There are several kinds of diabetes, but the two most common are:
- Type 1 diabetes, which usually develops before age 30 and tends to come on suddenly.
- Type 2 diabetes, which accounts for 90–95% of diabetes cases and usually starts later in life.
Type 1 Diabetes
In this type (formerly called insulin-dependent diabetes), the body's immune system attacks and destroys beta cells in the pancreas so it can no longer produce sufficient amounts of insulin. Type 1 diabetes is sometimes called juvenile-onset diabetes because it most often starts in childhood. It can develop in adults, but this is far less common.
Type 1 diabetes is a serious condition that cannot be treated simply by losing weight or watching what you eat. People with type 1 disease must take insulin injections several times a day to prevent blood glucose from rising to life-threatening levels.
Research shows that there may be 3 sub-types of type 1 diabetes: autoimmune, non-autoimmune fulminant, and non-autoimmune non-fulminant (also called non-autoimmune chronic). Further classification of diabetes may help develop a better understanding of the disease and how to treat it more effectively.
Type 2 Diabetes
In this type (formerly called adult-onset diabetes), beta cells still produce insulin, but the quantity may be reduced or the body's cells may be insulin resistant. Most people with type 2 diabetes are obese. This type of diabetes develops gradually and is usually diagnosed in adulthood. However, more and more children are being diagnosed with the disease as the frequency of childhood obesity rises.
Type 2 diabetes can often be controlled without insulin treatment through exercise, a proper diet, weight loss, and oral medications. That's why type 2 diabetes has also been called non-insulin-dependent diabetes.
Sub-types of diabetes type 2 may be determined by genetic factors and common traits in people who have the disease. However, more research is needed to determine if there are distinct sub-types, and if so, how further classification of type 2 diabetes might improve treatment.
The Metabolic Syndrome
Scientists have found that abdominal obesity is often accompanied by insulin resistance, increased blood glucose levels, high blood pressure (hypertension), low levels of high-density lipoprotein (HDL) cholesterol (the "good" cholesterol), and elevated triglycerides (another fat found in the bloodstream). This cluster of abnormalities, known as the metabolic syndrome, is an important risk factor not only for diabetes but also for heart disease and stroke.
Doctors are starting to pay more attention to the metabolic syndrome because its presence often suggests that diabetes is starting to develop. If you have a large waist circumference and unhealthy HDL and triglyceride levels, your doctor may order a test of your blood glucose levels after you have fasted for at least eight hours.
Anyone with a fasting blood glucose reading of 100–125 mg/dL has prediabetes - lood glucose levels higher than normal but not high enough for a diagnosis of diabetes. About 54 million Americans have prediabetes. Without lifestyle changes or medication, many of them will develop type 2 diabetes within 10 years.
Some women develop type 2 diabetes during pregnancy (a condition called gestational diabetes). Although the diabetes goes away after childbirth, studies show that these women have an increased risk of developing diabetes later in life.