Association of Bone Turnover Biomarkers and Subclinical Atherosclerosis in Subjects with Type 2 Diabetes: A Case-Control Study

Objective: The current study aims to assess the relationship between serum osteocalcin (OCN) and osteoprotegerin (OPG) levels and subclinical atherosclerosis. Material and methods: This case-control study included 80 male subjects divided into 2 groups: 40 subjects with type 2 diabetes (T2D) without coronary artery disease and 40 control subjects without diabetes. To assess the association of OCN and OPG with subclinical atherosclerosis (defined as carotid intima-media thickness (cIMT) ≥ 0.9mm), multivariable linear regression models were applied. Results: The mean age in the diabetes group was 54.1 ± 5.1 years while in the control group, it was 53.7 ± 6.6 years. The mean serum OCN level was significantly negatively correlated with hs-CRP, cIMT, HbA1c and FPG in the total sample (p = 0.001, < 0.001, < 0.001 and 0.006 respectively) while OPG level was significantly positively correlated with age and HbA1c (p = 0.047 and 0.009 respectively) in the total sample. Age and HbA1c were the only independent risk factors identifying subclinical atherosclerosis in multivariate analysis. A cut-off value of serum OCN level of ≤ 22 ng/mL was able to discriminate patients with subclinical atherosclerosis in the total sample (p = 0.003*) using receiver operator characteristic (ROC) curve analysis. Serum OCN level was significantly lower in the subclinical atherosclerosis group than in the control while OPG showed no significant difference between both groups. Conclusions: OCN may be a better marker for subclinical atherosclerosis than OPG. This effect is attenuated in the presence of DM.