Type 2 Diabetes

What is type 2 diabetes?

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by elevated blood glucose levels. In T2DM, the body either produces insufficient insulin or its cells become resistant to insulin’s effects. Insulin is the hormone that enables glucose to enter cells for energy. When insulin function is impaired, glucose accumulates in the bloodstream, leading to hyperglycemia.

Type 2 diabetes was once called adult-onset diabetes but now occurs at younger ages due to rising obesity rates. Genetics, lifestyle, and environmental factors all contribute to its development.

Causes and risk factors

  • Genetic predisposition and family history
  • Overweight and obesity, especially abdominal fat
  • Insulin resistance in muscle, fat, and liver cells
  • Physical inactivity and sedentary lifestyle
  • Diets high in refined sugars, unhealthy fats, and processed foods
  • Low levels of “good” HDL cholesterol and high triglycerides
  • Age (risk rises after age 45)
  • Ethnicity (higher risk in African Americans, Hispanics, Native Americans, Asian Americans, Pacific Islanders)
  • History of gestational diabetes
  • Medical conditions such as polycystic ovary syndrome (PCOS) and metabolic syndrome
  • Certain medications (e.g., corticosteroids, some antipsychotics)

Symptoms

Type 2 diabetes can develop gradually. Common signs include:

  • Increased thirst and frequent urination
  • Unexplained weight loss despite increased appetite
  • Persistent fatigue
  • Blurred vision
  • Slow wound healing and frequent infections
  • Tingling or numbness in the hands and feet
  • Darkened skin patches (acanthosis nigricans) in body folds

Diagnosis

Diagnosis typically involves one or more of the following blood tests:

  • Fasting plasma glucose ≥ 126 mg/dL on two occasions
  • Oral glucose tolerance test with 2-hour glucose ≥ 200 mg/dL
  • Random plasma glucose ≥ 200 mg/dL in a person with classic symptoms
  • Hemoglobin A1C ≥ 6.5%

Additional tests may include lipid panels, liver and kidney function, and screening for complications.

Treatment

Management combines lifestyle changes, monitoring, and medications:

  • Healthy eating: Emphasize whole grains, vegetables, lean proteins, and healthy fats
  • Regular physical activity: Aim for at least 150 minutes of moderate exercise per week
  • Weight management: Even modest weight loss can improve insulin sensitivity
  • Blood sugar monitoring: Self-monitoring or continuous glucose monitoring as advised
  • Oral and injectable medications:
    • Metformin to reduce liver glucose production
    • Sulfonylureas, DPP-4 inhibitors, SGLT2 inhibitors, GLP-1 receptor agonists
    • Insulin therapy when other agents are insufficient
  • Control of blood pressure and lipids to reduce cardiovascular risk
  • Education and support: Diabetes self-management training and regular follow-up

Complications

  • Heart disease, heart attack, and stroke
  • Kidney damage (nephropathy) leading to renal failure
  • Nerve damage (neuropathy) causing pain, numbness
  • Eye damage (retinopathy) and vision loss
  • Foot ulcers and risk of amputation
  • Skin infections and slow wound healing
  • Gum disease
  • Increased susceptibility to infections

Resources