This study raises important questions about drinking patterns and heart health among men and women, but an editorial warns that the results should be interpreted with caution and should not be used to justify potentially harmful drinking behaviour.
It is widely known that moderate drinkers have a lower risk of coronary heart disease than those who abstain, but most research in this field has been done on men and little is known about drinking patterns and risk of heart disease among women.
Researchers in Denmark studied over 50,000 men and women aged 50-65 years who were taking part in a national health study. Details on alcohol intake and drinking frequency over the preceding year were collected, and participants were monitored for an average of 5.7 years.
Coronary heart events were recorded and results were adjusted for known risk factors, such as age, smoking, education, physical activity and diet.
A total of 28,448 women and 25,052 men took part in the study. Women consumed an average of 5.5 alcoholic drinks a week and men consumed 11.3. During the study, 749 women and 1,283 men developed coronary heart disease.
Women who drank alcohol on at least one day a week had a lower risk of coronary heart disease than women who drank alcohol on less than one day a week.
However, risks were similar for drinking on one day a week (36% reduced risk), or seven days a week (35% reduced risk), suggesting that the amount of alcohol consumed is more important than drinking frequency among women.
In contrast, for men, risks were lowest for the most frequent drinkers. For example, men who drank on one day a week had a 7% reduced risk, while men who drank daily had a 41% reduced risk. This suggests that it doesn't matter how much men drink, as long as they drink every day.
To try to minimise bias, early cases of heart disease were analysed separately, but this did not change the conclusions. However, the authors stress that the benefits of alcohol on coronary heart disease are by far exceeded by the harmful effects of heavy alcohol drinking, and that their findings should be viewed in this context when giving public health advice.
But before the corks start popping, it is worth bearing several caveats in mind, writes Annie Britton, an epidemiology expert, in an accompanying editorial.
For instance, the Danish participants were middle-aged and therefore presumably at a greater risk of heart disease. The low response rate also means that extremes of drinking may not have been captured. Finally, the nature of this report - an observational study - may make it prone to other explanations for the findings.
In the UK, we are drinking well above the optimum level for health, so advice and legislation about keeping consumption safe and healthy are needed, she concludes.