Why Do Moderate Drinkers Live Longer?
By Kenneth Anderson, MA
Ever since research published by Raymond Pearl in 1926, scientists have known that the relationship between alcohol consumption and longevity is a J-shaped curve. In other words, moderate drinkers, on the average, live the longest with death rates at the bottom of the J-shaped curve. Lifelong abstainers, on the average, die earlier than moderate drinkers, and fall on the left-hand side of the J-shaped curve. Heavier drinkers have higher average mortality rates and on the average, die at the same age as lifelong abstainers. Very heavy drinkers have the highest mortality rates and form the peak at the right-hand side of the J-shaped curve. On the average, very heavy drinkers die earlier than any of the other groups.
Early researchers assumed that the reason that moderate drinkers lived the longest was due to a protective effect of alcohol. However, recent researchers have demonstrated that the reason that lifelong abstainers, on the average, die at younger ages than moderate drinkers is due to confounding factors, rather than to a protective effect of alcohol. Some lay people of my acquaintance have misinterpreted recent announcements that moderate drinking has no protective effect to mean that there is no J-shaped curve and that moderate drinkers die at younger ages than lifelong abstainers. This interpretation is incorrect. The J-shaped curve still stands as true, as does the fact that lifelong abstainers, on the average, die sooner than moderate drinkers. What the researchers have actually done is to identify some of the confounding factors which lead moderate drinkers to live longer than lifelong abstainers, and to demonstrate that this is not due to a protective effect of alcohol.
In 2023, Jinhui Zhao, PhD and his colleagues published a paper in the Journal of the American Medical Association titled “Association Between Daily Alcohol Intake and Risk of All-Cause Mortality.” This paper was a meta-analysis of 107 previous studies with a total of 4,838,825 subjects. This paper reported that several factors significantly confounded the difference in longevity between lifelong abstainers and moderate drinkers: including smoking status, socioeconomic status, race, drinking pattern, median age, and gender.
What does this mean? It means that lifelong abstainers are more likely to be smokers than moderate drinkers and this is a factor which significantly shortens the lifespan of the lifelong abstainer group compared to the moderate drinker group. A greater percentage of lifelong abstainers are poor in comparison to the moderate drinkers, and poor people on average die at a younger age than middle- or upper-class people.
The Zhao study did not go into detail about the impact of race on the difference in mortality rates between lifelong abstainers and moderate drinkers; however, a 2011 paper by Kerr and colleagues found that whites were significantly less likely to be lifelong abstainers than blacks or Hispanics and significantly more likely to be moderate drinkers. Blacks have significantly higher mortality rates than whites; however, paradoxically, Hispanics have significantly lower mortality rates than whites. This is why race is a confounding factor in the difference in mortality rates between lifelong abstainers and moderate drinkers.
The impact of drinking pattern was discussed in a 2018 paper by Saito and colleagues which found that having several abstinence days per week was healthier than daily drinking.
In its supplemental material, the Zhao study reported that additional statistical analyses were run for subjects age 55 and younger and subjects over 55, and that that median age had a significant confounding effect on the difference in mortality rates between lifelong abstainers and moderate drinkers; however, they failed to explain what this effect was. A 2019 paper by Ortola and colleagues found no protective effect of moderate drinking in a cohort of 3,045 individuals over 60 years old in Spain; however, a 2018 study of 99,654 adults aged 55-74 years by Kunzmann and colleagues and a 2019 study of 7,904 older adults by Keyes and colleagues both found lower mortality rates in moderate drinkers compared to lifelong abstainers. It is unfortunate that the Zhao study does not clearly describe how age impacts the difference in mortality rates between lifelong abstainers and moderate drinkers.
When subjects are divided by gender, many studies found that the difference in mortality rates between lifelong abstainers and moderate drinkers were found in men but not in women.
A question of interest which was not addressed by the 2023 Zhao study is whether there are psychological differences between lifelong abstainers and moderate drinkers. Other researchers have investigated this question with contradictory results. A 2022 study by Michelsen and colleagues investigated this question in a sample of 2,510 Danish men. The Michelsen study found that lifelong abstainers were significantly more likely than moderate drinkers to suffer from psychotic disorders, neurosis/anxiety disorders, adjustment disorders, and personality disorders than moderate drinkers.
However, a 2015 study of 11,191 Americans by Marti and colleagues found the exact opposite results. This study found that lifelong abstainers were significantly less likely than moderate drinkers to have a major depressive episode or a diagnosis of anxiety disorder at some point in their lifetimes.
In short, if you don’t currently drink, adding alcohol to your diet won’t increase your lifespan. However, quitting smoking will, whether you drink or not.
Liked this article? You might also be interested in: To Moderate or Abstain? That is the question!
