Cognitive function in normal-weight, overweight, and obese older adults: an analysis of the Advanced Cognitive Training for Independent and Vital Elderly cohort.
OBJECTIVE
To assess how elevated body mass index (BMI) affects cognitive function in elderly people.


METHODS
Cross-sectional study.


METHODS
Data for this cross-sectional study were taken from a multicenter randomized controlled trial, the Advanced Cognitive Training for Independent and Vital Elderly trial.


METHODS
The analytic sample included 2,684 normal-weight, overweight, or obese subjects aged 65 to 94.


METHODS
Evaluation of cognitive abilities was performed in several domains: global cognition, memory, reasoning, and speed of processing. Cross-sectional association between body weight status and cognitive functions was analyzed using multiple linear regression.


RESULTS
Overweight subjects had better performance on a reasoning task (beta=0.23, standard error (SE)=0.11, P=.04) and the Useful Field of View (UFOV) measure (beta=-39.46, SE=12.95, P=.002), a test of visuospatial speed of processing, after controlling for age, sex, race, years of education, intervention group, study site, and cardiovascular risk factors. Subjects with class I (BMI 30.0-34.9 kg/m2) and class II (BMI>35.0 kg/m2) obesity had better UFOV measure scores (beta=-38.98, SE=14.77, P=.008; beta=-35.75, SE=17.65, and P=.04, respectively) in the multivariate model than normal-weight subjects. The relationships between BMI and individual cognitive domains were nonlinear.


CONCLUSIONS
Overweight participants had better cognitive performance in terms of reasoning and visuospatial speed of processing than normal-weight participants. Obesity was associated with better performance in visuospatial speed of processing than normal weight. The relationship between BMI and cognitive function should be studied prospectively.
Kuo
Hsu-Ko
HK
Division on Aging, Harvard Medical School, Boston, Massachusetts, USA.
Jones
Richard N
RN
Milberg
William P
WP
Tennstedt
Sharon
S
Talbot
Laura
L
Morris
John N
JN
Lipsitz
Lewis A
LA
D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D016022:Case-Control Studies; D003071:Cognition / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology; D009765:Obesity / Q000523:psychology*; D011581:Psychological Tests; D014481:United States; D014796:Visual Perception / Q000502:physiology