Prevalence Of Cataract At Different Altitudes In Gansu Aged 50 Years And Over

Objective:To assess the prevalence and distribution of cataract at different altitudes in Gansu province.Methods:The cluster random sampling method was used to conduct the survey of cataract.The residents aged 50 years and over in different areas of Gansu Province(altitude span 900 meters to 3500 meters)were selected as the subjects of the survey.The survey was conducted at a village or township health service center.The investigation procedure includes pre-survey,field questionnaire survey and related ophthalmological examination.The diagnostic criteria for cataract are typical opacity of lens with visual acuity less than 0.7.The prevalence of cataract was calculated according to factors such as altitude,age and sex.Chi-square test and two-element unconditional logistic regression were used for statistical analysis.Results:The total number of people surveyed was 7560,and the prevalence rate of cataract was 39.7%,age-standardized prevalence was 37.7%.With age stratification,the prevalence of cataract at high altitude was higher than that at low altitude(?~2=26.74 and 16.06,P<0.05).Multivariate binary logistic regression analysis was used to explore the risk factors of cataract.The results showed that the cataract risk of 2000-2999m group was higher than that of less than 1000m group.The difference was significant(OR=1.42,95%CI=1.11~1.82).With the increase of altitude,the cataract risk of more than 3000m group was higher.The difference was significant(OR=1.76,95%CI=1.01~3.06).It was found that high educational background was a protective factor for cataract,while Diabetes is considered a risk factor for cataract.Conclusion:High altitude and old age are important risk factors for cataract,and high altitude is an independent risk factor for cataract.It is necessary for local government and health institutions to guide the public to take protective measures to reduce the incidence of cataract in local areas.