Visual impairment and dementia risk in two population‐based prospective cohorts: Epidemiology: Sensory impairment and cognition. (7th December 2020)

• Record Type: Journal Article
• Authors: Littlejohns, Thomas J; Hayat, Shabina; Luben, Robert; Conroy, Megan; Foster, Paul J; Kuzma, Elzbieta; Khawaja, Anthony P
• Is Part Of: Alzheimer's & dementia. Volume 16(2020)Supplement 10
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-12-07
• Subjects: Alzheimer's disease -- Periodicals; Alzheimer Disease -- Periodicals; Dementia -- Periodicals; Démence; Maladie d'Alzheimer; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); 616.83
• DOI: 10.1002/alz.041039
• Languages: English
• ISSNs: 1552-5260

Abstract

Abstract: Background: Visual impairment (VI) has been associated with an increased risk of cognitive decline and dementia, however studies using objective measures of visual function are lacking. Therefore, we investigated the association between objectively‐measured VI and risk of incident all‐cause dementia in two large population‐based prospective cohorts. Method: Cox‐proportional hazards models were used to assess the association between VI and incident all‐cause dementia in 62, 311 UK Biobank (UKB) and 7, 506 EPIC‐Norfolk participants aged ≥60 years and dementia free at baseline. In both cohorts, visual acuity was measured with habitual correction (glasses or contact lenses) using a logarithm of the minimum angle of resolution (LogMAR) chart with the participant sitting 4 metres away. VI was defined as a score of ≥0.24 LogMAR, which is the threshold used to meet UK driving standards. In both cohorts, incident dementia was ascertained through cohort‐wide linkage to longitudinal hospital inpatient and death registry records, and, additionally, mental health data in EPIC‐Norfolk. Result: In UKB and EPIC‐Norfolk, respectively, 3, 918 (6.3%) and 470 (6.2%) participants were visually impaired at baseline, and over 8 years (mean=6.5) and 14.5 years (mean=9.6) of follow‐up, 373 and 535 participants developed all‐cause dementia. In UKB, VI was associated with double the risk of developing all‐cause dementia when adjusting for age, sex, ethnicity, socioeconomic status, education, alcohol consumption, smoking, body mass index, self‐reported diabetes and cardiovascular disease (Hazard Ratio (HR)=2.06, 95% Confidence Interval (CI) 1.54‐2.75). In EPIC‐Norfolk, VI was associated with almost a 50% increased risk of developing all‐cause dementia when adjusting for the same covariates (HR=1.49, 95% CI 1.16‐1.92). After excluding participants who were diagnosed with all‐cause dementia within the first three years of follow‐up to account for reverse causation, the HRs were 1.86 (95% CI 1.32‐2.61) and 1.44 (95% CI 1.10‐1.88) in UKB and EPIC‐Norfolk, respectively. Conclusion: In two large, independent, cohorts of healthy, late middle‐ to older‐aged adults, VI was associated with an increased risk of developing all‐cause dementia. These findings suggest that VI could potentially be a modifiable risk factor for dementia or target for identifying those at high risk of the condition.