Type 2 Diabetes

Type 2 diabetes, sometimes called adult-onset diabetes, is the most common form of diabetes. It is commonly found in adults, but it is being seen more and more in young adults, too.

Insulin resistance and beta-cell failure in type 2 diabetes

Insulin is a hormone made by the pancreas. (More specifically, insulin is made by special cells in the pancreas, called beta cells.) The pancreas releases insulin to help the body use sugar. Insulin moves sugar to the cells, where it is used as energy. When blood sugar levels rise, such as after meals, the pancreas releases more insulin. When blood sugar levels are low, the pancreas releases less insulin. 

In type 2 diabetes, the body makes some insulin, but the body does not respond to it the way it used to. This is called insulin resistance. In addition to other factors, having too much body fat can contribute to insulin resistance. As a result of diabetes, the body needs more insulin to work. 

At first, the beta cells in the pancreas that produce insulin are able to keep up, and the pancreas churns out more insulin. But after a while, as more beta cells in the pancreas stop working, the pancreas is not able to keep up with the heavy demand, making less and less insulin until, in many people, it finally makes little to none. 

As a result of this lower amount of insulin, the sugar stays in the bloodstream, where it builds up and becomes too high. When blood sugar stays high for a long time, there’s a greater risk of developing some diabetes-related problems, like problems with the eyes (diabetic retinopathy) and the nerves in places like the hands and feet (neuropathy). This is why it is so important to keep blood sugar under control. 

People with type 2 diabetes need help controlling their blood sugar. The first things doctors usually suggest are diet, exercise, and often, diabetes medicines.  


Type 2 diabetes symptoms

People with type 2 diabetes may not show any symptoms at first, or symptoms can be mild. Symptoms of type 2 diabetes can be similar to type 1 symptoms and may include:

  • Increased thirst and hunger
  • Frequent urination
  • Blurry vision
  • Feeling very tired


People with type 2 diabetes may also have problems with:

  • Infections of the skin, gums, or bladder
  • Scrapes or bruises healing slower than usual
  • Tingling or numbness in the limbs


What causes type 2 diabetes?

We don’t know exactly why, over time, the pancreas makes less and less insulin. But we do know that some people have a higher chance of developing type 2 diabetes than others. For example, three-fourths of all people with type 2 diabetes are, or have been, overweight. Other risk factors include not being physically active, being older than 45 years, and having a family history of diabetes.


Type 2 diabetes treatment

It's important for people with this form of diabetes to watch portion sizes and try to make better food choices. Staying active and losing weight can also be very helpful. Doing these things may help you better control blood sugar.

Several diabetes medicines can also be helpful in lowering blood sugar, especially in people whose bodies are still producing some insulin. You can read more about these medicines here

Your treatment may have started with diabetes pills, like metformin. But as diabetes changes over time, the pancreas may not produce enough insulin on its own, and insulin injections may be needed. Around 30% to 40% of people with type 2 diabetes take insulin regularly by injection


Basal and bolus insulin

In people without diabetes, the body makes insulin in 2 different ways. First, it releases insulin at a steady “basal” rate throughout the day and night so the body will produce energy.

If you have type 2 diabetes, and your body isn’t producing enough insulin on its own throughout the day, your health care provider may prescribe a “basal”, or long-acting, insulin to be taken by injection. 

In people without diabetes, the body also releases short bursts of insulin at mealtime to cover the spikes in blood sugar caused by food. This is called a “bolus” of insulin. If you have type 2 diabetes, your body may produce enough insulin throughout the day, but may not be producing enough insulin to handle blood sugar spikes that happen when you eat. If this is the case, your health care provider may want you to take a "bolus", or fast-acting insulin like NovoLog®, along with your “basal” insulin. This is called basal-bolus insulin therapy.

If you need help talking with your doctor about adding NovoLog® mealtime insulin to your care plan, you can use our Doctor Discussion Guide to organize your thoughts.

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