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

<b>Objectives:</b> 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). <b>Methods:</b> 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. <b>Results:</b> There was no significant correlation between miR-21-5p and any of the BTMs (CTx, <i>r</i> = 0.094, <i>p</i> = 0.19; P1NP, <i>r</i> = 0.05, <i>p</i> = 0.485). Significant correlation between miR-21-5p and P1NP was found when participants were further categorized into those aged ≥70 years (<i>r</i> = 0.46, <i>p</i> = 0.05) and those having osteoporosis (<i>r</i> = 0.51, <i>p</i> = 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 (<i>p</i> <b>Conclusion:</b> 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.