s 405 Advantage competitive binding chemiluminescence immunoassay (reference range 10-68 ng/mL, intra-assay precision 3.9% at 20.3 ng/mL, 3.0% at 49.9 ng/ mL, and 3.6% at 57.8 ng/mL, lower limit of sensitivity 7 ng/mL; Quest Diagnostics Clinical Trials Laboratory Test Development Department, Van Nuys, CA, USA) from a central laboratory. Lumbar spine (L2-L4) BMD was measured by DXA (GE Healthcare Lunar Prodigy). Lumbar spine TBS was derived from DXA lumbar spine examinations. Results: Mean serum (25OHD) level was 27.2 12.2 ng/ml and mean BMI was 26.9 5.2 kg/m. Age, weight, height and BMI were not correlated to serum (25OHD). Age, weight, height, BMI and serum (25OHD) were not correlated to TBS. Conclusion: These results suggest that serum (25OHD) is not a determinant of TBS in postmenopausal women. Further research is needed to identify the determinants of TBS in postmenopausal women. Disclosure of Interest: None Declared