Obesity & Metabolic Syndrome: Definition, Causes, Prevention & Management
Obesity: Definition and Characteristics
Definition
Obesity is defined as:
- Abnormal or excessive fat accumulation that presents a risk to health.
- Body Mass Index (BMI), a measurement which compares weight and height, is used to classify weight status:
- Overweight (pre-obese): BMI is between 25 and 30 kg/m2
- Obese: BMI greater than 30 kg/m2
Central obesity is the accumulation of abdominal fat resulting in an increase in waist size. There is a strong correlation between central obesity and cardiovascular disease.
Characteristics
- Over 50% of the worldwide adult population is overweight or obese.
- It affects virtually all age and socioeconomic groups.
- Overweight and obesity are major risk factors for a number of chronic diseases, including diabetes, cardiovascular diseases, and cancer.
- Consequently, obesity also increases the risk for premature death due to serious chronic conditions that reduce the overall quality of life.
- Generally, although men may have higher rates of overweight, women have higher rates of obesity.
Measurement of Fat
- BMI = weight (kg)/height2
- Skinfold thickness
- Waist-hip circumference ratio
Cause
- Most commonly: a combination of excessive food energy intake and a lack of physical activity.
- Rarely, obesity is primarily due to genetics, medical reasons, or psychiatric illness.
Co-morbidities
Obesity is associated with several co-morbidities, particularly cardiovascular diseases, type 2 diabetes, obstructive sleep apnea, certain types of cancer, osteoarthritis, and asthma.
Preventing and Managing the Global Obesity Epidemic
The main treatment for obesity consists of dieting and physical exercise. At the individual level, choosing to eat a healthy diet and exercise regularly is crucial.
Individual Actions
People can:
- Maintain a healthy weight.
- Limit total fat intake and shift fat consumption away from saturated fats to unsaturated fats.
- Increase consumption of fruit, vegetables, pulses, whole grains, and nuts.
- Limit the intake of sugar and salt.
- Engage in regular physical activity: At least 30 minutes of regular, moderate-intensity physical activity most days of the week.
Diet programs may produce weight loss over the short term, but maintaining this weight loss is frequently difficult and often requires making exercise and a lower food energy diet a permanent part of a person’s lifestyle.
The most effective treatment for obesity is bariatric surgery. Surgery for severe obesity is associated with long-term weight loss and decreased overall mortality. However, due to its cost and the risk of complications, researchers are searching for other effective yet less invasive treatments.
Role of Governments and Organizations
Governments, international partners, civil society, non-governmental organizations, and the private sector all have a role to play in preventing and managing obesity.
- Supportive environments and communities are fundamental in shaping people’s choices and preventing obesity.
- Public health efforts should seek to understand and correct the environmental factors responsible for the increasing prevalence of obesity in the population.
- Solutions should look at changing the factors that cause excess food energy consumption and inhibit physical activity.
Examples of public health initiatives include:
- Federally reimbursed meal programs in schools.
- Limiting direct junk food marketing to children and decreasing access to sugar-sweetened beverages in schools.
- Increasing access to parks and developing pedestrian routes in urban environments.
Metabolic Syndrome
Definition
Metabolic syndrome is a multiplex risk factor that arises from insulin resistance accompanying abnormal adipose deposition and function. It is a risk factor for coronary heart disease, as well as for diabetes, fatty liver, and several cancers.
Diagnosis
According to guidelines, metabolic syndrome is diagnosed when a patient has at least 3 of the following 5 conditions:
- Fasting glucose ≥100 mg/dL (or receiving drug therapy for hyperglycemia)
- Blood pressure ≥130/85 mm Hg (or receiving drug therapy for hypertension)
- Triglycerides ≥150 mg/dL (or receiving drug therapy for hypertriglyceridemia)
- HDL-C < 40 mg/dL in men or < 50 mg/dL in women (or receiving drug therapy for reduced HDL-C)
- Waist circumference ≥102 cm (40 in) in men or ≥88 cm (35 in) in women; if Asian American, ≥90 cm (35 in) in men or ≥80 cm (32 in) in women
Etiology
- Risk factors for metabolic syndrome include family history, poor diet, and inadequate exercise.
- Metabolic syndrome is thought to be caused by adipose tissue dysfunction and insulin resistance.
- The distribution of adipose tissue appears to affect its role in metabolic syndrome. Fat that is visceral or intra-abdominal correlates with inflammation, whereas subcutaneous fat does not.
Signs and Symptoms
- Hypertension
- Hyperglycemia
- Hypertriglyceridemia
- Reduced HDL-C
- Abdominal obesity
- Chest pain or shortness of breath, suggesting the rise of cardiovascular and other complications
- Acanthosis nigricans, hirsutism, peripheral neuropathy, and retinopathy in insulin resistance and hyperglycemia or diabetes
- Xanthomas or xanthelasmas in severe dyslipidemia
Prevention
Prevention of metabolic syndrome focuses on physical activity (such as walking 30 minutes every day) and a healthy, reduced-calorie diet.
Management
- Lifestyle changes and weight loss are the first-line treatment for metabolic syndrome.
- The following medications can be used to treat dyslipidemia and other manifestations of metabolic syndrome:
- Elevated LDL-C levels: Statins
- Decreased HDL-C levels: Consider niacin
- Elevated triglyceride levels: Consider niacin, fibrates, and omega-3 fatty acids
- Hyperglycemia: Insulin-sensitizing agents, such as metformin
- Treatment of associated obstructive sleep apnea may also play a significant role in the management of metabolic syndrome.