title: Fat Infiltration in the Leg is Associated with Bone Geometry and Physical Function in Healthy Older Women.
abstract: The objective of this study was to estimate the associations between muscular fat infiltration, tibia bone mineral quantity and distribution, and physical function in healthy older women. Thirty-five women (aged 60-75 years, mean 70 years) were recruited from the community. Percent intramuscular fat (%IntraMF) within the right leg tibialis anterior, soleus, and gastrocnemius muscles and total intermuscular fat (IMF) were segmented from magnetic resonance imaging scans at the mid-calf. Intramyocellular lipid (IMCL) content in the right tibialis anterior was measured with proton magnetic resonance spectroscopy. Right tibia bone content, area, and strength were measured at the 4, 14, and 66% sites using peripheral quantitative computed tomography. Physical function was assessed by gait speed on the 20 m walking test. After adjusting for age, body size, and activity level, %IntraMF had a negative association with bone content and area at all tibia sites (r = -0.31 to -0.03). Conversely, greater IMF was associated with increased bone content and area (r = 0.04-0.32). Correlation coefficients for the association between IMCL and bone were negative (r = -0.44 to -0.03). All measures of fat infiltration had a negative association with observed physical function (r = -0.42 to -0.04). Our findings suggest that muscular fat infiltration in the leg of healthy postmenopausal women has a compartment-specific relationship with bone status and physical function. Minimizing fat accumulation within and between muscle compartments may prevent bone fragility and functional decline in women.
authors.affiliation: Institute for Aging Research, Hebrew SeniorLife and Harvard Medical School, 1200 Centre St., Rm. 620, Boston, MA, 02131, USA. amandalorbergs@hsl.harvard.edu.|School of Rehabilitation Science, McMaster University, 1400 Main Street West, IAHS 403, Hamilton, ON, L8S 1C7, Canada. amandalorbergs@hsl.harvard.edu.
authors.forename: Amanda L
authors.initials: AL
authors.lastname: Lorbergs
authors.affiliation: School of Biomedical Engineering, McMaster University, 1280 Main Street West, ETB 406, Hamilton, ON, L8S 4K1, Canada. nosewor@mcmaster.ca.|Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON, Canada. nosewor@mcmaster.ca.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Noseworthy
authors.affiliation: Department of Medicine, McMaster University, 501-25 Charlton Ave East, Hamilton, ON, L8N 1Y2, Canada. jd.adachi@sympatico.ca.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Adachi
authors.affiliation: School of Rehabilitation Science, McMaster University, 1400 Main Street West, IAHS 403, Hamilton, ON, L8S 1C7, Canada. stratfor@mcmaster.ca.
authors.forename: Paul W
authors.initials: PW
authors.lastname: Stratford
authors.affiliation: School of Rehabilitation Science, McMaster University, 1400 Main Street West, IAHS 403, Hamilton, ON, L8S 1C7, Canada. macint@mcmaster.ca.
authors.forename: Norma J
authors.initials: NJ
authors.lastname: MacIntyre
mesh_terms: D050154:Adiposity / Q000502:physiology*; D000368:Aged; D000886:Anthropometry; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007866:Leg; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D017698:Postmenopause; D013977:Tibia / Q000000981:diagnostic imaging* / Q000502:physiology*; D014057:Tomography, X-Ray Computed
keywords: Adipose tissue; Aged; Magnetic resonance imaging (MRI); Mobility limitation; Proton magnetic resonance spectroscopy (1H MRS); X-ray computed tomography