Alcohol consumption and cognitive performance: a Mendelian randomization study.
OBJECTIVE
To use Mendelian randomization to assess whether alcohol intake was causally associated with cognitive function.


METHODS
Mendelian randomization using a genetic variant related to alcohol intake (ADH1B rs1229984) was used to obtain unbiased estimates of the association between alcohol intake and cognitive performance.


METHODS
Europe.


METHODS
More than 34 000 adults.


METHODS
Any versus no alcohol intake and units of intake in the previous week was measured by questionnaire. Cognitive function was assessed in terms of immediate and delayed word recall, verbal fluency and processing speed.


RESULTS
Having consumed any versus no alcohol was associated with higher scores by 0.17 standard deviations (SD) [95% confidence interval (CI) = 0.15, 0.20] for immediate recall, 0.17 SD (95% CI = 0.14, 0.19) for delayed recall, 0.17 SD (95% CI = 0.14, 0.19) for verbal fluency and 0.12 SD (95% CI = 0.09, 0.15) for processing speed. The minor allele of rs1229984 was associated with reduced odds of consuming any alcohol (odds ratio = 0.87; 95% CI = 0.80, 0.95; P = 0.001; R(2)  = 0.1%; F-statistic = 47). In Mendelian randomization analysis, the minor allele was not associated with any cognitive test score, and instrumental variable analysis suggested no causal association between alcohol consumption and cognition: -0.74 SD (95% CI = -1.88, 0.41) for immediate recall, -1.09 SD (95% CI = -2.38, 0.21) for delayed recall, -0.63 SD (95% CI = -1.78, 0.53) for verbal fluency and -0.16 SD (95% CI = -1.29, 0.97) for processing speed.


CONCLUSIONS
The Mendelian randomization analysis did not provide strong evidence of a causal association between alcohol consumption and cognitive ability.
Department of Epidemiology and Public Health, University College London, London, UK; ISER, University of Essex, Colchester, UK.
Meena
M
Kumari
Michael V
MV
Holmes
Caroline E
CE
Dale
Jaroslav A
JA
Hubacek
Tom M
TM
Palmer
Hynek
H
Pikhart
Anne
A
Peasey
Annie
A
Britton
Pia
P
Horvat
Ruzena
R
Kubinova
Sofia
S
Malyutina
Andrzej
A
Pajak
Abdonas
A
Tamosiunas
Aparna
A
Shankar
Archana
A
Singh-Manoux
Mikhail
M
Voevoda
Mika
M
Kivimaki
Aroon D
AD
Hingorani
Michael G
MG
Marmot
Juan P
JP
Casas
Martin
M
Bobak
D000328:Adult; D000368:Aged; D000426:Alcohol Dehydrogenase / Q000235:genetics*; D000428:Alcohol Drinking / Q000009:adverse effects* / Q000235:genetics*; D003071:Cognition / Q000187:drug effects*; D003072:Cognition Disorders / Q000139:chemically induced*; D005060:Europe; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000187:drug effects; D057182:Mendelian Randomization Analysis; D008875:Middle Aged; D011930:Reaction Time / Q000187:drug effects; D012107:Research Design; D011795:Surveys and Questionnaires
C489332:ADH1B protein, human; D000426:Alcohol Dehydrogenase
ADH1B; alcohol intake; cognition; memory; processing speed; verbal fluency