Association of circulating osteocalcin with cardiovascular disease and intermediate cardiovascular phenotypes: systematic review and meta-analysis SeiduSamuel KunutsorSetor K KhuntiKamlesh 2019 <p><b><i>Objectives</i>.</b> Circulating osteocalcin (OC), a marker which is central in bone mineralization, may be involved in the atherosclerotic process and influence the risk of developing cardiovascular disease (CVD). We conducted a systematic review and meta-analysis of published observational evidence, to assess and quantify the associations of circulating OC (total, undercarboxylated, and carboxylated OC) with cardiovascular outcomes (clinical CVD endpoints and intermediate cardiovascular phenotypes).</p> <p><b><i>Design.</i></b> Relevant studies were identified in a literature search of MEDLINE, EMBASE, and reference lists of relevant studies to March 2019. Mean differences and risk ratios with 95% CIs were aggregated using random-effects models.</p> <p><b><i>Results</i>.</b> Thirty-three observational studies (prospective and retrospective cohort, case-control, and cross-sectional) with data on 21,021 unique participants were eligible. The pooled risk ratio in a comparison of extreme fourths of total OC levels was 0.98 (95% CI 0.89, 1.08) for composite CVD. Circulating total OC levels were significantly lower in patients with cardiovascular conditions compared with those without these conditions −2.58 ng/ml (95% CI −3.85, −1.32; <i>p <</i> .001). Prospective and cross-sectional data showed significant inverse associations between total OC and traits such as aortic or coronary calcification, coronary atherosclerosis or calcification, carotid intima-media thickness, and plaque score. There was limited data on carboxylated and undercarboxylated OC, with no evidence of associations.</p> <p><b><i>Conclusion</i>.</b> Observational evidence generally supports inverse associations of circulating total OC with risk of atherosclerotic outcomes and CVD endpoints; however, the data were mostly based on cross-sectional evaluations. Large-scale prospective data are needed.</p>