Lens opacities and mortality - The Barbados Eye Studies

Objective: To evaluate the association between cataract and mortality in a black population by type of opacity, which has not been documented previous ly. Design: Population-based cohort study. Participants: The Barbados Incidence Study of Eye Diseases reexamined the B arbados Eye Study cohort, identified through a simple random sample of pred ominantly black Barbadian-born citizens, aged 40 to 84 years. Of those elig ible, 85% (3427 participants) had a 4-year follow-up visit. Methods: Baseline and follow-up visits included an interview, blood pressur e and other measurements, and a detailed ophthalmologic examination with sl it-lamp lens gradings (Lens Opacities Classification System [LOCS] II proto col). Mortality at follow-up was verified from Ministry of Health records. Main Outcome Measures: Lens opacities were defined by a LOGS II score of 2 or more. Opacity types were classified in two ways: (1) single (cortical-on ly, nuclear-only, and posterior subcapsular-only) and mixed opacities; and (2) any cortical, any nuclear, or any posterior subcapsular opacities. Info rmation on dates and causes of death was obtained from death certificates. Results: Cardiovascular disease was the principal cause of death in black p articipants (3.6%), followed by malignant neoplasms (1.4%). The cumulative 4-year mortality varied with lens types, increasing from 3.2% for those wit hout cataract to 6.0% for cortical-only, 8.8% for nuclear-only, and 20.9% f or mixed opacities. Persons with mixed opacities had a 1.6-fold increase in mortality, while controlling for other factors (age, male gender, diabetes , hypertension, obesity, cigarette smoking, cardiovascular disease, and fam ily history of diabetes) in Cox proportional-hazards regression analyses. P ersons with any nuclear opacities also had increased mortality (death rate ratio, 1.5). The death rate ratios increased with age, but peaked at age 60 to 69 years. Coexisting diabetes further increased mortality: people with mixed opacities and diabetes had a 2.7-fold increased risk of death. A tren d toward increased mortality from neoplasms was observed for individuals wi th mixed opacities or with any nuclear opacities. Conclusions: Participants with mixed opacities or any nuclear opacities had increased 4-year mortality rates, with diabetes acting as an effect modifi er. This study is the first to identify a relationship between type of cata ract and mortality in an African-descent population. (C) 2001 by the Americ an Academy of Ophthalmology.