Guest guest Posted January 20, 2005 Report Share Posted January 20, 2005 Hi All, Alcohol benefits brains, says the pdf-available article discussed and presented below. The full article is last. C B C . C A N e w s - F u l l S t o r y : ---------------------------------------------------------------------- ---------- Drink a day protects aging brain, women's study shows Last Updated Wed, 19 Jan 2005 20:54:05 EST CBC News TORONTO - Older women who enjoy having a glass of wine with dinner or an occasional nightcap may be helping to prevent the onset of dementia, a new study suggests. As part of the ongoing Nurses' Health Study, researchers in the U.S. looked at almost 12,500 women between the ages of 70 and 81 for up to 15 years. Low-to-moderate consumption of alcohol shows health benefits. The team tracked the women's alcohol consumption, and tested their memory and concentration. The study appears in Thursday's issue of The New England Journal of Medicine. Researchers found women who drank an average of one drink per day had a 20 per cent lower risk of cognitive impairment, compared to nondrinkers. Drinking less than 15 grams of alcohol per day in wine, beer and spirits all showed benefits. Doctors who study Alzheimer's and other forms of dementia say it makes sense that alcohol protects the brain since it's been shown to protect the heart. One theory suggests alcohol improves blood flow to both organs. " There's a lot of evidence now that the same kind of things that are good for your overall cardiovascular system are good for your brain as well, " said the study author and epidemiologist Francine Grodstein of Brigham and Women's Hospital in Boston. But it's impossible to say for sure that it's the alcohol alone that helps cognitive abilities based on an observational study like this one. The study's authors aren't sure that having more than one drink a day is beneficial since there weren't enough women in the study drinking that much to draw conclusions. The findings probably apply to men as well as women, although other studies with more measurements over time are needed. The take-home message is, " If you would like to enjoy a glass of red wine with your dinner go ahead and enjoy it, " said Carol Greenwood, a nutritional scientist at Toronto's Baycrest Centre. In an editorial accompanying the study, Dr. Denis and Bienias said those seeking to " maximize cognition in old age " should keep in mind the harmful effects of alcohol abuse. For those who can't drink alcohol or prefer not to, experts say diet and exercise can be just as beneficial for the heart and, by extension, the brain. This week in New Engl J Med, 352 (3) Jan 20, 2005 Effect of Moderate Alcohol Consumption on Cognitive Function in Women The adverse effects of excess alcohol intake on cognitive function are well established, but the effect of moderate alcohol consumption is uncertain. This study assessed cognitive function in relation to alcohol intake among women in the Nurses' Health Study who were 70 to 81 years of age and then reassessed it two years later. The data suggest that up to one drink per day does not impair cognitive function and may actually decrease cognitive decline. Related Editorial New Engl J Med, 352, Jan 20 (3) 2005 289-290 Alcohol Consumption and Cognition Denis A. , M.D., and L. Bienias, Sc.D. Related Article by Stampfer, M. J. Loss of cognitive function in old age, especially severe cognitive loss due to Alzheimer's disease, is a serious public health problem that will only increase as the number of people in the oldest age groups increases in the United States and other developed countries. Effective preventive measures are the key to coping with this potentially overwhelming problem as it emerges and are even more important than is treatment of affected persons. Unfortunately, very few effective means of either prevention or treatment have been identified to date. Studies that provide clues about prevention are therefore welcome. In this issue of the Journal, Stampfer et al.1 report that as compared with abstinence, low-to-moderate consumption of alcohol was associated with better cognition both cross-sectionally and over time in a study that involved more than 11,000 U.S. nurses. Consumption of 1.0 to 14.9 g of alcohol per day, or about one drink per day or less, was associated with a reduced risk of cognitive impairment (relative risk as compared with abstinence, 0.85; 95 percent confidence interval, 0.74 to 0.98). The women's cognitive status was characterized in terms of both their cross-sectional performance on brief telephone tests of cognitive function and the difference in results between tests administered an average of 1.8 years apart. The investigators clearly recognized the importance of prevention by focusing on the relation of a modifiable everyday behavior to the preservation of cognitive function in later life. They examined this relation in a large, longitudinal observational study — the Nurses' Health Study — and considered alcohol