A New Type of Diabetes in Adults: Type 1.5 or Latent Autoimmune Diabetes in Adults (LADA)

Diabetes occurs in people when their bodies no longer process blood sugar correctly. There are different types of diabetes that are classified according to the mechanism by which this occurs. Typically, patients with type 1 diabetes are diagnosed as children and must take insulin because their bodies no longer produce enough to maintain their blood sugar at normal levels. Type 2 diabetes patients are usually diagnosed as adults. These patients make insulin but don’t use it efficiently because their bodies have become resistant to its effects. Healthcare providers are now recognizing another type of diabetes, type 1.5 diabetes.

RecognizingType 1.5 Diabetes

Type 1.5 has features of both type 1 and type 2 diabetes. Patients are usually over the age of 35 when diagnosed, like type 2 diabetes, but soon require insulin for treatment like type 1 patients. For this reason, type 1.5 diabetes is sometimes called Slow Onset Type 1 diabetes. Patients are often misdiagnosed with type 2 diabetes due to their age at onset. Type 2 diabetes is typically associated with obesity or being overweight, but Type 1.5 diabetics very often have a normal weight.

Testing for Type 1.5 Diabetes

Type 1.5 diabetes appears to be an autoimmune disease where antibodies attack insulin-producing cells in the pancreas. It is sometimes called latent autoimmune diabetes in adults (LADA). Patients carry antibodies known as GADA which can be measured with a simple blood test. These antibodies are also found in type 1 diabetics, and may mean patients are more likely to have other auto immune diseases like celiac disease. Patients with type 2 diabetes do not have these antibodies. Approximately 10% of type 2 patients will be found to have insulin antibodies, indicating that they may actually be type 1.5.

Treatment of Type 1.5 Diabetes

LADA patients are able to use oral medications to lower blood sugar for the first few years after diagnosis. Typically within roughly six years of diagnosis, patients will need to take insulin. This is different from type 2 patients who may never use insulin for treatment. A 2008 study in the Journal of Clinical Endocrinology and Metabolism showed that latent autoimmune diabetes patients with high levels of antibodies may do better by starting insulin earlier, rather than relying on oral medications in the initial phase of the disease.

Questions about Type 1.5 Diabetes

Patients with questions regarding type 1.5 diabetes should talk to their healthcare providers for more information. A blood test for insulin auto-antibodies can help differentiate type 1.5 from type 2 diabetes. Type 2 diabetes patients who are of normal weight and having difficulty controlling their blood sugar on oral medications may be candidates for testing.

References

The Other Diabetes: LADA, or Type 1.5. Diabetes Forecast. May 2010.

Insulin Intervention in Slowly Progressive Insulin-Dependent (Type 1) Diabetes Mellitus. J Clin Endocrinol Metab. 2008; 93:2115.