Prevalence and risk factors of lens opacities in urban and rural chinese in Beijing

Abstract

Abstract Purpose: To determine the prevalence of lens opacities in the elderly Chinese population in an urban and a rural region of Beijing. Methods: The study included 4439 subjects out of 5324 subjects invited to participate (response rate 83.4%). It was divided into a rural part (1973 (44.4%) subjects) and an urban part (2466 (55.6%) subjects). The study was limited to participants age 40 and older and the mean age was 56.2 ± 10.6 years (range, 40 – 101 years). Nuclear, cortical and posterior subcapsular lens opacities were assessed based on standardized slit lamp photographs of the lens using a modification of the grading score of the Age‐Related Eye Disease Study (AREDS). Results: Of the 4439 persons examined, 4378 (98.6%) subjects (8724 eyes) provided lens data. Prevalence of any cataract surgery was 1.3% (95% confidence interval [CI]: 1.0, 1.7), being statistically independent of gender (p=0.51; odds ratio [OR]: 0.86; 95%CI: 1.00, 1.34), rural area versus urban region (p=0.25), and level of education (p=0.84). Prevalence of any nuclear lens opacity was 82.0% (95%CI: 80.8, 83.2), of any cortical lens opacity was 10.3% (95%CI: 9.4, 11.3), and of any posterior subcapsular opacity 4.3% (95%CI: 3.7, 4.9). If grade “2” of nuclear lens opacity was considered to be normal, prevalence of nuclear cataract was 50.3% (95%CI: 48.8, 51.8), and the overall prevalence of any cataract was 53.1% (95%CI: 51.6, 54.6), increasing from 6.5% (95%CI, 5.2, 7.8) in those 40 to 49 years old, to 52.3% (95%CI: 47.4, 55.3) in those 50 to 59 years old, and to 97.8% (95%CI: 96.4, 99.2) in those 70 years and older (p<0.001). Frequencies of any cortical cataract and any subcapsular posterior cataract, respectively, were 10.3% (95%CI: 9.4, 11.3), and 4.3% (95%CI: 3.7, 4.9), respectively. Conclusions: Cataract is common among adult Chinese residents in Beijing with age as the most important associated factor. In view of the relatively low rate of cataract surgery performed so far, one may expect a marked increase in the number of cataract surgeries to meet the visual needs of the growing elder population in China.