consumption over a long period, up to 15 years. Cognitive function was assessed by a telephone interview, a fairly new technique, but there is little suggestion that the use of this technique underestimated cognitive decline because of undue loss of impaired subjects on repeated testing. Overenthusiasm for a potentially preventive measure, however, can be risky, and as with all studies, this report has important limitations that we must recognize and understand. The use of an observational study to provide information on the relation of a lifestyle variable or a health habit to cognition presents difficult and complex challenges, especially when that potentially beneficial habit is alcohol consumption. Low-to-moderate alcohol consumption has previously been linked to several positive health outcomes, most convincingly to a decreased risk of coronary heart disease,2 but alcohol abuse is also linked to a wide range of health and social problems according to both common knowledge and formal study.3 Two limitations of the present report deserve particular attention. The first is the direction of the observed association. This study examined whether light-to-moderate alcohol consumption was related to a change in cognitive function. We must recognize, however, that older persons who are in good cognitive and physical health may be more likely than less healthy peers to indulge in low- to-moderate alcohol consumption as part of their social activities. Precise information about older people is limited, but persons who consume moderate amounts of alcohol appear, on average, to have more favorable general health and social characteristics than abstainers.4 Although the observed relation between alcohol and cognition persisted after Stampfer et al. adjusted their analyses for a number of social and health characteristics, demonstrating that the changes in cognition are actually attributable to alcohol consumption is impossible in an observational study. A second and perhaps more important limitation is complex and concerns meaningful measurement of cognition as an outcome. As already noted, Stampfer et al. assessed cognition in two ways, cross- sectionally and as change over time. Assessment of cognition at a single point in time, as in a cross-sectional analysis, is very likely not an informative means of examining cognitive impairment among older persons. Education and culture strongly influence the results of cognitive testing and may also be related to health habits such as alcohol consumption in subtle, difficult-to-measure ways. Among older persons, however, the educational and cultural factors that influence the results of cognitive testing are usually constant over time. To the extent that this is true, these factors influence the measurement of cognition at each point in time, but they do not influence the change in results over time for each person. Thus, a change in results is a far more meaningful measure of cognition than is cross-sectional testing. One must estimate how well Stampfer et al. were able to assess changes in cognitive function over time. The authors attempted to do so by setting a standard for impaired test performance at the second measurement and including the baseline level of performance as a predictor in the model. Unfortunately, the intuition that one can fully assess change as an outcome and distinguish it from the initial level of performance on the basis of measurements at only two times is misleading, since any difference between performance at two points in time necessarily reflects much of the initial cross-sectional level.5 A model assessing change from measurement at three or more times6,7 can adjust for this problem by allowing simultaneous but separate estimation of the level and the change over time and can more accurately distinguish factors associated with the level of cognitive performance (e.g., cultural influences) while empirically testing whether other factors of interest (e.g., alcohol consumption) are related to a change in cognitive performance. The prevention of cognitive decline in old age as well as the conditions underlying it is one of the major public health challenges of the 21st century. Few things are as valuable as the unimpaired ability to reason. In the light of the importance and complexity of the issue, what can readers reasonably conclude about the relation between mild-to-moderate alcohol consumption and cognition? The report by Stampfer and colleagues represents an incremental advance but necessarily leaves a substantial residue of uncertainty. We must await future studies, preferably population-based, that combine the strengths of the present investigation — large size, rigorous conduct, and measurement of the exposure over a long period — with measurement of cognition at a sufficient number of points in time to ensure that we are actually examining changes in cognition. In the meantime, persons seeking to maximize cognition in old age must keep in mind both the uncertainty of the current results and the knowledge that alcohol consumption can be a double-edged sword, with the dangers of overindulgence being all too familiar. References Stampfer MJ, Kang JH, Chen J, Cherry R, Grodstein F. Effects of moderate alcohol consumption on cognitive function in women. N Engl J Med 2005;352:245-253.