Type 1 diabetes (T1D) is an autoimmune disease in which the body attacks the insulin-producing cells in the pancreas.
As is common with many medical conditions, various abbreviations and alternate terms are used to identify type 1 diabetes. However, not all of these terms are accurate, and many are confusing.
Here is a list of terms people may use to refer to the different types of diabetes, both those that are type 1 diabetes and those that are not.
Type 1 diabetes / T1D / Type 1
Type 1 diabetes, T1D, and type 1 are the preferred, correct terms to use when referring to diabetes caused by the body’s autoimmune attack of the insulin-producing cells in the pancreas. This is based on the consensus of leaders and experts in the scientific and clinical fields.
aT1D
aT1D is short for autoimmune type 1 diabetes. aT1D is redundant because all type 1 diabetes is autoimmune (even when no autoantibodies can be detected at the time of diagnosis). When referring to types of diabetes caused by autoimmunity (regardless of whether autoantibodies can be detected at the time of diagnosis), people should use the terms type 1 diabetes, T1D, or type 1 instead of the term aT1D.
Childhood-onset diabetes or juvenile diabetes
Childhood-onset diabetes and juvenile diabetes are outdated terms for type 1 diabetes. Today, we know that type 1 diabetes is an autoimmune disease that can be diagnosed in anyone at any age, not just children. Additionally, while rare, children can be diagnosed with other types of diabetes, not just T1D (see maturity onset diabetes of the young/MODY, neonatal diabetes, and type 2 diabetes). When referring to diabetes caused by autoimmunity (in any person of any age), people should use the terms type 1 diabetes, T1D, or type 1 instead of the terms childhood onset diabetes or juvenile diabetes.
Diabetes mellitus
Diabetes mellitus can refer to all types of diabetes. It was derived from the Greek word diabetes, meaning to siphon or to pass through, and the Latin word mellitus, meaning honeyed or sweet. When a person has diabetes, excess sugar is found in the blood and urine. Today, we know that many different underlying diseases, including the many other types of diabetes, share these symptoms. When referring to diabetes caused by autoimmunity (in any person of any age), people should use the terms type 1 diabetes, T1D, or type 1 instead of the term diabetes mellitus.
Double diabetes or Diabetes 1.5
Double diabetes, or diabetes 1.5, is type 1 diabetes. These are terms that have been used to refer to individuals with type 1 diabetes who are overweight, have a family history of type 2 diabetes, and/or have clinical features of insulin resistance. Diabetes 1.5 may also be referred to as latent autoimmune diabetes in adults (LADA). Double diabetes and diabetes 1.5 are not clearly defined diseases recognized by the medical community. When referring to diabetes caused by autoimmunity (in any person of any age), people should use the terms type 1 diabetes, T1D, or type 1 instead of the terms double diabetes or diabetes 1.5.
Gestational diabetes
Gestational diabetes is not type 1 diabetes. This type of diabetes is diagnosed for the first time during pregnancy (gestation). Gestational diabetes causes high blood sugar that can affect the pregnancy and the baby’s health. Unlike T1D, gestational diabetes is not autoimmune or caused by a lack of insulin but by other hormones produced during pregnancy that can make insulin less effective. Gestational diabetes usually goes away after the baby is born, but there is a 50% higher risk of developing type 2 diabetes later in life, possibly within five years post-partum. Some women who develop gestational diabetes may have had undiagnosed diabetes before pregnancy.
Insulin-dependent diabetes mellitus (IDDM)
Insulin-dependent diabetes mellitus (IDDM) is an outdated term for type 1 diabetes. Like people with T1D, many people with non-autoimmune forms of diabetes (such as type 2 diabetes) can also require insulin for treatment. When referring to diabetes caused by autoimmunity (in any person of any age), people should use the terms type 1 diabetes, T1D, or type 1 instead of the term insulin-dependent diabetes mellitus (IDDM).
Latent autoimmune diabetes of adults (LADA)
Latent autoimmune diabetes of adults (LADA) is type 1 diabetes that begins in adulthood and has a slow progression. Adults diagnosed with T1D may not require insulin for glycemic control at least during the first six months after diagnosis. This kind of T1D progression shares genetic, immunologic, and metabolic features with type 1 and type 2 diabetes, as some residual beta cell function may be present. When referring to diabetes caused by autoimmunity (in any person of any age), people should use the terms type 1 diabetes, T1D, or type 1 instead of the term latent autoimmune diabetes of adults (LADA).
Maturity-onset diabetes of the young (MODY)
Maturity-onset diabetes of the young (MODY) is not type 1 diabetes. It is a term for rare forms of diabetes that were first described as mild and asymptomatic and were observed in non-obese children, adolescents, and young adults. We know now that at least 13 dominantly inherited single-gene mutations causing defects in insulin production are at the root of this type of diabetes. Rather than maturity-onset diabetes of the young (MODY), it is becoming more common for people to use the name of the underlying genetic cause for this type of diabetes (for example, mutation in the HNF1A, GCK, HNF4A, or HNF1B gene).
Neonatal diabetes
Neonatal diabetes is not type 1 diabetes. This type of diabetes is defined by the onset of persistent high blood glucose within the first six months of life. T1D in this age group is extremely rare. Neonatal diabetes is frequently caused by a mutation in a single gene affecting pancreatic beta cell function and/or impaired insulin function.
Non-insulin-dependent diabetes mellitus (NIDDM)
Non-insulin-dependent diabetes mellitus (NIDDM) is not type 1 diabetes. It is an outdated term for type 2 diabetes. As many people with type 2 diabetes also need insulin, they cannot be described as having non-insulin-dependent diabetes.
Type 2 diabetes (T2D)
Type 2 diabetes (T2D) is not type 1 diabetes. T2D is not caused by an autoimmune attack on the insulin-producing cells in the pancreas. Rather, T2D is mainly the result of cells in muscle, fat, and the liver becoming resistant to insulin. This is often—but not always—associated with obesity, and the pancreas can’t make enough insulin to keep blood sugar levels within a healthy range. T2D mainly occurs in adults, with chances of onset increasing with age. It can, however, also occur in children and teens and has been rising with rates of childhood obesity. Approximately 40% of adult-onset T1D is initially misdiagnosed as T2D. Learn more about the difference between type 1 diabetes and type 2 diabetes.
Type 3 diabetes (T3D)
Type 3 diabetes (T3D) is not type 1 diabetes. Furthermore, it is not an officially recognized health condition. Some healthcare professionals have suggested this term for rare, often genetic, diabetes forms. Others use the term to describe a disease where insulin dysregulation in the brain causes Alzheimer’s disease and dementia. The term type 3c diabetes is sometimes used for types of diabetes that develop because of non-autoimmune attack damage to the pancreas.
