The association between dual sensory impairment and dementia: A systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational cohort and case-control studies
PubMed 39801060 · doi:10.1177/13872877241304127
What was done
A systematic review and meta-analysis of MEDLINE, EMBASE, and Cochrane Library databases identified prospective or retrospective cohort studies and case-control studies examining dual sensory impairment (combined vision and hearing impairment) and dementia risk. The primary outcome was incident dementia or subtypes (Alzheimer's disease [AD], vascular dementia [VaD]). Effect sizes were pooled using random-effects hazard ratios (HRs).
What was found
Eleven observational studies comprising 346,659 participants were included: - All-cause dementia: Dual sensory impairment was significantly associated with incident dementia compared to no sensory impairment (9 studies; HR: 1.46; 95% CI: 1.29–1.65). - Alzheimer's disease: Dual sensory impairment was significantly associated with AD onset (4 studies; HR: 2.07; 95% CI: 1.45–2.94). - Vascular dementia: The association was not statistically significant (2 studies; HR: 1.65; 95% CI: 0.96–2.85).
Why it matters
This study quantifies the increased risk of all-cause dementia and Alzheimer's disease in individuals suffering from both vision and hearing loss, emphasizing dual sensory impairment as an important target for clinical screening and cognitive risk assessment.
Limits
All included data derive from observational studies, precluding causal inference. Subtype meta-analyses included very few studies (4 for AD, 2 for VaD). The abstract does not specify whether sensory loss was measured objectively or via self-report, nor does it detail adjustments for common confounders across the included cohorts.