High BMI linked to death from stroke
NEW YORK (Reuters Health) - Among men who've suffered a stroke, the likelihood of dying from the stroke is increased if their body mass index (BMI) puts them in the overweight range; BMI is not a factor in stroke mortality for lean men, according to a large Chinese study.
"Despite previous investigations, substantial uncertainty remains about the relation between body mass index (BMI) and stroke, especially in populations with a relatively low BMI but a high stroke rate," Dr. Zhengming Chen, of the University of Oxford in the UK and colleagues point out.
The researchers studied the association between BMI and deaths from stroke in a nationally representative cohort of more than 200,000 Chinese men without known cardiovascular disease recruited between 1990 and 1991.
After 10 years, a total of 5766 stroke deaths were recorded, according to the investigators' report in the medical journal Stroke.
The researchers saw that the higher the blood pressure at the start of the study, the greater were the number of deaths from stroke -- and that blood pressure increased as BMI rose.
However, the risk of dying from a stroke did not increase uniformly with increasing BMI, and in fact the risk increased substantially only when BMI was greater than 25. A BMI of 25 is classified as overweight.
Approximately 90 percent of the subjects had BMIs less than 25, and BMI was not associated with stroke mortality among these men.
Chen's team says that this is the largest forward-looking study of the relationship between BMI and stroke mortality in a relatively lean, nationally representative population of Chinese men.
SOURCE: Stroke, March 2008.