Perhaps the most important fact to recognize about diabetes - a disorder that affects about 16 million Americans - is that a great many people who have the disorder, as many as one half, don't know they have it. Like high blood pressure or high cholesterol, diabetes doesn’t produce symptoms right away in the vast majority of people affected by it. But in common with those two chronic disorders, diabetes can be detected before symptoms appear - and it also can be controlled and in some cases prevented with straightforward lifestyle measures.

Diabetes is a metabolic disorder characterized by a breakdown in the body's ability to utilize glucose efficiently. Glucose is the main type of sugar produced when foods are digested, and all cells in the body need glucose for energy. But most cells can absorb adequate glucose only in the presence of the hormone insulin, which is produced by the pancreas.

A person who has diabetes either isn't producing enough insulin or isn’t able to utilize it efficiently - two underlying problems that have led medical experts to make a distinction between the two types of diabetes. In both types, initial symptoms are usually related to hyperglycemia, the medical term for high blood glucose. And in both types, high levels of excess sugar pass into the urine, a characteristic that gives the disorder its proper name, diabetes (Greek for "siphon") mellitus (Latin for "honey-sweet").

In type 1 diabetes, previously known as juvenile diabetes or insulin-dependent diabetes mellitus (IDDM), the body produces little or no insulin. This type of diabetes develops suddenly, usually in people under age 30 (the average age of onset is 12 to 14 years).

In type 2 diabetes, insulin production is normal or close to normal, but cells respond to insulin inefficiently - a condition called insulin resistance. Previously known as adult-onset diabetes and non-insulin dependent diabetes mellitus, or NIDDM, type 2 diabetes is far more common than type 1, accounting for at least 90 percent of cases. It develops gradually and primarily affects people older than 30, particularly individuals who are overweight. Only about 50 percent of people diagnosed with type 2 diabetes present with classic symptoms; the rest are diagnosed through routine screenings or during exams for unrelated medical problems.

The rise in type 2 diabetes in the United States has been dramatic. It is three times as common today as it was in 1960. This increase is due in large part to the fact that Americans are living longer, are becoming fatter, and are less physically active. Also, more people are being screened for the disease. About 800,000 cases are diagnosed each year.

Diabetes also develops in some women during pregnancy. Although gestational diabetes, as it is called, usually disappears after childbirth, it does increase a woman's risk of developing type 2 diabetes later in life.

Treating type 1 diabetes entails taking daily insulin injections, usually for life. Type 2 diabetes can be controlled with lifestyle measures if it is detected early enough. And in recent years there has been growing evidence that diet and exercise in particular may actually help prevent or delay the onset of the disease.With more advanced stages of type 2 diabetes, treatment with medications is usually necessary to control symptoms.

What Causes It?

The exact cause of diabetes is unknown. Type 1 diabetes is thought to be an autoimmune disorder, in which the body's immune system mistakenly attacks and damages the cells in the pancreas that produce insulin. Type 2 diabetes is clearly linked to obesity - most people with type 2 diabetes are significantly overweight. Heredity appears to play a role in both types, but figures more prominently in type 2 diabetes than in type 1. Certain racial and cultural groups are at increased risk of type 2 diabetes, including African-Americans, Hispanics, Native Americans, and Pacific Islanders.

Less commonly, diabetes can develop because of certain medical disorders that affect the pancreas or that increase the production of hormones that interfere with insulin action. Certain medications, such as corticosteroids, can increase the risk of type 2 diabetes.

Other causes of diabetes include frequent overeating, insulin deficiency, insulin resistance, high blood pressure and lack of exercise or physical activities.


The Complete Home Wellness Handbook

John Edward Swartzberg, M.D., F.A.C.P., Sheldon Margen, M.D., and the editors of the UC Berkeley Wellness Letter

Updated by Remedy Health Media

Publication Review By: the Editorial Staff at

Published: 10 Nov 2011

Last Modified: 31 Jul 2014