Serum vitamin D level and micro-ribonucleic acid-146a expression pattern in dry eye disease associated with rheumatoid arthritis in an Egyptian population

Abstract

Aim The aim of this research was to study serum vitamin D and micro-ribonucleic acid-146a (miRNA-146a) expression in dry eye disease (DED) associated with rheumatoid arthritis (RA) and their clinical correlations to DED parameters. Setting and design This is an observational cross-sectional study that was conducted at Cairo University, Cairo, Egypt. Patients and methods The study participants were divided into three groups: group A, DED/RA (n=35); group B, non-DED/RA (n=36); and group C, non-DED/non-RA (n=35). All participants were assessed for ocular surface disease index, tear breakup time (TBUT), serum level of vitamin D, and miRNA-146a expression. In the DED group (with TBUT˂10 s), DED evaluation was performed, including Schirmer I test, corneal and conjunctival scoring, and impression cytology. Results The mean serum vitamin D level was 17.1±16.2 ng/ml in group A, 35.1±13.4 ng/ml in group B, and 38.1±8.7 ng/ml in group C, with a statistically significant difference (P˂0.001). The mean miRNA-146a expression was 4.7±1.5 in group A compared with 4.8±1.8 in group B (P=0.959) and 1.0±0.1 in group C (P˂0.001, compared with each of groups A and B). In group A, serum vitamin D level showed a significant moderate negative correlation to each of impression cytology grading (r=−0.456, P=0.019) and miRNA-146a expression (r=−0.387, P=0.041). Both serum vitamin D and miRNA-146a expression showed nonsignificant correlations to ocular surface disease index, TBUT, Schirmer I test, and corneal and conjunctival scoring. Conclusion DED associated with RA showed a statistically significantly lower serum level of vitamin D, which was negatively correlated to impression cytology grading and miRNA-146a expression. Expression of miRNA-146a did not differ between the dry eye and non-dry eye RA groups.