Diabetes is a chronic (lifelong) disease marked by high levels of sugar in the blood.
Currently, more than 29 million Americans have diabetes.
Causes, incidence, and risk factors
Insulin is a hormone produced by the pancreas to control blood sugar. Diabetes can be caused by too little insulin, resistance to insulin, or both.
To understand diabetes, it is important to first understand the normal process by which food is broken down and used by the body for energy. 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
Their muscle, fat, and liver cells do not respond to insulin normally
Both of the above
There are three major types of diabetes:
Type 1 diabetes is usually diagnosed in childhood. Many patients are diagnosed when they are older than age 20. In this disease, the body makes little or no insulin. Daily injections of insulin are needed. The exact cause is unknown. Genetics, viruses, and autoimmune problems may play a role.
Type 2 diabetes is far more common than type 1. It makes up most of diabetes cases. It usually occurs in adulthood, but young people are increasingly being diagnosed with this disease. The pancreas does not make enough insulin to keep blood glucose levels normal, often because the body does not respond well to 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 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. Women who have gestational diabetes are at high risk of type 2 diabetes and cardiovascular disease later in life.
There are many risk factors for type 2 diabetes, including:
Age over 45 years
A parent, brother, or sister with diabetes
Gestational diabetes or delivering a baby weighing more than 9 pounds
High blood cholesterol level
Not getting enough exercise
Polycystic ovary disease (in women)
Previous impaired glucose tolerance
Some ethnic groups (particularly African Americans, Native Americans, Asians, Pacific Islanders, and Hispanic Americans)
High blood levels of glucose can cause several problems, including:
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
Patients with type 1 diabetes usually develop symptoms over a short period of time. The condition is often diagnosed in an emergency setting.
Symptoms of type 2 diabetes: