The Relationship Between Alcohol Intake and Cognitive Function

Studies
examining alcohol’s impact on cognitive impairment have produced
varying results. To clarify the relationships between midlife alcohol
consumption, and mild cognitive impairment and dementia in old
age, researchers from Finland randomly selected subjects from a
population-based study in the 1970s and re-examined them in 1998.
Of these 1018 men and women aged 65–79 years, 61 developed
mild cognitive impairment (based on various diagnostic criteria)
and 48 were diagnosed with dementia. Analyses were adjusted for
potential confounders (e.g., age, sex, body mass index, other cardiovascular
risk factors).

• The
  relationship between alcohol frequency at baseline and subsequent
  mild cognitive impairment was U-shaped: non-drinkers and frequent
  drinkers (those who consumed alcohol several times per month)
  had significantly higher risk of cognitive impairment (relative
  risks, RRs, 2.2 and 2.6, respectively) than did infrequent drinkers.
• Alcohol
  frequency was significantly related to dementia only among carriers
  of the apolipoprotein E4 allele. Carriers who were infrequent
  or frequent drinkers had a higher risk (RRs 2.3 and 3.6, respectively)
  than did non-carriers who did not drink.

Comments:

Unfortunately, this study suffers from very small numbers (e.g., totals of only 14–17 subjects with dementia in each alcohol
category) and inadequate estimates of alcohol use (e.g.,
no data on amount consumed). Further, frequent drinkers—68%
of whom drank only 1–2 times per month—were
defined quite differently in this study than in others.
Nonetheless, the results do suggest that apolipoprotein
E4 status modifies alcohol’s influence on dementia. Beyond
that, better studies are needed to elucidate the relationship
between moderate drinking and cognitive health.

R.
Curtis Ellison, MD

Reference:

Anttila T, Helkala EL, Viitanen M, et al. Alcohol drinking in middle age and subsequent risk of mild cognitive impairment and dementia in old age: a prospective population based study. BMJ. 2004;329(7465):539.
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