Diabetes Mellitus Classification and Prevalence

Main Types of Diabetes and Their Prevalence

Type 1 diabetes results from autoimmune β-cell destruction, usually leading to absolute insulin deficiency, and accounts for approximately 5-10% of all diabetes cases 1, 2, 4
Type 2 diabetes is caused by progressive loss of β-cell insulin secretion frequently on the background of insulin resistance, and accounts for 90-95% of all diabetes cases 1, 2, 4
Gestational diabetes mellitus (GDM) is diabetes diagnosed in the second or third trimester of pregnancy that was not clearly overt diabetes prior to gestation, and its prevalence varies widely based on population risk factors 1, 2
Specific types of diabetes due to other causes, such as monogenic diabetes syndromes and diseases of the exocrine pancreas, account for approximately 3-5% of all diagnosed diabetes cases 1, 2

Higher prevalence of type 2 diabetes is observed among certain ethnic groups, including Native Americans and Alaskan Natives (15.1%), non-Hispanic blacks (12.7%), and Hispanics (12.1%) compared with Asians (8.0%) and non-Hispanic whites (7.4%) 5
Age-adjusted incidence of diabetes is two times higher for people with less than a high school education compared to those with more than a high school education 5
Diabetes prevalence increases with age: 4% in individuals 18-44 years old, 17% in those 45-64 years old, and 25% in those 65 and older 5

Latent autoimmune diabetes in adults (LADA) is phenotypically similar to type 2 diabetes but patients have autoantibodies 6
Prediabetes, now referred to as "categories of increased risk for diabetes", includes impaired fasting glucose, impaired glucose tolerance, or an A1C level of 5.7-6.4%, and affects approximately 33.9% of U.S. adults (84.1 million people) 5, 6