For any adult looking to keep his risk for a stroke at a minimum, health care professionals recommend two drinks (8 ounces of wine) for men and one drink (4 ounces of wine) for women a day. That one to two drinks a day recommendation tends to become skewed around 5:00 p.m. A recent study published in the American Heart Association journal Stroke has found that heavily drinking in middle age can increase our risk for suffering a stroke more than any other common risk factor.

"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, a statistician at St. Anne's University Hospital's International Clinical Research Center in the Czech Republic, said in a statement. "For mid-aged adults, avoiding more than two drinks a day could be a way to prevent stroke in later productive age (about 60s).”

Kadlecová and her colleagues gathered data using the Swedish Twin Registry, which generated 43 years of follow-up, including hospital discharge, cause of death, and more information from medical records. A total of 11,644 Swedish twins, who were under the age of 60 at the start of the study, responded to questionnaires between 1967 and 1970. While some studies have investigated the relationship between stroke and heavy drinking, rarely have they covered differences in age.

Researchers classified “heavy drinking” as more than two drinks a day and “light drinking” as less than half a drink a day. Questionnaires were used to categorize respondents as either light, moderate, heavy, or non-drinkers. Alcohol consumption was compared to other common risk factors associated with a stroke, including high blood pressure, diabetes, and smoking. Drinking heavily over a period of time can lead to spikes in blood pressure as well as heart failure and irregular heartbeats.

By the end of the 43 years of follow-up, 30 percent of respondents had suffered a stroke. Respondents classified as a “heavy” drinker had around a 34 percent higher risk for a stroke compared to “light” drinkers. Heavily drinking in their 50s and 60s also increased a respondent’s risk for suffering a stroke five years earlier in life. Heavy drinking increased stroke risk during mid-life more than any other risk factor, but blood pressure and diabetes became more significant at around age 75.

According to the American Stroke Association, stroke risk factors are generally broken into two categories: those that can’t be changed, and those that can be changed, treated, or controlled. Risk factors that can’t be changed include age, heredity, race, and sex, while risk factors that can be changed, treated, or controlled include high blood pressure, smoking, poor diet, and physical inactivity. Alcohol, on the other hand, is considered a “less well-documented risk factor.” It could be time for physicians to rethink the degree to which alcohol affects our stroke risk.

Source: Andel R, Mikulik R, Kadlecová P, et al. Alcohol Consumption at Midlife and Risk of Stroke During 43 Years of Follow-Up. Stroke. 2015.