**

Overview

Type 2 diabetes mellitus (T2DM) is the most common form of diabetes, accounting for roughly 90‑95 % of all cases worldwide. It develops when the body’s cells become less responsive to insulin—a hormone produced by the pancreas that facilitates glucose uptake—and the pancreas cannot produce enough insulin to overcome this resistance. The resulting hyperglycemia (high blood sugar) can damage blood vessels, nerves, and organs over time, increasing the risk of cardiovascular disease, kidney failure, vision loss, and peripheral neuropathy.

Risk factors are multifactorial and include genetic predisposition, excess body weight (particularly abdominal adiposity), physical inactivity, advancing age, and certain ethnic backgrounds (e.g., South Asian, African‑American, Hispanic). Lifestyle modifications such as weight loss, regular aerobic exercise, and a balanced diet rich in fiber and low in refined sugars are first‑line strategies for prevention and early management. Pharmacologic therapy—most commonly metformin, followed by additional oral agents or injectable GLP‑1 receptor agonists and insulin—may be required when lifestyle changes alone cannot achieve glycemic targets.

Because T2DM is progressive, regular monitoring of HbA1c, blood pressure, lipid profiles, and renal function is essential. Patients should seek professional medical care promptly if they experience symptoms such as unexplained weight loss, persistent thirst, frequent urination, blurred vision, or signs of infection, as early intervention can prevent complications.

History/Background

The clinical picture of diabetes has been recognized for millennia, with descriptions in ancient Egyptian papyri (≈1500 BC) and Ayurvedic texts. However, the distinction between insulin‑dependent (type 1) and non‑insulin‑dependent (type 2) forms emerged only in the 20th century. In 1936, Elliott Joslin and colleagues noted a “milder” form of diabetes that responded poorly to insulin, coining the term “adult‑onset diabetes.” The discovery of insulin in 1921 and subsequent epidemiologic studies after World War II revealed a rising prevalence linked to urbanization and dietary changes. By the 1970s, the Oral Glucose Tolerance Test (OGTT) became a standard diagnostic tool, and the World Health Organization (WHO) formally defined T2DM criteria in 1980. The epidemic accelerated in the 1990s with the global spread of obesity, prompting the International Diabetes Federation (IDF) to launch worldwide awareness campaigns and research initiatives.

Key Information

- Pathophysiology: Central features are insulin resistance in muscle and liver tissue and progressive β‑cell dysfunction in the pancreas. Chronic low‑grade inflammation, ectopic fat deposition, and altered gut microbiota contribute to disease progression. - Diagnostic criteria (2023 ADA): Fasting plasma glucose ≥ 126 mg/dL (7.0 mmol/L), 2‑hour OGTT glucose ≥ 200 mg/dL (11.1 mmol/L), HbA1c ≥ 6.5 % (48 mmol/mol), or a random plasma glucose ≥ 200 mg/dL with classic symptoms. - Management hierarchy: 1) Lifestyle intervention (5‑10 % weight loss, ≥150 min/week moderate activity); 2) Metformin as first‑line pharmacotherapy; 3) Additional agents (SGLT2 inhibitors, GLP‑1 agonists) chosen based on comorbidities; 4) Insulin when glycemic targets remain unmet. - Complications: Macrovascular (coronary artery disease, stroke, peripheral arterial disease) and microvascular (diabetic retinopathy, nephropathy, neuropathy). Early detection of albuminuria and retinal changes is vital. - Epidemiology: As of 2022, over 537 million adults live with diabetes globally; > 90 % have T2DM. Prevalence is highest in the Western Pacific and Southeast Asian regions, reflecting rapid lifestyle transitions. - Prevention: The Diabetes Prevention Program (DPP) demonstrated a 58 % risk reduction through modest weight loss and increased physical activity, underscoring the power of behavioral change.

Significance

T2DM represents a major public‑health challenge due to its high prevalence, chronic nature, and costly complications. Economically, diabetes care consumes an estimated 10‑15 % of national health expenditures in many high‑income countries, straining healthcare systems. Socially, the disease disproportionately affects disadvantaged populations, amplifying health inequities. Advances in pharmacotherapy—particularly SGLT2 inhibitors and GLP‑1 receptor agonists—have shifted the therapeutic paradigm from glucose‑centric to cardiorenal‑protective strategies, reducing mortality and hospitalizations. Moreover, emerging research on genetics, precision nutrition, and digital health tools (continuous glucose monitors, telemedicine) promises more personalized and proactive disease management. Public‑policy initiatives, such as sugar‑taxes and urban planning that encourages active transport, aim to curb the upstream drivers of obesity and insulin resistance, highlighting the societal importance of addressing T2DM holistically.

When to seek professional care: Anyone experiencing classic diabetes symptoms, unexplained weight loss, or persistent hyperglycemia should consult a healthcare provider promptly. Even individuals without symptoms but with risk factors (family history, obesity, gestational diabetes) should undergo screening, as early diagnosis enables interventions that can delay or prevent complications.

INFOBOX:
- Name: Type 2 Diabetes Mellitus
- Type: Chronic metabolic disease
- Date: First distinguished as “adult‑onset diabetes” in 1936
- Location: Worldwide (global prevalence)
- Known For: Being the most common form of diabetes and a leading cause of preventable morbidity and mortality

TAGS: diabetes, type 2, insulin resistance, metabolic syndrome, chronic disease, public health, obesity, glucose monitoring