Context: Although sphingosine 1-phosphate (S1P) plays diverse roles in bone metabolism, the most prominent role seems to be the augmentation of bone resorption.
Objective: The objective of the study was to investigate the possibility of using S1P as a predictor for osteoporotic vertebral fracture (VF) risk.
Design and setting: This was a case-control study conducted in a clinical unit in Korea.
Participants: Sixty-nine cases having radiological VF and 69 age- and body mass index-matched controls among 460 eligible postmenopausal women participated in the study.
Main outcome measures: Lateral thoracolumbar radiographs, bone mineral density (BMD), bone turnover markers, and plasma S1P levels were obtained from all subjects.
Results: S1P levels were markedly higher in subjects with VF (7.49±3.44 μmol/liter) than in those without VF (5.58±2.01 μmol/liter; P=0.001) and increased in a dose-response manner as the number of VF increased (P for the trend<0.001), even after adjustment for lumbar spine BMD and potential confounders. The odds ratio for VF was markedly higher in subjects in the highest S1P quartile category compared with those in the lowest S1P quartile category after adjustment for confounders (odds ratio 9.33, 95% confidence interval 2.68-32.49). S1P levels were inversely correlated with BMD at various sites (P=0.015 to 0.044), whereas they were positively correlated with bone resorption markers (P=0.016 to 0.098).
Conclusion: These findings suggest that plasma S1P may be a potential biomarker for the risk of VF, independent of BMD, in postmenopausal women.