Studies in women are at odds on alcohol’s risks and benefits
Last May, a huge Harvard study of more than 85,000 women showed that moderate drinking — about one drink a day — lowers the overall risk of death, without apparently raising the odds of dying from breast cancer.
Six weeks later, another big study — of more than 16,000 women — came to a more sobering conclusion: Over a lifetime, even one drink a day may slightly raise breast cancer risk.
Given that women are roughly six times more likely to die of heart disease than breast cancer, and that alcohol protects against heart disease in both men and women, perhaps women shouldn’t worry about a small increase in breast cancer risk from drinking.
But many do.
Which is precisely why the new data on women and drinking is so frustrating. Taken together, the data suggest that drinking decisions for women may be even more complex than for men because risks and benefits are more closely balanced.On top of that, evidence is piling up that women’s bodies are far more vulnerable than men’s to the toxic effects of booze.
All of which suggests that before you pour the next drink, ladies, you might want to ponder the research — on both sides.
Medically, the main argument for drinking is that it protects against heart disease, the leading killer of both men and women.
Alcohol can change the balance of lipoproteins in the blood, boosting ”good” cholesterol (HDL) and lowering “bad” (LDL), notes Dr. Enoch Gordis, director of the National Institute on Alcohol Abuse and Alcoholism.
It can also reduce, at least temporarily, the ability of platelets in the blood to form clots that can block coronary arteries.
And at least some types of alcohol, notably red wine, contain anti-oxidants that may keep LDL from oxidizing. In oxidized form, LDL leads to fatty plaques that clog vessels.
Primarily because of the cardiovascular effects, the Nurses’ Health Study of 85,709 women showed that moderate drinkers (women who had between one-half and one drink a day) had a 12 percent lower risk of death from all causes than women who drank nothing and a 26 percent lower risk those who drank heavily.
A drink was defined as a 4-ounce glass of wine, a 12-ounce can or bottle of beer and a half-ounce of spirits.
But not all women benefit from moderate drinking. In fact, the Nurses’ study showed that if a woman is at low risk of heart disease to begin with, either because she is under 50 or has no coronary risk factors, moderate drinking doesn’t carry any health benefit, though it won’t hurt either.
The women who do benefit are those at higher-than-normal risk of heart disease, notes Dr. Walter Willett , one of the authors and a professor of epidemiology and nutrition at the Harvard School of Public Heath.
Factors that raise heart disease risk include high blood pressure, high cholesterol, diabetes, obesity, a sedentary lifestyle and having a parent who had a heart attack before age 60.
And there’s other evidence that a drink or two may do more than just keep the heart doctor away.
One study of nearly 10,000 women over 65, published last year in the Journal of the American Medical Association, showed that women who drank moderately did better than nondrinkers on physical function tests, perhapsbecause alcohol was a sign that the drinkers had a more active lifestyle.
Another study, published in 1994 in the American Journal of Public Health, showed that women — and men — who drank moderately got less depressed under stress than teetotallers or heavy drinkers, again perhaps because moderate drinking was a marker for other healthful habits that offset stress.
But drinking clearly has a dark side for women, too, quite apart from the obvious — alcoholism and fetal alcohol syndrome.
At one and a half to two drinks a day, the Nurses’ study showed, the risk of dying from breast cancer — a risk that was invisible at lower levels — increases, perhaps because alcohol raises levels of the hormone estrogen, which promotes some breast cancers. At more than two and a half drinks a day, overall mortality begins to rise, too.
And the risk of breast cancer may increase with as little as one drink a day, says Matthew Longnecker, an epidemiologist at the National Institute of Environmental Health Sciences whose report on more than 16,000 women was published in June.
In contrast to the Nurses’ study, which focused on death rates, Longnecker studied the risk of getting breast cancer and found a daily drink was linked to a 40 percent increase in risk, suggesting that 5 to 10 of the 184,300 cases of breast cancer expected this year might be attributed to alcohol consumption.
“That is a stronger association than what had been found in previous studies,” he says, perhaps because he studied lifetime consumption, not recent drinking.
On the other hand, Dimitrios Trichopoulos, an epidemiologist at the Harvard School of Public Health, found in a smaller study of 2,400 women last year that it takes three drinks a day to increase breast cancer risk at all.
To some, like epidemiologist Lynn Rosenberg of Boston University, all this simply means that any causal link between alcohol and breast cancer is farfrom established. But she adds that since “we don’t know how to reduce the risk of breast cancer, even the hint of an increased risk may be enough to persuade some women, particularly younger women at low risk of heart disease, not to drink.”
