Heavy drinkers who are middle-aged may have a higher stroke risk - more so than based solely on traditional factors such as high blood pressure and diabetes, according to a new study.

Heavy drinking is defined as having more than two alcoholic beverages daily. The American Heart Association recommends that men limit themselves to one drink per day (about 8 ounces of wine) and women just one drink per day (about 4 ounces).

"For mid-aged adults, avoiding more than two drinks a day could be a way to prevent stroke in later productive age (about 60s)," researcher Pavla Kadlecová said in a statement.

To find this out, researchers studied 11,644 middle-aged Swedish twins over a period of 40 years, comparing heavy drinkers with those who drank less than half a drink daily ("light drinking").

What they found was that heavy drinkers had a staggering 34 percent increased risk of stroke compared to light drinkers. And regardless of genetic and early-life factors, heavy drinkers in their 50s and 60s had a stroke five years earlier than the other study participants.

Normally high blood pressure and diabetes are two main factors that influence stroke risk, but researchers say that they did not really become influencing factors until age 75.

In total, almost 30 percent of the participants had a stroke. Among identical twin pairs, siblings who had a stroke drank more than their siblings who hadn't had a stroke. This suggests that mid-life drinking raises stroke risk regardless of genetics and early lifestyle.

While researchers have long known that alcohol impacts stroke risk, this is the first study to pinpoint differences with age.

"We now have a clearer picture about these risk factors, how they change with age and how the influence of drinking alcohol shifts as we get older," Kadlecová concluded.

The results were published in the American Heart Association journal Stroke.

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