Researchers know that both hormones and alcohol can affect cognitive abilities. A study in the July issue of Alcoholism: Clinical & Experimental Research closely examines specific elements of those effects. Results indicate that long-term moderate drinking may be associated with enhanced visuospatial processes among postmenopausal women. The data also suggest that estrogen replacement therapy (ERT) alone and in combination with the hormone progestin is associated with enhanced visuospatial processes, but only when the visuospatial task is difficult.
"Cyclic hormonal changes that occur naturally for premenopausal women make it difficult to include young women in research studies," explained Laura J. Tivis, associate professor of research at The University of Oklahoma Health Science Center and first author of the study. "Hormones can affect a number of things about us, including cognition and mood state. Thus, if the women involved in a research study are at different phases of their menstrual cycles, which is likely to be the case, a confound exists since we know that hormones may directly or indirectly affect the study variable, in this case, cognition."
"People’s differences – whether due to race, age or gender – do effect how the body responds to stress, medications, toxins and disease," added Richard Trautman, M.D. of The University of Oklahoma Health Science Center. "The body's response to alcohol is no exception. There is a difference in the way a woman's body reacts to alcohol as compared to a man. An example is the effect that alcohol has on the liver in the two sexes. Women develop liver disease with a lower average intake of alcohol and in a shorter length of time than men."
Tivis said that although several studies have examined moderate drinking and its potential effects on cognitive abilities, none of them specifically looked at visuospatial abilities. Furthermore, although it has been established that acute administration of alcohol impairs visuospatial performance, this study examines the chronic effects of moderate amounts of alcohol on visuospatial functioning. (Acute effects are studied within a controlled laboratory environment when alcohol is given to participants, who are then asked to perform certain cognitive tasks. Chronic effects are studied when people drink at a designated level over long periods of time.)
For this study, researchers examined 214 postmenopausal women (168 were moderate drinkers, 46 were teetotalers) who were part of a larger study on the effects of moderate alcohol consumption and ERT on cognition. Of the total 214, 139 used ERT; 75 did not. Of the 139 ERT users, 76 used progestin in addition to ERT; 63 did not. All of the women who used ERT with/without progestin had been doing so for at least one full year prior to enrollment. All of the women were given the Block Design (BD) test from the Wechsler Adult Intelligence Scale-Revised as a measure of visuospatial functioning. Data were gathered using a traditional BD raw score for which points were given dependent upon the length of time to completion. In addition, progress was assessed at 30-second intervals.
"When evaluating the process of visuospatial functioning," said Tivis, "and not just the final product, we found that performance was different for moderate drinkers compared to teetotalers. When performance for all of the nine-block designs were summed and averaged, we found that in the period beginning 60 seconds after we said ‘go ahead and start,’ and 120 seconds into the task, teetotalers did not ‘improve’ as much as the moderate drinking groups. Imagine if someone were putting together a complex puzzle, and we want to see how many pieces they could correctly place. We start timing them when we say ‘go.’ We decide to count pieces placed between 60 and 120 seconds after they have begun. Now imagine that the moderate drinkers, as a group, placed significantly more pieces correctly during that period than did the teetotalers, as a group. This analogy is similar to what we found. Importantly, the three different levels of moderate drinkers did not differ from one another. We can only say that they differed from the teetotalers."
Tivis explained that her study differentiated between women using ERT with/without progestin and those who did not use ERT to determine whether or not ERT and progestin use might be associated with visuospatial functions independent of moderate alcohol use.
"Because postmenopausal women do not cycle," she said, "we did not have to worry about the ‘up and down’ nature of hormone levels like we would have seen in younger women. However, postmenopausal women still have some estrogen in their systems. For those who do not use ERT, these levels are very low. In contrast, those who do take ERT have relatively high levels of estrogen. In women who use hormone replacement, these levels remain fairly stable so long as they take their hormone replacement regularly. The same can be said for those who do not take hormone replacement; their levels tend to stay fairly stable and low. We differentiated so that we could compare visuospatial functioning between groups who were theoretically different only with respect to their estrogen and progestin levels; users were fairly high and nonusers were fairly low."
Tivis and her colleagues found that the ERT non-users performed significantly worse than the women who used ERT alone or in combination with progestin, but only on the most difficult block design. "This is an interesting finding because it suggests that ERT use may facilitate visuospatial functioning," said Tivis, "and that’s not an effect that we would expect, given early findings that estrogen in young women appears to have a negative effect on visuospatial functioning."
Clearly, said Trautman, "not all postmenopausal women are the same." A point, he added, that needs to be taken into consideration when utilizing this population in alcohol research. Tivis agrees, adding that "alcohol researchers who study aging women should carefully consider potential effects of ERT and ERT plus progestin in their work. Likewise, ERT researchers should carefully evaluate the quantity and frequency with which their subjects drink alcohol. In addition, this study suggests that the relationship among ERT, progestin, and cognition is not yet clearly established."
Tivis reiterated that "drinking moderate amounts of alcohol or using ERT does not cause postmenopausal women to have better visuospatial skills. However, our data suggest that moderate drinking – no more than one drink per day – and use of estrogen replacement therapy may be associated with better visuospatial performance," she said.