For a variety of reasons, diabetes is increasing in the American pop- ulation at an alarming rate, even among younger people. Most authorities place most of the blame on the increase in overweight and obesity, along with a sedentary lifestyle. Diabetes is a serious disease in which the body does not produce or properly use a hormone called insulin. Produced in the pancreas, insulin is necessary to turn the sug- ars in the blood and in food into energy. In a person with diabetes, because insulin is de?cient or not working well, sugars (glucose) build
up to dangerously high levels in the blood.
There are two types of diabetes: type 1, also known as juvenile diabetes, and type 2, the most common form, usually diagnosed in adults. In a person with type 2 diabetes, the body does not use its sup- ply of insulin ef?ciently—a condition called insulin resistance. At ?rst the body can compensate by making more insulin. With time, however, the pancreas begins to fail and loses its ability to make enough insulin to overcome the body’s resistance to insulin. Once this occurs, blood sugar levels rise to unhealthy levels. In this section, the focus is on type 2 diabetes and its role as a major risk factor in the development of car- diovascular disease.

The Link between Diabetes and Heart Disease

Diabetes can lead to many serious medical problems, but the most life-threatening of these is cardiovascular disease. Most people with diabetes—about two out of three—die of heart disease, stroke, or peripheral vascular disease. Treatment, through lifestyle changes and one particular medication (metformin), can help control diabetes and also reduce the risk of heart disease. With more people developing dia- betes or its precursor, prediabetes (see below), it is important to get the message across that diabetes and heart disease are very strongly linked. The sooner you begin to control prediabetes or diabetes and reduce your risk of heart disease, the healthier and longer your life will be.
Diabetes appears to lead to heart disease through the process of ath- erosclerosis, which is a narrowing of the arteries caused by the buildup of plaque deposits, beginning with damage to the inner layer of the artery walls (the endothelium). The damaged walls promote the accu- mulation of lipids that develop into plaque, and the plaque buildup increases the likelihood of blood clots. Atherosclerosis can lead to a heart attack (when the blood supply to your heart muscle is cut off), coronary artery disease (when the blood supply to your heart is reduced), peripheral artery disease (when blood vessels in your legs are blocked), or a stroke (when a blood clot cuts off the blood supply to your brain). Although the entire disease process is not fully understood, diabetes may contribute to the initial damage to the endothelium, impair the ability of the artery walls to expand to accommodate blood ?ow, and render the body prone to make clots.
Some groups, including people of African American, Hispanic, or Native American descent, are at greater risk of developing diabetes because of their genetic makeup. Those with a parent or sibling with diabetes are at the highest risk. For reasons that are unclear, diabetes is more common and more severe in women than in men. But there is also a group of factors often typical of people with diabetes: obesity, physi- cal inactivity, high blood pressure, and high cholesterol. All of these factors also contribute to the development of heart disease.


As more of the U.S. population develops diabetes or the insulin resist- ance syndrome associated with it , doctors have become more aggressive about diagnosing and treating it, or preferably preventing it in the ?rst place. A new term, prediabetes, has sprung up to identify people whose blood glucose levels are higher than normal but not high enough to be diagnosed as diabetes. Both the oral glucose tolerance test and the fasting plasma glucose test measure your blood glucose level (in milligrams per deciliter, or mg/dL) after you have fasted overnight. Either test can be used, but they result in differ- ent readings (see box on page 108).
If you are overweight and age 45 or older, ask your doctor to arrange a test for prediabetes at your next routine physical examination. If you are at a healthy weight and are 45 or older, you can ask your doctor if a test is appropriate. If you are younger than 45 and overweight, your doctor may recommend a test, depending on the presence of other risk factors such as a family history of diabetes, high blood pressure, or high cholesterol readings.
If you are in the prediabetes range, you can and should do something about it right away to prevent or delay the development of diabetes. Many people can return their blood glucose levels to normal with relatively small changes in lifestyle alone. You can bene?t from even a modest weight loss of 5 to 10 percent of your body weight. If you can’t get down to your ideal weight, even a loss of 10 or 15 pounds can make a signi?cant difference. Similarly, increasing your level of activity to just moderate exercise (like walking) for 30 minutes a day is enough to make a difference. It’s worth it to change your lifestyle at this early stage. Your doctor will also talk to you about other risk factors such as high blood pressure, high cholesterol, and smoking.

If You Have Diabetes

Having diabetes means that you are at much higher risk for developing heart and peripheral vascular disease (in your legs). You and your doc- tor will closely monitor your diabetes (by regularly measuring your blood glucose levels) and your blood pressure and cholesterol levels. Taking care of your heart will involve lifestyle changes including a healthful diet (see pages 83–98); losing weight or making sure you don’t gain too much ; quitting smoking if you smoke now; keeping your alcohol consumption moderate, if you drink at all; and perhaps taking medication, also.

What Is Insulin Resistance Syndrome?

Insulin resistance syndrome, also called metabolic syndrome, is a combination of harmful health characteristics that dramatically increases the likelihood that a person will develop either type 2 diabetes, cardiovascular disease, or both. The syndrome is on the rise in the United States; more than one in four Amer- icans has it. The underlying causes of insulin resistance syndrome and its increase in the U.S. population are overweight or obesity, a sedentary lifestyle, and some genetic factors. You are considered to have the syndrome if you have three or more of the following characteristics:
• An accumulation of fat around the waist (an apple shape, see page
102): a waist measurement of more than 40 inches for a man or 35 inches for a woman
• A high triglyceride level (see page 29): more than 150 mg/dL
• A low “good” HDL cholesterol level: less than 40 mg/dL for a man or less than 50 mg/dL for a woman
• A blood pressure level of 130/85 mm Hg or more
• A high fasting glucose level (see page 108), an indicator of insulin resistance: 110 mg/dL or more