Obesity is a condition affecting many people in modern life, particularly as excessive consumption of rich foods and lack of physical activity have led to widespread obesity. This condition poses significant health risks. Below is an overview of the main classifications of obesity:
Simple Obesity
Simple obesity refers to cases without identifiable endocrine or metabolic causes.Based on age of onset and adipose tissue pathology, it can be further divided into two subtypes:
1. Constitutional Obesity (Childhood-Onset Obesity)
Characterized by:
Family history of obesity;
Obesity beginning in infancy, typically around six months of age, due to excessive nutrition persisting into adulthood.
Fat is distributed throughout the body, with enlarged and proliferated adipocytes (proliferation indicates increased cell numbers).
Dietary restriction and increased exercise yield poor results, and insulin sensitivity is not significantly improved.
2. Acquired obesity (adult-onset obesity)
Onset between ages 20-25 due to overnutrition and genetic predisposition;
Predominantly peripheral obesity with simple adipocyte hypertrophy but no significant hyperplasia;
Responsive to dietary control and exercise; insulin-sensitive; can return to normal weight with treatment.
Secondary Obesity
Obesity secondary to neuroendocrineendocrine-metabolic disorders. Patients exhibit obesity as a complication of the primary disease. Based on etiology, it is classified into seven groups:
1. Hypothalamic disorders
Hypothalamic syndromes caused by various factors, including post-inflammatory sequelae, trauma, tumors, and granulomas, can lead to obesity.
2. Pituitary disorders
Observed in mild hypopituitarism, pituitary tumors (especially chromophobe tumors), and empty sella syndrome.
3. Islet disorders
Excessive insulin secretion leads to hyperlipogenesis
① Early-stage type 2 diabetes
② Islet β-cell tumors (insulinomas)
③ Functional spontaneous hypoglycemia
4. Hypothyroidism
Both primary hypothyroidism and hypothalamic-pituitary hypothyroidism are associated with obesity, likely due to mechanisms such as reduced metabolic rate and diminished fat mobilization, often accompanied by myxedema.
5. Adrenal Cortical Hyperfunction Primarily Cushing's syndrome, presenting as central obesity.
6. Hypogonadism
① Female menopause and some polycystic ovary syndrome cases
② Male anorchism or cryptorchidism.
Drug-Induced Obesity
This category accounts for approximately 2% of obese patients. Certain medications, while effectively treating specific conditions, may have the side effect of causing weight gain.For instance, corticosteroids (such as dexamethasone) used to treat allergic disorders, rheumatic diseases, rheumatoid arthritis, asthma, etc., may cause secondary obesity. Estrogens and estrogen-containing contraceptives can sometimes lead to weight gain in women or increase their susceptibility to obesity.