Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced. It is a serious, lifelong condition. The three main types of diabetes are:
Type 1 diabetes results from the body's failure to produce insulin, and presently requires the person to inject insulin.
Type 2 diabetes results from insulin resistance, a condition in which cells fail to use insulin properly, sometimes combined with an absolute insulin deficiency.
Gestational diabetes is when pregnant women, who have never had diabetes before, have a high blood glucose level during pregnancy. It may precede development of type 2 diabetes.
Glucose levels vary before and after meals, and at various times of day. The normal range for most people (fasting adults) is about 80 to 110 mg/dl. A subject with a consistent range above 126 mg/dl is generally held to have hyperglycemia, whereas a consistent range below 70 mg/dl is considered hypoglycemic. In fasting adults, blood plasma glucose should not exceed 126 mg/dL. Sustained higher levels of blood sugar cause damage to the blood vessels and to the organs they supply, leading to the complications of diabetes.
All forms of diabetes have been treatable since insulin became available in 1921, and type 2 diabetes may be controlled with medications. Both types 1 and 2 are chronic conditions that usually cannot be cured. Gestational diabetes usually resolves after delivery. Diabetes without proper treatments can cause many complications. Serious long-term complications include cardiovascular disease, chronic renal failure, and diabetic retinopathy (retinal damage).
Adequate treatment of diabetes is thus important, as well as blood pressure control and lifestyle factors such as smoking cessation and maintaining a healthy body weight.