Diabetes is a life-long disease marked by high levels of sugar in the blood. It can be caused by too little insulin (a hormone produced by the pancreas to regulate blood sugar), resistance to insulin, or both.
Causes, incidence, and risk factors:
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 glucose. 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 required to sustain life. Without proper daily management, medical emergencies can arise.
Type 2 diabetes is far more common than type 1 and makes up 90% or more of all cases of diabetes. It usually occurs in adulthood. Here, 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 person who does not have diabetes.
Diabetes affects about 18 million Americans. There are many risk factors for diabetes, including:
A parent, brother, or sister with diabetes
Age greater than 45 years
Some ethnic groups (particularly African-Americans 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
The American Diabetes Association recommends that all adults be screened for diabetes at least every three years. A person at high risk should be screened more often.
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:
Weight loss in spite of increased appetite
Symptoms of type 2 diabetes:
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.)
Patients with type 1 diabetes usually develop symptoms over a short period of time, and the condition is often diagnosed in an emergency setting. In addition to having high glucose levels, acutely ill type 1 diabetics have high levels of ketones.
Ketones are produced by the breakdown of fat and muscle, and they are toxic at high levels. Ketones in the blood cause a condition called “acidosis” (low blood pH). Urine testing detects both glucose and ketones in the urine. Blood glucose levels are also high.
This version of the Encyclopedia has no treatment information. Please discuss any and all treatment options for your condition with your healthcare professional.
For additional information, see diabetes resources.
The risks of long-term complications from diabetes can be reduced.
The Diabetes Control and Complications Trial (DCCT) studied the effects of tight blood sugar control on complications in type 1 diabetes. Patients treated for tight blood glucose control had an average HbA1c of approximately 7%, while patients treated less aggressively had an average HbA1c of about 9%. At the end of the study, the tight blood glucose group had dramatically fewer cases of kidney disease, eye disease, and nervous system disease than the less-aggressively treated patients.
In the United Kingdom Prospective Diabetes Study (UKPDS), researchers followed nearly 4,000 people with type 2 diabetes for 10 years. The study monitored how tight control of blood glucose (HbA1c of 7% or less) and blood pressure (less than 144 over less than 82) could protect a person from the long-term complications of diabetes.
This study found dramatically lower rates of kidney, eye, and nervous system complications in patients with tight control of blood glucose. In addition, there was a significant drop in all diabetes-related deaths, including lower risks of heart attack and stroke. Tight control of blood pressure was also found to lower the risks of heart disease and stroke.
The results of the DCCT and the UKPDS dramatically demonstrate that good blood glucose and blood pressure control, many of the complications of diabetes can be prevented.
Emergency complications include diabetic hyperglycemic hyperosmolar coma.
Long-term complications include:
Peripheral vascular disease
Hyperlipidemia, hypertension, atherosclerosis, and coronary artery disease
Calling your health care provider:
Go to the emergency room or call the local emergency number (such as 911) if symptoms of ketoacidosis occur:
Increased thirst and urination
Deep and rapid breathing
Loss of consciousness
Go to the emergency room or call the local emergency number if symptoms of extremely low blood sugar (hypoglycemic coma or severe insulin reaction) occur:
Lack of coordination
Convulsions or unconsciousness
Maintaining an ideal body weight and an active lifestyle may prevent the onset of type 2 diabetes. Currently there is no way to prevent type 1 diabetes.