Low Level of Osteocalcin Is Related With Arterial Stiffness in Korean Adults: An Inverse J-Shaped Relationship.

CONTEXT: The relationship between bone turnover markers and atherosclerosis is controversial. OBJECTIVE: The purpose of this study was to determine the association of arterial stiffness with the levels of osteocalcin and C-terminal telopeptide of type I collagen (CTx). DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study included 1691 men and 1913 women who participated in the medical examination programs of a hospital from March 2008 to December 2011. MAIN OUTCOME MEASURES: Arterial stiffness was estimated by brachial-ankle pulse wave velocity (baPWV). Osteocalcin and CTx were assayed by chemiluminescence immunoassay. Bone mineral density was measured by dual-energy X-ray absorptiometry. RESULTS: The mean baPWV was elevated at both ends of the osteocalcin quintiles in both men and women. However, the adjusted mean was higher in the lowest quintile of osteocalcin than in the other quintiles in men and women. Before adjustment, negative and positive relationships of baPWV with the levels of osteocalcin and CTx were observed in men (ß = -0.123 and -0.078 for osteocalcin and CTx, respectively) and women (ß = 0.151 and 0.193), respectively. After adjustment for age and metabolic parameters, osteocalcin was negatively related with baPWV at lower osteocalcin levels (Q1-Q2) in both sexes (in the fully adjusted model, ß = -0.090 for men and -0.053 for women). No significant relationship was observed at higher values. The osteocalcin level was fit for a quadratic model for baPWV showing an inverse J-shape. CONCLUSIONS: The level of serum osteocalcin showed an inverse J-shaped relationship with arterial stiffness in both men and women. However, the association between the CTx level and arterial stiffness was not significant.