Body mass index and neurocognitive functioning across the adult lifespan

Cognitive dysfunction and structural brain abnormalities have been observed in obese versus lean individuals, but with variability across age and weight groups. The current study was designed to clarify the cognitive profile of obesity by examining performance across multiple cognitive domains in adults with wide-ranging age and weight status.

Participants (N = 732; 61% women; ages 18-88; BMI range 19-75) underwent assessment of cognitive functioning and relevant medical/demographic covariates. Neuropsychological tests were grouped by cognitive domain (via confirmatory factor analysis), and standardized scores were averaged into composite variables.

Hierarchical linear regression analyses revealed main effects for BMI on motor (ΔR2 = .02, β = -.15) and attention/processing speed (ΔR2 = .01, β = -.07), whereas a significant interaction between BMI and age was observed (ΔR2 = .01, β = -.08) for predicting executive functioning (p < .05). BMI was not independently associated with memory or language functioning and no interaction effects were observed for these variables. Although BMI was not independently related to executive dysfunction, a significant age × BMI interaction suggests that obesity-related executive deficits may increase with age.

Overall, these findings may support an independent association between obesity and a frontal-subcortical pathology, though prospective studies are needed to further clarify this possibility.