Epidemiology and the risk factors of myopia among children and youths in Yunnan province

Objective: The purpose of the study was to describe the prevalence of myopia and to explore the associated factors of myopia among Han and Yi students aged 5-16 years in Yunnan province, China. Methods: A total of 5 971 Han and Yi students were included in the data analysis from the Yunnan eye study which was conducted from March to August, 2014. Information regarding demographic factors, socioeconomic status and lifestyle-related exposures were collected by per-designed questionnaires. The ophthalmic examinations including distance visual acuity, anterior segment examination, cycloplegic auto-refraction, and ocular motility examination were conducted. Logistic regression models were fitted to estimate the risk factors for myopia. Results: The age of 5 971 subjects was (10.68±2.24)years old, and the total prevalence of myopia and high myopia was 48.05% and 0.59%. Myopia prevalence was found to be higher in Han students compared with Yi ethnicity (50.20% vs. 47.10%,P=0.029). In multivariate analysis, the occurrence of myopia was associated with age (OR=1.28, 95%CI: 1.25-1.31), girls (OR=1.32, 95%CI: 1.18-1.48), increasing reading and writing time per day (OR=1.13, 95%CI: 1.07-1.20), having self-reported myopia among friend(s) (OR=1.15, 95%CI: 1.02-1.29), having myopic father (OR=1.38, 95%CI: 1.06-1.79), having myopic mother (OR=1.43, 95%CI: 1.12-1.83) and higher educated mother (OR=1.24, 95%CI: 1.03-1.51). Conclusions: We observed a high prevalence of myopia among Mangshi students. The presence of myopia was associated with increasing age, girls, increasing reading and writing time per day, having self-reported myopia among friend(s), having myopic father, having myopic and high educated mother.