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

Postmenopausal women with osteoporotic fracture (OF) had higher plasma dipeptidyl-peptidase 4 (DPP4) levels than those without. Furthermore, higher plasma DPP4 levels were significantly associated with higher bone turnover and a higher prevalence of OF. These results indicated that DPP4 may be associated with OF by mediating bone turnover rate.

INTRODUCTION: 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, including osteoporotic fracture (OF). Therefore, we performed a case-control study to investigate these associations in postmenopausal women.

METHODS: This 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.

RESULTS: After adjustment for potential confounders, subjects with OF had significantly higher DPP4 levels than those without (P = 0.021). Higher DPP4 levels were significantly positively 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. BTMs explained approximately half of the relationship between DPP4 and OF. The risk of OF was 3.80-fold (95% confidence interval = 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.

CONCLUSIONS: DPP4 may be associated with OF by at least partly mediating the bone turnover rate. Circulating DPP4 levels may be a potential biomarker that could increase the predictive power of current fracture risk assessment models.