There's also no one accepted level for a diagnosis of insulin resistance. The condition is a known risk factor for heart disease but its effect on stroke hasn't yet been teased out.
These researchers followed 1,509 non-diabetic individuals (almost 60 percent Hispanic and 64 percent women) for close to nine years.
Individuals with the highest HOMA scores had an almost threefold increased risk of ischemic stroke, but not of heart attack, compared with lower-scoring participants, the researchers found.
People in the top group also had higher rates of obesity, were more sedentary and had higher blood pressure compared to the other participants, Kelly pointed out.
"These are patients we should probably already target as candidates for aggressive risk modification," he said.
Women with insulin resistance were at higher risk of having a first stroke than men (the reasons are unclear), but there were no racial or ethnic differences in the group studied, the authors noted.
It's also unclear if insulin resistance is actually causing stroke, or whether it's just another indicator of increased risk.
For now, Kelly said, "if you have patients who are having vascular events that don't appear to have any of these traditional vascular risk factors, it might be reasonable to check the HOMA score if that would make you treat their conventional risk factors or ask them to change their lifestyle more aggressively than you would have otherwise."
In the meantime, people can improve their insulin resistance with "diet and exercise and one or two medications," said Dr. Roger Bonomo, director of the stroke center at Lenox Hill Hospital in New York City.
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