Christian Dehlendorff, M.S., Ph.D., of the Danish Cancer Society Research Center, Copenhagen, Denmark, and colleagues sought to determine whether the obesity paradox in stroke was real or an artificial finding because of selection bias in studies. To overcome selection bias, authors only studied deaths caused by the index stroke using a Danish register of stroke and a registry of deaths.
They found no evidence of this obesity paradox, where overweight or obese patients had lower mortality rates than underweight or normal weight patients in patients with stroke.
The study included 71,617 Danes for whom information was available on factors that included body mass index (BMI), age, stroke type and stroke severity. Of the 71,617 patients, 7,878 (11 percent) died within the first month and, of these, stroke was reported as the cause of death of 5,512 patients (70 percent). Of the patients for whom BMI information was available, 9.7 percent were underweight, 39 percent were normal weight, 34.5 percent were overweight and 16.8 percent were obese. BMI was inversely related to average age of stroke onset (high BMI associated with younger age of onset).
“This study was unable to confirm the existence of an obesity paradox in stroke. … Obesity was not associated with a lower risk for death after a stroke. … The risk of obese patients with stroke for death did not differ from that of normal-weight patients with stroke nor was there evidence of a survival advantage associated with being overweight,” the authors write.
Citation: JAMA Neurol. Published online June 2, 2014. doi:10.1001/.jamaneurol.2014.1017.