['Patients with type 2 diabetes mellitus (T2DM) have a high risk of fracture although they have slightly higher bone mineral density (BMD). There is no evidence that dipeptidyl peptidase-4 (DPP-4) is involved in the bone fragility of the patients. The aim of this study was to investigate the association between serum DPP-4 levels and vertebral fractures (VFs) in men with T2DM.', 'We conducted a cross-sectional study and investigated the relationships between serum DPP-4 levels vs BMD at lumbar spine, femoral neck and radius, bone turnover markers and presence of VFs in 204 Japanese male patients.', 'Multiple regression analyses adjusted for confounders such as age, duration of diabetes, body mass index, serum creatinine, HbA1c, serum albumin, log(alanine transaminase), and log(C-reactive protein) showed that serum DPP-4 was positively associated with bone formation markers (bone-specific alkaline phosphatase and osteocalcin) as well as a bone resorption marker [tartrate-resistant acid phosphatase 5b (TRACP-5b)] (β = 0·25, P < 0·01; β = 0·17, P < 0·05; and β = 0·30, P < 0·01, respectively), but not BMD at each site. Multivariate logistic regression analyses adjusted for the confounders described above revealed that serum DPP-4 levels were associated with the presence of multiple VFs (odds ratio 1·61, 95% confidential interval 1·05-2·49 per SD increase, P < 0·05). This association was still significant after additional adjustment for any sites of BMD or bone turnover markers except for TRACP-5b.'] Is serum dipeptidyl peptidase-4 associated with multiple vertebral fractures in type 2 diabetes mellitus?