Smoking May Erase Heart Benefits of Light Drinking

TUESDAY April 13, 2010 - If you indulge in moderate drinking, you've probably heard that it might reduce your risk for heart trouble, including stroke.

A new British study supports that notion, but it also finds that light drinking's benefit in lowering stroke risk does not apply to smokers.

"Any potential beneficial effect of drinking moderate amounts of alcohol on stroke may be counteracted by cigarette smoking," said lead researcher Yangmei Li, a doctoral candidate in the Institute of Public Health at the University of Cambridge.

Li presented her findings Monday at a press conference held by the American Academy of Neurology during its annual meeting in Toronto.

The authors note that prior studies exploring the potential protective relationship between stroke risk and light-to-moderate drinking have found conflicting results. The fact that many people both drink and smoke might be a factor.

Smoking is a significant risk factor for stroke, Li noted, with current smokers having a 64 percent higher risk for stroke than those who have never smoked.

To help tease out these relationships, the authors tracked the drinking and smoking histories of more than 22,500 British residents (approximately 10,000 men and 12,000 women) for an average of 12 years.

The study began as early as 1993 and ended by 2008. All the study subjects were between the ages of 39 and 79, and none had a history of heart attack, cancer, or stroke prior to the study launch. By the end of the study, 864 strokes had occurred.

The researchers found that heavy drinkers gained no protection from stroke relative to non-drinkers. In fact, excessive alcohol use was linked to a potential rise in stroke risk.

On the other hand, light-to-moderate drinking did appear to lower the odds for stroke compared to no alcohol consumption. That's in keeping with other studies on moderate drinking and cardiovascular health.

However, the apparent protective effect of moderate tippling did not hold true for smokers.

The lowest stroke risk was observed among nonsmokers who consumed between three to 14 "units" of alcohol per week, each unit being equal to about a glass of wine.

This level of consumption -- below what the authors defined as the upper "moderate consumption" limit of 21 glasses per week -- afforded participants a 37 percent reduction in stroke risk.

However, smokers who drank a similar amount of alcohol had no such decline in their odds for stroke.

Li and her colleagues conclude that "smoking may modify [the] relationship between alcohol and stroke risk."

For his part, Dr. Ralph Sacco, chairman of the department of neurology at the University of Miami, said the finding confirms that "smoking is a powerful risk factor for stroke".

"In my own research, the protective affect of moderate alcohol consumption was seen among both smokers and nonsmokers," he noted. "However, it is possible that we'll ultimately find that smoking wipes out the benefit, because it certainly does increase stroke risk in general."

"And so while it's hard for us to advocate that people should start drinking a little alcohol if they don't do so already, we do need to get the message out that if you're currently drinking heavy amounts of alcohol you need to reduce down to small amounts," Sacco said. "And we need to make sure that people don't smoke."

More information

Find out more about stroke risk factors at the National Stroke Association .

Posted: April 2010


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