By Joseph E. Scherger, MD, MPH

Vice President, Primary Care, Eisenhower Medical Center; Clinical Professor, Keck School of Medicine, University of Southern California

Dr. Scherger reports no financial relationships relevant to this field of study.

SYNOPSIS: Controlling 10 modifiable risk factors would prevent 90.7% of strokes, according to results from a 32-country study.

SOURCE: O’Donnell MJ, Chin SL, Rangarajan S, et al. Global and regional effects of modifiable risk factors associated with acute stroke in 32 countries. Lancet 2016; Jul 15 doi: http// [Epub ahead of print].

The INTERSTROKE investigators from 32 countries in Asia, the Americas, Europe, Australia, the Middle East, and Africa conducted a case-control study of patients suffering acute stroke compared with controls. Researchers compared 13,447 acute stroke cases (10,388 with ischemic stroke and 3,059 with hemorrhagic stroke) with 13,472 matched controls. The investigators identified 10 modifiable risk factors that may have prevented 90.7% of strokes.

The most important modifiable risk factor is hypertension. Eliminating high blood pressure would reduce stroke risk by 48%. There were regional variations, with hypertension causing about 39% of strokes in North America, Australia, and Western Europe, and nearly 60% of strokes in Southeast Asia.

The other modifiable risk factors, with obvious overlap in many patients are:

  • Physical inactivity: 36%
  • Hyperlipidemia: 27%
  • Poor diet: 23%
  • Obesity: 19%
  • Smoking: 12%
  • Heart disease: 9%
  • Alcohol: 6%
  • Diabetes: 4%
  • Stress: 6%


Stroke is the third leading cause of death and a major cause of disability, and as this study shows is highly preventable. Unhealthy lifestyle leads to more than 90% of all strokes worldwide. The same could be said of heart disease and many cancers. Most instances of poor health and premature demise are self-inflicted.

An argument can be made about personal responsibility in avoiding preventable chronic illness and events such as stroke. Individuals are in charge of their own lifestyle decisions. However, one also can make an argument that these risk factors are a public health problem, with culture and environment leading to poor health choices. In his book Fat Chance, Robert Lustig from the University of California, San Francisco makes this argument forcefully.1 Lustig points to the ill effects of added sugars and high fructose corn syrup leading to obesity, type 2 diabetes, metabolic syndrome, and fatty liver, with the food industry largely to blame by hooking the population on these addictive sweets. The public health response has been lukewarm at best.

Science is coming together with medical practice to put more focus on modifiable risk factors in chronic disease and preventing major events such as stroke. Had this study been conducted 20 years ago, smoking would have been a much greater factor. We have the resources to become much healthier worldwide by adopting healthy lifestyles and protecting the environment. The public is becoming better educated in this area, and those businesses that sell unhealthy products are beginning to feel the effect. Physicians, especially those in primary care, should be “captains” in the battle against the poor health choices that surround us every day.


  1. Lustig R. Fat Chance: Beating the Odds Against Sugar, Processed Food, Obesity, and Disease. New York: Penguin Group; 2012.