Abstract: TH-PO577
Associations Between Body Composition on Cortical Bone Quality in CKD
Session Information
- Bone and Mineral Metabolism: Bone Disease
November 07, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Bone and Mineral Metabolism
- 402 Bone and Mineral Metabolism: Clinical
Authors
- Aponte Farias, Maria A., Columbia University Medical Center, New York, New York, United States
- Khairallah, Pascale, Columbia University Medical Center, New York, New York, United States
- Cortez, Natalia Erika, University of California, Davis, Davis, California, United States
- Agarwal, Sanchita, Columbia University, New York, New York, United States
- Sung, Joshua, Columbia University, New York, New York, United States
- Nickolas, Tom, Columbia University Medical Center, New York, New York, United States
Background
Obesity is considered beneficial to bone health due to well-established positive effects of mechanical loading of weight on bone formation. However, studies have reported that excessive fat mass may not protect against osteoporosis: high fat mass was associated with low total bone mineral density. Renal osteodystrophy (ROD) is associated with impaired cortical bone quality due to hyperparathyroidism, but the effects of fat and muscle mass on cortical bone in ROD are unclear. We hypothesized that body composition independently affects cortical bone and that muscle and fat mass have opposing effects on the cortex.
Methods
In 77 patients with mean +/- SD age of 59+/-10 years and with CKD stages 3-5D, we scanned the distal radius and tibia by high-resolution peripheral quantitative CT to measure cortical density, thickness and porosity. We measured total fat, muscle mass and percent body fat by whole body dual-energy X-ray absorptiometry. Cortical measures were correlated with age, sex, BMI, percent body fat, fat free muscle index, PTH, calcium, phosphorus and 25(OH)D. Linear regression models adjusted for age, sex and PTH determined whether muscle and fat mass were independent predictors of cortical bone quality.
Results
At the radius, higher muscle mass was associated with thicker cortices and higher percent body fat was associated with thinner cortices that had fewer and smaller pores (Table). At the tibia, higher muscle mass was associated with thicker, while higher fat content was associated with thinner cortices. In MV regression, higher muscle mass was associated with thicker cortices at the radius and tibia while higher fat mass was associated less porous cortices at the radius. Older age was associated with more severe cortical porosity at the radius (p=0.03) and tibia (p<0.001).
Conclusion
In CKD 3-5D, muscle and fat mass independently predicted, and had opposing effects, on cortical bone quality. Further studies evaluating underlying mechanisms linking muscle and fat to cortical bone quality are needed.
Associations between cortical parameters and body composition adjusted for age and sex from MV linear regression
| Radius | Tibia | |||||||
| Cortical Mineral Density [mg HA/ccm] | Cortical Thickness [mm] | Cortical Porosity [1] | Cortical Pore Diameter [mm] | Cortical Mineral Density [mg HA/ccm] | Cortical Thickness [mm] | Cortical Porosity [1] | Cortical Pore Diameter [mm] | |
| BMI | -2.40 | 0.0003 | -0.00002 | -0.00007 | -0.54 | 0.01* | 0.000006 | -0.001 |
| Body Fat % | 0.45 | -0.0004 | -0.0002* | -0.0008 | -0.41 | -0.003 | 0.00004 | -0.0006 |
| Fat Free Muscle Index | -6.13 | 0.016* | -0.000003 | -0.0003 | -0.21 | 0.03* | -0.000005 | -0.0009 |
*p<0.05
Funding
- NIDDK Support