The American Diabetes Association (ADA) defines latent autoimmune diabetes of adulthood (LADA) as the development of type 1 diabetes in adults. LADA also has some characteristics of, and is sometimes confused with, type 2 diabetes. It is known by a host of names as scientists attempt to classify this form of diabetes, which normally develops gradually in adults over the age of 30. Some of the other terms used to describe this condition include:

• Type 1.5 diabetes
• Autoimmune diabetes of adults
• Latent type 1 diabetes
• Late-onset autoimmune diabetes of adulthood
• Progressive insulin-dependent diabetes mellitus
• Slowly progressive type 1 diabetes
• Slow-onset type 1 diabetes
• Youth-onset diabetes of maturity
• Type one-and-a-half diabetes

While researchers continue to debate the proper name and classification for this type of diabetes, the two most common terms for this condition appear to be LADA and type 1.5. It should be noted that the term “type 1.5 diabetes” has also been used to describe at least two other conditions: double diabetes and maturity-onset diabetes of the young (MODY).

Compared to a child who develops symptoms of type 1 diabetes over a few weeks, the onset of LADA is more of a steady decrease in insulin production over months or years. The additional signs of ketoacidosis or ketosis (increased levels of acidic waste products called ketones in the blood and urine) and rapid unexplained weight loss, normally associated with type 1 diabetes, are also absent.

Most people diagnosed with LADA are not overweight or obese and have no family history of type 2 diabetes. They may or may not have a family history of type 1 diabetes.

Treatment for LADA patients incorrectly diagnosed with type 2 diabetes will ultimately fail, and patients will become insulin dependent. Although the physician may initially believe that the patient has failed to adhere to the recommended diet or medication regimen, a physiologic reaction is actually occurring inside the body.

At this point, the islets of Langerhans in the pancreas are under attack by the autoimmune process. The result is the failure of beta cells to release insulin, and thus the production of insulin stops. For patients with LADA, little or no insulin production takes place because body’s own immune system has destroyed the pancreatic beta cells. 

LADA is considered a less aggressive form of autoimmune diabetes than standard type 1. That may be the reason for the considerable amount of time that insulin is not required for these patients. LADA patients seldom possess some of the more common characteristics of a type 2 diabetic patient, including:

• Obesity or overweight
• A high occurrence of metabolic syndrome
• High blood pressure
• Unhealthy levels of triglycerides and cholesterol (hyperlipidemia)

As with other forms of diabetes, however, LADA can lead to complications such as heart problems. Some research suggests that people with LADA might be more prone to conditions involving microangiopathy (diseases of the small blood vessels), such as diabetic retinopathy. Patients can reduce their risk by controlling their glucose (blood sugar) and adhering to other aspects of their treatment plan.

Scientists have not established the incidence of LADA. With LADA patients sometimes misdiagnosed as having type 2 diabetes, some estimates attribute as many as 15 to 20 percent of diabetes cases to LADA. If correct, such figures would make LADA more common than (childhood-onset) type 1 diabetes, which accounts for 5 to 10 percent of diabetic cases, according to federal health agencies.

  Distinguishing LADA From Other Forms of Diabetes