Relationship between serum osteocalcin level and carotid intima-media thickness in a metabolically healthy Chinese population

Background: The relationship between osteocalcin and atherosclerosis remains unclear. This might be due to different degrees of confounding from factors that are associated with serum osteocalcin level, such as metabolic-related variables. This study aimed to investigate the relationship between serum osteocalcin level and carotid intima-media thickness (C-IMT) in a metabolically healthy population. Methods: A total of 476 subjects with normal values for weight, glucose tolerance, blood pressure, and lipids (age range, 20-75 years; 155 men, 201 premenopausal women, 120 postmenopausal women) from the Shanghai Obesity Study were recruited for this cross-sectional study. Subjects with a history of cardiovascular disease or carotid plaque were excluded. C-IMT was measured by ultrasonography. Serum osteocalcin level was assessed by an electrochemiluminescence immunoassay. Results: Median C-IMT in the entire study population was 0.55 mm with an interquartile range of 0.50-0.60 mm. C-IMT in premenopausal women was significantly lower than that in men and postmenopausal women (all P < 0.001). The median (interquartile range) of serum osteocalcin level in the entire population was 17.02 (13.31-21.47) ng/mL. Serum osteocalcin level in postmenopausal women was significantly higher than that in men and premenopausal women (all P < 0.001), while the level of serum osteocalcin in men was also significantly higher than that in premenopausal women (P < 0.001). No significant correlation was found between C-IMT and serum osteocalcin level in either men or postmenopausal women. There was a significant, inverse correlations between C-IMT and serum osteocalcin level in premenopausal women after adjustment of age, but this association was eliminated after adjustment for other confounding factors. Conclusions: Serum osteocalcin level was not independently associated with C-IMT in a metabolically healthy Chinese population.