Bone Abstracts (2016) 5 P426 | DOI: 10.1530/boneabs.5.P426

Association of circulating dipeptidyl-peptidase 4 levels with osteoporotic fracture in postmenopausal women

Beom-Jun Kim1, Hyeonmok Kim1, Ki Hyun Baek2, Seong Hee Ahn1, Seung Hun Lee1, Jung-Min Koh1, Yumie Rhee3, Chong Hwa Kim4, Deog-Yoon Kim5, Moo-Il Kang2 & Yong-Ki Min6

1Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea; 2Seoul St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul, Republic of Korea; 3Severance Hospital, Endocrine Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea; 4Sejong General Hospital, Bucheon, Republic of Korea; 5Kyunghee University School of Medicine, Seoul, Republic of Korea; 6Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.

Evidence indicates that dipeptidyl-peptidase 4 (DPP4) plays a distinct role in bone metabolism. However, there has been no report on the association, if any, between circulating DPP4 levels and osteoporosis-related phenotypes. This study aimed to determine if DPP4 predicts osteoporotic fracture (OF) risk in postmenopausal women. This case–control study was conducted in multiple centers in Korea. We enrolled 178 cases with OF and 178 age- and body mass index-matched controls. OF was assessed by an interviewer-assisted questionnaire and lateral thoracolumbar radiographs. Bone turnover markers (BTMs), bone mineral density (BMD), and plasma DPP4 levels were obtained in all subjects. After adjustment for potential confounders, subjects with OF had significantly higher plasma DPP4 levels than those without (P=0.021). Higher DPP4 levels were significantly associated with higher levels of all BTMs, but not with BMD at all measured sites. The differences in DPP4 levels according to OF status disappeared after an additional adjustment for each BTM, but not after adjustment for any BMD values. The risk of OF was 3.80-fold (95% CI=1.53–9.42) higher in subjects in the highest DPP4 quartile than in those in the lowest quartile after adjustment for potential confounders, including femoral neck BMD. Finally, mediation analyses demonstrated that bone turnover explained about half of the relation between DPP4 and OF. In conclusion, DPP4 may be associated with OF by partially mediating the bone turnover rate. The circulating DPP4 levels may be a potential biomarker that could increase the predictive power of current fracture risk assessment models.