Stroke Risk May Fluctuates with Body Mass Index Changes

A healthy body mass index was associated with a higher ischemic stroke risk compared with a high body mass index.

Findings from a recent study suggest that types of strokes, ischemic and hemorrhagic, have a different risk profile that may be influenced by body mass index.

It is well-known that obesity increases stroke risks, specifically the common ischemic stroke. However, the relationship with hemorrhagic strokes and obesity has not previously been clear.

In a study published by Neurology, scientists examined the associations between a high body mass index and stroke. Included in the study were 1.3 million women in the UK with an average age of 57-years-old who were followed for 12 years.

Over the course of the study, 20,549 patients had a stroke. Of the 344,534 patients with a healthy body mass index (between 22.5 and 25%), only 2253 (0.7%) had an ischemic stroke, and 1583 (0.5%) had a hemorrhagic stroke.

Of the 228,274 patients with obesity (body mass index of 30 or more), 2393 (1%) had an ischemic stroke, and 910 (0.4%) had a hemorrhagic stroke. They found that each category of higher body mass index increased the risk of all types of strokes.

A 5-unit increase in body mass index was associated with a 21% increase in ischemic stroke risk, and a 12% increase in hemorrhagic stroke risk, according to the study. Interestingly, women with obesity were seen to have a higher risk of ischemic strokes compared with women with lower body mass indexes.

Although these women had a lower risk of the more serious hemorrhagic stroke, the overall stroke risk was not lessened with a higher body mass index.

“Higher body mass index, or BMI, was not associated with protection or reduced risk of total stroke,” said researcher Kathryn Rexrode, MD, MPH. “Obesity is a substantial stroke risk factor for all ages and even more alarming for young adults.”

These findings suggest that ischemic and hemorrhagic strokes may be associated with different risks, according to the study. A high body mass index has also been shown to accelerate brain aging by as much as 10 years; therefore, weight control may be an important factor in preventing adverse effects on the brain.

“It is important to understand the differences in risk factors for hemorrhagic and ischemic stroke,” Dr Rexrode concluded. “However, this report emphasizes the importance of obesity as a risk factor for total stroke. In order to improve public health, we need far-reaching efforts for the prevention and management of obesity.”