THURSDAY, March 5, 2009 (HealthDay News) -- If you're over 50, and your friends have noted that you can't handle that third glass of wine as well as you used to, a new study confirms it's not their imagination.
Older adults who are social drinkers can become impaired by alcohol after only one or two drinks and not realize it, University of Kentucky researchers report.
Most studies on drinking are done with college students and involve binge drinking, but little attention has been paid to the effects of social drinking among older adults. As the population ages, there are more older drinkers. Yet little is known about age-related differences in the effects of alcohol, the researchers noted.
"Even though younger and older adults appear to have similar metabolism, the behavioral implications are different," said lead researcher Sara Jo Nixon, now a professor in the department of psychiatry, division of addiction medicine, and director of the Neurocognitive Laboratory at the University of Florida in Gainesville.
Small amounts of alcohol affect older adults more than younger adults, Nixon said. "Older adults thought they were fine when they weren't," she said. "You really can't rely on asking, 'Are you alright to drive,' even with lower amounts of alcohol. This may be particularly true for older adults."
The report was published in the March issue of the Journal of Studies on Alcohol and Drugs.
For the study, Nixon's group recruited 42 men and women aged 50 to 74 and 26 people aged 25 to 35. Participants were given alcohol or placebo to drink. Those given alcohol were given enough to reach the same blood alcohol level.
The researchers then had each person take a test called the Trail Making Test. In this exercise, people are asked to connect numbered and lettered dots as quickly as possible. The test evaluates visual-motor coordination, planning, and the ability to move from one thought to the next.
Each person took the test twice, first 25 minutes after drinking and then 75 minutes after drinking.
The researchers found that older adults did worse on the first test than younger people. "There was a five-second difference that looks to be due primarily to the alcohol," Nixon said. "That's important when you are out driving a car."
Yet, when asked if they felt drunk, the older drinkers said they felt fine, Nixon said. Curiously, during the second test there were no differences between older and younger drinkers, but older drinkers said they were impaired when they weren't, she noted.
"Even moderate drinking can result in cognitive differences that are subtle but significant, and we need to be aware of them," Nixon said.
Dr. James Garbutt, medical director of the Alcohol & Substance Abuse Program at the University of North Carolina at Chapel Hill, said this study highlights the difference between older and younger social drinkers.
"The biggest take-home message for me is that older adults had impairment on this measure of attention and performance with a relatively small amount of alcohol -- about two to three drinks -- compared to younger subjects," Garbutt said. "This highlights the possibility of increased neurocognitive impairment with alcohol in the older population."
The study also noted that older adults were less able to perceive deficits than younger individuals, Garbutt said.
"This raises the possibility that older individuals might be less aware of their impairment after drinking and engage in a potentially dangerous task such as driving," he said.
"However, younger individuals may have other problems, such as impulsivity or lack of experience, that leads them to do dangerous things after drinking. I think it is also important to note that the take-home message is not that younger folks can drink and not have psychomotor problems," he said. "Tests of simulated driving have shown that young folks are, of course, impaired after drinking even when they may think they are not."
For more on drinking, visit the U.S. National Institute on Alcohol Abuse and Alcoholism.