Mild Obesity Provides Better Survival Following Stroke

Overweight and mildly obese people have better 10-year survival after ischemic stroke compared with normal-weight peers, according to a new study.

Researchers at Boston University (BU; MA, USA) conducted a study that compared all- cause mortality in 3,128 participants of the Framingham Heart Study (FHS), who were stratified by body mass index (BMI) prior to their stroke, and followed for up to 10 years thereafter. The researchers then matched the stroke cases to other FHS participants of similar age, sex and BMI category (normal weight, overweight, or obese). They then separately analyzed both groups to see if overweight or obesity had any effect on survival over 10 years, compared to people who were normal weight.

The results revealed a total of 782 stroke cases (Mean age 71, 51% female, 87% ischemic stroke) among study participants. Overweight participants with ischemic stroke had a lower mortality compared with those with normal weight. The association of reduced mortality in those with BMI over 25, compared with normal-weight BMI, was pronounced among ischemic stroke cases, but diminished with inclusion of hemorrhagic strokes. According to the researchers, the results add to the 'obesity paradox' seen in previous studies, where increased body weight appears to have a protective effect. The study was published on June 24, 2017, in Journal of the American Heart Association.

“We found that participants who were overweight or mildly obese had better survival after stroke than normal weight participants, and the survival benefit was strongest in males or in those younger than age 70,” said corresponding author assistant professor of neurology Hugo Aparicio, MD, MPH. “Observing this so-called 'obesity paradox' has important clinical implications, and it is essential for clinicians and researchers to better understand the role of body weight in recovery after stroke so that they can make proper recommendations on weight loss or weight maintenance.”

The obesity survival paradox was first described in 1999 in overweight and obese people undergoing hemodialysis, and has subsequently been found in those with heart failure (HF) and peripheral artery disease (PAD). In people with HF, those with a BMI between 30 and 34.9 had lower mortality than those with a normal weight. This has been attributed to the fact that people often lose weight as they become progressively more ill. Similar findings have been made in other types of heart disease.

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