title: Prevalence and associations of respiratory-related leg movements: the MrOS sleep study.
abstract: OBJECTIVE
  Obstructive respiratory events often terminate with an associated respiratory-related leg movement (RRLM). Such leg movements are not scored as periodic leg movements (periodic limb movements during sleep, PLMS), although the criteria for distinguishing RRLM from PLMS differ between the American Academy of Sleep Medicine (AASM) and the World Association of Sleep Medicine (WASM)/ International Restless Legs Syndrome Study Group (IRLSSG) scoring manuals. Such LMs may be clinically significant in patients with obstructive sleep apnea (OSA). The prevalence and correlation of RRLM in men with OSA were examined.
  
  
  METHODS
  A case-control sample of 575 men was selected from all men with an apnea-hypopnea index (AHI, ≥3% desaturation criteria) ≥ 10 and good data from piezoelectric leg movement sensors at the first in-home sleep study in the MrOS cohort (mean age = 76.8 years). Sleep studies were rescored for RRLMs using five different RRLM definitions varying in both latency of leg movement onset from respiratory event termination and duration of the leg movement. The quartile of RRLM% (the number of RRLM/the number of hypopneas + apneas) was derived.
  
  
  RESULTS
  The nonparametric densities of RRLM% were most influenced by alterations in the latency rather than the duration of the LM. The most liberal RRLM definition (latency 0-5 s, duration 0.5-10 s) led to a median RRLM% of 23.4 (interquartile range 12.41, 37.12) in this sample. The average AHI and arousal index increased as the quartile of RRLM% increased, as well as the prevalence of chronic obstructive pulmonary disease (COPD). The prevalence of those with a history of hypertension decreased as RRLM% increased. The non-Caucasian race was associated with lower RRLM%.
  
  
  CONCLUSIONS
  Within an elderly sample with moderate to severe OSA, piezoelectric-defined RRLM% is associated with a number of sleep-related and demographic factors. Further study of the optimal definition, predictors, and consequences of RRLM is warranted.
authors.affiliation: Division of Sleep Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Japan Society for the Promotion of Science (JSPS), Tokyo, Japan.
authors.forename: Sayaka
authors.initials: S
authors.lastname: Aritake
authors.affiliation: California Pacific Medical Center Research Institute, San Francisco Coordinating Center, San Francisco, CA, USA.
authors.forename: Terri
authors.initials: T
authors.lastname: Blackwell
authors.affiliation: California Pacific Medical Center Research Institute, San Francisco Coordinating Center, San Francisco, CA, USA.
authors.forename: Katherine W
authors.initials: KW
authors.lastname: Peters
authors.affiliation: Division of Sleep Medicine, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Rueschman
authors.affiliation: Division of Sleep Medicine, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Mobley
authors.affiliation: Division of Sleep Medicine, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Morrical
authors.affiliation: Division of Sleep Medicine, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: Samuel F
authors.initials: SF
authors.lastname: Platt
authors.affiliation: Division of Geriatric Medicine and Aging, Department of Medicine, Columbia University, New York, NY, USA.
authors.forename: Thuy-Tien L
authors.initials: TT
authors.lastname: Dam
authors.affiliation: Division of Sleep Medicine, Department of Medicine, Brigham and Women's Hospital and Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
authors.forename: Susan
authors.initials: S
authors.lastname: Redline
authors.affiliation: Division of Sleep Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA. Electronic address: jwwinkelman@partners.org.
authors.forename: John W
authors.initials: JW
authors.lastname: Winkelman
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000503:physiopathology; D007866:Leg / Q000503:physiopathology*; D008297:Male; D009068:Movement / Q000502:physiology*; D017286:Polysomnography; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000503:physiopathology; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000503:physiopathology*
keywords: Cardiovascular disease; Hypertension; Leg movement; Obstructive sleep apnea; Respiratory-related events