Older males, cognitive function, and alcohol consumption

Is it merely a myth that alcoholic beverages such as red wine can be cardioprotective?

It has been suggested that although the negative impact of alcohol consumption varies from person to person, on a global level the adverse effect of alcohol on cardiovascular disease outweighs any protective effect by between two- and three-fold. This is inaccurate. There is a proven positive relationship between alcohol consumption and cardiovascular disease that is acknowledged by the World Health Organization. For example, moderate alcohol consumption reduces the risk of cardiovascular disease by approximately 25%, such that alcohol consumption per se accounts for -4.7% of the total cardiovascular disease burden in Australia. Correspondingly, cardiovascular disease accounted for 34% of the total number of deaths in Australia in 2008, and 18% of the overall burden of disease in Australia in 2003, with coronary heart disease and stroke contributing over 80% of this burden. Australia is not substantially different from other developed countries having similar demographics to, and the same leading causes of burden as, other high-income developed countries. This article examines the suggestions and evidence surrounding the relationship between light-to-moderate alcohol consumption and benefits to human health.

Alcohol consumption and health status in very old veterans

Previous research has linked drinking with health, but has yet to address alcohol consumption and the relationship between drinking and health among very old veterans. To help fill this gap, the authors present a cross-sectional self-report study on 1105 veterans age 90 and older who completed the national Veteran's Affairs (VA) Survey of the Health Experiences of Patients (SHEP) for fiscal year (FY) 2005. Alcohol consumption was measured using Alcohol Use Disorders Identification Test scores (AUDIT-C). Health status was measured using the Veterans Rand Health Survey: VR-12. Among men (n = 1063), 60% were abstainers. No significant differences in mental health component (MCS; F(3,1040) = 1.80, P = .15) or physical health component (PCS; F(3,1040) = 1.48, P = .22) scores were detected across consumption categories. Among women (n = 42), 47% were abstainers. These results suggest many very old veterans abstain from alcohol and, among men, the associations between health status and drinking observed in younger groups may not be present in very old age.

Moderate alcohol consumption and cognitive risk

We reviewed 143 papers that described the relationship between moderate drinking of alcohol and some aspect of cognition. Two types of papers were found: (1) those that provided ratios of risk between drinkers and nondrinkers (74 papers in total) and (2) those that, although they did not provide such ratios, allowed cognition in drinkers to be rated as "better," "no different," or "worse" than cognition in nondrinkers (69 papers in total). The history of research on moderate drinking and cognition can be divided into two eras: 1977-1997 and 1998-present. Phase I (1977-1997) was the era of neuropsychological evaluation involving mostly young to middle-aged (18-50 years old) subjects. Although initial studies indicated moderate drinking impaired cognition, many later studies failed to confirm this, instead finding no difference in cognition between drinkers and nondrinkers. Phase II (1998-present) was and is the era of mental status exam evaluation involving mostly older (≥55 years old) subjects. These studies overwhelmingly found that moderate drinking either reduced or had no effect on the risk of dementia or cognitive impairment. When all the ratios of risk from all the studies in phase II providing such ratios are entered into a comprehensive meta-analysis, the average ratio of risk for cognitive risk (dementia or cognitive impairment/decline) associated with moderate "social" (not alcoholic) drinking of alcohol is 0.77, with nondrinkers as the reference group. The benefit of moderate drinking applied to all forms of dementia (dementia unspecified, Alzheimer's disease, and vascular dementia) and to cognitive impairment (low test scores), but no significant benefit against cognitive decline (rate of decline in test scores) was found. Both light and moderate drinking provided a similar benefit, but heavy drinking was associated with nonsignificantly higher cognitive risk for dementia and cognitive impairment. Although the meta-analysis also indicated that wine was better than beer or spirits, this was based on a relatively small number of studies because most studies did not distinguish among these different types of alcohol. Furthermore, a number of the studies that did make the distinction reported no difference among the effects of these different types of alcohol. Therefore, at present this question remains unanswered. Analysis also showed that the presence of the apolipoprotein E epsilon 4 allele eliminated the benefit of moderate drinking. However, this was based on a relatively small number of studies and several other studies have found a beneficial effect of the epsilon e4 allele. Further studies are necessary to settle this question. The benefit of moderate alcohol for cognition was seen in both men and women, although the amount and pattern of drinking is very different between the two sexes. Lastly, the finding of unaffected or significantly reduced cognitive risk in light to moderate drinkers was seen in 14/19 countries for which country-specific ratio data were available, with three of the five remaining countries showing nonsignificant reductions as well. Overall, light to moderate drinking does not appear to impair cognition in younger subjects and actually seems to reduce the risk of dementia and cognitive decline in older subjects.

