The Association Between Osteocalcin and C-Reactive Protein; A Relation of Bone with Inflammation: A Systematic Review...

A meta-analysis was performed to summarize the evidence from observational studies regarding the association between serum osteocalcin (OC) and C-reactive protein (CRP). A systemic research of the literature databases including PubMed, SCOPUS, and Google Scholar was performed to identify the relevant studies up to March 2018. We used the random-effects model by the method of DerSimonian and Laird to calculate the overall effect size. Q-test and I ²-statistics were used to assess between-study heterogeneity. In addition, we did subgroup analysis to detect possible sources of heterogeneity based on BMI range, gender, type of study population and age. We identified 21studies of association between serum osteocalcin and CRP eligible for the meta-analysis. The overall effect size showed a significant inverse association between OC and CRP (Fisher's z=-0.127; 95% CI: -0.166, -0.088, p<0.0001). However, the significant chi-squared statistic result, indicates a heterogeneity of effect sizes (I ²=61.6, df=20, p<0.0001). The subgroup analysis found BMI range, type of study population, and age were the potential sources of heterogeneity. In addition, the strongest correlation was observed in the subgroup of obese subjects (Fisher's z=-0.264, p=0.002), less than 40 years old (Fisher's z=-0.115, p<0.0001) and healthy subjects (Fisher's z=-0.115, p<0.0001). These findings suggest that there is a significant inverse association between serum OC and CRP levels in the adult population.