Variables which influence concentrations of sclerostin in patients with diabetes mellitus type 2 and its association with bone metabolism

Background and objectives: Diabetes mellitus type 2 (DM2) is associated with an increased risk of fractures whose underlying mechanisms are complex. The objective of this study was to analyse the variables which influence blood concentrations of sclerostin and the relationship with bone metabolism in a group of DM2 patients. Patients and methods: A transversal study of 76 patients with DM2. Clinical data, basic biochemical parameters, calciotropic hormones, markers for bone remodelling, vertebral X-rays and bone mineral density (BMD) were gathered. Blood concentrations of sclerostin were determined using ELISA (Biomedica, Austria). Results: The males had higher concentrations than the females (63.15 +/- 27.03 vs 43.14 +/- 17.08 pmol/L, p<0.001). We found positive relationships between sclerostin and age in males with DM2 (r=0.338, p=0.031) and between sclerostin and creatinine in the whole sample (adjusted for age: r=0.362, p<0.001). Also, it had a negative relationship with bone alkaline phosphatase (BAP) (r=-0.259, p=0.029), carboxy-terminal telopeptide of type 1 collagen (CTX) (r=-0.356, p=0.002) and tartrate-resistant acid phosphatase 5 beta (TRAP beta) (r=-0.289, p=0.013). BMD in the lumbar spine, femoral neck and total hip were positively associated with sclerostin (r=0.373, r=0.492, r+0.524, p<0.001) adjusted for age. Blood levels of sclerostin were lower in patients with DM2 and osteoporosis than those who were non-osteoporotic (42.96 +/- 19.16 vs 56.95 +/- 25.98 pmol/L, p=0.041). Conclusions: Sex, age and renal function are determining factors of levels of sclerostin in the circulation of patients with DM2. There is a negative relationship with remodelling markers and a positive one with BMD. Blood levels of sclerostin are lower in patients with DM2 and osteoporosis.