Bone marrow adipose tissue (BMAT) is increased in postmenopausal women with post-surgical hypoparathyroidism

Context: Suppression of bone turnover, greater trabecular volume, and normal-high normal all-site BMD are hallmarks of post-surgical hypoparathyroidism (HypoPT). Impairment in the trabecular microarchitecture with possible higher risk of vertebral fractures (VF) in postmenopausal HypoPT women has been described, as well. Currently, no data on bone marrow adipose tissue (BMAT) are available in HypoPT. Objective: To assess BMAT by Magnetic Resonance Imaging (MRI) and proton magnetic resonance spectroscopy (1H-MRS) in postmenopausal women with chronic post-surgical hypoparathyroidism. Design: Cross-sectional pilot study. Setting: Ambulatory referral center. Patients or other participants: Twenty-nine postmenopausal women (mean age 66 ± 8.4 years) with post-surgical hypoparathyroidism and 31 healthy postmenopausal women (mean age 63 ± 8.5). Main outcome measures: Lumbar spine MRI was performed and BMAT was measured by applying the PRESS sequences on L3 body. Lumbar spine, femoral neck and total hip BMD were measured by dual X-ray absorptiometry (DXA) (Hologic Inc., USA); site-matched spine TBS was calculated by TBS iNsight (Medimaps, Switzerland); VF were assessed by VFA (iDXA, Lunar GE, USA). Results: Fat content (FC) and saturation level (SL) were higher (p<0.0001 and p<0.001), while water content (W) was lower in HypoPT compared to controls (p<0.0001). FC significantly correlated with years since menopause and body weight (p<0.05) in HypoPT, while TBS negatively correlated with FC and SL (p<0.05) and positively with residual lipids (RL) and W (p<0.05). Conclusion: We demonstrate for the first time that BMAT is increased in postmenopausal women with postsurgical hypoparathyroidism and negatively associated with trabecular microarchitecture.