One or Two Drinks a Day May Keep Stroke Away
Lead Researcher: Ralph L. Sacco
Moderate alcohol consumption protects against the risk of the most common type of stroke, ischemic stroke (damage to part of the brain caused by blood clots in the brain arteries). Heavy drinkers are at significantly higher risk for ischemic stroke, but they can lower their risk if they cut back or stop, according to the research, reported in the Jan. 6, 1999, issue of the Journal of the American Medical Association. This is the first study to show protective effects of alcohol in Hispanics and confirms benefits to African-Americans.
Dr. Ralph L. Sacco, associate professor of neurology and public health in the Gertrude H. Sergievsky Center, and colleagues examined data from the Northern Manhattan Stroke Study, one of the first population-based studies to compare stroke incidence among Caucasians, African-Americans, and Hispanics living in the same community. The researchers studied 677 multiethnic people 40 years of age or older in northern Manhattan who had suffered a first ischemic stroke between July 1993 and June 1997 to determine the association between alcohol consumption and risk of ischemic stroke. They compared the test population, comprising 19.5 percent whites, 28.4 percent African-Americans, and 50.7 percent Hispanic (mostly Dominican), with a community sample of 1,139 adults (55 percent women) reached through a random telephone survey. The mean age of the study population was 70.
The researchers found that people who consumed moderate alcohol, defined as up to two drinks per day, were at 45 percent lower risk of suffering from ischemic stroke compared with non-drinkers. The protective effect was found in both younger and older groups, in men and women, in whites, African-Americans, and Hispanics, even after adjusting for other possible risk factors for stroke, such as heart disease, high blood pressure, diabetes, current smoking habits, obesity, and level of education.
However, those who consume seven or more drinks per day are at almost three times higher risk for ischemic stroke. A drink is usually defined as a 12-ounce bottle of beer or wine cooler, a five-ounce glass of wine, or 1.5 ounces of 80-proof distilled spirits.
We found this protective effect no matter what type of alcohol was consumed, whether it was wine, beer, or liquor. This is in accord with the majority of studies of the protective effect of alcohol on coronary artery disease, says Dr. Sacco.
While the protective effect of alcohol on heart disease appears to be at least partially related to levels of high-density lipoprotein (HDL, or the so-called good cholesterol), the relative importance of HDL in mediating alcohols effect on stroke risk has not been well studied. Data from the P&S study suggest that the protective effect of alcohol was independent of HDL.
The researchers acknowledge that the effect of moderate alcohol consumption on stroke remains controversial. While several case-control and prospective studies have investigated the effect of alcohol consumption on hemorrhagic stroke (bleeding in the brain caused by the rupture of a blood vessel), the data available on ischemic stroke, which accounts for 80 percent of all stroke cases, are contradictory. This study supports previous studies, conducted predominantly among white subjects, about the relationship between ischemic stroke and alcohol and is the first to find a protective relationship between moderate alcohol use and ischemic stroke in Hispanics.
Many studies have shown that moderate alcohol consumption protects against cardiac disease, but until now its relationship with stroke risk was less certain. Our study provides the first important evidence that moderate alcohol use is associated with a significantly decreased risk of ischemic stroke in a multiethnic, urban, elderly population, says Dr. Sacco.
We were . . . able to demonstrate that former heavy drinkers who decrease their drinking to no more than two drinks per day do not maintain an increased risk of stroke, the authors wrote. Our study supports the advice that heavy drinkers can decrease their risk of ischemic stroke by decreasing or discontinuing their alcohol intake.
While no study has shown a benefit in recommending alcohol use to people who dont drink, our data support the view, endorsed by the National Stroke Association in its stroke prevention guidelines, that among those who are moderate drinkers, continued consumption may provide a reduction of ischemic stroke risk.
The research was supported by grants from the National Institute of Neurological Disorders and Stroke and the General Clinical Research Center.