Open AccessVisual Impairment and Risk of Dementia in 2 Population-Based Prospective Cohorts: UK Biobank and EPIC-Norfolk
Author(s) -
Thomas J Littlejohns,
Shabina Hayat,
Robert Luben,
Carol Brayne,
Megan Conroy,
Paul J. Foster,
Anthony P Khawaja,
Elżbieta Kuźma
Publication year - 2021
Publication title -
the journals of gerontology. series a, biological sciences and medical sciences
Language(s) - English
Resource type - Journals
eISSN - 1758-535X
pISSN - 1079-5006
DOI - 10.1093/gerona/glab325
Subject(s) - hazard ratio , medicine , biobank , visual impairment , dementia , epic , european prospective investigation into cancer and nutrition , confidence interval , visual acuity , prospective cohort study , population , proportional hazards model , demography , pediatrics , ophthalmology , psychiatry , disease , environmental health , bioinformatics , art , literature , sociology , biology
Visual impairment has emerged as a potential modifiable risk factor for dementia. However, there is a lack of large studies with objective measures of vision and with more than 10 years of follow-up. We investigated whether visual impairment is associated with an increased risk of incident dementia in UK Biobank and European Prospective Investigation into Cancer in Norfolk (EPIC-Norfolk). In both cohorts, visual acuity was measured using a "logarithm of the minimum angle of resolution" (LogMAR) chart and categorized as no (≤0.30 LogMAR), mild (>0.3 to ≤0.50 LogMAR), and moderate to severe (>0.50 LogMAR) impairment. Dementia was ascertained through linkage to electronic medical records. After restricting to those aged ≥60 years, without prevalent dementia and with eye measures available, the analytic samples consisted of 62 206 UK Biobank and 7 337 EPIC-Norfolk participants, respectively. In UK Biobank and EPIC-Norfolk, respectively, 1 113 and 517 participants developed dementia over 11 and 15 years of follow-up. Using multivariable Cox proportional-hazards models, the hazard ratios for mild and moderate to severe visual impairment were 1.26 (95% confidence interval [CI]: 0.92-1.72) and 2.16 (95% CI: 1.37-3.40), in UK Biobank, and 1.05 (95% CI: 0.72-1.53) and 1.93 (95% CI: 1.05-3.56) in EPIC-Norfolk, compared to no visual impairment. When excluding participants censored within 5 years of follow-up or with prevalent poor or fair self-reported health, the direction of the associations remained similar for moderate impairment but was not statistically significant. Our findings suggest visual impairment might be a promising target for dementia prevention; however, the possibility of reverse causation cannot be excluded.