title: Association between kyphosis and subacromial impingement syndrome: LOHAS study.
abstract: BACKGROUND
  Kyphosis is a cause of scapular dyskinesis, which can induce various shoulder disorders, including subacromial impingement syndrome (SIS). This study aimed to clarify the impact of kyphosis on SIS with use of cross-sectional data from the Locomotive Syndrome and Health Outcome in Aizu Cohort Study (LOHAS).
  
  
  METHODS
  The study enrolled 2144 participants who were older than 40 years and participated in health checkups in 2010. Kyphosis was assessed by the wall-occiput test (WOT) for thoracic kyphosis and the rib-pelvic distance test (RPDT) for lumbar kyphosis. The associations between kyphosis, SIS, and reduction in shoulder elevation (RSE) were investigated.
  
  
  RESULTS
  Age- and gender-adjusted logistic regression analysis demonstrated significant association between SIS and WOT (odds ratio, 1.65; 95% confidence interval, 1.02, 2.64; P < .05), whereas there was no significant association between SIS and RPDT. Multivariable logistic regression analysis demonstrated no significant association between SIS and both WOT and RPDT, whereas there was significant association between SIS and RSE.
  
  
  CONCLUSIONS
  RSE plays a key role in the development of SIS, and thoracic kyphosis might influence the development of SIS indirectly by reducing shoulder elevation induced by the restriction of the thoracic spine extension and scapular dyskinesis.
authors.affiliation: Department of Orthopaedic Surgery, Fukushima Medical University School of Medicine, Fukushima, Japan. Electronic address: kootoshi@fmu.ac.jp.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Otoshi
authors.affiliation: Department of Preventive Medicine and Epidemiologic Informatics, National Cerebral and Cardiovascular Center, Osaka, Japan.
authors.forename: Misa
authors.initials: M
authors.lastname: Takegami
authors.affiliation: Department of Orthopaedic Surgery, Fukushima Medical University School of Medicine, Fukushima, Japan.
authors.forename: Miho
authors.initials: M
authors.lastname: Sekiguchi
authors.affiliation: Institute for Health Outcomes and Process Evaluation Research (iHope International), Kyoto, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Onishi
authors.affiliation: Department of Healthcare Epidemiology, Graduate School of Medicine and Public Health, Kyoto University, Kyoto, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Yamazaki
authors.affiliation: Department of Orthopaedic Surgery, Fukushima Medical University School of Medicine, Fukushima, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Otani
authors.affiliation: Department of Orthopaedic Surgery, Fukushima Medical University School of Medicine, Fukushima, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Shishido
authors.affiliation: Department of Orthopaedic Surgery, Fukushima Medical University School of Medicine, Fukushima, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Kikuchi
authors.affiliation: Department of Orthopaedic Surgery, Fukushima Medical University School of Medicine, Fukushima, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Konno
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D020820:Dyskinesias / Q000150:complications / Q000503:physiopathology; D005260:Female; D006306:Health Surveys; D006801:Humans; D007738:Kyphosis / Q000150:complications / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular; D012540:Scapula / Q000503:physiopathology; D012782:Shoulder / Q000503:physiopathology; D019534:Shoulder Impingement Syndrome / Q000209:etiology / Q000503:physiopathology*; D012785:Shoulder Joint / Q000503:physiopathology*; D013904:Thoracic Vertebrae / Q000503:physiopathology
keywords: Epidemiologic study; LOHAS; kyphosis; rib-pelvic distance test; scapular dyskinesis; subacromial impingement syndrome; wall-occiput test