New research suggests that drinking more than two alcoholic beverages daily in middle-age could substantially raise stroke risk more than traditional factors such as high blood pressure and diabetes.

Researchers found that heavy drinkers had about a 34 percent higher risk of stroke compared to light drinkers. Mid-life heavy drinkers (in their 50s and 60s) were likely to have a stroke five years earlier in life irrespective of genetic and early-life factors.

Past studies have shown that alcohol affects stroke risk, but 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," Pavla Kadlecová, researcher and a statistician at St. Anne's University Hospital's International Clinical Research Center in the Czech Republic, said in a statement.

For the study, researchers collected data from nearly 12,000 middle-aged Swedish twins who were followed for 43 years, researchers compared the effects of an average of more than two drinks daily ("heavy drinking") to less than half a drink daily ("light drinking").

Researchers sorted the data based on stroke, high blood pressure, diabetes and other cardiovascular incidents.

Heavy drinkers had increased stroke risk in their mid-life compared to well-known risk factors like high blood pressure and diabetes.

At around age 75, blood pressure and diabetes appeared to take over as one of the main influences on having a stroke.

Almost 30 percent of participants had a stroke. They were categorized as light, moderate, heavy or non-drinkers based on the questionnaires. Researchers compared the risk from alcohol and health risks like high blood pressure, diabetes and smoking.

Among identical twin pairs, siblings who had a stroke drank more than their siblings who hadn't had a stroke, suggesting that mid-life drinking raises stroke risks regardless of genetics and early lifestyle.

The study is consistent with the American Heart Association's recommended limit of two drinks a day for men and one for women. That's about 8 ounces of wine (two drinks) for a man and 4 ounces (one drink) for a woman.

The findings are detailed in the American Heart Association journal Stroke.