Men in Belfast, Northern Ireland--a city where heavy drinking on weekends is common--were far more likely to suffer cardiovascular events than Frenchmen, whose overall alcohol intake may be higher but is spread evenly throughout the week, researchers said.
The prospective study of almost 10,000 middle-age men found that those in Belfast were 76 percent more likely to experience a heart attack or coronary death than Frenchmen of the same age after adjusting for traditional cardiovascular risk factors. The increased risk fell by half when drinking status was added to the adjustments.
Read this story on www.medpagetoday.com.
Findings from the two-nation study bolster previous evidence that binge drinking is particularly unhealthy, Dr. Jean-Bernard Ruidavets of Toulouse University in France and colleagues reported online in BMJ.
"Regular and moderate alcohol intake throughout the week, the typical pattern in middle aged men in France, is associated with a low risk of ischemic heart disease, whereas the binge drinking pattern more prevalent in Belfast confers a higher risk," Ruidavets and co-authors wrote.
The researchers indicated that the results are worrisome because binge drinking is on the rise in countries such as France and Spain, particularly among young people.
"The alcohol industry takes every opportunity to imbue alcohol consumption with a positive image, emphasising its beneficial effects on risk of ischemic heart disease, but people also need to be informed about the health consequences of heavy drinking," they wrote.
The study drew on data from the Prospective Epidemiological Study of Myocardial Infarction, or PRIME, which has followed 2,405 middle-age men in Belfast and 7,373 in three French cities (Toulouse, Lille, and Strasbourg) starting in the early 1990s. The men were ages 50 to 59 and free of ischemic heart disease at baseline.
Ruidavets and colleagues examined rates of cardiovascular events during 10 years of follow-up in these two cultures with very different drinking patterns.
Some 90 percent of the French participants reported current alcohol consumption, compared with 60 percent of the Belfast men.
At the same time, binge drinking was reported by 9 percent of participants in Belfast but by only 0.5 percent of the Frenchmen. The Belfast bingers had a mean weekly ethanol intake of 4 oz whereas the steady drinkers in France averaged 8 oz weekly.
MI and coronary death struck 5.3 percent of Belfast participants and 2.6 percent of the Frenchmen during follow-up. There was little difference between the three French centers.
Rates were higher in Belfast than in France for every level of average alcohol consumption. Among Frenchmen drinking nearly 3 oz daily, 2.9 percent suffered cardiac events, which was the highest rate among French drinkers.
In contrast, the lowest event rate seen in Belfast men of 3.8 percent was seen both in the heaviest and the lightest drinkers.
Ruidavets and colleagues did not report event rates stratified both by country and drinking pattern (i.e., periodic bingeing versus steady daily intake). However, they did calculate hazard ratios for weekend bingers, lifetime abstainers, and former drinkers relative to steady drinkers in the two countries.
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.