The largest threat faced by people with diabetes is the threat of artery disease. Artery damage can lead to heart attack, stroke, and, in extreme cases, a need for amputations caused by inadequate circulation in the legs. Diabetics are two to four times more likely than others to have a heart attack or a stroke. Many diabetics have a family member who has had a heart attack or stroke at a young age, placing them in a known risk group for heart disease before diabetes is even diagnosed. But family history is only one of several heart risks that are common among diabetics.

Why are diabetics so prone to artery disease? People with diabetes are more likely than others to develop additional heart risks (such as high blood pressure, obesity, and high cholesterol). When it comes to heart-disease risks, people with diabetes commonly receive an unfortunate "package deal," so that instead of one heart-disease risk, they have a collection.

When several heart- or artery-disease health risks occur together in one person, they present a powerful health threat and are known as the metabolic syndrome (also called syndrome X or insulin-resistance syndrome).

Metabolic syndrome is very common among diabetics. If you have type 2 diabetes, you are more likely to have each of the following risks. It is common for a person with diabetes to have all of them.

• Insulin resistance — Researchers have not proven it, but many suspect that insulin resistance (the cause of type 2 diabetes) can be the source of all other risks that follow in this list, since in many people insulin resistance shows up first. Some medicines for diabetes reduce insulin resistance, and these medicines may do a better job of preventing artery disease than medicines that lower blood sugar in other ways.
• Poorly controlled blood sugar — Artery damage in diabetes occurs faster if blood-sugar levels stay high. Careful control of blood sugar helps to protect against artery damage.
• High blood pressure — More than 60 percent of people with type 2 diabetes have high blood pressure, compared with much lower rates in the rest of the population.
• Cholesterol problems — A common cholesterol pattern in type 2 diabetes is a high triglyceride level and low HDL cholesterol level. The other cholesterol type, LDL (the "bad" cholesterol), often is present in an especially dangerous form, made up of small, dense molecules that make arteries highly vulnerable to developing a blood clot blockage.
• Obesity — It is especially risky to have excess fat deposits in the abdomen or abdominal organs. A waist circumference more than 40 inches in a man or more than 35 inches in a woman is worrisome. Some diabetics have a normal waist size but have internal organs (such as the liver) that are enlarged with fat deposits.
• Blood-clot risks — Research studies of most individuals with the metabolic syndrome show high levels of a chemical called plasminogen activator inhibitor 1. Although this chemical is not routinely tested or measured, it is known to promote blood-clot formation. A blood clot is what triggers a heart attack or a stroke, so blood-clot "chemistry" may contribute to the high risk for heart attack and stroke emergencies in people with metabolic syndrome.
• Exaggerated effects of smoking — Smoking is not more common among people with the metabolic syndrome, but it is more dangerous in this group than in any other. Smoking strongly multiplies your risk of artery disease. If you have most or all of the risks above, smoking will further increase your risk of a heart attack or premature death by about 40 percent.