The authors investigated if plasma Sphingosine 1-Phosphate (S1P) levels were a predictor for osteoporotic vertebral fracture (VF) risk. They found that 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.

http://jcem.endojournals.org/content/early/2012/08/09/jc.2012-2346.abstract?sid=ab70d3de-43f8-438f-b567-fb042313f8c0