Caffeine consumption and cognitive function at age 70: the Lothian Birth Cohort 1936 study.
OBJECTIVE
To investigate the association between caffeine consumption and cognitive outcomes in later life.


METHODS
Participants were 923 healthy adults from the Lothian Birth Cohort 1936 Study, on whom there were intelligence quotient (IQ) data from age 11 years. Cognitive function at age 70 years was assessed, using tests measuring general cognitive ability, speed of information processing, and memory. Current caffeine consumption (using multiple measures of tea, coffee, and total dietary caffeine) was obtained by self-report questionnaire, and demographic and health information was collected in a standardized interview.


RESULTS
In age- and sex-adjusted models, there were significant positive associations between total caffeine intake and general cognitive ability and memory. After adjustment for age 11 IQ and social class, both individually and together, most of these associations became nonsignificant. A robust positive association, however, was found between drinking ground coffee (e.g., filter and espresso) and performance on the National Adult Reading Test (NART, p = .007), and the Wechsler Test of Adult Reading (WTAR, p = .02). No gender effects were observed, contrary to previous studies. Generally, higher cognitive scores were associated with coffee consumption, and lower cognitive scores with tea consumption, but these effects were not significant in the fully adjusted model.


CONCLUSIONS
The present study is rare in having childhood IQ in a large sample of older people. The results suggest that the significant caffeine intake-cognitive ability associations are bidirectional-because childhood IQ and estimated prior IQ are associated with the type of caffeine intake in old age-and partly confounded by social class.
Corley
Janie
J
Department of Psychology, Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, 7 George Square, Edinburgh EH8 9JZ, Scotland, UK.
Jia
Xueli
X
Kyle
Janet A M
JA
Gow
Alan J
AJ
Brett
Caroline E
CE
Starr
John M
JM
McNeill
Geraldine
G
Deary
Ian J
IJ
D000368:Aged; D000375:Aging / Q000502:physiology; D002110:Caffeine / Q000009:adverse effects / Q000494:pharmacology*; D002648:Child; D003069:Coffee / Q000737:chemistry; D003071:Cognition / Q000187:drug effects* / Q000502:physiology; D003072:Cognition Disorders / Q000139:chemically induced; D015331:Cohort Studies; D004327:Drinking Behavior / Q000502:physiology*; D005260:Female; D015577:Geriatric Assessment / Q000706:statistics & numerical data; D006801:Humans; D007360:Intelligence; D008137:Longitudinal Studies; D008297:Male; D008568:Memory / Q000187:drug effects; D009483:Neuropsychological Tests; D011597:Psychomotor Performance; D012923:Social Class; D011795:Surveys and Questionnaires; D013662:Tea / Q000737:chemistry; D014888:Wechsler Scales
D003069:Coffee; D013662:Tea; D002110:Caffeine