Others, notably the Wine Institute, a California-based industry association, put a cheerier spin on ambiguous findings, especially the hint — from Longnecker’s study — that the kind of alcohol a woman drinks may affect breast cancer risk.
Longnecker acknowledges that he found wine “was not related to risk of breast cancer,” while beer and liquor were. Beer drinkers had a 25 percent increase in breast cancer risk and liquor drinkers, an 18 percent increase. If wine has an advantage, it might be because it contains so-called “phenolic compounds” that may be protective, he and his team wrote, while beer and liquor “may contain substances that have estrogenic activity.”
But he and other epidemiologists stress that other studies, including somefrom Italy and France, found an increased breast cancer risk even among wine drinkers, which means the issue is far from settled.
And there is growing evidence that women’s bodies are more vulnerable than men’s to alcohol, says Dr. Charles S. Lieber , director of the alcoholism research and treatment center at the Bronx Veterans Affairs Medical Center and professor of medicine at the Mt. Sinai School of Medicine in New York.
In men and women of equal size who consume equal amounts of alcohol, he says, blood levels of alcohol are higher in women, partly because women’s bodies contain less water and more fat, which means alcohol is less diluted in their blood. But women also make less of a stomach enzyme called alcohol dehydrogenase, which helps digest alcohol.
Lieber, whose team recently cloned the gene for this enzyme, says that unlike male alcoholics, who still make some alcohol dehydrogense, female alcoholics make virtually none. And for some women, the ulcer drug Tagamet also exacerbates the problem, making alcohol dehydrogenase even less active.
Women’s livers are particularly vulnerable to alcohol, too, he adds. French studies show men must have about five drinks a day to cause cirrhosis, or heavy scarring, of the liver, while women can get cirrhosis drinking only a glass and a half to two and a half glasses of wine a day.
The bottom line, he says, is that “one drink in a woman of average size is equivalent to two drinks for a man.”
And that is precisely what the revised US government dietary guidelines, issued last week, recommend for those trying to get the health benefits but not the risks of alcohol:
No more than one drink a day for women, two for men.
At this level of consumption, says Willett, alcohol “won’t have overall harmful effects and might even help some women.”
SIDEBAR1EARLY ABUSE IS OFTEN A FACTOR IN ALCOHOLISM
Though male alcoholics outnumber female alcoholics 3 to 1, women seem to suffer medical complications from drinking at far lower levels of alcohol consumption than men. And different factors seem to predispose women to problems with alcohol.
As with men, a family history of alcoholism raises women’s risk of alcoholism, perhaps even more so than for men.
But women, to a greater degree than men, tend to start abusing alcohol during periods of transition like divorce, or when they are in relationships with heavy drinkers, says Norma Finkelstein, director of the Coalition on Addiction, Pregnancy and Parenting in Cambridge.
But perhaps the most telling factor is that many of the 4 million American women who abuse alcohol or are alcoholics were physically or sexually abused as children, says the National Council on Alcoholism and Drug Depencence, Inc., in New York.
But socioeconomic factors also play a part. Alcohol use is most prevalent among white women, according to the Commonwealth Fund Commission on Women’s Health. Seventeen percent of white women report moderate to heavy drinking, compared with 11 percent of African American women, 9 percent of Latinas and 6 percent of Asian women.
Alcohol use also increases with income and education, the Commonwealth Fund found. Roughly 8 percent of women without a high school education are moderate to heavy drinkers, versus 20 percent of those with at least some college. Heavy drinking was defined in this study as having more than two drinks a day.
Some states, Massachusetts foremost among them, have made a special effort to create women-only alcohol treatment programs. Research suggests that when men and women are treated together, “the men do better and the women do worse” because women “pay attention to what men need, not what they need,” says Finkelstein.
Co-ed treatment groups can make it more difficult for women to talk about sex abuse, incest, violence and feelings of guilt and shame about raising children while drinking or having drunk alcohol during pregnancy, which can lead to fetal alcohol syndrome, adds Alan Milner, director of the Massachusetts Drug and Alcohol Hotline.
Women drinkers also face more scorn from society than men, adds Dr. Roger Weiss, clinical director of the alcohol and drug abuse program at McLean Hospital in Belmont.
Once in treatment, though, women who are both depressed and alcoholic do better than women who are not depressed, he says, though this is not true for men. Perhaps, he says, depression makes women “more ready for treatment.”
SIDEBAR2
FOR MORE INFORMATION
If you need information or help with an alcohol problem, you may call:
The Coalition on Addiction, Pregnancy and Parenting, 617-661-3991.
The Alcohol and Drug Abuse Hotline, 617-445-1500 or 1-800-327-5050. For the deaf, the TTY number is 617-354-0997.
Alcoholics Anonymous, 617-426-9444.