Hearing healthy: physical activity moderates the association between age-related hearing loss and brain volume.

Hearing loss is one of the most common age-related health conditions and is associated with a number of adverse psychological, physical, and social outcomes. Chronic under-stimulation, due to reduced auditory input from the ear is hypothesised to result in cascading neural consequences, including atrophy in auditory and associated cortices. One key factor known to protect healthy brain ageing is exercise, potentially by providing an alternative source of stimulation and environmental enrichment. As such, we tested whether engaging with physical activity moderates the association between hearing loss and neural atrophy. Structural equation modelling from a large cohort of middle-aged and older adults sourced from the UK-Biobank (N = 28 994) replicated previous findings that hearing loss is associated with reduced grey matter volume in the frontal lobe, temporal lobe, and subcortical nuclei. The potential deleterious effect of hearing loss was reduced across all brain areas in adults who spent more time engaging in physical activity. Socioeconomic status was not a significant mediator of the hearing loss-brain volume association. Promoting physical activity through social prescribing may be effective in protecting healthy brain ageing in older adults with hearing loss. Further research should extend this population neuroscience approach with experimental interventions to assess practical implications for population health.