Obesity–stroke link extended to hemorrhagic stroke
MedWire News: Obesity is strongly predictive of both ischemic and hemorrhagic stroke in a Japanese population, with the relationship largely mediated by blood pressure, research shows.
The link between obesity and ischemic stroke has been established in studies such as the Framingham and Atherosclerosis in Communities Risk studies.
The current study, by Hiroshi Yatsuya (Nagoya University, Japan) and colleagues, assessed the relationship of obesity and stroke risk in the Japanese - a relatively lean population. About 4% of Japanese are obese, compared with 34% of Americans, says the team.
Their findings also extend the obesity-stroke link to hemorrhagic stroke, which is far more prevalent in Asian than Western populations.
The study included pooled data from 16 Japanese cohorts, comprising more than 45,000 participants who collectively suffered 1113 strokes (725 ischemic, 229 hemorrhagic) and 190 myocardial infarctions (MIs).
Having a body mass index (BMI) of at least 27 kg/m2, as compared with less than 21 kg/m2, increased ischemic stroke risk 1.81 fold in men and 1.65 fold in women after accounting for age, and smoking and drinking habits.
The corresponding risk increases for hemorrhagic stroke were higher, at 2.51 and 1.98 fold, the team reports in the journal Circulation: Cardiovascular Quality and Outcomes.
Systolic blood pressure (SBP) rose in line with BMI and appeared to account for most of the effect of obesity on stroke risk. For example, adjusting for SBP reduced the risk increases for ischemic and hemorrhagic stroke in men with obese versus normal BMIs to a nonsignificant 1.50 and 1.85 fold, respectively.
"The fact that stroke risks associated with obesity appeared largely explained by concomitant rise in blood pressure emphasizes the role of weight control including prevention of weight gain as a way to prevent and control hypertension, and thus stroke," say the researchers.
They add that obesity also raised MI risk in men, and that this was only partly attenuated by accounting for SBP. This "implies additional importance of obesity control in MI prevention in men," they say.
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010
By Eleanor McDermid