London – Having one large glass of wine a day in middle age raises the risk of a stroke, warn researchers.
A study of almost 12,000 twins followed for four decades found that ‘heavy drinkers’ – defined as those having 250ml of wine a day – had a stroke risk one-third higher than those having less than 60ml a day.
People in their 50s and 60s who were heavy drinkers had a stroke five years earlier as a result.
Traditional factors associated with stroke, such as high blood pressure and diabetes, became more important only around the age of 75.
One drink or unit is normally defined as containing 8g of alcohol, equivalent to about one small (125ml) glass of wine, just over half a pint of beer and less than one shot of spirits such as whisky or vodka.
A medium (175ml) glass of wine contains around two units and a large (250ml) glass contains three units. Red wines often have a higher alcohol content.
Past research has shown that alcohol affects stroke risk, but this study – published in the American Heart Association journal Stroke – is the first to pinpoint differences with age.
The study followed 11,644 middle-aged Swedish twins for 43 years, with researchers comparing the effects of heavy drinking – more than two drinks daily – to light drinking – less than half a drink daily.
It showed that heavy drinkers had a 34 per cent higher risk of stroke compared to light drinkers. Heavy drinkers in their 50s and 60 were likely to have a stroke five years earlier in life irrespective of other factors. At around age 75, blood pressure and diabetes appeared to take over as one of the main influences on having a stroke.
Study co-author Pavla Kadlecova said that if ‘mid-aged adults’ avoided having more than two drinks a day it could lower the risk of stroke in ‘later productive age’ (in their 60s).
‘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,’ she said.
The researchers analysed results from the Swedish Twin Registry of same-sex twins who answered questionnaires in 1967-70.
All twins were under age 60 at the start. By 2010, the registry yielded 43 years of follow-up, including cause of death data.
Researchers then sorted the information based on stroke, high blood pressure, diabetes and other cardiovascular incidences. Almost 30 per cent of participants had a stroke.
They were categorised as light, moderate, heavy or non-drinkers based on the questionnaires. Researchers compared the risk from alcohol and health risks such as high blood pressure, diabetes and smoking.
Among identical twins, siblings who had a stroke drank more than their siblings who had not had a stroke, suggesting that mid-life drinking raises stroke risks regardless of genetics and early lifestyle.
UK guidelines for ‘safe’ drinking recommend that men regularly drink no more than three to four units of alcohol a day, and women should not drink more than two to three units.
Daily Mail