A meta-analysis done by the Centre for Addiction and Mental Health (CAMH) into the relationship between alcohol consumption and heart disease provides new insight into the long-held belief that drinking a glass of red wine a day can help protect against heart disease.
"It's complicated," says Dr. Juergen Rehm, director of social and epidemiological research at CAMH. Dr. Rehm's paper, co-authored by Michael Roerecke, was recently published in the journal Addiction. "While a cardioprotective association between alcohol use and ischaemic heart disease exists, it cannot be assumed for all drinkers, even at low levels of intake," says Dr. Rehm.
Ischaemic heart disease is a common cause of illness and death in the Western world. Symptoms are angina, heart pain, and heart failure. Based on 44 studies, the analyses used 38,627 ischaemic heart disease events (including deaths) among 957,684 people.
"We see substantial variation across studies, in particular for an average consumption of one to two drinks a day," says Dr. Rehm. The protective association may vary by gender, drinking patterns, and the specific health effects of interest. Differential risk curves were found by sex, with higher risk for morbidity and mortality in women.
Moreover, for any particular individual, the relationship between alcohol consumption and ischemic heart disease should not be isolated from other disease outcomes. Even at low levels, alcohol intake can have a detrimental effect on many other disease outcomes, including on several cancers.
"Even one drink a day increases risk of breast cancer, for example," says Dr. Rehm. "However, with as little as one drink a day, the net effect on mortality is still beneficial. After this, the net risk increases with every drink."
"If someone binge drinks even once a month, any health benefits from light to moderate drinking disappear." Binge drinking is defined more than four drinks on one occasion for women, and more than five for men.
Given the complex, potentially beneficial or detrimental effects of alcohol on ischaemic heart disease in addition to the detrimental effects on other disease categories, any advice by physicians on individual drinking has to take the individual risk constellation (such as familial predisposition for certain diseases and behavior with respect to other risk factors) into consideration.
"More evidence on the overall benefit-risk ratio of average alcohol consumption in relation to ischaemic heart disease and other diseases is needed in order to inform the general public or physicians about safe or low-risk drinking levels," the study concludes. "Findings from this study support current low-risk drinking guidelines, if these recognize lower drinking limits for women."
The Centre for Addiction and Mental Health (CAMH) is Canada's largest mental health and addiction teaching hospital, as well as one of the world's leading research centres in the area of addiction and mental health. CAMH combines clinical care, research, education, policy development and health promotion to help transform the lives of people affected by mental health and addiction issues.
CAMH is fully affiliated with the University of Toronto, and is a Pan American Health Organization/World Health Organization Collaborating Centre.
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Michael Roerecke and Jürgen Rehm. The cardioprotective association of average alcohol consumption and ischaemic heart disease: A systematic review and meta-analysis. Addiction 107: doi: 10.1111/j.1360-0443.2012.03780.x
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Addiction (www.addictionjournal.org) is a monthly international scientific journal publishing more than 2000 pages every year. Owned by the Society for the Study of Addiction, it has been in continuous publication since 1884. Addiction is the top journal in the field of substance abuse and is number one in the 2010 ISI Journal Citation Reports © Ranking in the Substance Abuse Category. Addiction publishes peer-reviewed research reports on alcohol, illicit drugs and tobacco, bringing together research conducted within many different disciplines, as well as editorials and other debate pieces.