabolic syndrome refers to a set of disease risk factors that appear to increase the risk of cardiovascular disease and type 2 diabetes. It is also known as insulin resistance syndrome.
The American Heart Association (AHA) describe metabolic syndrome as a "cluster of metabolic disorders," that includes high blood pressure, high fasting glucose levels, and abdominal obesity, which, combined, increase the risk of heart disease.
According to the AHA, a doctor will often consider metabolic syndrome if a person has at least three of the following five symptoms:
- Central, visceral, abdominal obesity, specifically, a waist size of more than 40 inches in men and more than 35 inches in women
- Fasting blood glucose levels of 100 mg/dL or above
- Blood pressure of 130/85 mm/Hg or above
- Blood triglycerides levels of 150 mg/dL or higher
- High-density lipoprotein (HDL) cholesterol levels of 40 mg/dL or less for men and 50 mg/dL or less for women
Diagnosis initially aims to identify those people who could be at risk of metabolic syndrome, but who may benefit from lifestyle modifications rather than drug treatments.
High blood glucose levels, high blood pressure, and lipid and cholesterol abnormalities can often be targeted early with lifestyle measures.
However, some people may already be using medication for some aspect of metabolic syndrome, such as high blood pressure, when they receive their diagnosis.
Losing weight, especially in the upper body can be an effective treatment.
Suggested measures for preventing and treating abnormal cholesterol and other aspects of metabolic syndrome include
- eating a "heart-healthy diet" that is low in sugar, fat, and sodium.
- taking regular exercise
- avoiding smoking and reducing alcohol intake
The AHA suggest doing at least 150 minutes of moderate exercise each week. These can be broken up into 10-minute sessions. Brisk walking is a good way to start.
If drug treatment is recommended, this is usually with metformin.
This can help certain high-risk groups, especially people with high blood glucose levels and those on the spectrum of obesity that is not manageable with dietary and lifestyle modifications.
Metformin is sold under the following brand names in the U.S.:
The drug is not officially licensed for preventive use in people who have a high risk of diabetes because of metabolic syndrome.
However, some doctors do prescribe metformin "off-label" to prevent diabetes in people with raised glucose levels and abdominal obesity. Diabetes specialists and evidence from clinical trials support this use.
A study published in 2013 concluded that metformin is effective in reducing the risk of diabetes in adults with risk factors, but that diet and exercise changes are "approximately twice as effective."
Other drugs may also be used in treating metabolic syndrome, such as statins in people with high levels of low-density lipoprotein (LDL) cholesterol.
Antihypertensive drugs are used to treat high blood pressure.
Again, lifestyle measures are tried first or in low-risk groups.
- choosing foods from healthful sources
- limiting intake of red meats, sodium, saturated fats and total fats, and sweetened foods and drinks
- consuming plenty of fruits and vegetables, wholegrains, fish, and nuts
Not all medical guidelines agree on the exact thresholds to use for a diagnosis of metabolic syndrome.
The above criteria were created in an attempt to harmonize diagnoses. However, doctors will also consider an individual's circumstances.
Metabolic syndrome and childhood obesity
Metabolic syndrome, sometimes abbreviated to MetS, can start in childhood, alongside early obesity, dyslipidemia, and high blood pressure.
Due to concerns about the rise in obesity among young people in recent years, some have called for early screening to identify those with a higher cardiovascular risk.
This could make it possible to target changes toward a healthier lifestyle and reduce the chance of health problems later in life.
How and when to screen for and diagnose metabolic syndrome and obesity in children, however, remains controversial. One reason is that growing children show wide variance in these factors.
According to the Centers for Disease Control (CDC), in the United States overall,
Metabolic syndrome is a collection of risk factors, so there is not a single cause.
Having central obesity or overweight is a major factor, but abnormal blood lipid and cholesterol levels, high blood pressure, and prediabetes also contribute to cardiometabolic risk.
Unavoidable risk factors, such as family history and ethnic background, can increase the chance of developing some components.
However, lifestyle choices can impact all these factors.
A diet that is high in fat and sugar, together with a lack of exercise, has been associated with the development of obesity and related conditions.
However, symptoms such as insulin resistance do not necessarily accompany obesity or indicate metabolic syndrome.
Insulin resistance, is a feature of metabolic syndrome and obesity, and it can lead to cardiovascular disease and type 2 diabetes, but it can also be a sign of other conditions. Examples include Cushing's disease, polycystic ovary syndrome (PCOS), nonalcoholic fatty liver disease, and chronic kidney disease.
Other problems that are sometimes associated with metabolic syndrome, insulin resistance, and high blood sugar include low-level inflammation and blood clotting defects. These can also contribute to the development of cardiovascular disease.