Abstract
Purpose :
The role of vitamin D on myopia development is not certain. This is a systematic review and meta-analysis which aims to evaluate the association of myopia with 1) serum vitamin D level; and 2) vitamin D related genes.
Methods :
Literature searches were conducted via online database MEDLINE and EMBASE from their starting date to November 30, 2016. First, the association between serum vitamin D and myopia were evaluated by synthesizing the outcomes using meta-analysis: 1) Standard mean difference (SMD) between myopia group and non-myopia group; 2) unadjusted and adjusted Odd Ratios (ORs) of vitamin D level for myopia; and 3) unadjusted and adjusted coefficient of vitamin D for myopia. Adjustment was taken for time spent outdoor or sunlight exposure. Second, the association between vitamin D related genes and myopia were analyzed by combining the ORs and 95% CIs.
Results :
1) Association between Serum Vitamin D Level and Myopia
A total of 125 publications were retrieved for screening, and six articles were eligible for meta-analysis with a total of 19816 study subjects. Serum vitamin D level was significantly lower in the non-myopia group than myopia group. (SMD: -0.33, p=0.005) Furthermore, the risk of myopia is lower with higher level of serum vitamin D. (Unadjusted OR: 0.85 per 10nmol/L, P = 0.005). This association was stronger after adjustment for sunlight exposure or time spent outdoor (Adjusted OR: 0.92 per 10nmol/L, P = 0.0006). However, there were no significant association between the vitamin D level and refraction by linear regression. (Unadjusted coefficient: 9.15D per pmol/L, P=0.129; adjusted coefficient: 3.40D per pmol/L, P=0.140).
2) Association between vitamin D related genes and Myopia
A total of 41 publications were retrieved for screening and only two articles were eligible for meta-analysis. Association of four SNPs of a vitamin D related gene with myopia have been evaluated in both studies. The combined OR of one SNP showed a risk association of the vitamin related gene with myopia (OR: 1.30, P = 0.02).
Conclusions :
Serum vitamin D levels is associated with myopia status independent from sunlight or outdoor exposure. Vitamin D receptor gene may be a susceptibility gene for myopia development. Vitamin D may have association with myopia in addition to its role as biomarker for time spent outdoor.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.