Differences in biochemical bone markers by diabetes type and the impact of glucose

Abstract

Background: Diabetes mellitus is associated with an increased fracture risk, however the fracture risk is 7 fold increased in patients with type 1 diabetes (T1D) and 1.4 fold increased in patients with type 2 diabetes (T2D) with decreased and increased bone mineral density, respectively. Oral ingestion of glucose causes an acute decrease in bone turnover markers, and thus glucose levels may affect bone turnover in diabetes.

Objective: The aim was to examine disparities in bone turnover markers between patients with T1D and T2D and evaluate the effect of glucose on bone turnover.

Methods: A cross-sectional study was conducted. Patients diagnosed with T1D (n=98) or T2D (n=96) were included from the outpatient clinics at two University Hospitals. All individuals had normal renal function. Glucose and bone turnover markers were measured in non-fasting blood samples.

Results: P-procollagen type 1 amino terminal propeptide (P1NP), p-osteocalcin (OC), and s-Receptor Activator of Nuclear factor Kappa beta Ligand (RANKL) were lower in patients with T2D compared to T1D, and s-osteoprotegerin (OPG) was higher in T2D. P-C-terminal cross-linked telopeptide of type-I collagen (CTX), p-fibroblast growth factor-23 (FGF-23), p-sclerostin, and p-undercarboxylated osteocalcin (ucOC) were similar in between the two groups of patients. Increasing non-fasting glucose levels were inversely related to p-CTX, p-P1NP, p-OC, and p-ucOC and directly related to s-OPG in simple linear and multiple linear regressions adjusted for factors influencing bone turnover markers including HbA1c.

Conclusion: Bone turnover markers were lower in patients with T2D compared to T1D. Acute blood glucose alterations may change bone turnover mediated by OPG and have detrimental effects on bone health in diabetes.

Trial registration number: ClinicalTrials.govNCT01870557.

Keywords: Bone turnover; Bone turnover markers; Diabetes mellitus; Glucose.