Prevalence and risk factors of refractive error in Qinghai, China: a cross-sectional study in Han and Tibetan adults in Xining and surrounding areas

Background Our study aimed to explore the prevalence and risk factors of refractive error (RE) in Han and Tibetan population aged 50–79 years in Xining and surrounding areas in Qinghai Province on Qinghai-Tibet Plateau. Methods As part of the China National Health Survey, our cross-sectional study compared the age-adjusted prevalence of RE in Han and Tibetan older adults aged 50–79 years in Xining and surrounding areas. A multivariate logistic regression model was used to identify risk factors for myopia and hyperopia. Results Among 769 Han participants and 476 Tibetan participants, the age-adjusted prevalence of myopia (spherical equivalent (SE) < − 0.5D), hyperopia (SE > + 0.5D), high myopia (SE < -6.0D) and astigmatism (cylindrical equivalent > = 0.5D) is 28.56, 22.82, 2.80, and 69.38%. Han participants have higher age-adjusted prevalence of myopia (32.93% vs 21.64%, p < 0.001), high myopia (3.93% vs 1.02%, p = 0.001) and astigmatism (72.14% vs 64.94%, p = 0.021) compared to Tibetan participants. Being Tibetan is the protective factor of myopia compared to being Han (OR 0.58, 95%CI 0.42–0.79, p < 0.001). Older age ( p = 0.032), longer time length in rural area ( p = 0.048), undergraduate/graduate education level ( p = 0.031), lighter active level ( p = 0.007) and lower BMI ( p = 0.015) are risk factors for myopia. Older age (all p < 0.001) and pterygium status of the same eye ( p = 0.013) also increase the hyperopia risk. Conclusions Our study found an overall prevalence of myopia of 28.56% in Xining and surrounding areas in adults older than 50 years. Han population has higher myopia risk than Tibetan population. More medical and social resources should be allocated to improve the vision and life quality of older adults.