Type 2 Diabetes: Causes, Symptoms, and Diagnosis

Type 2 diabetes is more common than type 1 diabetes. It used to be called adult-onset diabetes or non-insulin dependent, and you may still hear it called that—but type 2 diabetes is more correct and current.

type 2 diabetes

The main issue in type 2 diabetes is that your body can't use insulin effectively. Insulin is a hormone made in your pancreas that's necessary for processing glucose, which our bodies use for energy. Insulin allows the glucose to travel from the blood into the cells that need that it. If your body can't use insulin well, then it'll be more difficult for glucose to pass into the cells.

Not being able to use insulin well is called insulin resistance. Some people with type 2 diabetes are insulin resistant; other people with type 2 diabetes don't produce enough insulin to handle the glucose in their blood, so they also have insulin deficiency.

Regardless of whether you're insulin resistant or simply don't have insulin, the end result is the same in type 2 diabetes: glucose builds up in the blood, leading to hyperglycemia and possible long-term damage from hyperglycemia and poor blood glucose control.

Type 2 Diabetes Causes
Type 2 diabetes generally develops gradually. Over time, your body becomes less capable of using insulin, or it starts producing less insulin.

Type 2 diabetes is caused by a combination of factors, including genetics and lifestyle choices.

Genetics: There is a genetic component to type 2 diabetes, but that doesn't mean that just because your mother or grandfather has type 2 diabetes, you will develop it.

It's better to think of it this way: if type 2 diabetes runs in your family, you're at a greater risk of developing it.

Lifestyle: Lifestyle choices play a sizable role in the development of type 2 diabetes. If type 2 diabetes runs in your family, you should work to take good care of your body and make healthy lifestyle choices so that you can reduce your risk of developing diabetes.

Lifestyle factors that play a role in developing type 2 diabetes are:

  • lack of exercise: Exercise keeps you healthy in many ways, and lack of physical activity has been named as a contributing factor to type 2 diabetes.
  • unhealthy eating habits: Eating lots of high-fat, high-sugar foods—and not keeping a balanced diet—can make you more likely to develop type 2 diabetes.
  • being overweight/obese: This is important to stress—although type 2 diabetes is often associated with people who are overweight, it is possible for people with a healthy weight to develop it.

    However, it is known that being overweight (having a body mass index of 25 or higher) increases your likelihood of type 2 diabetes. Extra fat makes you more likely to become insulin resistant, since it's known that fat interferes with how well insulin works.

Type 2 Diabetes Symptoms
Because type 2 diabetes develops gradually, the symptoms of type 2 diabetes also develop gradually. Your body slowly becomes more insulin resistant (or unable to make enough insulin), and some of the type 2 diabetes symptoms you may notice are:

  • fatigue
  • slow wound healing (or slow infection healing)
  • increased appetite and thirst
  • increased urination
  • blurred vision

If you notice these symptoms, contact your doctor.

Type 2 Diabetes Diagnosis
Diagnosing type 2 diabetes is done by taking into consideration your family history and current symptoms. Your doctor will also run some blood tests on you to confirm diabetes.

Those blood tests are:

  • Glycated hemoglobin (A1c) test: American Diabetes Association decided in 2010 that the A1c test can be used to help diagnose diabetes. This test gives an average of your blood glucose (blood sugar) levels over the past 2 to 3 months. If you have an A1c of 6.5% or higher on 2 separate occasions, then you have diabetes.
  • Random blood glucose test: If your random blood glucose level is 200 mg/dL or higher, then you have diabetes. As the name suggests, this is a random test of your blood glucose level; you don't have to prepare for this test.

  • Fasting blood glucose test: After you've fasted overnight (as instructed by your doctor), your doctor will check your blood glucose level. If the fasting blood glucose level is 126 mg/dL or higher on 2 separate occasions, then you have diabetes.

An excellent graphic illustrating what each test results means is available at the American Diabetes Association Web site.

What Happens After a Type 2 Diabetes Diagnosis
A type 2 diabetes diagnosis will change your life—and that may be frightening at first, but you will be able to handle it. By working with your diabetes treatment team, you'll learn how to take better care of yourself and better manage your blood glucose levels.

Updated on: June 13, 2019
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