[Abstract/Full Text] Stampfer MJ, Colditz GA, Willett WC, et al. A prospective study of moderate alcohol consumption and the risk of coronary disease and stroke in women. N Engl J Med 1988;319:267-273.[Abstract] 10th Special report to the U.S. Congress on alcohol and health: highlights from current research. Bethesda, Md.: National Institute on Alcohol Abuse and Alcoholism, June 2000. Fillmore KM, Golding JM, Graves KL, et al. Alcohol consumption and mortality. I. Characteristics of drinking groups. Addiction 1998;93:183-203.[CrossRef][iSI][Medline] Rogosa D, Brandt D, Zimowski M. A growth curve approach to the measurement of change. Psychol Bull 1982;92:726-748.[CrossRef][iSI] Laird NM, Ware JH. Random-effects models for longitudinal data. Biometrics 1982;38:963-974.[iSI][Medline] Diggle P J, Heagerty P, Liang K-Y, Zeger SL. Analysis of longitudinal data. 2nd ed. New York: Oxford University Press, 2002. New Engl J Med, 352 (3) Jan 20, 2005, 245-253. Effects of Moderate Alcohol Consumption on Cognitive Function in Women M. J. Stampfer, Jae Hee Kang, Sc.D., Chen, M.P.H., Cherry, M.D., and Francine Grodstein ABSTRACT Background The adverse effects of excess alcohol intake on cognitive function are well established, but the effect of moderate consumption is uncertain. Methods Between 1995 and 2001, we evaluated cognitive function in 12,480 participants in the Nurses' Health Study who were 70 to 81 years old, with follow-up assessments in 11,102 two years later. The level of alcohol consumption was ascertained regularly beginning in 1980. We calculated multivariate-adjusted mean cognitive scores and multivariate-adjusted risks of cognitive impairment (defined as the lowest 10 percent of the scores) and a substantial decline in cognitive function over time (defined as a change that was in the worst 10 percent of the distribution of the decline). We also stratified analyses according to the apolipoprotein E genotype in a subgroup of women. Results After multivariate adjustment, moderate drinkers (those who consumed less than 15.0 g of alcohol per day [about one drink]) had better mean cognitive scores than nondrinkers. Among moderate drinkers, as compared with nondrinkers, the relative risk of impairment was 0.77 on our test of general cognition (95 percent confidence interval, 0.67 to 0.88) and 0.81 on the basis of a global cognitive score combining the results of all tests (95 percent confidence interval, 0.70 to 0.93). The results for cognitive decline were similar; for example, on our test of general cognition, the relative risk of a substantial decline in performance over a two-year period was 0.85 (95 percent confidence interval, 0.74 to 0.98) among moderate drinkers, as compared with nondrinkers. There were no significant associations between higher levels of drinking (15.0 to 30.0 g per day) and the risk of cognitive impairment or decline. There were no significant differences in risks according to the beverage (e.g., wine or beer) and no interaction with the apolipoprotein E genotype. Conclusions Our data suggest that in women, up to one drink per day does not impair cognitive function and may actually decrease the risk of cognitive decline. ---------------------------------------------------------------------- ---------- Habitual excess alcohol intake impairs the brain,1 but the effect of moderate consumption is unclear. A cognitive benefit from moderate alcohol intake is plausible, given the strong link between moderate alcohol intake and the decreased risk of cardiovascular disease2,3; cognitive impairment and cardiovascular disease share common risk factors.4 In addition, Ruitenberg et al. reported that moderate alcohol consumption was related to a decreased risk of both vascular and nonvascular dementia5 and proposed that moderate alcohol consumption may increase the release of brain acetylcholine. Most studies,6,7,8,9,10,11,12,13,14,15 but not all,16,17,18 have tended to show that moderate drinkers do better on cognitive tests than nondrinkers; however, few studies have had samples that were large enough to yield statistically significant results or to assess long- term, stable patterns of alcohol intake and very early signs of cognitive decline. Also, many studies have been limited by inadequate control for confounding, and none have examined specific alcoholic beverages. We addressed these issues in the Nurses' Health Study. ... Mini–Mental State Examination (MMSE). ... we constructed separate regression models for alcohol from beer, white wine, red wine, and spirits and controlled for alcohol from the other sources within each level of total alcohol intake. In regression models, we considered the following potential