Vitamin D status in children with myopia

Introduction. A dramatic increase of myopia worldwide has been observed in recent years. New risk factors for the development of myopia have been the target of numerous investigations. The basis of our research is the correlation between serum levels of vitamin D [25(OH)D] and myopia itself.Purpose: To find out the relationship between serum levels of 25(OH) D and myopia. Patients and methods: The study included 222 children with different refraction status. Full ophthalmologic examination, cycloplegic refraction, echobiometry were performed. The serum levels of 25(OH)D were measured by liquid chromatographic mass spectrometry (level of insufficiency < 80 nmol/L).Results: The average patients’ age (51% boys and 48,2% girls) was 11,7 y (SD ± 3,03). They were subdivided into two groups – children with myopia (84,7%) and those without myopia (15,3%). The mean serum 25(OH)D level of all tested was 61,48 nmol/L (16-140 nmol/L; SD ± 20,15); of myopia – 59,67 nmol/L (16-140 nmol/L; SD ± 19,30) and of the non-myopia group – 71,91 nmol/L (33-111 nmol/L; SD ± 21,79). There was a statistically significant difference in serum levels between the two groups (Р = 0,001). The risk of myopia was higher with the decrease of 25(OH)D values (OR = 1,028 ; 95% CI 1,008-1,048). Conclusion. In our investigation group we established low serum levels of 25(OH)D which indicated the need for conducting a population study of its status among Bulgarian children. The correlation between the higher risk of myopia and the vitamin D scarcity has to be further studied, also considering the factor of outdoor/sun-exposure time.