Correlation of plasma microRNA-21 expression and bone turnover markers in postmenopausal women

Objectives: This study assessed the correlation of plasma microRNA-21 expression and bone turnover markers (BTMs: CTx, P1NP) in healthy Thai postmenopausal women. We secondarily compared microRNA-21 expression between participants with normal and low bone mineral density (BMD: osteopenia and osteoporosis). Methods: Postmenopausal women who had never been diagnosed with fracture or never used anti-osteoporosis drugs were included in this study. Baseline characteristics were collected from all 195 participants. BTMs and plasma miR-21-5p were analyzed from blood collection at 8:00 and 9:00 am after overnight fasting for at least 8 h. Results: There was no significant correlation between miR-21-5p and any of the BTMs (CTx, r = 0.094, p = 0.19; P1NP, r = 0.05, p = 0.485). Significant correlation between miR-21-5p and P1NP was found when participants were further categorized into those aged ≥70 years (r = 0.46, p = 0.05) and those having osteoporosis (r = 0.51, p = 0.06). Slight negative correlations were found between miR-21-5p and BMD. There was statistically significant higher expression of miR-21-5p in those with low BMD when compared to the normal BMD group (p < 0.01). Conclusion: In this study, we did not find significant correlation between plasma microRNA-21-5p expression and the BTMs. Nevertheless, there seemed to be higher expression of miR-21-5p in the low BMD participants.