DIABETES

Diabetes is a life-long disease marked by high levels of sugar in the blood.

Causes, incidence, and risk factors

Diabetes can be caused by too little insulin (a hormone produced by the pancreas to control blood sugar), resistance to insulin, or both.

To understand diabetes, it is important to first understand the normal process of food metabolism. Several things happen when food is digested:

• A sugar called glucose enters the bloodstream. Glucose is a source of fuel for the body.
• An organ called the pancreas makes insulin. The role of insulin is to move glucose from the bloodstream into muscle, fat, and liver cells, where it can be used as fuel.

People with diabetes have high blood sugar. This is because their pancreas does not make enough insulin or their muscle, fat, and liver cells do not respond to insulin normally, or both.

There are three major types of diabetes:

• Type 1 diabetes is usually diagnosed in childhood. The body makes little or no insulin, and daily injections of insulin are needed to sustain life.
• Type 2 diabetes is far more common than type 1 and makes up most of all cases of diabetes. It usually occurs in adulthood. The pancreas does not make enough insulin to keep blood glucose levels normal, often because the body does not respond well to the insulin. Many people with type 2 diabetes do not know they have it, although it is a serious condition. Type 2 diabetes is becoming more common due to the growing number of older Americans, increasing obesity, and failure to exercise.
• Gestational diabetes is high blood glucose that develops at any time during pregnancy in a woman who does not have diabetes.

Diabetes affects more than 20 million Americans. About 54 million Americans have prediabetes. There are many risk factors for diabetes, including:

• A parent, brother, or sister with diabetes
• Obesity
• Age greater than 45 years
• Some ethnic groups (particularly African Americans, Native Americans, Asians, Pacific Islanders, and Hispanic Americans)
• Gestational diabetes or delivering a baby weighing more than 9 pounds
• High blood pressure
• High blood levels of triglycerides (a type of fat molecule)
• High blood cholesterol level
• Not getting enough exercise

The American Diabetes Association recommends that all adults over age 45 be screened for diabetes at least every 3 years. A person at high risk should be screened more often.

Symptoms

High blood levels of glucose can cause several problems, including frequent urination, excessive thirst, hunger, fatigue, weight loss, and blurry vision. However, because type 2 diabetes develops slowly, some people with high blood sugar experience no symptoms at all.

Symptoms of type 1 diabetes:

• Increased thirst
• Increased urination
• Weight loss in spite of increased appetite
• Fatigue
• Nausea
• Vomiting

Patients with type 1 diabetes usually develop symptoms over a short period of time, and the condition is often diagnosed in an emergency setting.

Symptoms of type 2 diabetes:

• Increased thirst
• Increased urination
• Increased appetite
• Fatigue
• Blurred vision
• Slow-healing infections
• Impotence in men

Signs and tests

A urine analysis may be used to look for glucose and ketones from the breakdown of fat. However, a urine test alone does not diagnose diabetes. The following blood glucose tests are used to diagnose diabetes:

• Fasting blood glucose level -- diabetes is diagnosed if higher than 126 mg/dL on two occasions. Levels between 100 and 126 mg/dl are referred to as impaired fasting glucose or pre-diabetes. These levels are considered to be risk factors for type 2 diabetes and its complications.
• Random (non-fasting) blood glucose level -- diabetes is suspected if higher than 200 mg/dL and accompanied by the classic symptoms of increased thirst, urination, and fatigue. (This test must be confirmed with a fasting blood glucose test.)
• Oral glucose tolerance test -- diabetes is diagnosed if glucose level is higher than 200 mg/dL after 2 hours (This test is used more for type 2 diabetes.)

You should also ask your doctor how often to you need your hemoglobin A1c (HbA1c) level checked. The HbA1c is a measure of average blood glucose during the previous 2 to 3 months. It is a very helpful way to determine how well treatment is working.

Ketone testing is another test that is used in type 1 diabetes. Ketones are produced by the breakdown of fat and muscle, and they are harmful at high levels. The ketone test is done using a urine sample. High levels of blood ketones may result in a serious condition called ketoacidosis. Ketone testing is usually done at the following times:

• When the blood sugar is higher than 240 mg/dL
• During acute illness (for example, pneumonia, heart attack, or stroke)
• When nausea or vomiting occur
• During pregnancy