Cardiovascular disease (CVD) is the leading cause of death worldwide, with over a third of global deaths being attributed to a cardiovascular event.

In the United States, CVD accounts for 1 in every 4 deaths, killing around 610,000 people every year. More than half of these deaths occur in men, according to the Centers for Disease Control and Prevention (CDC).

Some studies have shown that drinking alcohol in moderation may have a positive effect on cardiovascular health.

However, these studies have been observational, and the exact causative mechanisms behind this association are unknown. Furthermore, the impact of drinking levels over time has not been fully understood.

New research examines the link between arterial stiffness - a significant indicator of cardiovascular health - and alcohol consumption over time.

The research was published in the Journal of the American Heart Association.

Studying the effects of long-term alcohol use on arterial health

Darragh O'Neill, Ph.D., who is an epidemiological researcher at University College London in the United Kingdom, led the research, which consisted of a longitudinal study aiming to determine the link between alcohol consumption over 25 years and changes in arterial stiffness.

Stiffness of the arteries occurs when the walls of the blood vessels lack elasticity, which can negatively impact the artery's response to variations in blood pressure.

The study examined the clinical data available from the Whitehall II cohort study of British civil servants, which assessed the participants' arterial stiffness every 4-5 years by measuring their pulse wave velocity (PWV). The latter is a measurement of arterial stiffness, which calculates the rate at which the pressure waves move through the vessels. A higher pulse wave velocity suggests a stiffer artery.

Participants were healthy individuals aged between 30-50, the majority of whom were nonsmokers. However, 68 percent of men and 74 percent of women did not meet the recommended exercise guidelines. One in 10 participants - both male and female - had type 2 diabetes, and men tended to be heavy drinkers, compared with women.

The study also repeatedly measured alcohol intake in order to classify participants into alcohol consumer types: consistent, long-term heavy intake was defined as more than 112 grams of ethanol each week - more than the U.K. guidelines of 14 weekly units.

Consistent moderate drinkers were defined as those who consumed between 1-112 grams of ethanol per week, so less than the 14 units. One U.K. alcohol unit is roughly the equivalent to a shot of whiskey or half a pint of beer.

In the U.S., moderate drinking is defined as an average of one to two drinks per day for men, and one drink for women.
 

Heavy drinking causes arteries to age prematurely

Researchers looked at the association between changes in PWV and drinking patterns defined as above.

They found that heavy drinking affects the elasticity of the arterial walls, as males who consistently drank heavily had significantly higher PWV than those who consistently drank moderately.

After adjusting for several factors including BMI, heart rate, and arterial pressure, the associations were not significant for women, even though 73 percent of the study participants were men.

The researchers' conclusion is that drinking heavily increases cardiovascular risk, especially in men. Consistent heavy drinking can age the arteries prematurely by interfering with the blood flow, thus affecting the elasticity of the arterial walls.

However, the exact way that alcohol causes arteries to lose elasticity remains unknown, says the study's lead author.

    "It has been suggested alcohol intake may increase high-density lipoprotein cholesterol levels - the good cholesterol - or decrease platelet stickiness. Conversely, heavier alcohol intake may activate certain enzymes that would lead to collagen accumulation, which could, in turn, exacerbate the rate of arterial stiffening."  Darragh O'Neill

In the future, the researchers wish to further investigate the relationship between alcohol and other markers of cardiovascular health.

"Based on these findings, the research team wants to look at multiple groups of people - since this study was limited to a single group that was mostly male - and identify the relationship that drinking patterns over time have with other indicators of cardiovascular disease," O'Neill says.

Learn how women are now drinking almost as much as men.