Relationship between pterygium and age-related cataract among rural populations living in two different latitude areas in China

Purposes: To evaluate the prevalence of pterygium and its relationship with the prevalence of age-related cataract (ARC) among rural populations age 50 years or older in two different latitude areas in Western China. Methods: Cluster sampling was used to randomly select individuals, aged 50 years or older in two rural sites (Qinghai and Guangxi) with different latitude in Western China. A total of 2,496 individuals received questionnaires and comprehensive ocular examinations. ARC was defined as visual impairment secondary to lens opacity, which graded with LOCS II. The geographical information of two investigated sites and the demographic data of two populations were collected and compared. Prevalence of pterygium and ARC were evaluated, and statistical analysis of the relationship between the prevalence of pterygium and ARC with different grading was performed. Results: The response rates were 86.20% and 90.40% for Qinghai and Guangxi, respectively. The prevalence rate of pterygium was 36.05% in Guangxi, the lower latitude area (latitude 22.24) and 12.65% in the Qinghai-Tibetan Plateau (latitude 36.63) among adults aged 50 years or older. In these pterygium patients, 91 in Qinghai (56.17%) and 224 in Guangxi (51.14%) also had ARC. The patients with pterygium had a higher prevalence rate of ARC than those without pterygium (39.77% for Qinghai and 32.82% for Guangxi respectively). Beside the regional difference, the risk factors of pterygium included older age, female and ARC. Conclusions: The prevalence of pterygium among rural adult populations is higher in lower latitude region, and it is strongly associated with age-related cataract.National Key Technologies R & D Program, China [2001BA611B-07]SCI(E)ARTICLE23494-35011