Boston, MA -- Hypertension affects some 65 million people in the United States, making it a massive public health burden. It's associated with a twofold increased risk of cardiovascular disease (CVD) and total mortality. Studies have shown that moderate consumption of alcohol, up to a limit of one to two drinks a day, may decrease the risk of CVD and total mortality. Drinking more than two drinks a day, however, may increase the risk of hypertension.
Previous studies that looked at the relationship between hypertension and CVD mortality showed a link between moderate consumption and lower CVD mortality in individuals with hypertension. But no prior studies had examined whether moderate consumption was associated with non-fatal myocardial infarction (MI), such as a heart attack or stroke, and none had repeatedly collected information on individual drinking habits. In a new, long-term study, researchers at the Harvard School of Public Health (HSPH), Beth Israel Deaconess Medical Center and Dutch research institute TNO Quality of Life and Wageningen University, the Netherlands, found that, among hypertensive men, moderate alcohol consumption was associated with a decreased risk of fatal and non-fatal heart attack. The researchers also found that rates of stroke and death from heart disease and all causes did not differ for hypertensive men who drank moderate amounts of alcohol and those who drank no alcohol.
"This was the first study to our knowledge that examined the risk of heart attacks among men with high blood pressure who drank moderately. Because excess alcohol intake clearly increases blood pressure, many men with hypertension are counseled not to drink, but our results suggest that may not be necessary if men drink safely and responsibly," said lead author Joline Beulens, a PhD-fellow at TNO Quality of Life and Wageningen University and a visiting scholar at HSPH when the study began.
The study appears in the January 2, 2007, issue of the Annals of Internal Medicine.
The researchers analyzed data from 11,711 hypertensive men from the Health Professionals Follow-Up Study, which was launched in 1986. Every four years, participants filled out a survey and noted the frequency with which they drank beer, red wine, white wine and liquor. Cases of non-fatal MI, fatal heart disease and stroke were documented from 1986 to 2002.
The results showed that, during that time span, 653 cases of total MI were documented, 279 fatal and 374 non-fatal. The authors found that consuming one to two drinks a day was associated with a decreased risk of fatal and non-fatal MI. No association was observed between alcohol consumption and risks of cardiovascular and total mortality. The study also investigated whether men changed their alcohol consumption after hypertension was diagnosed and whether specific alcoholic beverages or number of drinking days per week influenced the risk of heart attack.
Prior research has shown that one way alcohol consumption decreases the risk of heart disease is by increasing the levels of HDL cholesterol and possibly thinning the blood. Although those mechanisms were not the focus of this study, the relationship between alcohol drinking and lower heart attack risk remained after accounting for many differences between drinkers and non-drinkers, including their diet, physical activity and weight. Very light drinkers who consumed less than one drink every two to three days did not have lower risk than non-drinkers. However, because drinking three or more drinks a day increases blood pressure, it is important to adhere to the USDA guideline of one to two drinks a day or less.
The study's limitations include that only male health care professionals participated, so it is not known whether the findings apply to women or men in different occupations.
"It is important for all individuals with high blood pressure to discuss their alcohol intake with their physicians, as heavy consumption, even occasionally, can raise blood pressure. However, our results suggest that men with high blood pressure seem to have the same lower risk associated with moderate drinking that other men do," said Kenneth Mukamal, internist at Beth Israel Deaconess Medical Center and associate professor of medicine at Harvard Medical School.
The study was supported by grants from the National Institutes of Health, a travel grant from the Dutch Heart Association and a research exchange award from European Research Advisory Board.
"Alcohol Consumption and Risk for Coronary Heart Disease Among Men With Hypertension," Joline W.J. Beulens, Eric B. Rimm, Alberto Ascherio, Donna Spiegelman, Henk F.J. Hendriks, Kenneth J. Mukamal, Annals of Internal Medicine, 2007; 146:10-19.
Harvard School of Public Health is dedicated to advancing the public's health through learning, discovery, and communication. More than 300 faculty members are engaged in teaching and training the 900-plus student body in a broad spectrum of disciplines crucial to the health and well being of individuals and populations around the world. Programs and projects range from the molecular biology of AIDS vaccines to the epidemiology of cancer; from risk analysis to violence prevention; from maternal and children's health to quality of care measurement; from health care management to international health and human rights. For more information on the school visit: www.hsph.harvard.edu