title: Dipeptidyl peptidase-4 inhibitors and bone metabolism: is vitamin D the link?
abstract: OBJECTIVE
  Dipeptidyl peptidase-4 inhibitors (DPP4-Is) represent a promising class of agents for type 2 diabetes treatment. Experimental models and clinical studies have reported positive effects of DPP4-Is on bone; however, how DPP4-Is positively impact bone homeostasis in humans remains an unanswered question. Aim of this study investigated the relationship between treatment with DPP4-Is and vitamin D balance in patients with type 2 diabetes.
  
  
  METHODS
  This is a cross-sectional study. A total of 295 consecutive individuals with type 2 diabetes referring to our diabetes outpatient clinics were enrolled; among them, 53 % were in treatment with DPP4-Is. Metabolic profile and routine biochemistry were assessed by standard methods; serum 25(OH) vitamin D levels [25(OH)D] were measured by colorimetric method (LAISON, DiaSorin).
  
  
  RESULTS
  DPP4-Is-treated participants had significantly higher serum 25(OH)D levels then those undertaking other antidiabetic therapies (18.4 ± 10.7 vs. 14.9 ± 8.6 ng/ml, p = 0.004); this association persisted after adjusting for all major confounders. Increased 25(OH)D concentrations also correlated with the duration of DPP4-Is treatment and with a stronger DPP4 inhibitory activity.
  
  
  CONCLUSIONS
  DPP4-Is treatment is associated with improved vitamin D balance in people with type 2 diabetes; our findings suggest that vitamin D may underlie the link between DPP4-Is and bone metabolism.
authors.affiliation: Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Viale del Policlinico 155, 00161, Rome, Italy.
authors.forename: I
authors.initials: I
authors.lastname: Barchetta
authors.affiliation: Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Viale del Policlinico 155, 00161, Rome, Italy.
authors.forename: F A
authors.initials: FA
authors.lastname: Cimini
authors.affiliation: Diabetes Unit, San Giuseppe Hospital of Marino, Rome, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Bloise
authors.affiliation: Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Viale del Policlinico 155, 00161, Rome, Italy. gisella.cavallo@uniroma1.it.
authors.forename: M G
authors.initials: MG
authors.lastname: Cavallo
mesh_terms: D000368:Aged; D001842:Bone and Bones / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy*; D054873:Dipeptidyl-Peptidase IV Inhibitors / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D014807:Vitamin D / Q000097:blood*
chemical_list: D054873:Dipeptidyl-Peptidase IV Inhibitors; D007004:Hypoglycemic Agents; D014807:Vitamin D
keywords: Dipeptidyl peptidase 4 inhibitors; Therapy; Type 2 diabetes; Vitamin D