Positive Association between Blood 25-Hydroxyvitamin D Levels and Pterygium after Control for Sunlight Exposure.
OBJECTIVE
To investigate the association between blood 25-hydroxyvitamin D levels and pterygium.


METHODS
Korean National Health and Nutrition Examination Survey 2008-2011 were used for the present epidemiologic study. A total of 19,178 participants aged ≥ 30 years were evaluated for blood 25-hydroxyvitamin D levels and performed ophthalmic slit lamp examinations. Pterygium was considered as a growth of fibrovascular tissue over the cornea.


RESULTS
The average blood 25-hydroxyvitamin D levels were 18.6 ng/mL, and prevalence of pterygium was 6.5%. The odds of pterygium significantly increased across blood 25-hydroxyvitamin D quintiles after controlling sun exposure time as well as other confounders such as sex, age, smoking, diabetes, hypertension (P < 0.001). The odds ratios (OR) for pterygium was 1.51 (95% Confidence Interval[95%CI]; 1.19-1.92) in the highest blood vitamin D quintile. Stratified analysis by sex showed a positive association between blood 25-hydroxyvitamin D levels and pterygium in both men (quintile 5 versus 1, OR; 1.68, 95%CI; 1.19-2.37) and women (quintile 5 versus 1, OR; 1.37, 95% CI; 1.00-1.88).


CONCLUSIONS
Even after controlling sun light exposure time, we found a positive association between blood 25-hydroxyvitamin D levels and pterygium in a representative Korean population. The mechanism underlying this association is unknown.
Department of Ophthalmology and Visual Science, St. Vincent's Hospital, College of Medicine, Catholic University of Korea, Suwon, Korea.
Donghyun
D
Jee
Department of Ophthalmology and Visual Science, Bucheon St. Mary's Hospital, College of Medicine, Catholic University of Korea, Bucheon, Korea.
Eun Chul
EC
Kim
Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, United States of America.|Department of Dermatology, The Warren Alpert Medical School of Brown University, Providence, United States of America.
Eunyoung
E
Cho
Department of Ophthalmology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America.
Jorge G
JG
Arroyo
D003315:Cornea / Q000473:pathology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D016017:Odds Ratio; D015995:Prevalence; D011625:Pterygium / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology* / Q000473:pathology; D012307:Risk Factors; D013472:Sunlight; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
D014807:Vitamin D; C104450:25-hydroxyvitamin D