Prevalence and risk factors of myopia in Han and Yugur older adults in Gansu, China: a cross-sectional study

Abstract

few studies have investigated the prevalence of myopia in northwest china. this cross-sectional study aimed to investigate the prevalence and associated factors of myopia and high myopia in adults aged 40-80 years in the Han and Yugur populations living in Gansu Province, Northwest China. A total of 3,845 participants were included. The overall age-and sex-adjusted prevalence of myopia (spherical equivalent (SE) < −0.5 D), high myopia (SE < −6.0 D) and hyperopia (SE > + 0.5 D) were 16.4%, 0.7% and 26.2% in Yugur participants, respectively, and 34.3%, 5.0% and 19.2% in Han participants, respectively. The prevalence of myopia and high myopia in Han participants was significantly higher than that in Yugur participants (both P < 0.001). Yugur population, birth in rural areas, smoking history and outdoor work were found to be negatively associated with myopia. Higher education level and a family history of myopia were found to be positively associated with myopia in the study population. High myopia was negatively associated with Yugur population, aging, birth in rural areas and was positively associated with a family history of myopia. This study provided valuable information regarding the environmental risk factors of myopia and revealed an ethnic disparity in the prevalence of myopia in Gansu province, northwest china. Refractive error, especially myopia, is a common ocular abnormality. Complications associated with high myopia have become an important cause of low vision in adolescents and adults 1,2. The prevalence of myopia differs by region. Many studies have shown that the prevalence of myopia is high in East Asia 3-6. In China, the prevalence of myopia among school-age children in urban areas is 12.7-35.8% 7,8 and 70-87.7% 8-10 in people aged over 17. Although some studies explored that the prevalence of myopia among Chinese immigrants was the highest than other ethnicities of their place of residence 11-13 , the genetic susceptibility on the high prevalence of myopia in Chinese population is not sufficient as their cultural attitudes to education sustained impact the learning pressure. Previous studies have also indicated that myopia was more related to environmental factors (early learning 14 , near work 15 , and lack of outdoor activities 16,17) than genetic factors. China is a multiethnic country composed of the Han ethnicity and 55 other populations, which results in differences in health and clinical profiles. The disparities in the prevalence of myopia in different populations in China have been studied in teenagers 18,19. The prevalence of myopia among subjects aged 4-19 years of the Han population (27%) was significantly higher than those of the Hui (18%) and Uyghur (13%) living in Turpan, China 19. One study among Han and Yi adults in Yunnan Province showed that the Yi population had a lower prevalence of myopia (8.1% vs. 10.3%; P = 0.02) 20. Disparities in myopia susceptibility may be attributed to

High prevalence of refractive errors in an elderly population; a public health issue

“…Although various studies have investigated the prevalence of refractive errors in people above 40 years of age worldwide [3,5,6,8,9,13,14,[16][17][18][19][20][21][22][24][25][26][27][28][29][30][31][32], the present population-based study specifically examined refractive errors in an elderly population aged 60 years and above using a large sample size. Non-exclusion of individuals with a history of ocular surgery is one of the important points that should be considered first.…”

“…In recent years, various studies have investigated the prevalence of refractive errors in older adults [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Accordingly, the prevalence of refractive errors in this age group has been reported up to more than 80% [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”

“…In recent years, various studies have investigated the prevalence of refractive errors in older adults [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Accordingly, the prevalence of refractive errors in this age group has been reported up to more than 80% [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Due to the stabilization of ocular growth and slight biometric changes in older ages, the risk factors of refractive error in this age group are expected to be different from adolescents and individuals under 40 years of age.…”

“…Age-related structural changes in ocular media especially crystalline lens and ocular pathologies are the main causes of refractive errors in this age group [24,25]. Although a review of the literature indicates various studies in this regard, most previous studies investigated refractive errors in people above 40 years of age and included a small sample of the elderly [3,5,6,8,9,13,14,[16][17][18][19][20][21][22][24][25][26][27][28][29][30][31][32]. This is while controlling infectious diseases and increasing life expectancy in recent years has led to the increased growth of the elderly population as well as an increase in the proportion of this age group in the total population [33].…”

Is Peripheral Motion Detection Affected by Myopia?

“…The condition is mainly manifested as a reduction of distance visual acuity (Morgan et al, 2012). The global prevalence of myopia has reached very high as reported in multiple epidemiological studies Scott, 1993, 1994;Dirani et al, 2009;Lim et al, 2012), particularly in Asian populations (Wang et al, 2020;Xie et al, 2020). It was predicted that almost half of the world population would have myopia by 2050 (Holden et al, 2016).…”