The more alcoholic drinks that men have at any time of day - not just before bedtime - the greater are the risks of breathing problems during sleep, a new study shows. However, this effect was not seen among women.

Sleep-disordered breathing has been associated with high blood pressure and blood vessel disease, and many studies have found that drinking alcohol before going to sleep increases the likelihood of abnormally shallow breathing or even episodes in which breathing stops, Dr. Paul E. Peppard and colleagues from the University of Wisconsin-Madison report.

However, whether or not light-to-moderate drinking, at any time of the day, affects breathing during sleep has not been clear, they report in the Journal of Clinical Sleep Medicine.

To investigate, the researchers looked at 775 men and 645 women participating in a sleep study. Two hundred eighty-one men (36 percent) and 332 women (51 percent) did not drink. The majority of the rest (42 percent of men and 41 percent of women) reported, on average, having less than one drink per day.

The subjects consumed two or fewer drinks in the afternoon of the days that the evaluation was done. All of the subjects had been reporting their drinking habits for five years before their breathing was evaluated, and

After the researchers accounted for the effects of body size, smoking and medications that can cause breathing problems, they found that for every additional drink a man habitually took per day, his risk of sleep-disordered breathing increased by 25 percent.

No such relationship was seen among women, which could have been because only 10 percent of the women reported having an average of more than one drink per day, the researchers note. There is also evidence that women may be less vulnerable to the effects of alcohol on breathing.

Men who were moderate drinkers were more likely to have five or more episodes of interrupted breathing per hour during sleep than men who didn’t drink at all.

This level of sleep-disordered breathing is seen in one of every four men in the United States, the researchers note, and “this ‘mild’ degree of sleep-disordered breathing is associated with cardiovascular and behavioral outcomes.”

The investigators conclude that “men with sleep-disordered breathing and those at risk for sleep-disordered breathing (are) advised to minimize alcohol consumption regardless of proximity to bedtime.”

SOURCE: Journal of Clinical Sleep Medicine, April 15, 2007.