Associations of adiposity and physical fitness with hippocampaldependent mnemonic discrimination in postmenopausal women

[Purpose] This study examined the associations of adiposity indices and physical fitness components with domain-specific cognitive function in postmenopausal women, focusing on hippocampus-dependent mnemonic discrimination.[Methods] The study involved 68 postmenopausal women aged ≥ 40 years who were at least one year postmenopausal. Body composition was assessed using dual-energy X-ray absorptiometry, and adiposity indices comprised body fat mass, body fat percentage, fat mass index, fat-to-lean mass ratio, and android-to-gynoid fat ratio. Cognitive function was assessed using the color-word Stroop task and the object and spatial versions of the Mnemonic Discrimination Task. Physical fitness was evaluated based on grip strength, sit-and-reach flexibility, and peak oxygen uptake. Correlation and hierarchical multiple linear regression analyses were performed (n = 61).[Results] Adiposity indices were not significantly associated with Stroop performance. Body fat mass and fat mass index were negatively associated with object-version recognition score and spatial-version lure discrimination index, and body fat mass was also negatively associated with spatial-version recognition score. Spatial-version lure discrimination index was positively correlated with flexibility and peak oxygen uptake. In hierarchical regression, adding fat mass index and peak oxygen uptake to age significantly improved the model predicting spatial-version lure discrimination index; peak oxygen uptake was significant at this step. However, flexibility provided no significant additional explanatory power, and no predictor remained significant in the final model.[Conclusion] Hippocampus-dependent mnemonic discrimination in postmenopausal women may be related to adiposity and overall fitness status at the level of simple associations; however, the independent contribution of specific fitness components requires further investigation.