The Association Between Lens Opacities and Five Year’s Mortality –Reykjavik Eye Study–

Abstract

Abstract: : Purpose: To investigate the association between lens opacities and five year’s mortality in the Icelandic population > 50 years of age. Methods: The Reykjavik Eye Study (RES) is a population based study using the population census. Of the 1,379 subjects randomly selected for the RES in 1996, 1,045 (Mean age 64.7±9.7 years old) or 75.3% were examined and followed up 5 years later. Changes in the crystalline lens were photographed using an Anterior Eye Segment Analysis System (EAS–1000, NIDEK) under maximal pupillary dilation and examined. Classification of nuclear (N), cortical (C), cortical opacity within a 3mm diameter of the pupil (CEN) and posterior subcapsular cataract (PSC) were determined from the photographed images by a single observer using the simplified cataract classification and grading system established by the WHO. Associations between mortality and cataract at baseline were assessed using the multivariate logistic regression model, controlling for age, sex, smoking and diabetes. Results: The five–year mortality rate was 8.3% (87 cases). The presence at baseline of any type of cataract rated over grade 1 was independently associated with increased mortality risk (risk ratio [RR], 2.21; 95% confidence interval, 1.24–3.95, p<0.01). The presence of N over grade 1 ([RR], 2.86, 1.35–6.05, p<0.01) was also significantly associated with increased mortality risk, however, no significant association was found in C, CEN and PSC. Conclusions: The five year mortality risk was high in cases with progressed cataract classified over grade 1 on the WHO system, in particular cases with nuclear cataract.

Keywords: cataract • clinical (human) or epidemiologic studies: risk factor assessment • aging