Risk Factors for High Myopia in Koreans: The Korea National Health and Nutrition Examination Survey

Purpose: To investigate risk factors for high myopia in the general Korean population.Methods: In this nationwide population study, the dataset of the Korea National Health and Nutrition Examination Survey 2008-2012 was analyzed. The study cohort included 11703 participants, aged 25-49years, who underwent neither refractive nor cataract surgery. The association between demographic, socioeconomic, behavioral, and systemic variables and high myopia was investigated.Results: The mean participant age was 37.96.8years, and the prevalence of high myopia -6.0D was 7.0 +/- 0.3% in the study population. The right eyes (-1.76 +/- 0.03 D) were more myopic than the left eyes (-1.70 +/- 0.03 D; P<0.001). In multivariate logistic regression analysis, high myopia was associated with age (odds ratio [OR], 0.97 per 1year-increase) and female sex (OR, 1.24). Other identified risk factors included education level university graduation (OR, 1.91), the presence of hypertension (OR, 1.69), and serum glucose level (OR, 1.01 per 1mg/dL). Sunlight exposure of 5h/day (OR, 0.67) and serum 25-hydroxyvitamin D level (OR, 0.97 per 1ng/mL) showed protective effect against high myopia.Conclusion: High myopia is associated with younger age, female sex, high education level, longer sunlight exposure, and some other systemic conditions.