Metabolic syndrome: risk factors, tests and lifestyle management

Metabolic syndrome is not a single disease. It is a cluster of risk factors that tend to appear together and raise the chance of serious conditions later. This article explains what it is, why it develops, how it is found and what helps. It draws on MedlinePlus, the US National Heart, Lung, and Blood Institute (NHLBI) and the NHS.

1. Introduction

MedlinePlus describes metabolic syndrome as a name for a group of risk factors that raise the chance of coronary artery disease, stroke and type 2 diabetes ^[1]. The NHS adds that it is different from the rare inherited "metabolic disorders" ^[4]. It goes by other names, including insulin resistance syndrome ^[1].

Insulin is the hormone that moves sugar from the blood into the body's cells. In insulin resistance, the cells respond poorly to it, so blood sugar rises and the body makes more insulin ^{[1, 2]}. MedlinePlus says that about 1 in 3 Americans is affected, and that risk rises with age ^[1]. The NHS calls it very common ^[4].

2. Causes and risk factors

MedlinePlus names two key risk factors: extra weight around the abdomen and upper body, and insulin resistance ^[1]. NHLBI explains that fat cells in the abdomen release free fatty acids, which affect blood sugar control, and that insulin resistance can raise blood pressure and triglycerides (blood fats) and lower "good" HDL cholesterol ^[2].

Risks you can change

NHLBI lists a lack of physical activity, an unhealthy diet and large portions, too little good-quality sleep, smoking and heavy alcohol use. It also says shift work can disrupt the body's daily rhythm and raise risk ^[2]. The NHS also lists a diet high in saturated fat ^[4]. NHLBI adds that immune cells in extra fat tissue release chemicals that drive inflammation, which can add to insulin resistance, high blood pressure and heart and blood vessel disease ^[2].

Risks you cannot change

• Age, since risk rises over the years ^{[2, 4]}
• Family history and genes ^[2]
• Ethnic background: the NHS notes a higher risk in people with a Hispanic or South Asian background ^[4]
• Some conditions, such as polycystic ovary syndrome, sleep apnoea and certain medicines ^[2]

3. Signs and symptoms

The NHS says many people have no symptoms, and that the condition is usually discovered through a blood test or check-up ^[4]. MedlinePlus says conditions that may be early signs include pre-diabetes, early high blood pressure and mildly raised blood fats, and advises contacting a provider if you think you may have signs of the condition ^[1].

4. Diagnosis and tests

A doctor will ask about your medical and family history and check your weight (body mass index), waist measurement and blood pressure. Blood tests check blood sugar and blood fats such as cholesterol, and the NHS says you may be asked to fast for up to 12 hours beforehand ^[4].

According to MedlinePlus, diagnosis is likely when three or more of these are present ^[1]:

1. Blood pressure of 130/85 mm Hg or higher, or use of blood pressure medicine
2. Fasting blood sugar of 100 to 125 mg/dL, or diabetes treated with medicine
3. A large waist: 40 inches (102 cm) or more for men and 35 inches (89 cm) or more for women, with lower limits of 35 and 30 inches for people of Asian ancestry
4. Low HDL cholesterol, or use of medicine for it
5. High fasting triglycerides, or use of medicine for them

5. Treatment and management

NHLBI says the main goals are to lower the risk of heart disease and to prevent type 2 diabetes, and that heart-healthy lifestyle changes are the first line of treatment ^[3]. The NHS agrees that treatment is mainly lifestyle change, with medicines sometimes offered for weight, blood sugar, cholesterol or blood pressure ^[4].

• Eating: NHLBI describes the DASH eating plan, which stresses fruits, vegetables and whole grains and limits saturated fat, salt, added sugars and alcohol ^[3]. The NHS suggests less saturated fat and meat and more fruit, vegetables and whole grains ^[4].
• Weight: NHLBI says losing 3% to 5% of body weight can help manage risk factors ^[3]. MedlinePlus mentions a goal of 7% to 10% ^[1].
• Activity: MedlinePlus and the NHS both point to at least 150 minutes a week of moderate activity, and MedlinePlus also suggests muscle-strengthening exercise on 2 days a week. The NHS advises avoiding sitting for long periods. Check with your doctor before starting a new programme ^{[1, 4]}.
• Sleep and stress: NHLBI advises 7 to 9 hours of good sleep for adults and learning to manage stress ^[3].
• Smoking: stopping is advised, including vaping, and MedlinePlus says medicines and programmes can help ^{[1, 3, 4]}.
• Medicines or weight-loss surgery: these may be considered when lifestyle change is not enough. Your doctor decides what is suitable ^[3].

6. Complications and outlook

People with metabolic syndrome have a higher long-term risk of heart disease, type 2 diabetes, stroke, kidney disease and poor blood supply to the legs ^[1]. The NHS adds fatty liver disease, osteoarthritis, gout and some cancers ^[4]. NHLBI says treatment aims to lower the risk of heart disease and prevent type 2 diabetes ^[3].

7. When to see a doctor

The NHS advises seeing a GP if you think you may be at risk ^[4]. NHLBI advises routine check-ups to monitor cholesterol, triglycerides, blood pressure and blood sugar ^[2].

In an emergency, call your local emergency number (112 in India, 911 in the United States). Chest pain, sudden weakness on one side or trouble speaking need emergency care.

8. Conclusion

Metabolic syndrome groups together risk factors that often have no symptoms but raise the chance of heart disease and diabetes. Healthy eating, regular activity, a healthy weight, good sleep and not smoking are the foundation of care, with medicines when your doctor judges them necessary.