Using existing data from six different aging cohorts, we undertook in-depth epidemiological analyses to explore in detail the associations of vision and/or hearing loss with anxiety, depression, suicidal ideation, trajectory of cognitive decline and risk of dementia. Using the Tromsø Study data from Norway, we examined associations of anxiety and depression with hearing and vision loss. We examined similar questions using the Three City (3C) Study dataset from three cities in France, including associations with different dimensions of depression and suicidality. Concurrently, using English (English Longitudinal Study of Aging) and pan-European longitudinal datasets, we undertook complex growth curve analyses to understand the trajectory of cognitive decline in people with hearing and vision impairment over time and risk of developing dementia. Finally, using data from the Rotterdam Study of Aging, we sought associations between the risk of developing dementia and particular changes in the retina of the eye. Retinal changes have the potential to be an early marker for the onset of Alzheimer disease and other dementias.
Results and potential impact
Prior to our work in SENSE-Cog, the literature on the associations of mental illness and cognitive and sensory impairment was scarce. By analysing extensive data from multiple large-scale aging cohorts and one pan-European aging meta-dataset, we have added significantly to the understanding of the associations among anxiety and depression and hearing and vision impairment. Using unique datasets from different EU countries has enabled us to verify our findings and strengthen our conclusions. Key findings thus far include: (1) dual (hearing and vision combined) sensory loss may pose a significantly increased risk for depression in seniors; (2) mild and severe hearing loss is associated with new onset depression; (3) anxiety is uniquely related to hearing loss and over a several year period subthreshold anxiety symptoms may emerge; and (4) suicidal risk is greater in older people with hearing and/or vision loss or both.
Our examinations of associations over longer periods are particularly important and have deepened the understanding of the trajectory of cognitive decline in relation to sensory impairment, particularly in the very old population (over 90s). Until our SENSE-Cog studies using ELSA and the pan-European SHARE data set, epidemiological data on the relation between sensory impairment and cognitive decline were scarce and inconsistent. Describing and understanding trajectories of cognitive decline and how they relate to sensory impairments may offer insight into the dynamics of cognitive decline and identify opportunities for intervention to maximise cognitive function and longevity in older age.
Overall, the analyses performed in WP1 have generated an unprecedented body of evidence of the epidemiological associations in this field.