Adiposity and Cognitive Performance in Older Men and Women from the Study of Muscle, Mobility and Aging (SOMMA).
Abstract
Background
Aging is accompanied by changes in body composition and cognition. Although adiposity has been linked to metabolic dysfunction and dementia risk, associations with specific cognitive domains in later life remain unclear.
Methods
This cross-sectional study examined associations between adiposity and cognitive performance in 769 community-dwelling, healthy older adults (70-94 years) from the Study of Muscle, Mobility and Aging (SOMMA). Adiposity was assessed using anthropometric measures (body mass index, waist circumference) and MRI-derived regional fat volumes, including visceral and abdominal subcutaneous adipose tissue. Cognitive performance was evaluated using a screening measure (Montreal Cognitive Assessment), processing speed (Digit Symbol Coding Test), executive function (Trail Making Test B), and memory (California Verbal Learning Test-II Short Form). Multivariable linear regression models were sequentially adjusted for demographic, cardiometabolic, psychosocial, and behavioral factors.
Results
Greater age was associated with lower adiposity and poorer cognitive performance (p < 0.05). Most adiposity measures were inversely associated with processing speed after adjustment for age, sex, race, and testing site (p < 0.05). These associations generally persisted after adjustment for cardiometabolic conditions and were attenuated after inclusion of education, depressive symptoms, and behavioral covariates. No significant associations were observed between adiposity and executive function. Memory outcomes showed modest, exploratory associations with abdominal subcutaneous adipose tissue measures only in fully adjusted models (p = 0.03-0.07).
Conclusions
In healthy older adults, adiposity is most consistently related to processing speed, whereas associations with memory and executive function are weaker or absent. Processing speed may be especially sensitive to adiposity-related differences. Longitudinal studies are needed to clarify temporal relationships.