To evaluate risk factors for the 4-year incidence of cortical and posteriorsubcapsular (PSC) lens opacities.
Population-based cohort study with 85% participation at 4-year follow-up.
Three thousand one hundred ninety-three black participants of the BarbadosEye Studies, Barbados, West Indies, of whom 2040 and 2954 were free of corticaland PSC lens opacities, respectively, at baseline.
The standardized protocol at baseline and follow-up included an interview,anthropometric and blood pressure measurements, and ophthalmic measurementsincluding slitlamp lens grading, fundus photography, and an ophthalmologicexamination. Factors associated with incident cortical and PSC opacities (LensOpacities Classification System II, ≥2) were evaluated by logistic regression.
Main Outcome Measure
Relative risks (RRs) with 95% confidence intervals.
The 4-year incidence of cortical lens opacities was 22.2% (452/2040);the factors increasing risk were older age, female gender (RR = 1.3), lowsocioeconomic status (RR = 1.4), and a history of diabetes mellitus (RR =2.4), while aspirin use was associated with a lower RR (RR = 0.2; 95% confidenceinterval, 0.1-0.8), a result based on small numbers. The 4-year incidenceof PSC opacities was lower at 3.3% (97/2954), and risk also increased withage and a history of diabetes mellitus (RR = 2.9). A dose-response relationshipwas evident between incident opacities and increased levels of glycosylatedhemoglobin at baseline, with the highest risk of cortical (RR = 3.60; 95%confidence interval, 2.23-5.81) and PSC (RR = 4.93; 95% confidence interval,2.69-9.05) opacities at more than an 11.5% glycosylated hemoglobin level.
Diabetes mellitus and hyperglycemia are major modifiable risk factorsfor the development of cortical and PSC lens opacities in this African-descentpopulation with a high rate of diabetes mellitus. Prevention and improvedcontrol of diabetes mellitus are likely to reduce the burden of cataract.The finding of a reduced incidence of cortical lens opacities in aspirin usersmerits further investigation, given its potential for cataract prevention.