Prevalence and risk factors for refractive error in older adults in eight ethnicities in China: The China National Health Survey (CNHS)

Abstract Background China is a multiethnic country; however, the study of the prevalence of RE in western areas and in ethnic minorities in China is limited. This study was to investigate the prevalence and influences of REs (refractive errors) in older adults in the Han and minority ethnicities in 7 provinces in China. Methods The current cross-sectional study is part of the ophthalmic data of the China National Health Survey (CNHS). Face-to-face interviews and ophthalmic examinations were conducted in 7 provinces in Northwest and Southwest China. The age- and sex-adjusted prevalence of RE in Han and 7 other ethnicities, aged 50–80 years, were compared. A mixed effects model was used to identify the risk factors for RE. Results A total of 12902 participants, 8808 Han and 4102 ethnic minorities, were included. The age- and sex-adjusted prevalence of myopia, high myopia, hyperopia and astigmatism were ranged 15.3% (Manchu) -22.9% (Han), 0.2% (Yugur) -2.8% (Han), 21.6% (Tibetan) -48.9% (Uyghur) and 38.7% (Yi) -57.5% (Manchu) in different ethnicities, respectively. Compared to Han population, ethnicities of Mongolian, Tibetan, Uyghur, Yi and Yugur was less likely to have myopia, while there is no significant difference in the prevalence of myopia between the Manchu, Korean and Han ethnic groups. Other protective factors for myopia including: rural residence; higher BMI index, living in higher latitude area and smoking history. High myopia was negatively associated with Mongolian and Yugur populations and living in rural areas. Older age; ethnicities of Mongolian, Uyghur, Yi and Yugur; rural residence, living in higher latitude area and past smoking history were positively associated with hyperopia. Conclusions The prevalence of myopia in older adults was relatively low in Northwest China. Significant differences in RE prevalence were observed between minority ethnicities and Han people, except for the Manchu and Korean populations.