While the debate over the possible health benefits of drinking continues to bubble, a new study finds that abstainer's and heavy drinkers have a higher mortality risk than moderate drinkers.
"This fascinating, detailed and very meticulous study approached the well-established association between moderate alcohol intake and health benefits with a skeptical eye," said Dr David L. Katz, director of the Prevention Research Centre at Yale Medical School, who was not involved in the study.
"In essence, the authors asked, 'What if people who abstain from alcohol have a higher mortality risk than moderate drinkers not because they don't drink, but because they are sicker or are former problem drinkers?'" he said.
Their analysis shows this proposition to be partly true, but not the whole truth, Katz said.
"Indeed, some of the mortality disadvantage seen in nondrinkers is explained by prior problem drinking, or established health problems. But even when all such factors are accounted for, moderate drinking still conferred a net survival advantage," he said.
The report is published in Alcoholism: Clinical & Experimental Research.
For the study, a team led by Charles J. Holahan, a professor in the department of psychology at the University of Texas at Austin, collected data on 1,824 older adults, aged 55 and 65. They divided the subjects into four groups - light, moderate and heavy drinkers and abstainer's - and did a 20-year follow-up analysis from the study baseline.
"Although alcohol misuse is linked to many medical conditions, considerable epidemiological evidence indicates that moderate alcohol use is related to reduced total mortality," Holahan said.
The participants were asked about daily alcohol consumption, problem drinking, and other questions about their health and social behaviour.
"Controlling only for age and gender, mortality was highest among abstainer's and heavy drinkers and lowest in moderate drinkers," Holahan said.
When the researchers took into account former problem drinking, existing health problems, and key sociodemographic and social-behavioural factors, they found a substantially reduced mortality benefit among moderate drinkers compared to abstainer's.
Yet even after adjusting for all these factors, people who didn't drink and heavy drinkers still had increased mortality risks of 49% and 42%, respectively, compared with moderate drinkers, researchers noted.
Abstainer's usually have other health issues
The slightly higher relative risk for light drinkers disappeared when all the factors were taken into account, they added.
The health benefits of moderate drinking are complicated because a number of health risks are associated with not drinking in later life, the researchers said.
"Our findings demonstrate that abstainer's were significantly more likely to have had prior drinking problems, to be obese, and to smoke cigarettes than moderate drinkers and scored significantly higher than moderate drinkers on health problems, depressive symptoms and avoidance coping," Holahan said.
"In addition, abstainer's were significantly lower than moderate drinkers on socioeconomic status, physical activity, number of close friends and quality of friend support, and significantly less likely to be married than moderate drinkers. Moreover, all of these factors that were associated with abstention significantly predicted mortality."
In the study, Holohan and colleagues noted several potential limitations of their study: the findings were not experimental, alcohol consumption was based on self-reports, and lifetime abstainer's were not included in the study, among other things.
The researchers also caution that any health benefits are linked to moderate drinking only. Federal health agency guidelines recommend no more than two drinks a day for men, and no more than one a day for women.
"Older persons drinking alcohol should remember that consuming more than two drinks a day exceeds recommended alcohol consumption guidelines in the US and is associated with increased falls, a higher risk of alcohol use problems, and potential adverse interactions with medications," Holahan said "Moreover, nondrinkers should not start drinking to try to enhance their health, and individuals who are or plan to become pregnant, or have alcohol problems or medical conditions that could be worsened by alcohol should not drink."
Key is moderation
There are several take-away messages, Katz said. The first is that moderate drinking does, indeed, confer a health benefit.
"The second is that benefit is probably somewhat smaller than most prior studies suggest; alcohol intake should not be anyone's primary health promotion strategy. And, the third is that alcohol is the quintessential double-edged sword. Some habitual intake - that glass of wine with dinner, for instance, is decisively good for most people, but an excess is decidedly bad," he said.
Other studies have also suggested that the benefits of moderate drinking are due to other factors than the alcohol itself.
A recent major French study published in the European Journal of Clinical Nutrition links moderate drinking to a lower risk for cardiovascular disease, but challenges the notion that moderate drinking gets the credit.
Instead, the researchers say, people who drink moderately tend to have a higher social status, exercise more, suffer less depression and enjoy superior health overall compared to heavy drinkers and lifetime abstainer's. (August 2010)
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