| Objective This study intends to study the association between serum retinol-binding protein 4(RBP4), bone mineral density (BMD), and other bone metabolic related parameters in type 2 diabetic patients older than 50 years, with or without osteopenia or osteoporosis. Methods Patients with type 2 diabetes (n = 204) who were diagnosed between April 2016 and August 2017 were enrolled in this study. The bone mineral density (BMD) was recorded by the dual-energy X-ray absorptiometer, and patients were divided into normal bone mineral density group (110 cases), osteopenia (69 cases), and osteoporosis group (25 cases) group. The serum adipokine RBP4 and other biomarkers were determined accordingly. Results Serum RBP4, body weight, calcium, and body mass index (BMI) demonstrated a positive correlation with BMD at all tested body sites in osteopenia and osteoporosis group compared with normal bone mineral density group. In contrast, age, duration of diabetes, and alkaline phosphatase(ALP) were inversely correlated with BMD at all tested body sites. In non-adjusted analyses, age, gender, duration of diabetes, and ALP were inversely associated with BMD at the femoral neck, total hip, and lumbar spine, while, body weight, BMI, and RBP4 were positively associated with BMD at all sites. In multiple regression analyses, adjusted for age, weight, BMI, and other bone-related factors, it was showed a graded stepwise positive association between serum RBP4 and BMD, at all sites. Conclusion Serum RBP4 was positively associated with BMD at all sites after adjustments for other factors in osteopenia and osteoporosis group compared with normal bone mineral density group of type 2 diabetic patients. |