Excess Weight Can Lead to Stroke

Source: Tufts University
February 14, 2003

You may know that being overweight can increase your risk of a heart attack. A recent study has linked excess weight to an increased risk of stroke, as well. Stroke, which occurs when blood flow to the brain tissue is disrupted by either a blockage or a hemorrhage, can cause serious mental and physical disabilities, as well as death. The report was published in the Archives of Internal Medicine.

Associating BMI and stroke risk

Boston-area researchers followed 21,414 men enrolled in the Physicians' Health Study in an effort to study the association between stroke risk and body mass index (BMI), a commonly used measurement to classify people's weight status.

The subjects were male physicians between the ages of 40 and 84, who had no previous history of heart attack, stroke, or cancer. At the beginning of the study and during 12.5 years of follow-up, the subjects filled out detailed questionnaires, supplying information about their height, weight, and medical history, among other things.

The researchers used the subjects' self-reported weight and height measurements to calculate their BMIs. They then used patient reports and medical records to determine how many men experienced stroke during the course of the study.

As BMI goes up, so does the stroke risk

A total of 747 strokes occurred during the study. The men with the highest BMIs (30 or more, classified as "obese") were at significantly higher risk for stroke than were men with the lowest BMIs (< 23, "normal weight"). In addition, when the researchers examined the BMI on a continuum, they found that as BMI increased, so did the stroke risk. Each unit increase in BMI was associated with a 6% increase in stroke risk in the study population.

How does weight influence stroke risk?

It is unknown from these results what the potential mechanisms are behind the association between increased BMI and stroke risk. Other factors that might influence stroke risk, such as high blood pressure and high cholesterol level, were taken into account and ruled out as factors that explained the increase in risk associated with higher BMIs. This suggests that BMI had an effect independent of these factors.

It could be that excess fat tissue increases levels of certain substances in the body that may contribute to blood clots that cause strokes. This theory, however, remains under study.

It's important to remember that this study was conducted in a relatively homogenous group of people - male physicians - so that the results cannot necessarily be applied to women or to more diverse populations.

Another good reason for weight control

Nevertheless, the results underscore the advice of many health professionals and organizations that advocate weight control. In the case of stroke, weight control may play an important preventive role. According to the authors of the study, treatment of stroke is often limited, so that prevention may be crucial in reducing the rates of death and disability that occur from stroke.

Source

• Body mass index and the risk of stroke in men. T. Kurth, M. Gaziano, K. Berger,  et al., Arch Int Med, 2002, vol. 162, pp. 2557--2562

Related Links
Stroke Can be Prevented
Fitness Helps Men Avoid Stroke
Excess Weight Adds Health Problems
Tool: Find Out Your BMI
Weighing Your Longevity Series
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