Last Updated: 2008-03-17 10:45:34 -0400 (Reuters Health)

NEW YORK (Reuters Health) – Obese and overweight individuals are less likely to die after a stroke than are their normal-weight peers, new research suggests.

According to the authors, the link between obesity and poor disease outcomes, in general, is usually mediated through the presence of other conditions. Obese individuals who are otherwise healthy may fare just as well as, or perhaps in the case of stroke, better than their lean counterparts.

The findings, which are reported in the February 29th online issue of Neuroepidemiology, are based on an analysis of data from 21,884 stroke patients in Denmark who had their body mass index determined. The subjects were followed for up to 5 years after their stroke.

The patients were placed into one of five BMI groups: underweight (BMI < 18.5), normal weight (18.5 to 24.9), overweight (25.0 to 29.9), obese (30.0 to 34.9), and severely obese (35 and greater).

Compared with the normal weight individuals, the overweight, obese and severely obese subjects were 27%, 16%, and 16% less likely, respectively, to die during follow-up, lead author Dr. Tom Skyhoj Olsen, from Hvidovre University Hospital and colleagues note.

Underweight patients, by contrast, were 63% more likely to die, the report indicates.

High BMI remained a predictor of post-stroke survival, independent of sex, age, civil status, stroke severity, stroke subtype and risk factors.

"Recently, the use of BMI as a risk factor marker in primary and secondary prevention of cardiovascular disease has been questioned," the authors state. "The result of our study lends support to the suggestion from (prior) studies of a redefinition of overweight and obesity, for example by the waist-to-hip ratio."

Neuroepidemiology 2008;30:93-100.

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