Abstract

Young-onset type 2 diabetes mellitus (T2DM), defined as diagnosis before the age of 40 years, has emerged as a major public health challenge worldwide. Its prevalence has risen markedly over the past decade, paralleling the increase in obesity rates among adolescents and young adults. Compared with later-onset disease, youngonset T2DM exhibits distinct clinical and pathophysiological characteristics, including more severe insulin resistance, rapid ß-cell decline, and early deterioration of glycemic control. Contributing factors include obesity, strong familial predisposition, genetic susceptibility, intrauterine hyperglycemia, puberty-related insulin resistance, and early-life determinants such as small for gestational age (SGA) or low birth weight (LBW). Patients with this condition experience a substantially higher risk of premature microvascular and macrovascular complications; furthermore, long-term mortality—reflected by substantial standardized mortality ratios—far exceeds that of the general population. Despite the aggressive nature of the disease, therapeutic options remain limited for adolescents, highlighting the need for individualized management. Early, intensive lifestyle intervention and weight reduction can induce diabetes remission in selected patients, whereas novel agents such as Glucagon-Like Peptide-1 (GLP-1) receptor agonists and Sodium-Glucose Cotransporter 2 (SGLT2) inhibitors show promise for expanded use. To optimize long-term outcomes in this high-risk population, clinicians must understand the epidemiology, pathophysiology, and clinical course of young-onset T2DM.