There are three main types of diabetes: type 1, type 2, and gestational diabetes. Pancreatic disease and/or damage can also cause diabetes if the insulin-producing beta cells are destroyed.

Type 1 diabetes , which used to be called insulin dependent or juvenile diabetes, makes up about 10% of the diabetes cases in the United States. Most cases of type 1 diabetes are diagnosed in those under the age of 30. Symptoms often develop abruptly and the diagnosis is often made in an emergency room setting. The patient may be seriously ill, even comatose, with very high glucose levels and high levels of ketones (ketoacidosis). Type 1 diabetics make very little or no insulin. Any insulin-producing beta cells they do have at the time of diagnosis are usually completely destroyed within 5 to 10 years, leaving them entirely reliant on insulin injections to live.

The exact cause of type 1 diabetes is unknown, but a family history of diabetes, viruses that injure the pancreas, and autoimmune processes , in which the body’s own immune system destroys the beta cells, are all thought to play a role. Type 1 diabetics may have more severe medical complications sooner than other diabetics. For instance, about 40% of those with type 1 diabetes will develop serious kidney problems leading to kidney failure by the age of 50.

Those with Type 2 diabetes, which used to be known as non-insulin dependent diabetes or adult onset diabetes, do make their own insulin but it is either not in a sufficient amount to meet their needs or their body has become resistant to its effects. At the time of diagnosis, those with type 2 diabetes will frequently have both high glucose levels and high insulin levels, but they may not have any symptoms. About 90% of diabetes cases in the United States are type 2. It generally occurs later in life, in those who are obese, sedentary, and over 45 years of age. Risk factors include:

• Obesity
• Lack of exercise
• Family history of diabetes
• Pre-diabetes
• Ethnicity: African-American, Hispanic-American, Native American, Asian-American, Pacific Islander
• Gestational diabetes during pregnancy or baby weighing more than 9 pounds
• High blood pressure
• High triglycerides, high cholesterol, low HDL

Since Americans are becoming more obese and not getting enough regular exercise, the number of those diagnosed with type 2 diabetes is continuing to rise and it is developing at younger ages.

Gestational diabetes is a form of hyperglycemia seen in some pregnant women, usually late in their pregnancy. The cause is unknown, but it is thought that some hormones from the placenta increase insulin resistance in the mother, causing elevated blood glucose levels. Most women are screened for gestational diabetes between their 24th and 28th week of pregnancy. If gestational diabetes is found and not addressed, the baby is likely to be larger than normal, be born with low glucose levels, and be born prematurely. The hyperglycemia associated with gestational diabetes usually goes away after the baby's birth, but both the women diagnosed with gestational diabetes and their babies are at an increased risk of eventually developing type 2 diabetes. A woman who has gestational diabetes with one pregnancy will frequently experience it with subsequent pregnancies.

Pre-Diabetes is a new term for impaired fasting glucose or impaired glucose tolerance. It is characterized by glucose levels that are higher than normal, but not high enough to be diagnostic of diabetes. Recent data suggest that at least 54 million adults in the U.S. had pre-diabetes in 2002. Usually those who have pre-diabetes do not have any symptoms but, if nothing is done to lower their glucose levels, they are at great risk of developing diabetes within about 10 years. Experts are recommending that everyone who has any of the risk factors for type 2 diabetes be tested for pre-diabetes.