Editor’s note: In this, the ninth article in our year-long series on diabetes, learn about diabetes’ most serious complication.

Diabetes and heart disease are closely linked. What is harmful for diabetes almost always makes heart disease worse; and vice versa. Both diseases are partly caused by, as well as helped by, lifestyle choices. Let’s examine this close relationship.

Diabetes is a complex disease. It can cause many complications, including blindness, amputations, kidney disease, and problems with teeth, skin and nerves. The most serious problem caused by diabetes is heart disease, also called cardiovascular disease (CVD).

If you have diabetes, your risk for heart disease or stroke is two to four times greater than for non diabetics. In fact, more than 65 percent of people with diabetes die from heart disease or stroke.

Even when people with diabetes have their glucose levels under control, they still have a higher risk of heart disease and stroke. According to the National Institutes of Health, that’s because they are more likely to have:

  • High blood pressure (hypertension), common in people with diabetes, doubles the risk for heart disease.
  • High blood fat (lipids) levels, including high LDL cholesterol, low HDL (the “good” type of cholesterol) and high triglycerides. Cholesterol problems are also common in people with premature heart disease.
  • Obesity – being overweight causes harmful changes to the heart and is closely linked to insulin resistance.
  • Insulin resistance (also called impaired insulin sensitivity) is a lipid disorder associated with diabetes and heart disease. Insulin resistance means the body blocks insulin from doing its job of converting food to energy. After eating, the normal process is for blood glucose levels to rise, triggering the body to produce insulin. The insulin travels throughout the body making fat and muscle cells absorb the excess glucose. It is stored for later use. However, people with insulin resistance have built up a tolerance to insulin so their bodies need more insulin after they eat. The body can produce more, but only for a while. Eventually, the body’s ability to produce enough insulin starts to wear out. The result is prediabetes or type 2 diabetes. The more insulin resistant a person is, the harder it is to manage diabetes. Medication is needed to get enough insulin into the body to achieve a healthy blood glucose level.
  • Lack of physical activity is also closely linked to heart disease, diabetes and insulin resistance.
  • Metabolic syndrome is a group of traits that puts people at risk for both heart disease and type 2 diabetes. Any three of these five traits will cause metabolic syndrome: carrying fat around your waist (35 inches or more in women; 40 inches or more in men); triglycerides of 150 mg. or higher; low levels of the good cholesterol (HDL); high blood pressure (BP) or high fasting blood glucose levels.

Diabetic heart disease develops in people with diabetes. Diabetes raises the risk of having more severe heart problems and heart problems that start at a younger age. Diabetic heart disease can include:

  • Coronary heart disease (CHD) is caused by plaque build-up inside the arteries (called atherosclerosis). CHD narrows the arteries that supply blood to the heart. The reduced blood flow increases the risk that blood clots will form. Clots can partially or completely block blood flow. High blood glucose levels over time increase the chance of fatty deposits on the insides of blood vessel walls. CHD can also cause irregular heartbeats (arrhythmias), heart attack or death.
  • Coronary artery disease (CAD), also known as “hardening of the arteries,” is caused by a hardening or thickening of blood vessel walls that go to your heart. This causes the blood supply to be reduced or, if cut off, causes a heart attack. Insulin resistance can cause artery wall thickening.
  • Heart failure means that your heart cannot pump enough blood. You may tire more easily and have to reduce activities. Heart failure may be caused by heart attack, CAD or high BP. CHD can weaken the heart and also lead to heart failure.
  • Cardiomyopathy refers to several diseases of the heart muscle. It can damage the heart’s structure and function as the heart muscle becomes enlarged, thick or rigid. This can lead to heart failure and arrhythmias.
  • Congestive heart failure causes fluid to build up inside body tissues, such as the lungs, making breathing difficult.
  • Peripheral artery disease (PAD) causes narrowed or blocked arteries that supply blood to the arms and legs, and increases heart attack and stroke risks.
  • Cerebral vascular disease (CVD) affects blood flow to the brain, leading to strokes and transient ischemic attacks (TIAs). CVD is caused by narrowing, blocking or hardening of the blood vessels that go to the brain, or by high BP. A TIA is a temporary blockage of a blood vessel to the brain. TIAs increase the risk of stroke in the future.
  • Stroke results when the blood supply to the brain is suddenly cut off, caused by a blood vessel that is blocked or bursts. A stroke can also be caused by a bleeding blood vessel in the brain – an aneurysm.

What you can do:

Adopt a team approach. If you regularly see a cardiologist or other heart disease specialist, be sure he or she is part of your treatment team. Other treatment team members may include an endocrinologist, dietitian, diabetes educator, pharmacist, dentist, eye doctor (ophthalmologist) and foot doctor (podiatrist). Your doctor will determine if you have diabetic heart disease with a series of screening tests, including BP check, urine test, and blood tests for fats, cholesterol, sugar and proteins in your blood. You may have a chest X-ray to look at your heart, lungs, blood vessels and for signs of heart failure. An EKG is a painless test that looks at your heart’s electrical activity. A stress test tells your doctor you well your heart works during physical activity.

Have blood pressure checked regularly, at least monthly. A study published in 2008 found that almost 70 percent of people with diabetes had BP greater than or equal to 140/90 or used prescription medications for hypertension. Most doctors want BP below 140/90. But check with your doctor about what’s the best BP range for your health. Good BP control can reduce the risk of heart disease among people with diabetes by 33 to 50 percent. High BP causes your heart to work harder to pump blood, straining the heart, damaging blood vessels and increasing your risk of heart attack, stroke and other complications of diabetes. Research has found that reducing the bottom BP number (diastolic reading) from 90 to 80 can reduce the risk of heart attacks and other major heart disease events by 50 percent. BP control is, for most people, easy to control with medication and/or lifestyle changes.

Have cholesterol checked at least once a year, including triglyceride levels. Improved control of cholesterol (the amount of fat in your blood) can reduce cardiovascular complications by up to 50 percent. Know the cholesterol and BP numbers your doctor wants you to maintain.

Take your medications exactly as your doctor prescribes. People with diabetes often take medications to manage diabetes, cholesterol and heart disease. Metformin, a drug commonly used to treat diabetes, helps prevent thickening of artery walls. Your doctor will probably prescribe a statin drug to help with cholesterol and heart disease. Keep your immunizations current, especially an annual flu shot and pneumonia vaccines for people over age 65.

Quit smoking immediately. This is the single most important thing you can do to protect your heart. Smoking doubles your risk of getting heart disease. It reduces the blood flow to your legs and feet, which can cause infections and possible amputations. Smoking also directly affects the health of your blood vessels, eyes, nerves and kidneys. There are many ways to quit. Ask your doctor what’s best for you – nicotine gum, medications, support groups or telephone counseling. Call 1-800-QUIT-NOW to speak to a trained counselor who can explain the many free resources to help to quit for good.

Be active every day. Exercise is the best way to reduce insulin resistance, in both the short and long term. Exercise builds muscle that can absorb blood glucose. It also opens up an alternative gateway for glucose to enter muscle cells without insulin. Being active also helps you keep your weight at a healthy level.

Lose weight to help with insulin resistance. Foods that are low in fat and high in carbohydrates can make insulin resistance worse. The latest recommendation for people with diabetes is to have a body mass index (BMI) at or below 23. Obesity is a major risk for diabetes and heart disease, and is strongly associated with insulin resistance. Extra belly fat increases the production of bad cholesterol. Start today to lose at least 5 percent of your body weight through portion control, better food choices and regular exercise.