Latent autoimmune diabetes of adults

Latent autoimmune diabetes in adults (LADA) is a form of diabetes mellitus type 1 that occurs in adulthood, often with a slower course of onset than type 1 diabetes diagnosed in juveniles. Adults with LADA may initially be diagnosed incorrectly as having type 2 diabetes based on their age, particularly if they have risk factors for type 2 diabetes such as a strong family history or obesity. Latent autoimmune diabetes in adults (LADA) is a form of diabetes mellitus type 1 that occurs in adulthood, often with a slower course of onset than type 1 diabetes diagnosed in juveniles. Adults with LADA may initially be diagnosed incorrectly as having type 2 diabetes based on their age, particularly if they have risk factors for type 2 diabetes such as a strong family history or obesity. The diagnosis is typically based on the finding of hyperglycemia together with the clinical impression that islet failure rather than insulin resistance is the main cause; detection of a low C-peptide and raised antibodies against the islets of Langerhans support the diagnosis. It can only be treated with the usual oral treatments for type 2 diabetes for a certain period of time, after which insulin treatment is usually necessary, as well as long-term monitoring for complications. The concept of LADA was first introduced in 1993, though The Expert Committee on the Diagnosis and Classification of Diabetes Mellitus does not recognize the term, instead including it under the standard definition of diabetes mellitus type 1. The symptoms of latent autoimmune diabetes in adults are similar to those of other forms of diabetes: polydipsia (excessive thirst and drinking), polyuria (excessive urination), and often blurred vision. Compared to juvenile type 1 diabetes, the symptoms develop comparatively slowly, over a period of at least six months. It is estimated that more than 50% of persons diagnosed as having non-obesity-related type 2 diabetes may actually have LADA. Glutamic acid decarboxylase autoantibody (GADA), islet cell autoantibody (ICA), insulinoma-associated (IA-2) autoantibody, and zinc transporter autoantibody (ZnT8) testing should be performed on all adults who are not obese who are diagnosed with diabetes. However, some overweight patients are misdiagnosed with type 2 due to their weight. Moreover, it is now becoming evident that autoimmune diabetes may be highly underdiagnosed in many individuals who have diabetes, and that the body mass index levels may have rather limited use in connections with latent autoimmune diabetes. Persons with LADA typically have low, although sometimes moderate, levels of C-peptide as the disease progresses. Those with insulin resistance or type 2 diabetes are more likely to have high levels of C-peptide due to an over production of insulin. Glutamic acid decarboxylase autoantibodies (GADA), islet cell autoantibodies (ICA), insulinoma-associated (IA-2) autoantibodies, and zinc transporter autoantibodies (ZnT8) are all associated with LADA; GADAs are commonly found in cases of diabetes mellitus type 1. The presence of islet cell complement fixing autoantibodies also aids in a differential diagnosis between LADA and type 2 diabetes. Persons with LADA often test positive for ICA, whereas type 2 diabetics only seldom do. Persons with LADA usually test positive for glutamic acid decarboxylase antibodies, whereas in type 1 diabetes these antibodies are more commonly seen in adults rather than in children. In addition to being useful in making an early diagnosis for type 1 diabetes mellitus, GAD antibodies tests are used for differential diagnosis between LADA and type 2 diabetes and may also be used for differential diagnosis of gestational diabetes, risk prediction in immediate family members for type 1, as well as a tool to monitor prognosis of the clinical progression of type 1 diabetes.