title: Leg Muscle Mass and Foot Symptoms, Structure, and Function: The Johnston County Osteoarthritis Project.
abstract: BACKGROUND
  Loss of muscle mass occurs with aging and in lower limbs it may be accelerated by foot problems. In this cross-sectional analysis, we evaluated the relationship of leg muscle mass to foot symptoms (presence or absence of pain, aching, or stiffness), structure while standing (high arch or low arch), and function while walking (pronated or supinated) in a community-based study of Caucasian and African American men and women who were 50-95 years old.
  
  
  METHODS
  In the Johnston County Osteoarthritis Project, leg muscle mass was measured with whole body dual-energy x-ray absorptiometry, and plantar foot pressure data, using predetermined values, were used to classify foot structure and function. Sex-specific crude and adjusted (age, body mass index, and race) linear regression models examined associations of leg muscle mass index (Leg muscle mass [kg]/Height [m](2)) with foot symptoms, structure, and function.
  
  
  RESULTS
  Complete data were available for 1,037 participants (mean age 68 years, mean body mass index 31 kg/m(2), 68% women, 29% African American). In women, pronated foot function was associated with lower leg muscle mass in crude (p = .02), but not adjusted (p = .22), models. A low arch was associated with a higher leg muscle mass in adjusted models for both men and women (p < .01).
  
  
  CONCLUSIONS
  Leg muscle mass was associated with foot structure in our biracial sample, whereas relations between leg muscle mass and foot function were attenuated by age, body mass index, and race. Future longitudinal analyses are needed to explain the temporal relationship between these conditions and how they relate to other aspects of impairment and physical function.
authors: Department of Epidemiology, Thurston Arthritis Research Center, and Injury Prevention Research Center, University of North Carolina, Chapel Hill. golight@email.unc.edu.
authors: Yvonne M
authors: YM
authors: Golightly
authors: Institute for Aging Research, Hebrew SeniorLife, Boston, Massachusetts. Department of Gerontology, Beth Israel Deaconess Medical Center, Boston, Massachusetts. Department of Medicine, Harvard Medical School, Boston, Massachusetts.
authors: Alyssa B
authors: AB
authors: Dufour
authors: Institute for Aging Research, Hebrew SeniorLife, Boston, Massachusetts. Department of Gerontology, Beth Israel Deaconess Medical Center, Boston, Massachusetts. Department of Medicine, Harvard Medical School, Boston, Massachusetts.
authors: Marian T
authors: MT
authors: Hannan
authors: Department of Rehabilitation, Hospital for Special Surgery, New York, New York.
authors: Howard J
authors: HJ
authors: Hillstrom
authors: Department of Medicine, University of California, San Francisco.
authors: Patricia P
authors: PP
authors: Katz
authors: Department of Epidemiology, Thurston Arthritis Research Center, and Department of Medicine and Department of Orthopedics, University of North Carolina, Chapel Hill.
authors: Joanne M
authors: JM
authors: Jordan
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000375:Aging / Q000502:physiology*; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D005528:Foot / Q000503:physiopathology*; D005684:Gait / Q000502:physiology*; D006801:Humans; D015994:Incidence; D007866:Leg / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism / Q000503:physiopathology; D009657:North Carolina / Q000453:epidemiology; D010003:Osteoarthritis / Q000453:epidemiology / Q000378:metabolism / Q000503:physiopathology*; D011312:Pressure; D011446:Prospective Studies; D016138:Walking / Q000502:physiology*
keywords: Cohort study; Foot; Gait; Muscle; Pain