Bone and muscle have shown to interact, but little is known about fat within bone and muscle. Clinical studies have isolated fat within bone and muscle using MRI. In this cross-sectional study, we hypothesized that bone marrow adiposity and muscle adiposity are related and that this relationship is associated with osteoporosis. Postmenopausal women aged 60 to 85 years were recruited as part of the Appendicular Muscle and Bone Extension Research Study (AMBERS). Participants completed dual-energy X-ray absorptiometry (DXA) of the hip and spine to diagnose osteoporosis. Muscle adiposity was measured with MRI at the 66% site of the leg. Fat segmentation was achieved using a semi-automated iterative threshold-optimizing algorithm (error < 5%). Peripheral quantitative computed tomography measured marrow density of the 4% distal tibia (surrogate for marrow fat) by threshold-based, edge-detection segmentations and by examining residuals from trabecular bone density regressed on trabecular tissue mineral density. Muscle adiposity from MRI was regressed on marrow density using linear regression. Models were further examined with an interaction with osteoporosis status. Among 312 women (aged 75.4 ± 5.9 years, body mass index [BMI] 29.5 ± 5.7 kg/m2 ), a larger amount of muscle fat was associated with lower marrow density at the 66% mid-tibia (B = 84.08 [27.56], p = 0.002) and at the 4% distal tibia (B = 129.17 [55.96], p = 0.022) after accounting for age, height, weight, average daily energy expenditure, hypertension, and diabetes. Interactions of this relationship with osteoporosis status were also significant. Upon probing these interactions, the relationships were significant only in women with osteoporosis but not in those without osteoporosis. Fat from bone marrow and muscle may be related to one another through the same phenomenon, which is likely also responsible for osteoporosis, but independent of hypertension and diabetes. More research should focus on the potential abnormalities in muscle and bone fat metabolism and mesenchymal cell commitment to fat within patients with osteoporosis. © 2019 American Society for Bone and Mineral Research.

中文翻译：

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绝经后骨质疏松妇女的骨髓和肌肉脂肪浸润相关：AMBERS队列研究。

骨骼和肌肉已显示出相互作用，但对骨骼和肌肉中的脂肪知之甚少。临床研究已使用MRI分离出骨骼和肌肉中的脂肪。在这项横断面研究中，我们假设骨髓脂肪和肌肉脂肪是相关的，并且这种关系与骨质疏松症有关。招募了60至85岁的绝经后妇女作为阑尾肌肉和骨骼延伸研究（AMBERS）的一部分。参与者完成了髋部和脊柱的双能X线骨密度仪（DXA），以诊断骨质疏松症。使用MRI在腿部66％的部位测量肌肉肥胖。使用半自动迭代阈值优化算法（错误<5％）实现了脂肪分割。外围定量计算机断层扫描通过基于阈值的边缘检测分割，并通过检查从小梁组织矿物质密度回归而来的小梁骨密度，测量了4％胫骨远端（骨髓脂肪的替代物）的骨髓密度。使用线性回归，将MRI产生的肌肉肥胖症按骨髓密度进行回归。进一步检查了模型与骨质疏松状态的相互作用。在312名女性中（75.4±5.9岁，体重指数[BMI] 29.5±5.7 kg / m2），在66％的胫骨中部，大量的肌肉脂肪与较低的骨髓密度相关（B = 84.08 [27.56] ，p = 0.002）和胫骨远端4％（B = 129.17 [55.96]，p = 0.022），这要考虑到年龄，身高，体重，平均每日能量消耗，高血压和糖尿病。这种关系与骨质疏松状态的相互作用也很显着。在探究这些相互作用之后，这种关系仅在患有骨质疏松症的女性中才有意义，而在没有骨质疏松症的女性中则不明显。骨髓和肌肉中的脂肪可能通过相同的现象相互关联，这可能也是造成骨质疏松的原因，但与高血压和糖尿病无关。更多研究应集中在骨质疏松症患者中肌肉和骨脂肪代谢的潜在异常以及间质细胞对脂肪的摄取。©2019美国骨骼和矿物质研究学会。骨髓和肌肉中的脂肪可能通过相同的现象相互关联，这可能也是造成骨质疏松的原因，但与高血压和糖尿病无关。更多研究应集中在骨质疏松症患者中肌肉和骨脂肪代谢的潜在异常以及间质细胞对脂肪的摄取。©2019美国骨骼和矿物质研究学会。骨髓和肌肉中的脂肪可能通过相同的现象相互关联，这可能也是造成骨质疏松的原因，但与高血压和糖尿病无关。更多研究应集中在骨质疏松症患者中肌肉和骨脂肪代谢的潜在异常以及间质细胞对脂肪的摄取。©2019美国骨骼和矿物质研究学会。