RE: "ASSOCIATION BETWEEN REPORTED ALCOHOL INTAKE AND COGNITION: RESULTS FROM THE WOMEN'S HEALTH INITIATIVE MEMORY STUDY"

Renzo Rozzini1 and Marco Trabucchi2

1 Department of Internal General Medicine and Geriatrics, Poliambulanza Hospital, Brescia, 25124 Italy
2 Geriatric Research Group, Brescia, 25122 Italy

We read with great interest the Journal paper by Espeland et al. (1Go) regarding a protective effect of moderate alcohol consumption on the cognitive function of a large number of elderly women. This observation is in line with those from other recently published epidemiologic studies of older persons (2Go–6Go).

We would like to contribute to the discussion with our own data, reporting results obtained in 1986 in a population of 1,201 persons aged 70–75 years living in Brescia, northern Italy, and followed for 12 years. A questionnaire assessing demographics; social, mental, and functional status; chronic conditions; and health-care utilization was delivered to the elderly subjects and was collected at the subjects' home by trained community researchers (7Go). The response rate was 92.2 percent.

Alcohol consumption was evaluated by using a specific questionnaire asking for amount of intake computed in grams (8Go). Subjects were divided into three groups: abstainers, moderate drinkers, and heavy drinkers (males whose alcohol intake was >60 g/day and females whose intake was >40 g/day were classified as heavy drinkers (n = 197) and were not considered in this analysis).

In this study, incident probable dementia was computed as a loss of 2 or more points on the Mental Status Questionnaire (9Go) subsequent to a 12-year follow-up period. Survival rates were assessed for abstainers (n = 307) and moderate drinkers (n = 697) 12 years after baseline assessment.

Overall, at baseline in 1986, the clinical and psychosocial characteristics of moderate drinkers were better in comparison with those of abstainers; the former had a better mood pattern (adjusted Beck Depression Inventory Scale), a higher mean cognitive function (Mental Status Questionnaire), and a lower prevalence of scores of less than or equal to 8 on the Mental Status Questionnaire (indirectly suggesting a diagnosis of dementia). Moreover, they were less disabled (in terms of instrumental activities of daily living and basic activities of daily living), had a lower number of chronic diseases, had a higher level of education, and lived alone more often (table 1). However, after 12 years of follow-up, we were unable to detect a protective effect of moderate alcohol consumption on the risk of incident dementia (no significant differences in the relative risk of incident dementia were detected in moderate drinkers in comparison with abstainers (relative risk = 0.9, 95 percent confidence interval: 0.5, 1.6)), but, at the same time, mortality was significantly lower in the group of moderate drinkers in comparison with abstainers (44.2 percent vs. 56.2 percent) (10Go).


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TABLE 1. Characteristics of 1,004 elderly community-dwelling subjects aged 70–75 years according to alcohol consumption, Brescia, northern Italy, 1996

 
Data suggest that the population of moderate drinkers is characterized by better physical and mental health. In this group, the higher rate of subjects living alone further confirms the hypothesis of overall better health, since only these persons may live without support. The higher survival at 12 years is related to a better clinical and psychological condition at baseline. Probably a mix of genetic and nongenetic factors plays a causative role in reducing mortality in the cluster of elderly people characterized by moderate drinking. On the contrary, we were unable to replicate the longitudinal observation of Espeland et al. (1Go) regarding cognitive function, but the reason may be ascribed to the test adopted in 1986 (i.e., the Mental Status Questionnaire measures mostly basic cognitive and not other functions such as crystallized intelligence or verbal fluency).

In conclusion, moderate drinking may be interpreted as an attitude that characterizes a subpopulation of persons with a higher physical and mental performance, those who are more open to social contacts, are more able to exert mastery over their own lives, and have a longer life expectancy. From our point of view, the effect of alcohol on cognitive impairment should not be interpreted as the result of a biologic mechanism but rather as a consequence of the association of moderate alcohol consumption with a behavior characterized by a higher level of mental performance and social functioning.


    ACKNOWLEDGMENTS
 
Conflict of interest: none declared.


    References
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