title: Intramuscular fat and physical performance at the Framingham Heart Study.
abstract: Intramuscular fat may mediate associations between obesity and physical disability. We examined the associations between muscle attenuation, a proxy for intramuscular fat, and physical function. Paraspinous muscle computed tomography attenuation was obtained on a Framingham Heart Study subgroup (n = 1152, 56 % women, mean age 66 years). Regressions modeled cross-sectional associations between muscle attenuation and mobility disability, grip strength, and walking speed with standard covariates; models additionally adjusted for body mass index (BMI) and visceral adipose tissue (VAT). Separate models investigated associations between VAT and subcutaneous adipose tissue (SAT) and physical function. Per 1 standard deviation decrement in muscle attenuation (i.e., more muscle fat), we observed 1.29 (95 % CI = 1.11, 1.50; p = 0.0009) increased odds of walking speed ≤1 m/s in women and men. This persisted after separate BMI and VAT adjustments (p < 0.02). In men, there was a 1.29 kg (95 % CI = 0.57, 2.01; p = 0.0005) decrement in grip strength, which persisted after BMI and VAT adjustments (p ≤ 0.0004). For VAT and SAT, similar associations were not observed. Intramuscular fat is associated with increased odds of walking speed ≤1 m/s in both sexes and lower grip strength in men. There were no similar associations for VAT and SAT, highlighting the specificity of intramuscular fat in association with physical function.
authors.affiliation: National Heart, Lung, and Blood Institute's Framingham Heart Study, 73 Mt Wayte Ave Suite #2, Framingham, MA, 01702, USA.|Boston University School of Medicine, Boston, MA, 02118, USA.
authors.forename: Kate E
authors.initials: KE
authors.lastname: Therkelsen
authors.affiliation: National Heart, Lung, and Blood Institute's Framingham Heart Study, 73 Mt Wayte Ave Suite #2, Framingham, MA, 01702, USA.
authors.forename: Alison
authors.initials: A
authors.lastname: Pedley
authors.affiliation: Department of Medicine and Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA.
authors.forename: Udo
authors.initials: U
authors.lastname: Hoffmann
authors.affiliation: National Heart, Lung, and Blood Institute's Framingham Heart Study, 73 Mt Wayte Ave Suite #2, Framingham, MA, 01702, USA.|NHLBI Division of Intra-mural Research and the Center for Population Studies, Framingham, MA, USA.|Division of Endocrinology and Metabolism, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA.
authors.forename: Caroline S
authors.initials: CS
authors.lastname: Fox
authors.affiliation: National Heart, Lung, and Blood Institute's Framingham Heart Study, 73 Mt Wayte Ave Suite #2, Framingham, MA, 01702, USA. murabito@bu.edu.|Section of General Internal Medicine, Boston University School of Medicine, Boston, MA, 02118, USA. murabito@bu.edu.
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Murabito
mesh_terms: D050154:Adiposity / Q000502:physiology*; D000328:Adult; D000368:Aged; D000375:Aging; D001706:Biopsy; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D009043:Motor Activity / Q000502:physiology*; D061330:Multidetector Computed Tomography / Q000379:methods*; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000503:physiopathology*; D009765:Obesity / Q000175:diagnosis* / Q000503:physiopathology / Q000534:rehabilitation; D012189:Retrospective Studies; D012307:Risk Factors; D050151:Subcutaneous Fat / Q000000981:diagnostic imaging*; D014481:United States / Q000453:epidemiology
keywords: Adipose tissue; Epidemiology; Muscle; Physical function