What are the differences between type 1 and type 2 diabetes?

Type 1 diabetes is an autoimmune disease. It occurs when the insulin-producing islet cells in the pancreas are completely destroyed, so the body can’t produce any insulin.

In type 2 diabetes, the islet cells are still working. However, the body is resistant to insulin. In other words, the body no longer uses insulin efficiently.

Type 1 diabetes is far less common than type 2. It used to be called juvenile diabetes because the condition is typically diagnosed in early childhood.

Type 2 diabetes is more commonly diagnosed in adults, though we’re now seeing more and more children being diagnosed with this disease. It’s more commonly seen in those who are overweight or obese.

Type 2 diabetes can’t turn into type 1 diabetes, since the two conditions have different causes.

It’s possible for someone with type 2 diabetes to be misdiagnosed. They may have many of the symptoms of type 2 diabetes, but actually have another condition that may be more closely related to type 1 diabetes. This condition is called latent autoimmune diabetes in adults (LADA).

Researchers estimate that between 4 and 14 percent of people diagnosed with type 2 diabetes might actually have LADA. Many physicians are still unfamiliar with the condition and will assume a person has type 2 diabetes because of their age and symptoms.

In general, a misdiagnosis is possible because:

  • both LADA and type 2 diabetes typically develop in adults
  • the initial symptoms of LADA — such as excessive thirst, blurred vision, and high blood sugar — mimic those of type 2 diabetes
  • doctors don’t typically run tests for LADA when diagnosing diabetes
  • initially, the pancreas in people with LADA still produces some insulin
  • diet, exercise, and oral drugs usually used to treat type 2 diabetes work well in people with LADA at first

As of now, there’s still a lot of uncertainty over how exactly to define LADA and what causes it to develop. The exact cause of LADA is unknown, but researchers have identified certain genes that may play a role.

LADA may only be suspected after your doctor realizes that you’re not responding (or no longer responding) well to oral type 2 diabetes medications, diet, and exercise.

Many doctors consider LADA the adult form of type 1 diabetes because it’s also an autoimmune condition.

As in type 1 diabetes, the islet cells in the pancreas of people with LADA are destroyed. However, this process occurs much more slowly. Once it starts, it can take several months up to several years for the pancreas to stop being able to make insulin.

Other experts consider LADA somewhere in between type 1 and type 2 and even call it “type 1.5” diabetes. These researchers believe that diabetes can occur along a spectrum.

Researchers are still trying to figure out the details, but in general, LADA is known to:

  • develop in adulthood
  • have a slower course of onset than type 1 diabetes
  • often occur in people who aren’t overweight
  • often occur in people who don’t have other metabolic issues, such as high blood pressure and high triglycerides
  • result in a positive test for antibodies against the islet cells

The symptoms of LADA are similar to those of type 2 diabetes, including:

In addition, the treatment plans for LADA and type 2 diabetes are similar at first. Such treatment includes:

Unlike people with type 2 diabetes who may never need insulin and who can reverse their diabetes with lifestyle changes and weight loss, people with LADA can’t reverse their condition.

If you have LADA, you’ll eventually be required to take insulin to stay healthy.

If you were recently diagnosed with type 2 diabetes, understand that your condition can’t eventually turn into type 1 diabetes. However, there’s a small possibility that your type 2 diabetes is actually LADA, or type 1.5 diabetes.

This is especially true if you’re a healthy weight or if you have a family history of autoimmune diseases, such as type 1 diabetes or rheumatoid arthritis (RA).

It’s important to correctly diagnose LADA since you’ll need to start on insulin shots early to control your condition. A misdiagnosis can be frustrating and confusing. If you have any concerns about your type 2 diabetes diagnosis, see your doctor.

The only way to properly diagnose LADA is to test for the antibodies that show an autoimmune attack on your islet cells. Your doctor may order a GAD antibody blood test to determine whether you have the condition.