ABSTRACT
BACKGROUND: The uncarboxylated osteocalcin (ucOC) has been described as a regulator of glucose metabolism in mice, and it is decreased in human type 2 diabetes mellitus (T2D). Although inversely correlated with serum glucose, insulin, and glycated hemoglobin, it is unclear if ucOC decrement is caused by diabetes or plays a role in the pathogenesis and/or progression of the disease. Whatever the case may be, diabetes affects osteoblast gene expression, and possibly the proportion of ucOC over carboxylated OC (cOC). The association of ucOC/cOC index with glycemic status markers in patients with T2D has not been described before. OBJECTIVE: The objective of this study was to assess the ucOC/cOC index and its relationship with glycemic status markers in patients with T2D. METHODS: The ucOC/cOC index was determined by the quotient of ucOC and cOC serum levels in 80 T2D patients and 160 healthy subjects. The relationship between the ucOC/cOC index and glycemic status markers was evaluated. RESULTS: The ucOC/cOC index was low and negatively correlated to fasting plasma glucose and homeostasis assessment-insulin resistance model in T2D patients. The odds ratio for T2D patients with an ucOC/cOC index below the cut-point obtained by receiver operating characteristic analysis was 12.64 (confidence interval, 5.75-27.77; P < 0.001). CONCLUSIONS: A value of ucOC/cOC index less than 0.3 is associated with markers of poor metabolic control in patients with T2D.