Alcohol consumption and domain-specific cognitive function in older adults: longitudinal data from the Johns Hopkins Precursors Study

OBJECTIVES

The association of alcohol consumption with performance in different cognitive domains has not been well studied.

METHODS

The Johns Hopkins Precursors Study was used to examine associations between prospectively collected information about alcohol consumption ascertained on multiple occasions starting at age 55 years on average with domain-specific cognition at age 72 years. Cognitive variables measured phonemic and semantic fluency, attention, verbal memory, and global cognition.

RESULTS

Controlling for age, hypertension, smoking status, sex, and other cognitive variables, higher average weekly quantity and frequency of alcohol consumed in midlife were associated with lower phonemic fluency. There were no associations with four other measures of cognitive function. With respect to frequency of alcohol intake, phonemic fluency was significantly better among those who drank three to four alcoholic beverages per week as compared with daily or almost daily drinkers. A measure of global cognition was not associated with alcohol intake at any point over the follow-up.

DISCUSSION

Results suggest that higher alcohol consumption in midlife may impair some components of executive function in late life.

Social involvement, behavioural risks and cognitive functioning among older people

This study analyses the relationships between cognitive performance, social participation and behavioural risks, taking into account age and educational attainment. We examine individual data for 11 European countries and Israel from the first wave of the Survey on Health, Ageing and Retirement in Europe (SHARE). The stochastic frontier approach methodology enables us to identify different sources of plasticity on cognitive functioning while taking into account age-related decline in cognitive performance. Several social participation variables were examined: employment status, attending educational courses, doing voluntary or charity work, providing help to family, friends or neighbours, participating in sports, social or other clubs, in a religious organisation and in a political or community organisation, and we controlled for age, education, income, physical activity, body-mass index, smoking and drinking. In the pooled sample, the results clearly show that all kinds of social involvement enhance cognitive functions, in particular in work. Moreover, behavioural risks such as physical inactivity, obesity, smoking or drinking were clearly detrimental to cognitive performance. Models for men and women were run separately. For both genders, all social involvement indicators associated with better cognitive performance. The results varied by countries, however, particularly the signs of the associations with a number of indicators of social involvement and behavioural risks.

Paradoxical facilitatory effect of low-dose alcohol consumption on memory mediated by NMDA receptors

Epidemiological studies have suggested a negative correlation between alcohol intake and Alzheimer's disease. In vitro, ethanol negatively modulates NMDA receptor function. We hypothesized that chronic moderate alcohol intake leads to improved memory via adaptive responses in the expression of NMDA receptors and downstream signaling. We fed liquid diets containing no, moderate, or high amounts of ethanol to control and matched rats with hippocampal knock-down of the NR1 subunit. Rats with increased hippocampal NR1 expression were also generated to determine whether they had a phenotype similar to that of ethanol-fed animals. We found that moderate ethanol intake improved memory, increased NR1 expression, and changed some aspects of neurotrophin signaling. NR1 knock-down prevented ethanol's facilitatory effects, whereas hippocampal NR1 overexpression mimicked the effect of chronic low-dose ethanol intake on memory. In contrast, high-dose ethanol reduced neurogenesis, inhibited NR2B expression, and impaired visual memory. In conclusion, adaptive changes in hippocampal NMDA receptor expression may contribute to the positive effects of ethanol on cognition.