Sex-Specific Contributions to Single- and Dual-Task Walking in Adults at Risk of Alzheimer Disease and Related Dementias

BACKGROUND/OBJECTIVE: Walking reflects a complex interaction between physiological systems that deteriorate with age and do so more rapidly in those living with diseases. We conducted a sex-specific cross-sectional analysis to determine the contribution of modifiable (risk) factors to single- and dual-task gait performance in older adults at risk of Alzheimer disease and related dementias. METHODS: We included participants (n = 103; 60.4% female; mean age 63.7 ± 6.2) who had completed a preintervention assessment for a randomized controlled trial. We used the following factors in hierarchical regressions while controlling for age, muscle strength, cardiorespiratory fitness, and global cognition. Participants walked at their usual pace on an electronic walkway and completed the two-back version of the n-back test either separately or together. RESULTS: Males and females demonstrated reduced gait speed when comparing single to dual tasking (p < .001), but only females demonstrated increasing (i.e., worse) gait variability (p = .007). In females, the dual-task velocity model was significant, F(3, 56) = 5.173, with muscle strength (p = .006) and cardiorespiratory fitness (p = .049) contributing significantly. For males, the models were significant across all conditions, but muscle strength was the only significant (modifiable) factor (single task, p = .023; dual task, p = .046). CONCLUSION: Dual-task gait velocity is associated with a combination of modifiable factors. However, the importance of each factor differs between males and females. Significance/Implications: Such findings have implications for understanding gait decline and potential sex-specific intervention strategies in those at risk of Alzheimer disease and related dementias.