Overweight and obesity have been linked to increased risks of high blood pressure , high cholesterol , coronary heart disease (CHD) , stroke , and type 2 diabetes . But researchers are not yet sure whether excess weight directly increases the risk of CHD, independent of these risk factors. In other words, if your blood pressure and cholesterol levels are under control, do you still need to lose excess weight to help prevent CHD?

A new study in the January 11, 2006 issue of the Journal of the American Medical Association found that, compared with being normal weight, being obese during middle age significantly increases the risk of hospitalization or death from CHD and diabetes, independent of other risk factors.

About the Study

This large study included 17,643 men and women ages 31-64. At the start of the study, the researchers measured the participants’ height, weight, blood pressure, and cholesterol levels. The participants were divided into five levels of cardiovascular risk (low, moderate, intermediate, elevated, and high), based on blood pressure, cholesterol levels, smoking status, and use of blood pressure lowering or cholesterol lowering medications. Each risk category was then subdivided into three weight groups (normal weight, overweight, and obese), based on body mass index (BMI, a measure of weight in relation to height). The researchers followed the participants until they were older than 65, and tracked whether they were hospitalized or died from CHD or diabetes.

Within each risk category, overweight and obese participants were more likely to be hospitalized for or die from CHD and diabetes than their normal weight counterparts. For example, obese participants in the low risk group were 43% more likely to die from CHD and 11 times more likely to die from diabetes than normal weight participants.

This study is limited because height, weight, and risk factors were measured only once. It is possible that having a higher BMI in middle age led to the occurrence of other risk factors later in life, which may have contributed to the risks of hospitalization and death.

How Does This Affect You?

These findings suggest that your weight in middle age may have a significant impact on your risk of CHD and diabetes—the leading causes of death among older adults—after age 65. Obesity is not currently included in the Framingham Risk Score, a tool commonly used to calculate cardiovascular risk. This study suggests that weight at midlife should be considered when determining cardiovascular risk.

To reduce your risk of cardiovascular disease, it is important to eat a healthful diet, exercise regularly, and control your blood pressure and cholesterol levels. On top of that, this study adds to other evidence that advocates maintaining a healthful weight to reduce your risk of hospitalization and death from cardiovascular disease and diabetes.