Visceral Fat Metabolic Activity Evaluated by 18F-FDG PET/CT Predicts Osteoporosis in Healthy Postmenopausal Korean Women

초록

Purpose: Traditionally, obesity is believed to be protective against osteoporosis. However, recent accumulating evidences suggest that visceral obesity increases the risk of osteoporosis and obesity-driven dysfunctional metabolic activity in visceral adipose tissue (VAT) is considered as a possible underlying mechanism for the development of obesity-related osteoporosis. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is an established method to assess the degree of VAT metabolic activity. We aimed to investigate the predictive role of VAT metabolic activity evaluated by 18F-FDG PET/CT for osteoporosis in healthy postmenopausal Korean women. Materials and methods: A total of 115 postmenopausal women who underwent routine health check-up between January 2016 and December 2018 were enrolled in this study, retrospectively. They all underwent dual-energy X-ray absorptiometry and 18F-FDG PET/CT. Osteoporosis was defined as bone mineral density (BMD) T-score <= -2.5 at either lumbar spine or femoral neck. Metabolic activity of VAT was defined as the maximum standardized uptake value (SUVmax) of VAT divided by the SUVmax of subcutaneous adipose tissue (V/S ratio). Results: The participants with osteoporosis showed significantly higher V/S ratio than the participants without osteoporosis. V/S ratio of 1.33 was proposed as an optimal cut-off value for predicting osteoporosis (sensitivity; 93%, specificity; 43.1%, area under the curve; 0.716, p < 0.001). Furthermore, V/S ratio was significantly associated with osteoporosis in postmenopausal woman by uni-and multivariate analyses. Interestingly, V/S ratio showed significant positive correlation with high sensitivity C-reactive protein, which is a surrogate marker of systemic inflammatory condition. Conclusions: VAT metabolic activity as measured by V/S ratio predicts osteoporosis in healthy postmenopausal Korean women.