Pet Ownership, Living Alone, and Cognitive Decline Among Adults 50 Years and Older.

IMPORTANCE: It remains unclear whether pet ownership is associated with cognitive decline and to what extent pet ownership mitigates the association between living alone and cognitive decline.

OBJECTIVE: To explore the association of pet ownership with cognitive decline, the interaction between pet ownership and living alone, and the extent to which pet ownership mitigates the association between living alone and cognitive decline in older adults.

DESIGN, SETTING, AND PARTICIPANTS: This cohort study used data from waves 5 (June 2010 to July 2011) to 9 (from June 2018 to July 2019) in the English Longitudinal Study of Ageing. Participants included adults 50 years and older. Data were analyzed from April 1 to June 30, 2023.

EXPOSURES: Pet ownership and living alone in wave 5.

MAIN OUTCOMES AND MEASURES: In waves 5 to 9, verbal memory and verbal fluency were assessed, and composite verbal cognition was further calculated.

RESULTS: Of the 7945 participants included, the mean (SD) age was 66.3 (8.8) years, and 4446 (56.0%) were women. Pet ownership was associated with slower rates of decline in composite verbal cognition (β = 0.008 [95% CI, 0.002-0.014] SD/y), verbal memory (β = 0.006 [95% CI, 0.001-0.012] SD/y), and verbal fluency (β = 0.007 [95% CI, 0.001-0.013] SD/y). Three-way interaction tests showed that living alone was a significant modifier in all 3 associations. Stratified analyses showed that pet ownership was associated with slower rates of decline in composite verbal cognition (β = 0.023 [95% CI, 0.011-0.035] SD/y), verbal memory (β = 0.021 [95% CI, 0.008-0.034] SD/y), and verbal fluency (β = 0.018 [95% CI, 0.005-0.030] SD/y) among individuals living alone, but not among those living with others. Joint association analyses showed no significant difference in rates of decline in composite verbal cognition, verbal memory, or verbal fluency between pet owners living alone and pet owners living with others.

CONCLUSIONS AND RELEVANCE: In this cohort study, pet ownership was associated with slower rates of decline in verbal memory and verbal fluency among older adults living alone, but not among those living with others, and pet ownership offset the associations between living alone and declining rates in verbal memory and verbal fluency. Further studies are needed to assess whether pet ownership slows the rate of cognitive decline in older adults living alone.