Unlike previous studies, new research conducted at Universidad Autónoma de Madrid (UAM) using more rigorous methods, concludes that moderate alcohol consumption does not have any beneficial effect on mortality in older people.
Although alcohol consumption is a leading cause of disease, disability and death throughout the world, some studies had found certain benefits of low-to-moderate alcohol consumption.
Specifically, epidemiological studies, especially in Anglo-Saxon countries, argued that having one or two drinks per day was associated with lower mortality because of the reduction of deaths due to cardiovascular disease. However, the quality of these studies has been questioned recently due to several methodological issues.
To overcome the limitations of previous studies and clarify whether alcohol consumption has an impact on mortality, researchers of Universidad Autónoma de Madrid (UAM), CIBERESP and IMDEA Food Institute studied 3,045 people aged 60 years and older, representative of the older adult population of Spain.
Between 2008 and 2010 they collected data on alcohol consumption at that time and in each decade of the participants’ life, as well as on lifestyles, illnesses and functional limitations. Later, the participants were followed through 2017 to identify the deaths occurred from the beginning of the study.
“When analyses used lifetime alcohol consumption to prevent selection bias, no differences were found between participants who did not drink at all and those with low-to-moderate alcohol consumption, that is, up to three drinks per day in men and two drinks per day in women”, the authors explain.
“However —they add—, in those who consumed higher amounts of alcohol, mortality was twice as high as in non-drinkers. When only participants without functional limitations were studied, to reduce reverse causation, mortality increased 12% per daily drink”.
In summary, these new findings, published in the journal Addiction, do not evidence any beneficial effects of low-to-moderate alcohol consumption on mortality.
Rosario Ortolá, first author of this work and researcher of Universidad Autónoma de Madrid (UAM), says that “health professionals can use these results in their clinical practice: Never recommend alcohol consumption to their patients. And if they drink because they do not have medical conditions that could be aggravated by alcohol or they do not take medications that can interact with alcohol, the recommendation must always be the same: ‘the least, the better’”.
Methodological issues solved
Some of the problems of previous research are the errors in the selection of study participants. For example, in some studies the apparently lower mortality of low-to-moderate drinkers could be explained by the fact that they are being compared with non-drinkers, a group that also includes ex-drinkers (many of them quit alcohol because of health problems and, therefore, have a higher risk of death). A potential solution is to assign ex-drinkers to other drinking categories according to their lifetime alcohol intake until they quit alcohol.
Another issue is that part of the potential benefits of alcohol in previous studies may be due to health status influencing alcohol consumption, rather than the opposite. Specifically, it is known that healthy people generally consume more alcohol than ill people, because the latter ones quit or reduce intake when they are diagnosed with their condition. This methodological problem, known as “reverse causation”, can be palliated by restricting analyses to people in good health.
Reference:
Ortolá R, García-Esquinas E, López-García E, León-Muñoz LM, Banegas JR, Rodríguez-Artalejo F. Alcohol consumption and all-cause mortality in older adults in Spain: an analysis accounting for the main methodological issues. Addiction. 2019;114:59-68. doi: 10.1111/add.14402.