confounding variables, possibly related to both cognitive function and alcohol intake: age at the time of the interview (continuous); highest educational degree (registered nurse or associate's degree, bachelor's degree, or graduate degree); a history of hypertension, high cholesterol levels, diabetes, or heart disease (yes vs. no); level of physical activity, measured in metabolic-equivalent hours per week (quintiles); age at menopause; use of postmenopausal hormone therapy (current, past, or never); use of vitamin E supplements (yes vs. no); body-mass index (the weight in kilograms divided by the square of the height in meters [less than 22.0, 22.0 to 24.9, 25.0 to 29.9, or 30.0 or more]); cigarette-smoking status (current, past, or never); aspirin use (once or twice per week, three or more times per week, or none); ibuprofen use (yes vs. no); scores for the mental health index ... Results In this cohort, 51 percent of the women were nondrinkers, 44 percent drank 1.0 to 14.9 g of alcohol per day (up to about one drink), and 5 percent consumed 15.0 to 30.0 g per day. Health and lifestyle characteristics generally did not vary substantially according to alcohol intake (Table 1). Women consuming less than 15.0 g of alcohol per day tended to have slightly better mean cognitive scores than nondrinkers (Table 1). After adjustment for potential confounding factors, such women had significantly better mean cognitive scores than nondrinkers on all three primary outcomes (Table 2 and Figure 1). We found no significant differences in cognitive performance between nondrinkers and those drinking 15.0 to 30.0 g of alcohol per day, although the size of the latter group was small (648 women). For the TICS, each additional year of age was associated with a mean difference of 0.15 point; thus, for participants who were 70 to 81 years of age, drinking 1.0 to 14.9 g of alcohol per day was cognitively equivalent to being approximately a year and a half younger (mean difference, 0.21; range, 0.11 to 0.30). Women who drank less than 15.0 g of alcohol per day had a risk of cognitive impairment that was approximately 20 percent lower than that among nondrinkers (Table 2), with and without adjustment for confounders, which was statistically significant for all three primary outcomes. For example, for the global cognitive score, women who drank 1.0 to 14.9 g of alcohol per day had an adjusted relative risk of cognitive impairment of 0.81 (95 percent confidence interval, 0.70 to 0.93), as compared with nondrinkers. Although we measured cognitive decline over a short period (mean, 1.8 years), women who drank 1.0 to 14.9 g of alcohol per day had a lower risk of substantial cognitive decline during this period than did nondrinkers (Table 3). The findings were statistically significant for the TICS score and the verbal memory score. For women who drank 1.0 to 14.9 g of alcohol per day, as compared with nondrinkers, each type of beverage was significantly associated with a lower risk of cognitive impairment, with relative risks according to the global cognitive score ranging from 0.68 for beer to 0.84 for red wine. All the confidence intervals for specific beverages broadly overlapped. When we analyzed the likelihood of a substantial decline in cognitive function, the results were similar to those for baseline analyses, with no marked differences according to the type of beverage. Finally, excluding women with diabetes from the analysis did not change the results. Also, we found no material interactions between alcohol intake and the apolipoprotein E 4 allele. With respect to the global cognitive score, the relative risk of cognitive impairment among moderate drinkers, as compared with nondrinkers, was 0.84 (95 percent confidence interval, 0.59 to 1.21) among those without the 4 allele and 0.84 (95 percent confidence interval, 0.46 to 1.53) among those with the allele. Discussion We found that older women who consumed up to one drink per day had consistently better cognitive performance than nondrinkers. Overall, as compared with nondrinkers, women who drank 1.0 to 14.9 g of alcohol per day had a decrease in the risk of cognitive impairment of about 20 percent. Moreover, moderate drinkers were less likely to have a substantial decline in cognitive function over a two-year period. We found similar inverse associations for all types of alcoholic beverages. Our study had several limitations. We could not assess the effect of high levels of alcohol intake, since there were few heavy drinkers in our cohort. Also, cognitive decline was assessed only over a two- year interval; thus, the association between alcohol consumption and longer-term cognitive decline could not be evaluated. Information on alcohol consumption was self-reported, perhaps leading to some misclassification. However, our assessment of alcohol intake was validated on the basis of dietary records and levels of biochemical markers and has been used to predict several disease outcomes in this cohort.34,35 Our telephone