January 17, 2014
News Review From Harvard Medical School -- Heavy Drinking May Speed Mental Decline
Years of heavy drinking in middle age can lead to faster mental decline in later life for men, results of a long-term study suggest. The study included 5,054 men and 2,099 women. They were asked about their drinking habits 3 times in 10 years. Then, in their mid-50s, they took a mental-skills test. It assessed memory and executive function, which includes reasoning and planning abilities. They repeated the test twice in the next 10 years. Mental decline occurred about 1½ to 6 years faster in men who had at least 2½ drinks a day (36 grams of alcohol) than in men who drank less. No such differences were seen for women, however. Researchers said there were not enough heavy drinkers among women in the study to show any clear effects for them. The journal Neurology published the study January 15. The Associated Press and HealthDay News wrote about it.
By Howard LeWine, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
For most adults, a little alcohol use is linked with multiple health benefits. In general, a little alcohol use means no more than one drink per day for women and no more than two per day for men. It also means avoiding binge drinking.
The usual definition of one drink is:
- 12 ounces of 5% beer
- 5 ounces of table wine (about 12% alcohol)
- 1.5 ounces (a shot) of 80-proof spirits (about 40% alcohol)
The health benefits that have been linked with drinking small amounts of alcohol include better brain function and a lower risk of dementia.
But according to this study, it doesn't take much more alcohol to have just the opposite effect on brain function, at least in men.
The researchers examined the relationship between alcohol use and the rate of decline in memory and thinking. The subjects were middle-aged (ages 44 through 69) at the time their brain function was first tested.
The researchers had previously collected information about their alcohol intake during the last 10 years. Men who had more than an average of 2½ standard drinks per day over a 10-year period had faster declines in memory and thinking than those who drank less or not at all.
The results for women showed a trend toward a faster decline in brain function among heavy drinkers. But the number of women who were heavy drinkers was relatively small. So the difference could have been the result of chance.
It's interesting that the women who did not drink at all had faster decline of brain function than women who had an average of one drink per day. This supports the results of prior studies on the potential benefits of light drinking.
The study only shows that men who are heavy drinkers tend to have a faster decline in brain function. It does not prove that heavy drinking causes the decline. There may be differences in the health habits and behaviors of the heavy drinkers that researchers did not identify. For example, in this study, heavy drinkers were three times as likely to smoke as light drinkers and those who didn't drink.
What Changes Can I Make Now?
There seems to be a fine line between the amount of alcohol that is linked with some health benefits and the amount that clearly is unhealthy. For example, even light to moderate alcohol use is linked with a higher risk of some cancers, such as breast cancer in women.
So what to do? If you don't drink alcohol now, there's no reason to start. But also don't worry if you occasionally have a drink.
How do you know if you may be drinking too much? You can ask yourself this question:
"How many times in the last year have you had X or more drinks in a day?" X equals 5 for men. For women and all adults 65 and older, X equals 4.
If your answer is anything greater than "once in the last year," it could be a sign of unhealthy alcohol use. Or it could suggest that you are at risk of becoming dependent on alcohol.
To consider if you already have a significant alcohol problem, the CAGE test is a better tool. It's called the CAGE test because the first letters of a key word in each question spell "cage."
- Have you ever felt you should cut down on your drinking?
- Have people annoyed you by criticizing your drinking?
- Have you ever felt guilty or bad about your drinking?
- Have you ever had a drink first thing in the morning to steady your nerves, get rid of a hangover, or as an eye-opener?
If you responded "yes" to more than one question, it's highly likely that you have a dependence on alcohol.
What Can I Expect Looking to the Future?
The current advice about reasonable alcohol use will remain the same:
- An average of no more than one drink per day for women and two per day for men
- No more than three drinks in one sitting for women and no more than four for men