Having one small alcoholic drink a day raises the risk of developing an irregular heartbeat, a condition that causes dizziness and palpitations and leaves people more prone to strokes, a study has found.
Researchers examined the heart health and drinking habits of 108,000 people aged 24 to 97 by combining records from Sweden, Norway, Finland, Denmark and Italy that stretched over 14 years.
Their analysis confirmed the long-held belief that a small amount of alcohol protects against heart failure, with 20g of ethanol a day being optimum – but the same was not true for a condition called atrial fibrillation, or heart arrhythmia.
According to their report in the European Heart Journal, people who consumed as little as 12g of ethanol a day – equivalent to a 330ml beer, a 120ml glass of wine, or 40mls of spirits – were 16% more likely than teetotallers to develop atrial fibrillation over the course of the study.
“The take-home message is that in contrast to other cardiovascular diseases, even low and moderate alcohol consumption leads to an increased risk of atrial fibrillation,” said Prof Renate Schnabel, a consultant cardiologist and co-author on the study at the University Heart and Vascular Center in Hamburg-Eppendorf.
“Many people have palpitations and dizziness, but one of the bad things about atrial fibrillation is that it’s asymptomatic and can lead to other problems such as stroke. In many people, a stroke is the first manifestation of the disease,” she added. People with atrial fibrillation are thought to have a 5% to 7% annual risk of stroke.
The risk of heart failure – when the heart pumps too weakly – follows a J-shaped curve with alcohol intake, meaning that it is lower for people who drink a little than for those who are teetotal or heavy drinkers.
But in the study, the increased risk of atrial fibrillation rose steadily from 16% for those who had one small drink a day, to 28% for up to two drinks, and 47% for more than four drinks.
For those consuming a small glass of alcohol a day, Schnabel said the absolute increase in risk of an irregular heartbeat was small, but people should still be aware of the issue.
“People have to balance the risks and the benefits,” she said. The lifetime risk of developing atrial fibrillation ranges from about 23% to 38% depending on a person’s health – including how much alcohol they drink.
The findings may be most important for those who were more likely to develop heart arrhythmias because of obesity or high blood pressure, or those who had already been diagnosed, since reducing alcohol intake could lower the risk, Schnabel said.
In an accompanying editorial, Jorge Wong and David Conen at the Population Health Research Institute at McMaster University in Canada write: “These data suggest that lowering alcohol consumption may be important for both prevention and management of atrial fibrillation.”
June Davison, a senior cardiac nurse at the British Heart Foundation, said: “It is well known that drinking alcohol can increase the risk of atrial fibrillation. This observational study suggests that regularly drinking even small amounts of alcohol may increase this risk – and that reducing intake even further could help to prevent and manage this condition.
“If you have AF, ask your doctor for advice on whether you can drink alcohol and the amount you can consume. Also, if you are taking medication, always check with your doctor or pharmacist first about how much alcohol you can safely drink.”