Stroke is one of the top 5 leading causes of death in the US alone. Moreover, it dominates the causes of disability in adults. Annually, approximately 185,000 people die of stroke.  It is a known fact that obesity is a major risk factor for stroke, but a recent study suggests that the survival rate of stroke victims is better in those who are overweight or slightly obese.  These findings add to the ‘obesity paradox’ which has been observed in many other conditions like chronic heart failure, chronic obstructive pulmonary disease, chronic kidney disease, rheumatoid arthritis and others wherein increased body weight has a protective effect. 
The study participants were a group of patients from the Framingham Heart Study (FHS). These participants were followed over time; measurements included their body mass index (BMI) prior to the stroke. Stroke cases were then matched with other FHS participants who were of similar age and sex and belonged to the same BMI category, i.e., normal weight, overweight, or obese. Both groups were then separately analyzed to determine the effect of being overweight or obese on survival over 10 years, in comparison to people with normal weight. Researchers found that the participants had better survival rates when they were overweight or mildly obese in comparison to their normal weighing counterparts. Furthermore, the survival benefit was maximum in males and in those below 70 years of age.
During this study, factors like smoking, cancer, dementia, and vascular risk factors like high blood pressure, diabetes, and cholesterol, were controlled.
There have been other studies with similar outcomes, like the Feed or Ordinary Diet Trial collaboration, a multicenter randomized trial evaluating various feeding policies, examined a cohort of 2955 patients with stroke for 6 months and assessed nutritional status by body mass index. It was observed that underweight patients (BMI <20 kg/m2) had poorer survival and more complications than those with BMI >20 kg/m2. These outcomes from the different BMI sub-groups surfaced immediately after a stroke and were consistent during 8 months of the follow-up period.
A Greek study considered 2785 patients with stroke and conducted a follow-up for up to 10 years. In this study, it was seen that obesity was associated with better outcomes. Compared to normal BMI which is >25 kg/m2, obese patients with BMI around ≥30 kg/m2 and overweight patients with BMI 25–29.9 kg/m2 had a 29% and 18% lower risk of 10-year mortality, respectively. Another striking observation that was made during this study was that there was an inverse association between body weight and mortality which was seen as early as 1-week post stroke and continued throughout the 10-year follow-up. 
From these studies, it cannot be concluded that obesity is protective in the overall population, but there may be some mechanism by which increased weight assists in survival after stroke. It may be due to various other factors like medicines, not smoking, or some change in diet.  This so-called “obesity paradox” can assist clinicians and researchers in better understanding the role of body weight in recovery after stroke, thereby they can provide optimum guidance for weight loss or weight maintenance to stroke survivors.
Credit: Dr. Neha on behalf of Borderless Access
Copyright © 2017 BorderlessAccess
- Hugo J. Aparicio, Jayandra J. Himali, Alexa S. Beiser, Kendra L. Davis‐Plourde, Ramachandran S. Vasan, Carlos S. Kase, Philip A. Wolf, Sudha Seshadri. Overweight, Obesity, and Survival After Stroke in the Framingham Heart Study.