Lens opacification in Icelanders 50 years and older, risk factors. Reykjavik eye study

Abstract

Abstract Purpose: To examine prevalent and 5‐year incident risk factors for cortical and nuclear lens opacification in adult citizens of Reykjavik. Methods: For baseline examination we used a random sample from the population census for citizens of Reykjavik ≥50 years, equal proportion for both gender and each year of birth. Participation rate was 76% (1045). 5 years later 88% of the survivors participated. For diagnosis of opacification we used Scheimpflug and retroilluminated images of the lenses. For statistical analysis we used logistic regression analysis. Results: Cigarette‐smoking more than 20 pack‐years increased the risk for nuclear lens opacification (OR=2.52: 95% CI 1.52‐4.13: p<.001) as did pipe‐ or cigar smoking (OR=2.48:95% CI 1.20‐5.12: p<.05). Systemic corticosteroid use was a risk factor for cortical cataract (OR=3.70: 95% CI 1.43‐9.56: p<.05). Spending more than 4 hours/day outside on weekdays increased the risk of grade II & III cortical cataract, OR= 2.91 (1.13‐9.62: p<.05). Comparing positive rate ratio of early cortical opacities in Reykjavik and Melbourne, by upper and lower lens hemispheres, the rate is about 90 for both cities for the lower half of the lens while for the upper half of the lens this figure is 70.6 for Reykjavik and 46.8 for Melbourne. This is in an a agreement with the difference in zenith angle between the two cities. After adjusting for age, sex and smoking nuclear cataract is associated with twofold increased 5‐year mortality risk (p<.05). Conclusions: Modifiable risk factors include smoking, solar UV radiation and the use of cortical steroids. Nuclear lens opacification carries increased 5‐year risk of mortality and may be a suitable index for projected life span.