By David Oliver

Nine out of 10 strokes are preventable, according a global study that shines light on one of the world’s leading causes of death and disability.

New research published Friday in The Lancet confirms 10 risk factors that can be modified account for 90 percent of strokes — which occur when an area of the brain loses blood flow — across the world. The study, dubbed INTERSTROKE, examined nearly 27,000 people in 32 countries across all continents, building on the breadth of an earlier version of the study that identified the same 10 risk factors.

Hypertension, or high blood pressure, is the leading risk factor; others include physical inactivity, obesity, stress, diabetes and a poor diet.

Researchers looked at the proportion of strokes per factor and quantified them through population attributable risk factors. This means that for each one of these 10 risk factors, there’s a corresponding percentage of reduced stroke risk if one risk factor didn’t exist. For example, without hypertension, a person’s stroke risk is down 47.9 percent; 35.8 percent reduction for physical inactivity; and 23.2 percent reduction for poor diet. Since many of these risks can overlap, when added together, this translates to a 90.7 percent reduction probability. This was comparable for each region studied and all age ranges in both men and women.

However, PARs were different across regions. The PAR for hypertension, for instance, was 38.8 percent in western Europe, North America and Australia — but 59.6 percent in Southeast Asia.

Researchers anticipate the study will help overarching initiatives to reduce strokes.

“Our findings will inform the development of global population-level interventions to reduce stroke, and how such programmes may be tailored to individual regions, as we did observe some regional differences in the importance of some risk factors by region,” said study author Salim Yusuf, of the Population Health Research Institute at McMaster University, in a press release. “This includes better health education, more affordable healthy food, avoidance of tobacco and more affordable medication for hypertension and dyslipidaemia.”

Stroke symptoms include difficulty with walking and talking and numbness of the face, arm or leg. About 85 percent of strokes are ischaemic, caused by blood clots. The rest are haemorrhagic, prompted by bleeding in the brain