title: Muscle strength and fall rates among residents of Japanese and American nursing homes: an International Cross-Cultural Study.
abstract: OBJECTIVE
  In Western society, aging if often associated with adoption of a sedentary lifestyle and associated disuse muscle atrophy and weakness. Recent studies suggest a relationship between quadriceps muscle weakness and falls in elderly residents of US nursing homes (NHs). We hypothesized that fall rates would be lower in Japanese NHs, where lifestyle differences such as squatting to toilet or sleeping on the floor may maintain quadriceps strength and result in fewer falls. Therefore, we examined the relationships between falls, muscle strength, lifestyle, and other clinical characteristics in residents of a Japanese and an American NH.
  
  
  METHODS
  Cross-culture, prospective, cohort study.
  
  
  METHODS
  We evaluated disease histories and current medications, quadriceps strength, and mobility of ambulatory American (n = 76) and Japanese (n = 89) NH residents, then followed these residents prospectively for the development of falls. Project staff from both sites trained together to assure uniform data ascertainment.
  
  
  RESULTS
  During a 6-month follow-up period, fall rates were nearly 4-fold higher in the American than in the Japanese residents (49% vs 13%, respectively; P < 0.0001). In the American sample, fall rates declined with increasing muscle strength, while in Japan there was no relationship between fall rates and quadriceps strength. Residents also differed in number of medical diagnoses and use of medications, which were greater among American residents. The Japanese had slower gait speeds. Very few Japanese residents practiced squatting behaviors while living in the NH.
  
  
  CONCLUSIONS
  The relationship between muscle weakness and falls is probably modified by multiple characteristics of the individual, their culture, and their environment. Information from cross-cultural studies may provide new insights into effective fall prevention strategies for nursing home residents.
authors.affiliation: Hebrew Rehabilitation Center for Aged, Beth Israel Hospital, Boston, Massachusetts.
authors.forename: L A
authors.initials: LA
authors.lastname: Lipsitz
authors.forename: I
authors.initials: I
authors.lastname: Nakajima
authors.forename: M
authors.initials: M
authors.lastname: Gagnon
authors.forename: T
authors.initials: T
authors.lastname: Hirayama
authors.forename: C M
authors.initials: CM
authors.lastname: Connelly
authors.forename: H
authors.initials: H
authors.lastname: Izumo
authors.forename: T
authors.initials: T
authors.lastname: Hirayama
mesh_terms: D000058:Accidental Falls / Q000706:statistics & numerical data*; D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D003431:Cross-Cultural Comparison; D005260:Female; D006801:Humans; D007326:Institutionalization; D007564:Japan; D007866:Leg / Q000502:physiology*; D016015:Logistic Models; D008297:Male; D009132:Muscles / Q000502:physiology*; D009735:Nursing Homes; D011446:Prospective Studies; D012307:Risk Factors; D014481:United States