Depression and Heart Disease in Diabetes

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Depression and all-cause and coronary heart disease mortality among adults with and without diabetes, by L.E. Egede, P.J. Nietert, and D. Zheng. Diabetes Care 28:1339–1345, 2005.

What is the problem and what is known about it so far?

Depression affects about 18 million adults, or about 9% of the U.S. population. People with depression are more likely to develop disabilities, miss work, be less productive, and spend more money and time on health care.

Studies have shown that there is a link between depression and diabetes. Ten to thirty percent of people with diabetes also have depression. Some people with diabetes who also have depression might be depressed about not being able to control their blood glucose levels, which can lead to complications, and having to pay more for health care.

Although studies have shown that many people with diabetes also have depression, there have not been any studies that link having diabetes and depression to a higher risk of death from all causes and from coronary heart disease.

Why did the researchers do this particular study?

The researchers wanted to find out if there was a connection between diabetes and depression and a higher risk of death from all causes and from coronary heart disease among people with and without diabetes.

Who was studied?

A total of 10,025 people from the National Health and Nutrition Examination Survey I (NHANES I) and the Epidemiologic Follow-Up Study (NHEFS) who were interviewed in 1982 and were still alive.

How was the study done?

Researchers interviewed people about their health in NHANES I and NHEFS between 1971 and 1975. The participants were interviewed again in 1982 and were asked questions about what medical conditions they had and whether they had depression, based on the Center for Epidemiologic Studies Depression Scale (CES-D). They were interviewed again in 1986, 1987, and 1992. The people studied were then divided into four groups:

• People who didn't have diabetes or depression
• People who didn't have diabetes but had depression
• People who had diabetes but didn't have depression
• People who had both diabetes and depression.

What did the researchers find?

The group of people with both diabetes and depression was more likely to be older, included more women and ethnic minorities, included more people who didn't exercise, included more people who were overweight or obese, and included more people who had a history of high blood pressure, heart disease, and stroke.

The people in this group were also more likely to be poorer, less educated, and less likely to be married than the people in the other three groups. This group also had the highest death rates; people without diabetes and depression had the lowest. The people who had diabetes had the highest death rates in general.

What were the limitations of the study?

There were five possible limitations to this study. First, the information was based on what people said in their interviews; second, depression wasn't clinically diagnosed; third, the people with diabetes were not divided into type 1 and type 2 diabetic groups; fourth, people who didn't have diabetes in 1982 may have developed it later but were still counted as not having diabetes; and fifth, the researchers did not have information about how long the people with diabetes had the disease or how severe it was or how severe their depression was.

What are the implications of the study?

People with diabetes should be checked to see if they have any symptoms of depression. Past studies have found that depression is associated with bad blood glucose control, lower quality of life, and spending more time and money on health care.

This study shows that people who have both diabetes and depression have a higher risk of death than people who have either diabetes or depression alone. Also, diabetes has been shown to be a leading cause of dying from coronary heart disease, and more studies are showing that people with depression also have a higher risk of dying from coronary heart disease.

FOR MORE INFORMATION

Diabetes, depression, and quality of life: a population study, by R.D. Goldney and colleagues. Diabetes Care 27:1066-1070, 2004.

Diabetes Burnout: What to Do When You Can’t Take it Anymore, by W.H. Polonsky (Alexandria, Va., ADA, 1999).
Available at http://store.diabetes.org

Depression

“Depression: A Different Kind of Low,” by S. Guzman. Diabetes Forecast, October 2004.