title: Association between knee pain and gait speed decline in rural Japanese community-dwelling older adults: 1-year prospective cohort study.
abstract: OBJECTIVE
  The present study examined whether knee pain was associated with decline in maximum gait speed (MGS) in a rural mountainous region.
  
  
  METHODS
  This was a population-based 1-year prospective cohort study. A total of 658 men and women aged 60 years and older participated in the baseline survey in 2006, and 400 individuals participated in the follow-up survey in 2007. We compared the incidence of meaningful decline in gait speed (≥0.1 m/s) in older adults with different knee pain levels (none, mild, severe), estimating incidence rate ratio (IRR) by multivariable-adjusted Poisson regression model.
  
  
  RESULTS
  Meaningful decline in MGS presented in 24.3% of participants, especially in men (30.3%). Baseline knee pain level was significantly related to meaningful decline in MGS after adjustment of potential confounders (IRR 1.79 for mild pain, 1.84 for severe pain; P for trend <0.01). In sensitivity analyses with change in MGS as the continuous variable, the association was not significant, but a similar negative association with knee pain was confirmed (mild pain β = -0.040, severe pain β = -0.088; P for trend = 0.104). In addition, older adults with knee pain at both baseline and follow up had a higher risk of meaningful decline in MGS (IRR 2.33, 95% CI 1.59-3.40) compared with those who had no pain at baseline or follow up.
  
  
  CONCLUSIONS
  Knee pain was associated with a decline in gait speed at 1-year follow up. Prevention and treatment of knee pain might be important for suppression of decline in physical function in older adults.
authors.affiliation: Physical Education and Medicine Research Center UNNAN, Unnan City, Shimane.|Department of Environmental Symbiotic Studies, Tokyo University of Agriculture, Tokyo, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Kitayuguchi
authors.affiliation: Department of Health Promotion and Exercise, National Institute of Health and Nutrition, Tokyo, Japan.|Japan Society for the Promotion of Science, Tokyo, Japan.|Division of Preventive Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Kamada
authors.affiliation: Center for Community-based Health Research and Education (COHRE), Organization for the Promotion of Project Research, Shimane University, Izumo, Shimane.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Hamano
authors.affiliation: Department of Functional Pathology, Shimane University School of Medicine, Izumo, Shimane.
authors.forename: Toru
authors.initials: T
authors.lastname: Nabika
authors.affiliation: Department of Environmental and Preventive Medicine, Shimane University School of Medicine, Izumo, Shimane.
authors.forename: Kuninori
authors.initials: K
authors.lastname: Shiwaku
authors.affiliation: Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, Japan.
authors.forename: Hiroharu
authors.initials: H
authors.lastname: Kamioka
authors.affiliation: Physical Education and Medicine Research Foundation, Tomi City, Nagano, Japan.
authors.forename: Shimpei
authors.initials: S
authors.lastname: Okada
authors.affiliation: The Research Institute of Nippon Sport Science University, Tokyo, Japan.
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Mutoh
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018771:Arthralgia / Q000150:complications* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007564:Japan; D007719:Knee Joint; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012111:Residence Characteristics; D012424:Rural Population; D013997:Time Factors; D000072797:Walking Speed / Q000502:physiology*
keywords: Japan; community-dwelling older adults; knee pain; maximum gait speed