Visual acuity change and mortality in older adults.
OBJECTIVE
Several studies indicate an increased mortality rate in older adults who have visual impairment, but few have attempted to address a potential causal mechanism. The goals of this study are to determine whether visual acuity loss increases the risk of dying and to examine whether depressive symptoms act as a mediator in this relationship.


METHODS
Data were derived from the 2520 older adults who participated in the Salisbury Eye Evaluation project, a population-based prospective 8-year cohort study. Presenting binocular visual acuity was measured with the Early Treatment Diabetic Retinopathy Study [ETDRS] eye chart and depressive symptoms with the General Health Questionnaire Part D subscale. Mortality data were collected by staff follow-up. Analyses were performed with the Cox proportional hazards regression.


RESULTS
Worse baseline acuity was associated with a higher mortality rate (hazard ratio [HR] = 1.05; 95% confidence interval [CI], 1.01-1.09). Also, those who gained two or more lines of visual acuity over 2 years had a lower adjusted risk of dying (HR = 0.47; 95% CI, 0.23-0.95). An interaction was detected, in that women who lost > or =3 lines of visual acuity over a 2-year period had a higher adjusted risk of dying (HR = 3.97; 95% CI, 2.21-7.15), whereas men did not (HR = 1.32; 95% CI, 0.66-2.63). Depressive symptoms did not mediate these relationships.


CONCLUSIONS
If the relationship between visual acuity and mortality is indeed causal, it most likely acts via numerous pathways through a variety of intervening variables. The identification of these intervening variables could give additional targets for intervention if acuity cannot be restored.
Freeman
Ellen E
EE
Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Baltimore, MD 21250, USA. efreeman@jhsph.edu
Egleston
Brian L
BL
West
Sheila K
SK
Bandeen-Roche
Karen
K
Rubin
Gary
G
D000368:Aged; D000369:Aged, 80 and over; D002423:Cause of Death; D003866:Depressive Disorder / Q000401:mortality*; D005260:Female; D006801:Humans; D008297:Male; D008396:Maryland / Q000453:epidemiology; D016016:Proportional Hazards Models; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014786:Vision Disorders / Q000401:mortality*; D014792:Visual Acuity; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*