title: Association Between Serum 25-Hydroxyvitamin D Levels and Dry Eye in Korean Adults: A Study Based on Korean National Health and Nutrition Examination Survey, 2010-2011.
abstract: BACKGROUND
  Dry eye is a common disease. Many patients continue to experience residual symptoms despite optimal treatment. Thus, new treatment options are required. The purpose of this study was to evaluate the association between serum 25-hydroxyvitamin D [25(OH)D] levels and dry eye.
  
  
  METHODS
  This study was performed using data from the fifth Korean National Health and Nutrition Examination Survey, which is a cross-sectional study of the Korean population that was conducted from 2010 to 2011. We included adults aged >19 years who underwent ophthalmologic interviews and examinations. We excluded subjects who had comorbid conditions (rheumatoid arthritis, thyroid disease, chronic kidney disease, or depression) that are associated with dry eye. The subjects were divided into normal and dry eye groups. The dry eye group consisted of those who had clinically diagnosed dry eye syndrome or symptoms. Multiple logistic regression analysis was conducted to determine the association between serum 25(OH)D levels and dry eye.
  
  
  RESULTS
  In the univariate model, the 25(OH)D levels were lower in the dry eye group than in the normal group (P=0.01). A significant association was found between severe vitamin D deficiency (<10 ng/mL) and dry eye (P=0.04). However, after multivariate adjustment, the statistical significance of the association disappeared (P-values= 0.49, vitamin D insufficiency; P=0.33, vitamin D deficiency; P=0.18, severe vitamin D deficiency).
  
  
  CONCLUSIONS
  Severe vitamin D deficiency was associated with dry eye in an unadjusted model, but the association was not statistically significant after adjustment.
authors.affiliation: Department of Family Medicine, Pusan National University Hospital, Busan, Korea.
authors.forename: Min Ji
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Department of Family Medicine, Pusan National University Hospital, Busan, Korea.; Department of Family Medicine, Pusan National University School of Medicine, Yangsan, Korea.
authors.forename: Hye Rim
authors.initials: HR
authors.lastname: Hwang
authors.affiliation: Department of Family Medicine, Pusan National University Hospital, Busan, Korea.; Department of Family Medicine, Pusan National University School of Medicine, Yangsan, Korea.
authors.forename: Yun-Jin
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Department of Family Medicine, Pusan National University School of Medicine, Yangsan, Korea.; Department of Family Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea.; Medical Education Unit, Medical Research Institute, Pusan National University School of Medicine, Yangsan, Korea.
authors.forename: Sang-Yeoup
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Department of Family Medicine, Pusan National University Hospital, Busan, Korea.; Department of Family Medicine, Pusan National University School of Medicine, Yangsan, Korea.
authors.forename: Jeong-Gyu
authors.initials: JG
authors.lastname: Lee
authors.affiliation: Department of Family Medicine, Pusan National University School of Medicine, Yangsan, Korea.; Department of Family Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea.
authors.forename: Dong-Wook
authors.initials: DW
authors.lastname: Jeong
authors.affiliation: Department of Family Medicine, Pusan National University Hospital, Busan, Korea.
authors.forename: Yun Hee
authors.initials: YH
authors.lastname: Kim
keywords: 25-Hydroxyvitamin D; Dry Eye; Dry Eye Syndromes; Vitamin D