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Obesity

When people have 20 percent (or more) extra body fat for their age, height, sex, and bone structure. Fat works against the action of insulin. Extra body fat is thought to be a risk factor for diabetes.

Obstetrician

A doctor who sees and gives care to pregnant women and delivers babies.

OGTT

See: Oral glucose tolerance test.

Ophthalmologist

A doctor who sees and treats people with eye problems or diseases.

Optometrist

A person professionally trained to test the eyes and to detect and treat eye problems and some diseases by prescribing and adapting corrective lenses and other optical aids and by suggesting eye exercise programs.

Oral Glucose Tolerance Test (OGTT)

A test to see if a person has diabetes. See: Glucose tolerance test.

Oral Hypoglycemic Agents

Pills or capsules that people take to lower the level of glucose (sugar) in the blood. The pills work for some people whose pancreas still makes some insulin. They can help the body in several ways such as causing the cells in the pancreas to release more insulin.

Six types of these pills are for sale in the United States. Four, known as "first-generation" drugs, have been in use for some time. Two types, called "second-generation" drugs, have been developed recently. They are stronger than first-generation drugs and have fewer side effects. All oral hypoglycemic agents belong to a class of drugs known as sulfonylureas. Each type of pill is sold under two names: one is the generic name as listed by the Food and Drug Administration; the other is the trade name given by the manufacturer. They are:

First-Generation Agents:

Generic Name: Tolbutamide
Trade Name: Orinase

Generic Name: Acetohexamide
Trade Name: Dymelor

Generic Name: Tolazamide
Trade Name: Tolinase

Generic Name: Chloropropamide
Trade Name: Diabinese

Second-Generation Agents:

Generic Name: Glipizide Trade Name: Glucotrol

Generic Name: Glyburide Trade Name: Diabeta, Micronase

Overt Diabetes

Diabetes in the person who shows clear signs of the disease such as a great thirst and the need to urinate often.