Jan. 17, 2024 – When it comes to alcohol consumption, moderation is everything.
Many studies over the past 20 years have suggested that people who have a drink a day or less may have a lower risk of cancer, heart disease, or all-cause mortality than those who abstain from drinking. Yet a growing body of newer research shows that those claims may be a mirage.
A JAMA review of 107 studies published from 1980 to 2021 found that occasional or low-volume drinkers did not have a lower risk of all-cause mortality than lifetime nondrinkers did. But there was a significantly increased risk of mortality among those who had a few drinks per day or more.
The study, which included nearly 5 million people, found that low-volume drinkers had a significantly lower mortality risk than did lifetime abstainers. After adjusting for biases in the studies, such as non-representative samples and the inclusion of people who used to drink in the abstainer groups, the mortality risk from alcohol consumption increased for all drinking categories but became insignificant for low-volume and occasional drinkers.
One reason that might explain the link between moderate drinking and lower mortality risk seen in some studies, the authors said, is that light and moderate drinkers tend to be healthier than abstainers. On average, they have a better diet, exercise more often, and have better dental hygiene than people who don’t drink at all.
Why would moderate drinkers engage in healthy behavior to a greater extent than abstainers? William Schaffner, MD, a professor of preventive medicine and infectious diseases at Vanderbilt University, said it might be because many of them are religious. “Their abstinence can be an isolated commitment in life, while they go about over-indulging in food and becoming chubby, not exercising, smoking, etc.,” he said. “Those factors don’t always relate to abstaining in that population. So the total abstainers are influenced substantially by religious commitments.”
Mirza Rahman, MD, president of the American College of Preventive Medicine, said that good health behavior in areas such as diet, exercise, and sleep may not be enough to reduce the negative impact of moderate drinking. Large studies published in the past several years, he said, have established that no level of drinking is safe.
A 2018 review paper in The Lancet, including more than 1,200 studies worldwide, found that while light drinking offers some protection from heart disease, the harmful effects of alcohol on health start with even low-volume drinking. For example, alcohol use had a significant link to cancer in people over 50, especially women. Twenty-seven percent of cancer deaths in women and 19% of those in men were linked to their drinking habits.
The JAMA study didn’t go as far as the Lancet article in linking low levels of drinking to mortality risk. While moderate drinking doesn’t equal a health benefit, it also doesn’t seem to raise the risk of death by very much, the authors said. But heavier drinking is definitely dangerous, in their view.
The paper also found a significant interaction between the age of study subjects and their mortality risk. While there wasn’t much of a difference in risk between younger and older groups who drank moderately, younger people in the study had greater mortality risks than the older ones at high consumption levels.
The study also found that female drinkers had a higher risk of all-cause mortality than male drinkers did. According to Rahman, this finding “might be a surrogate for weight.” While both men and women can be overweight, he said, “women have more fatty adipose tissue and can convert hormones into potentially carcinogenic substances. Heavier women, for example, have a particular risk of breast cancer.”
Other studies have looked at claims that light drinking has a health benefit. For example, one study noted that drinking at all levels is linked to a higher risk of high blood pressure and coronary artery disease. But, the study said, “Light to moderate alcohol consumption was associated with healthier lifestyle factors.”
Another study found that it is widely assumed that light or moderate drinking is the safest way to to drink alcohol. “Non‐drinkers, both ex‐drinkers and lifelong teetotalers, consistently show an increased prevalence of conditions likely to increase morbidity and mortality compared with occasional or light drinkers. In addition, regular light drinkers tend to have characteristics extremely advantageous to health,” the authors wrote.
A third paper goes even further. Of 30 things linked to diseases of your heart and blood vessels, it said, 90% are found more often among nondrinkers, including body weight.
Neither Schaffner nor Rahman could explain why light drinkers have a lower risk of all-cause mortality than nondrinkers. But they agreed that alcohol is a major public health challenge, not only in the U.S. but around the world. There are 140,000 alcohol-related deaths in this country each year, Rahman said, and there were 2.8 million deaths globally in 2016, according to the Lancet paper.
So whether you raise a glass to Schaffner’s takeaway from the review paper (“don’t drink too much”) or lower it in response to Rahman’s (“don’t drink”), it’s best to imbibe responsibly, if at all.
