How can diabetes increase the risk of heart disease?

Diabetes is a disease that makes it hard for your body to use sugar. Extra glucose (sugar) in your blood may damage your arteries. Untreated diabetes increases your risk for a heart attack or stroke.

The relationship between diabetes and heart disease is clear, but the causes are complex. Over time, too much glucose in the blood damages nerves and blood vessels. This in turn can cause heart disease and other cardiovascular diseases. Damage to the arteries leading to the brain can result in stroke. In addition, damage to the blood vessels in the legs can result in poor circulation and increase the risk of foot ulcers and amputations, while damage to the blood vessels that supply blood to the kidneys can cause kidney failure. Damage to the small blood vessels in the eye can eventually cause blindness.

High blood glucose levels do not fully explain the relationship between diabetes and cardiovascular disease. People with diabetes also tend to have low-level inflammation of the lining of the arteries, which can interfere with the proper function of the blood vessels and make them more susceptible to developing atherosclerotic plaque—buildup of a fatty substance that narrows the artery. In addition, with diabetes there is a greater tendency for blood cells to clump together to form blood clots within the blood vessels. A blood clot that blocks the arteries supplying blood to the heart causes a heart attack, while a blood clot that blocks an artery supplying blood to the brain causes a stroke.

The blood vessels in patients with diabetes are also more vulnerable to the harmful effects of other heart disease risk factors. These risk factors include: 

  • Smoking
  • High blood pressure
  • Abnormal blood lipids - High LDL (bad) cholesterol
    • High triglycerides
    • Low HDL (good) cholesterol
  • Obesity
  • Lack of physical activity
  • Poorly controlled blood glucose levels
  • Insulin resistance (common in Type 2 diabetes)

More than 90 percent of people with diabetes have at least one of these additional heart disease risk factors.

Diabetes increases the risk of heart disease by accelerating the damage of the vessels in our body, especially the heart. It not only accelerates the formation of plaque, but it also causes a narrowing and a "shrinking" of the arteries that feed our bodies including our hearts. This rapid regression of disease is diffuse in nature and causes more complications for the doctors trying to treat the disease. Patients do not do as well with stents or bypass surgery and the long-term prognosis is made worse both because of the disease affecting the heart, but also the fact that the disease is associated with more damage to the brain causing strokes, kidneys causing the need for dialysis after the kidneys fail, and for amputation because of the narrowing of the arteries feeding the legs. Aggressive care of diabetics is extremely valuable in fighting this disease.

Dr. Rachel D. Keever, MD
Cardiologist (Heart Specialist)

Because women with type 2 diabetes have elevated levels of insulin in their bloodstreams, they're more prone to blood clots. This may explain why 75 percent of type 2 diabetics die of heart attacks or strokes. The risk of death from heart disease is three times greater for women with diabetes. Type 2 diabetes doubles the risk of a second heart attack in women but not in men.

Diabetes is a disease that affects blood vessels. While we hear about the blood vessels in the eyes or the feet more commonly in diabetes, all blood vessels are affected. Usually we see the effect on the small vessels, but we also see an effect on the large vessels of the heart. People with diabetes, independent of other problems, have more heart attacks.

Having diabetes increases your risk for heart disease in comparison to women without diabetes. To determine exact percentage of risk, factors such as any known history of heart disease, stroke or peripheral vascular disease must be taken blood pressure, cholesterol, age, smoking and into account.

An adult diagnosed with diabetes has the same high cardiac risk as someone who has already had a heart attack. At least 65 percent of people with diabetes will die from some type of cardiovascular disease—a death rate that is two to four times that of the general population. Diabetes can also cause chronic kidney disease, which, in turn, can increase the risk of cardiovascular disease even more.

Diabetes mellitus can increase the risk of heart disease because it raises cholesterol levels and increases atherosclerosis (hardening of the arteries). Furthermore, diabetics often are overweight thereby exacerbating their diabetes and increasing heart disease risks.

Diabetes is classified into two types. Type I (also called insulin dependent diabetes) and Type II (called non-insulin dependent diabetes). In Type I diabetes, little or no insulin is produced by the pancreas. This condition, therefore, is treated with insulin. In Type II diabetes, the pancreas still produces insulin but the body is resistant to it.

To treat type II diabetes, doctors recommend weight loss, a modified diet and an exercise regimen. In cases where these methods are unsuccessful, certain medications (called Oral Hypoglycemics) are used. These medications usually work because they increase the secretion of insulin by the pancreas. However, if these medications fail, insulin may be necessary.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.