Identifying factors associated with functional changes in the older population

Many studies have identified several risk factors associated with functional changes, but multiple time effect was not considered in the statistical analysis and relatively rare studies have been conducted in non-Western countries. The aim of this five-year cohort study was to examine the association between functional transitions and factors potentially associated with functional changes in older population in Taiwan. Data were from a three-wave cohort study of aging in Taipei. The cohort includes 907 older adults participating in the 2005 NHIS in Taiwan. Two follow-up interviews were conducted in 2006 and 2008-9. Physical function was assessed using six ADLs, six IADLs, and six mobility tasks. The levels of function were classified as being normal, with limitation, mild disability, and ADL disability. Fourty factors covering demography, chronic diseases, geriatric conditions, lifestyle, and physical assessments were considered in the study. We used the generalized estimating equation models and the generalized linear mixed-effects model to identify factors responsible for the changes of physical function across different waves. Results from both models were nearly identical. The main factors in the final models were age, living arrangement, social support, self-rated health, stroke, diabetes, Parkinson's disease, osteoporosis, depression, cognitive function, vision, history of fracture and falls, incontinence of urine and feces, physical activity, BMI, and short physical performance battery. Findings from our study suggest that the process leading to functional changes in the elderly is multi-factorial. The preventive strategies for functional decline should be set for older people with the characteristics identified in our study.