assessment of cognitive function may also have resulted in some misclassification. However, we found that this approach has high rates of reliability and validity in comparison with in-person assessments. Furthermore, using results from the telephone assessment method, we have observed strong associations with established predictors of cognitive function (age, level of education, and apolipoprotein E genotype); the magnitude of these associations is similar to that reported with the use of in-person cognitive interviews,27,30 further confirming the validity of our methods. Misclassification of alcohol intake or cognition would tend to result in an underestimate of the associations. We cannot exclude the possibility that women with poor cognition decreased their alcohol intake (reverse causation). This seems unlikely, however, since we specifically excluded heavier drinkers and limited our analyses to those with stable patterns of alcohol intake. Finally, there may be uncontrolled confounding. Moderate drinkers had several favorable health characteristics that may influence cognitive function, such as a decreased incidence of diabetes. However, analyses that excluded women with diabetes yielded similar results. Adjustment for many potential confounders had little effect on the results, suggesting that confounding is unlikely to explain the observed associations. The finding of similar effects for each alcoholic beverage also lends support to a causal interpretation of the association, since patterns of confounding tend to differ according to the type of beverage. Nonetheless, we cannot rule out the possibility of confounding by unmeasured factors. Our observations are generally similar to those in previous studies of alcohol intake and cognitive function. Such studies were all substantially smaller than ours and often showed nonsignificant inverse relations. Two small studies16,17 showed no correlation between the level of alcohol consumption and cognitive function, but four others showed nonsignificant trends toward better cognitive scores among moderate drinkers.6,7,8,9 Three large cross-sectional studies of U.S. blacks,10 French men and women,12 and Japanese Americans36 all showed significantly better cognitive performance among moderate drinkers than among nondrinkers. Similar results were obtained in five prospective studies.11,14,15,37,38 In a study of 333 men, Launer et al.13 reported that the prevalence of cognitive impairment was significantly lower among men with moderate alcohol intake than among nondrinkers, but alcohol intake was not associated with cognitive decline, perhaps owing to the small sample. Several studies showed an apparently stronger association between alcohol intake and cognitive function among women than among men. This difference may reflect a true effect of sex or perhaps less misclassification of moderate alcohol consumption among women. Several mechanisms have been proposed to explain the association of moderate alcohol consumption with better cognition. The most plausible relates to the consistently lower rates of cardiovascular disease among moderate alcohol drinkers in many studies.2,3 This risk reduction has been attributed partly to alcohol-induced elevations in HDL cholesterol and reductions in fibrinogen and other thrombotic factors.3 Thus, moderate intake of alcohol may also help preserve brain vasculature, may prevent subclinical strokes, and could thus result in better cognitive function. In support of this concept, Mukamal et al.39 found that among older persons without cerebrovascular disease, those with moderate alcohol intake had fewer white-matter abnormalities and infarcts on magnetic resonance imaging than nondrinkers. The same authors found pronounced reductions in the risk of both vascular dementia and Alzheimer's disease among persons consuming one to six drinks per week.40 Several studies have assessed whether there is an interaction between alcohol intake and the apolipoprotein E genotype. Ruitenberg et al.5 reported a stronger inverse association between the level of alcohol intake and the risk of dementia among persons with the apolipoprotein E 4 allele than among those without this allele, although the difference between the groups was not significant; Mukamal et al. reported the opposite trend.40 Conflicting findings were also reported for cognitive decline.28,29 On the basis of these results and our finding of no interaction between alcohol intake and the apolipoprotein E 4 genotype, any pronounced interaction seems unlikely. Although the adverse effects of excessive alcohol intake are well known and caution should be exercised in recommending even moderate alcohol intake, our results combined with those of other studies suggest that women who consume up to one drink per day have less cognitive impairment and better cognitive function than nondrinkers. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You are posting as a guest. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.