title: Knee Pain and Low Back Pain Additively Disturb Sleep in the General Population: A Cross-Sectional Analysis of the Nagahama Study.
abstract: BACKGROUND
  Association of knee and low back pain with sleep disturbance is poorly understood. We aimed to clarify the independent and combined effects of these orthopedic symptoms on sleep in a large-scale general population.
  
  
  METHODS
  Cross-sectional data about sleep and knee/low back pain were collected for 9,611 community residents (53±14 years old) by a structured questionnaire. Sleep duration less than 6 h/d was defined as short sleep. Sleep quality and the presence of knee and low back pain were evaluated by dichotomous questions. Subjects who complained about knee or low back pains were graded by tertiles of a numerical response scale (NRS) score and a Roland-Morris disability questionnaire (RDQ) score respectively. Multivariate regression analyses were performed to determine the correlates of short sleep duration and poor sleep quality.
  
  
  RESULTS
  Frequency of participants who complained of the orthopedic symptoms was as follows; knee pain, 29.0%; low back pain, 42.0% and both knee and low back pain 17.6%. Both knee and low back pain were significantly and independently associated with short sleep duration (knee pain: odds ratio (OR) = 1.19, p<0.01; low back pain: OR = 1.13, p = 0.01) and poor sleep quality (knee pain: OR = 1.22, p<0.01; low back pain; OR = 1.57, p<0.01). The group in the highest tertile of the NRS or RDQ score had the highest risk for short sleep duration and poor sleep quality except for the relationship between the highest tertile of the RDQ score and short sleep duration.(the highest tertile of the NRS: OR for short sleep duration = 1.31, p<0.01; OR for poor sleep quality = 1.47, p<0.01; the highest tertile of the RDQ: OR for short sleep duration = 1.11, p = 0.12; OR for poor sleep quality = 1.81, p<0.01) Further, coincident knee and low back pain raised the odds ratios for short sleep duration (either of knee or low back pain: OR = 1.10, p = 0.06; both knee and low back pain: OR = 1.40, p<0.01) and poor sleep quality (either of knee or low back pain: OR = 1.61, p<0.01; both knee and low back pain: OR = 2.17, p<0.01).
  
  
  CONCLUSIONS
  Knee and low back pains were independently associated with short sleep duration and poor sleep quality. Further, they additively increased the correlation with these sleep problems in the general population.
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Kimihiko
authors.initials: K
authors.lastname: Murase
authors.affiliation: Center for Genomic Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Tabara
authors.affiliation: Department of Orthopedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Hiromu
authors.initials: H
authors.lastname: Ito
authors.affiliation: Department of Orthopedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: Department of Health Informatics, Kyoto University School of Public Health, Kyoto University, Kyoto, Japan.
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Takahashi
authors.affiliation: Center for Genomic Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Setoh
authors.affiliation: Center for Genomic Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Kawaguchi
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Muro
authors.affiliation: Department of Psychiatry, Shiga University of Medical Science, Shiga, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kadotani
authors.affiliation: Department of Medical Ethics and Medical Genetics, Kyoto University School of Public Health, Kyoto, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Kosugi
authors.affiliation: Medical Research Support Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Sekine
authors.affiliation: Center for Genomic Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Yamada
authors.affiliation: Department of Health Informatics, Kyoto University School of Public Health, Kyoto University, Kyoto, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Nakayama
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Michiaki
authors.initials: M
authors.lastname: Mishima
authors.affiliation: Department of Orthopedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Matsuda
authors.affiliation: Center for Genomic Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Matsuda
authors.affiliation: Department of Respiratory Care and Sleep Control Medicine, Graduate school of medicine, Kyoto University, Kyoto, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Chin
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D017116:Low Back Pain / Q000150:complications* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D046788:Patellofemoral Pain Syndrome / Q000150:complications* / Q000453:epidemiology; D012890:Sleep; D012893:Sleep Wake Disorders / Q000453:epidemiology / Q000209:etiology*; D011795:Surveys and Questionnaires