Joint effect of cognitive decline and walking ability on incidence of wandering behavior in older adults with dementia: A cohort study

Objectives: Wandering behavior is one of the most troublesome behavioral disturbances in dementia. Inconsistent associations between physical function and wandering behavior were reported, and the effect of cognitive decline may be different according to walking ability. The purposes of this study are to investigate whether high walking ability is a risk factor for wandering behavior and to investigate the interaction of walking ability and cognitive function with wandering behavior in older adults with dementia. Methods: This retrospective cohort study included 3979 elderly adults with dementia. The association of cognitive function and walking ability with incidence of wandering behavior during a 5-year follow-up period were examined using a generalized linear model, and relative excess risk due to interaction (RERI) was calculated. Results: Severe cognitive decline and high walking ability were associated with a higher risk for wandering behavior. Additionally, some joint effects of cognitive decline and walking ability decline were higher than the sum of its individual effects (RERI [95% confidence interval], severe cognitive decline x 'walk with help': 1.58 [0.35, 2.81]; severe cognitive decline x 'independent': 3.09 [1.05, 5.14]). Conclusions: Effects of cognitive decline and walking ability on incidence of wandering behavior were observed, and the effects varied depending on their combination.