Drinking more than two alcoholic beverages daily in middle-age may raise your stroke risk more than traditional factors such as high blood pressure and diabetes, according to new research in the American Heart Association journal Stroke.
The study, led by Pavla Kadlecová, a statistician at the International Clinical Research Center of St. Anne’s University Hospital in the Czech Republic, found that people in their 50s and 60s who consume more than two alcoholic beverages daily have a 34 percent higher risk of stroke compared to lighter drinkers — and are more apt to suffer a stroke five years earlier in life regardless of their genetics or their other health habits.
“Individuals consuming more than 2 alcoholic drinks per day are putting themselves at a significantly increased risk of stroke, particularly in their early old age, when they should still be active and productive,” said Kadlecová.
Stroke is one of the leading causes of morbidity and mortality in the U.S., affecting more than 795,000 people and accounting for an estimated 130,000 deaths annually. High blood pressure (hypertension), diabetes, smoking, and high cholesterol are among the major, well-known risk factors for stroke. While past studies have shown that heavy alcohol use is also an important risk factor for stroke, the study by Kadlecová and colleagues is the first to pinpoint how this risk varies by age.
To reach their findings, the researchers analyzed the records of 11,644 same-sex twins from the Swedish Twin Registry. Between 1967 and 1970 — when the participants were under the age of 60 — they completed dietary questionnaires, from which researchers could gather information on their alcohol consumption.
The twins were followed for around 43 years, until 2010. The researchers analyzed their health data over this period, including hospital discharge information and details on causes of death, as well as information on blood pressure, smoking and diabetes, among other health risks.
Heavy drinking in midlife raises stroke risk by 34%
During the follow-up period, nearly 30% of participants had a stroke. The researchers divided the participants into three groups based on their alcohol consumption at study baseline: “light” drinkers (half an alcoholic drink a day), “moderate” drinkers (up to two drinks a day) and “heavy” drinkers (more than two drinks a day).
After accounting for confounding variables — including baseline age, sex, cardiovascular diseases, diabetes mellitus, stress reactivity, depression, body mass index, smoking, and exercise — the stroke risk was found to be lowest in the light drinkers. Overall, participants classified as heavy drinkers were 34% more likely to have a stroke than those classified as light drinkers. In addition, strokes began about five years earlier among heavy drinkers than among those who consumed little alcohol.
Notably, among identical twin pairs, siblings who had a stroke were found to have 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.
On comparing the effects of alcohol consumption on stroke risk with the effects of traditional risk factors — such as high blood pressure and diabetes — the team found that alcohol consumption was the biggest risk factor for stroke during middle age. However, high blood pressure and diabetes appeared to be stronger risk factors for stroke from the age of 75 and up.
“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,” said Kadlecová. “For mid-aged adults, avoiding more than two drinks a day could be a way to prevent stroke in later productive age (about 60s).”
The American Heart Association recommends that women consume no more than one alcoholic drink each year, and men limit themselves to two drinks. Regular heavy drinking of any kind of alcohol can raise blood pressure and cause heart failure or irregular heartbeats over time, in addition to stroke and other risks like cancer. In total, alcohol consumption is thought to be a causal factor in more than 200 different diseases and health conditions.