Cognition Mediates the Relationship Between Sensory Function and Gait Speed in Older Adults: Evidence from the English Longitudinal Study of Ageing

Background/Objective: Gait speed is an important indicator for assessing overall health status. Previous studies have reported the important role of sensory function in gait speed; however, the underlying mechanism is still unclear. This study aimed to examine whether cognition mediates the association of sensory function with gait speed among English older adults. Methods: Gait speed was assessed by timed walking test. Hearing was measured by using a hearing screening device. Vision was self-reported. Cognition was assessed by questionnaire. Baron and Kenny's causal steps method and Sobel test were used to examine the mediating effect. Results: Among 4,197 participants aged 60 years and older, 13.5% had poor hearing and 12.6% had poor vision, 2.6% had both poor hearing and poor vision. Multiple linear regression models suggested that poor hearing beta = -1.905, p < 0.001), poor vision beta = -1.309, p = 0.004), and poor dual sensory function beta =-2.442, p = 0.013) was associated with worse cognition. Cognition was correlated with gait speed beta = 0.004,p < 0.001). Poor hearing (beta = -0.072,p < 0.001), poor vision beta =-0.031, p = 0.029), and poor dual sensory function beta = -0.081, p = 0.011) was associated with slower gait speed. After introducing cognition into the models, regression coefficients between sensory function and gait speed decreased beta = -0.066, p < 0.001 for hearing; beta = -0.027, p = 0.054 for vision; beta = -0.073, p = 0.020 for combined hearing and vision). Sobel test identified the significant mediating effect of cognition on the association between sensory function and gait speed. Conclusion: Cognition partially mediates the association between sensory function and gait speed. Efforts to maintain mobility performance in older adults should consider protecting both sensory function and cognition.