Predictors of 10-year change in physical, cognitive and social function in Japanese elderly

Data from the longitudinal Koganei Study, Japan, have been used to predict long-term rate of change in three aspects of quality of life in community living elderly: physical, cognitive and social functioning. Two hundred and forty of the initially 69-71-year-old individuals (75% of the survivors) participated in all three examinations which took place in 1976, 1981 and 1986. Physical function was expressed by mobility and grip strength, cognitive function by visual memory, and social function by six social activities. Rate of change was defined as the regression coefficient of each function on time for each individual. Predictors at baseline of subsequent rate of change were calculated using multiple regression models controlling for initial level of functioning. Several predictors were common to rate of change in more than one function: socio-economic status, activity level, aspects of life style and precursors of chronic disease such as stroke. Rates of change were also affected by specific living arrangements, which suggests culture-specific mechanisms. Despite the variety of patterns of change observed, these results provide some indication that decline in important aspects of quality of life can be prevented.