Background: Lens opacities are associated with a higher risk of death, although there are some discrepancies regarding the specific types of cataract representing risk. The purpose of the present study was to further investigate the relationships between different types of lens opacity and patient survival.
Methods: In 1987, 860 residents of Priverno, Italy, aged 45-69 years underwent an ophthalmologic examination. Based on patient histories and the findings of the slit-lamp examination, each of the 860 patients was classified according to the type of opacity (pure cortical, pure nuclear, pure posterior subcapsular, mixed, and surgical aphakia). The survivors of the original cohort were re-examined in 1994. Death and survival rates were computed by the Kaplan-Meier method. Associations between mortality and significant factors were included in a stepwise Cox proportional-hazards regression model.
Results: Forty-four members of the original cohort had died during the 7-year follow-up. Age-adjusted survival curves based on Kaplan-Meier estimates showed significantly lower survival in those whose baseline examinations had revealed pure nuclear opacity (log rank test: P=0.020) and aphakia (log rank test: P<0.001). When adjusted for other mortality risk factors (age, sex, diabetes, cardiovascular diseases), the hazard ratio was 4.32 for pure nuclear opacity (95% CI 1.13-16.4) and 18.3 for aphakia (95% CI 3.21-104.0).
Conclusions: The analysis of the Priverno data seems to confirm an association between lower survival and cataracts, particularly those confined to the lens nucleus and those that had already prompted surgery.