FACTBOX-Nearly 200 million people have diabetes

WASHINGTON (Reuters) - One of the top-selling diabetes drugs, Avandia, may cause heart attacks and other heart deaths, researchers said on Monday.

Diabetes is the sixth-leading cause of death in the United States, and millions of people around the world take insulin or other drugs to treat it.

Here are some facts about diabetes:

-- At least 194 million people worldwide have diabetes. The World Health Organization expects the number to rise to more than 300 million by 2025.

-- Diabetes is caused when the body fails to produce or properly use insulin, a hormone needed to convert sugar, starches and other food into energy needed for daily life.

-- There are two major types: Type 1 diabetes, formerly known as juvenile diabetes, an auto-immune disease in which the body does not produce any insulin, and the far more common Type 2 diabetes, formerly known as adult-onset diabetes, a metabolic disorder associated with obesity and a sedentary lifestyle.

-- Treatments include insulin, the sulfonylurea drugs and the meglitinide drugs, both of which stimulate the release of insulin; biguanides such as metformin, which shut off the liver's excess glucose production; thiazolidinediones such as Avandia, which help the body use insulin more effectively; and alpha-glucosidase inhibitors, which slow the breakdown of food into glucose.

-- The annual direct health-care costs of diabetes worldwide, for people in the 20-79 age bracket, are estimated to be in the range of $153 billion to $286 billion.