Low Serum 25-Hydroxyvitamin D Is Associated with Myopia in Korean Adolescents.

Purposes: To assess the relationship between serum level of 25-hydroxyvitamin D (25(OH)D) and refractive error in Korean adolescents. Methods: A total of 2,038 adolescent aged 13-18 years, who participated in the Korea National Health and Nutrition Examination Survey (KNHANES) from 2008 to 2011 underwent refractive examination using an autorefractor. Serum 25(OH)D concentration and other potential risk factors were examined. Multivariate regression analysis was performed to investigate the association between serum 25(OH)D and spherical equivalent (SE). Results: Among the participants, 80.1% had myopia (-0.5 D or more myopic) and 8.9% had high myopia (-6.0D or more myopia). The age-adjusted distribution of SE according to serum 25(OH)D concentration showed a positive relationship (r = 0.067, P = 0.012).The myopia group had a significant positive relationship between SE and serum 25(OH)D tertile concentration (P = 0.020), whereas the non-myopia group did not have any significant relationship (P = 0.599).In multiple linear regression analyses, SE was significantly associated with low serum 25(OH)D concentration after adjustment for area of residence, parental income, total energy intake, dietary Ca intake, milk consumption and smoking experience (P=0.047). The prevalence of high myopia was significantly associated with the lowest tertile of serum 25(OH)D concentration after adjustment for the confounding factors (P=0.017). Smoking experience showed inverse associations with both SE and the prevalence of high myopia (P = 0.001 and 0.036) Conclusions: Low serum 25(OH)D concentration was associated with myopia prevalence in Korean adolescents. This relationship was particularly notable in adolescents with high myopia.