Latent Autoimmune Diabetes in Adults

Traditionally, doctors recognized only three types of diabetes.  The first was type 1 diabetes, which mainly affected children and young adults.  The second was type 2 diabetes, which often occurs in a person who is older.  Gestational diabetes is another type of diabetes that occurs during pregnancy.  Gestational diabetes looks a lot like type 2 diabetes and only occurs in the latter part of pregnancy.

Now doctors have identified another type of diabetes, called latent autoimmune diabetes in adults (LADA).  LADA occurs in about 10 percent of individuals with diabetes.  It is, in fact, more prevalent than type 1 diabetes.

Most people haven’t even heard of LADA.  It is a type of diabetes that is a variation of type 1 diabetes but progresses more slowly than type 1 diabetes.  It is often misdiagnosed as being type 2 diabetes and is treated with pills.  No one knows exactly how LADA develops and yet it is important for patients to recognize that they have the disease.

History of LADA

Researchers first came upon the diagnosis of LADA accidentally in the 1970s.  In testing for ways to identify the autoantibodies in patients who had type 1 diabetes, they discovered that type 1 diabetes is an autoimmune disease in which antibodies are made against the body’s own insulin-making cells (the beta cells) in the pancreas so that no insulin is being made.

While researching the phenomenon of type 1 diabetes and autoantibodies, the scientists looked for the presence of autoantibodies in normal people and in people who had type 2 diabetes, which isn’t considered to be an autoimmune disease.

They found no autoantibodies in people who did not have diabetes but about ten percent of type 2 diabetics showed antibodies to beta cells typical of type 1 diabetes.  They determined that there was a subset of individuals who had LADA rather than ordinary type 2 diabetes.  The symptoms of LADA were no different from those people who had type 2 diabetes.

Typical symptoms of LADA include:

• Increased frequency of urination
• Increased thirst
• Increased numbers of infections
• High blood sugar

Some people call this condition LADA, while others call it diabetes type 1.5 to distinguish it from type 1 diabetes and type 2 diabetes.  According to research on the disease, the main criteria for having LADA include the following:

• Having beta cell autoantibodies in the bloodstream
• Being an adult at the time of diagnosis
• Needing no insulin to treat the disease, at least not in the first 6 months of diagnosis

People who meet these criteria have LADA instead of type 1 diabetes or type 2 diabetes.  People with type 1 diabetes need insulin as soon as they are diagnosed and people with type 2 diabetes rarely need insulin at all and have no autoantibodies in their bloodstreams.

There is a lot of debate around the diagnosis of LADA.  Doctors have now come to believe that diabetes follows a continuum.  Some have autoimmune antibodies and need insulin right away, while others need insulin later on in the course of the disease.  Still others never need insulin.

Researchers have determined that there are different types of autoantibodies associated with diabetes.  Those who have type 1 diabetes have more types of autoantibodies and higher levels of autoantibodies when compared to people who have LADA so that the beta cells are destroyed much more quickly and the need for insulin happens right away.   Those who have type 1.5 diabetes (LADA) have lesser levels of autoantibodies and don’t need insulin right away.  Those who have type 2 diabetes have no autoantibodies and have mostly intact beta cells.

It was once believed that heredity could sort out the types of diabetes a person has.  A study out of the journal Diabetes, however, found that LADA carries features typical of both type 1 diabetes and type 2 diabetes, making LADA a condition that is between type 1 and type 2 diabetes, leaning more towards being type 1 diabetes than type 2 diabetes.

Is there a difference?

Defining the different types of diabetes is satisfactory for scientists studying these types of diseases; however, it isn’t clear whether it is worth it to screen people for LADA once the diagnosis of diabetes is made.  Doctors wonder if patients diagnosed with LADA would get better therapy if the exact diagnosis of LADA were to be made official early on in the diagnostic process.  They wonder if diagnosing LADA will help these diabetics have better blood sugar levels and less chance of complications.

In order to diagnose LADA, doctors need to measure the amount of autoantibodies in the blood as well as the amount of insulin produced by the body.  This may or may not change the treatment given and diagnosing LADA may be more expensive than it is worth. The treatment may not change if the patient is diagnosed with LADA versus being diagnosed with type 2 diabetes.

Testing for LADA may be a good idea in patients who are not overweight and who are generally physically active.  These people seem to be more likely to suffer from LADA and have less insulin resistance than is seen in type 2 diabetes.  In such cases, making the diagnosis of LADA might change the way the patient is treated.

There is some research evidence that treating LADA patients early on with insulin might help the person’s beta cells last longer.  In a research study out of the Journal of Clinical Endocrinology and Metabolism, researchers looked at giving insulin along with sulfonylurea drugs for 4000 patients with LADA.  The subset of individuals who were given insulin early in the disease kept their beta cell function longer and didn’t require total insulin replacement for a longer period of time when compared to those who weren’t given insulin right away.

Giving insulin right away to LADA patients can help the beta cells last longer. If just pills are given for patients with LADA, there is a higher likelihood that they will lose their beta cell function faster and will be totally dependent on insulin sooner.  This means that, in some cases, it might be beneficial to try to identify those patients who have LADA versus just having type 2 diabetes.

In addition, current therapies being developed to cure type 1 diabetes may also help those patients who have LADA.  There could be a medication out there besides insulin that change the way the disease develops. Currently, however, no such medication exists.

References:

• Stenstrom G, Gottsater A, e. al. Latent Autoimmune Diabetes in Adults. Definition, prevalence, beta cell function, and treatment. http://diabetes.diabetesjournals.org/content/54/suppl_2/S68.full.
• Gebel E. The other diabetes: LADA or Type 1.5. http://www.diabetesforecast.org/2010/may/the-other-diabetes-lada-or-type-1-5.html?referrer=https://www.google.com/.