The ability of aspirin, taken daily, to ward off stroke and heart attacks has long been known, so it is surprising that more Minnesotans don’t take it.

That was my contrarian reaction, anyway, to otherwise positive University of Minnesota research which found an increase in the number of Minnesotans taking aspirin since 1980 and predicted even more success from promoting the drug through a new “Ask About Aspirin” campaign.

Researchers surveyed 26,000 Minnesotans, ages 25 to 74, and found aspirin use for primary prevention of heart attacks and stroke increased in men from 1 percent in 1980 to 21 percent in 2009, and in women from 1 percent to 12 percent.

Primary prevention means people take aspirin before suffering disease. This isn’t recommended for men until age 45 and for women, age 55 — and only when they have risk factors such as high blood pressure. So the bigger news in the data was the rise in aspirin use in older Minnesotans; the rate among men 65 to 74 rose from 3 percent in 1980 to 57 percent in 2009.

Still, that means thousands of Minnesotans aren’t using this proven safeguard that costs just a penny per day.

Dr. Alan Hirsch, a cardiologist who led the research, blamed mixed messages by doctors and in the media: “There’s confusion about who should and who shouldn’t.”

“Ask About Aspirin” could change matters. The state launched the program last year to teach doctors and patients when aspirin is appropriate.

The U research, published last month in the Journal of the American Heart Association, estimated that the campaign could increase aspirin usage to the point that it would prevent 10,000 heart attacks and 1,200 strokes among Minnesotans who currently are at risk.

Increased aspirin usage also could lead to more drug side effects — 7,200 episodes of gastrointestinal bleeding and 2,800 hemorrhagic strokes.

The U research concluded that the low cost and benefits of preventive aspirin outweigh these risks.

But it will take a concerted effort to convince doctors and also patients who loathe taking pills when they aren’t sick, Hirsch said.

“The fear … of providing an innocent aspirin pill and causing a bleeding ulcer trumps the optimism of providing something that might prevent heart attack or stroke.”