MUSCLE STRENGTH AND FALL RATES AMONG RESIDENTS OF JAPANESE AND AMERICAN NURSING-HOMES - AN INTERNATIONAL CROSS-CULTURAL-STUDY

OBJECTIVE: In Western society, aging is often associated with adoption of a sedentary lifestyle and associated disuse muscle atrophy and wea kness. 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 li festyle differences such as squatting to toilet or sleeping on the flo or may maintain quadriceps strength and result in fewer falls. Therefo re, we examined the relationships between falls, muscle strength, life style, and other clinical characteristics in residents of a Japanese a nd an American NH. DESIGN: Cross-culture, prospective, cohort study. M EASUREMENTS: We evaluated disease histories and current medications, q uadriceps strength, and mobility of ambulatory American (n = 76) and J apanese (n = 89) NH residents, then followed these residents prospecti vely for the development of falls. Project staff from both sites train ed together to assure uniform data ascertainment. MAIN RESULTS: During a B-month follow-up period, fall rates were nearly 4-fold higher in t he American than in the Japanese residents (49% vs 13%, respectively; P < 0.0001). In the American sample, fall rates declined with increasi ng muscle strength, while in Japan there was no relationship between f all rates and quadriceps strength. Residents also differed in number o f medical diagnoses and use of medications, which were greater among A merican residents. The Japanese had slower gait speeds. Very few Japan ese residents practiced squatting behaviors while living in the NH. CO NCLUSIONS: The relationship between muscle weakness and falls is proba bly modified by multiple characteristics of the individual, their cult ure, and their environment. Information from cross-cultural studies ma y provide new insights into effective fall prevention strategies for n ursing home residents.