After adjusting for traditional risk factors such as lipid levels, blood pressure, and smoking, the hazard ratios for coronary events associated with bingeing and abstaining were close to 2.0 in Belfast and in the French cities--though the ratios were statistically significant only in Belfast.
French abstainers were significantly more likely to suffer events than regular drinkers. The association was weaker and nonsignificant among Belfast participants.
Comparing Belfast men to their French counterparts, the risk of heart attack and coronary death was double. Controlling for traditional risk factors dropped the ratio to 1.76.
When drinking status was included in the adjustments, the Belfast disadvantage fell further, to a barely significant ratio of 1.35.
And controlling for wine consumption (recorded as yes or no in the data) almost completely erased the increase in events in Belfast.
Steady drinkers who reported wine consumption were about 35-50 percent less likely to suffer major coronary events in both countries than those who said they never drank wine.
The PRIME study also included data on angina pectoris events. These generally showed a similar pattern as with "hard" events but the associations were often weaker.
In an accompanying editorial, Annie Britton of University College London agreed that the findings support the idea that binge drinking is uniquely unhealthy--even when compared with heavier but more regular drinking.
But she pointed out, as Ruidavets and colleagues acknowledged themselves, the study did not control for participants' diets.
"In the absence of large well-conducted randomized controlled trials, residual confounding cannot be ruled out. The authors discuss types of drinks, but this is so intricately linked with patterns and behaviors surrounding drinking that it is hard to extract evidence," Britton wrote in the BMJ editorial.
"It is not hard to imagine that factors other than the type of alcohol or drinking pattern are important in the relation between alcohol and heart disease," she added.
But Britton agreed that the trend toward increasing binge drinking should be discouraged, and not only among the young.
"Middle aged men should be made aware that if they are irregular heavy drinkers, the possible cardioprotective properties of alcohol consumption may not apply to them, and, in contrast, they may be putting themselves at increased risk of having a heart attack," she wrote.