This study is the first to look specifically at the effect of alcohol on the gradual stiffening of the arteries as people age, which causes increased systolic blood pressure (the top number in a blood pressure reading). Researchers also examined whether alcohol consumption alters the age-associated increase in intimal media thickness (IMT), which is the thickness of the innermost layers of an artery.
“Modest alcohol consumption has been associated with reduced cardiovascular morbidity and mortality,” says study co-author Jerome L. Fleg, M.D., staff cardiologist at the National Institute on Aging, Gerontology Research Center, Baltimore, Md. “We wanted to find out whether a beneficial effect on the arterial wall might help explain those findings.”
Researchers studied 563 volunteers from the Baltimore Longitudinal Study of Aging between ages 20 and 90 (average age 60 years).
Individuals who had undergone previous carotid artery surgery or had major carotid artery narrowing were excluded from the study.
Ultrasound was used to determine the arterial stiffness index and IMT of the participants’ carotid (neck) arteries. The arterial stiffness index is the relationship between the arterial blood pressure and the dimensions of the carotid artery. The researchers measured blood pressure and used ultrasound to measure the diameter of the artery. Participants also answered questionnaires about their use of beer, spirits (hard liquor) and wine.
Participants were categorized into four groups: those who never drank, occasional drinkers, light-to-moderate drinkers and heavy drinkers. A unit of alcohol is equal to one glass of wine (4 to 5 ounces), a 12-ounce beer or 2 ounces of hard liquor. Participants who drank less than one unit a week were considered occasional drinkers; light to moderate drinkers drank between one and 9.9 units a week; and heavy drinkers consumed 10 or more units a week, which would be equal to or greater than one and a half drinks a day.
“Numerous studies have shown that more than two drinks a day exerts more negative than beneficial effects on cardiovascular health. Our findings regarding alcohol’s effect on arterial stiffness are consistent with these prior observations,” Fleg says.
Similar effects on arterial stiffness were seen regardless of the type of alcohol (beer, wine or spirits) the participants drank. The researchers found that alcohol intake demonstrated a “U-shaped” relationship with arterial stiffness.
The arterial stiffness index in each age range – younger than 50, 50-70, and older than 70 years – was lowest among light to moderate drinkers. The “U-shaped” relationship between drinking and arterial stiffness is seen within any given age range. For example, for those aged 50-70, the index was 9.2 for never drinkers, 8.2 for occasional drinkers, 7.3 for light to moderate drinkers, and back up to 9.0 for heavy drinkers.
Thus, the arterial stiffness of the non-drinkers and heavy drinkers was about 10 to 20 percent higher than that of light to moderate drinkers. The researchers further determined that this beneficial effect of alcohol on arterial stiffness was greatest at older ages.
For example, light to moderate drinkers younger than 50 years showed only about 15 percent lower stiffness than never drinkers. For those aged 70 and older, however, arterial stiffness was nearly 30 percent lower in the light to moderate drinkers.
Although carotid artery IMT also displayed a U-shaped relationship with alcohol intake, the relationship disappeared after adjustment for other variables known to influence IMT.
“What we’re showing is that arterial stiffness goes up with age no matter what, but it seems to go up less steeply in the people who drink lightly to moderately,” says Fleg. “The occasional drinkers are in-between – their arteries are less stiff than those of the heavy and never drinkers but stiffer than those in the light to moderate group.”
According to Fleg, recent studies have shown that higher arterial stiffness, particularly in patients who already have cardiovascular diseases, predicts increased risk of death or cardiac events. “Although evidence is accumulating that arterial stiffness is an independent cardiac risk factor, additional studies are needed to determine whether lowering stiffness by lifestyle changes or medication will reduce cardiovascular risk.
“A little alcohol is probably good for your arteries, but we wouldn’t recommend that people start drinking purely for that reason,” he says. “If you are a light to moderate drinker, you certainly wouldn’t be encouraged to stop, based on our findings, plus other data suggesting that light to moderate alcohol consumption favorably affects cardiovascular risk.”
The American Heart Association also cautions people not to start drinking if they do not already drink alcohol. The association encourages consumers to consult their doctors on the benefits and risks of consuming alcohol in moderation.
Co-authors of the study are: Hidetaka Hougaku, M.D.; Edward G. Lakatta, M.D.; Mary K. Kemper; Christopher J. Earley, M.D.; and E. Jeffrey Metter, M.D.
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Abstract 2378
NR01 – 1362 (SS01/Fleg)