Light-to-moderate alcohol intake lowers dementia and Alzheimer's disease

Nutrition Research Newsletter, Nov, 2004

Multiple prospective, population-based studies have shown that individuals with light-to-moderate alcohol consumption have a lesser risk of dementia than do persons who abstain or have heavy alcohol use. The majority of studies find a relation with vascular dementia, which is consistent with the known beneficial impact of light-to-moderate alcohol consumption on vascular risk profile and risk of stroke. Therefore, a possible explanation for the associations that are seen between alcohol consumption and overall dementia or Alzheimer disease is that they have to do with an effect on vascular disease. However, other nonvascular mechanisms may also play a role.

In an attempt to further investigate what could underlie the relation between alcohol intake and risk of dementia, a study was designed to focus on the relation between alcohol intake and structural brain findings on magnetic resonance imaging (MRI) of older persons without dementia. It was hypothesized that, if the effect of alcohol on dementia risk purely had to do with an effect on vascular disease, an observed relation between alcohol intake and markers of cerebrovascular disease (for example, brain infarcts and white matter lesions), but not between alcohol intake and putative presymptomatic MRI markers of Alzheimer disease (for example, hippocampal and amygdalar atrophy) would be seen. This hypothesis was investigated in the population-based Rotterdam Scan Study.

Baseline examinations were performed in 1995 and 1996. At that time, a random selection in strata of age (5 years) and sex of 1904 persons aged 60-90 years originating from two population cohort studies was made. Subjects with dementia were excluded. A total of 1077 persons underwent MRI sequences for assessment of white matter lesions and brain infarcts. A physician used a structured questionnaire to evaluate the alcohol intake of each participant at baseline. Current and former drinkers were asked about the amount of their alcohol consumption. Current drinkers were categorized as very light (<1 drink per week), light ([greater than or equal to] 1 drink/ week to < 1 drink per day), moderate ([greater than or equal to] 1 drink per day to < 4 drinks per day), and heavy ([greater than or equal to] 4 drinks per day). The following covariates were assessed at baseline by interview and physical examination: pack-years of cigarette smoking, educational level, body mass index (BMI), diabetes mellitus and hypertension.

Subjects whose alcohol consumption was light to moderate had less severe white matter lesions and brain infarcts on MRI than did abstainers or heavy drinkers. Abstainers and very light drinkers had smaller hippocampal and amygdalar volumes on MRI than did light-to-moderate drinkers, but only if the former carried an apolipoproteins (APOE) [epsilon]4 allele.

It appears that light-to-moderate alcohol consumption is associated with a lower prevalence of vascular brain findings and, in APOE [epsilon]4 carriers, hippocampal and amygdalar atrophy on MRI.

T. den Heijer, S. Vermeer, E. van Dijk, et al. Alcohol intake in relation to brain magnetic resonance imaging findings in older persons without dementia. Am J Clin Nutr; 80:992-997 (October, 2004). [Correspondence: MMB Breteler, Department of Epidemiology and Biostatistics, Erasmus Medical Center, PO Box 1738, 3000 DR Rotterdam, Netherlands. E-mail: m.breteler@erasmusmc.nl].