Visual impairment, age-related cataract, and mortality

Abstract

Objective: To explore associations between visual impairment, cataract, and mortality in older persons after adjusting for other factors associated with mortality.

Methods: A population cohort of 3654 persons aged 49 years or older (82.4% of eligible residents in the Blue Mountains region, west of Sydney, Australia), were examined at the Blue Mountains Eye Study baseline period (1992-1994) and followed up 5 years later (1997-1999). Australian National Death Index data were used to confirm persons who had died since baseline. Associations between mortality and presence of visual impairment and cataract at baseline were assessed using the Cox proportional hazards regression model, controlling for age, sex, demographic and socioeconomic status, medical history, and health risk behaviors.

Results: By June 30, 1999, 604 participants (16.5%) had died. The age- and sex-standardized 7-year cumulative mortality rate was 26% among persons with any visual impairment and 16% in persons without visual impairment. After adjusting for factors found significantly associated with mortality, including age, male sex, low self-rated health, low socioeconomic status, systemic medical conditions, and negative health risk behaviors, the presence at baseline of any visual impairment was independently associated with increased mortality risk (risk ratio [RR], 1.7; 95% confidence interval, 1.2-2.3). The presence of age-related cataract, either nuclear (RR, 1.5), cortical (RR, 1.3), or posterior subcapsular cataract (RR, 1.5), was also significantly associated with increased mortality risk. These associations remained statistically significant when visual impairment and each type of cataract were included simultaneously in the multivariate Cox model.

Conclusion: Visual impairment and age-related cataract may be independent risk factors for increased mortality in older persons.