Comparing the loss of functional independence of older adults in the US and China

Background: Functional loss among older adults is known to follow a hierarchical sequence, but little is known about whether such sequences differ across socio-cultural contexts. The aim of this study is to construct activities of daily livings (ADL) scales for oldest-old adults in the United States and China so as to compare their functional loss sequences. Methods: We use data from the Asset and Health Dynamics of the Oldest Old (n = 1607) and Chinese Longitudinal Healthy Longevity Survey (n = 5570) for years 1998-2008. ADL items are calibrated within a scale using the Rasch measurement model. Rasch scores are averaged across survey waves to identify the ADL loss sequence for each study population. We also assess scale stability over measurement periods. Results: Factor analyses confirm that the ADL items in each study population can be combined meaningfully to form a hierarchical sequence. Internal consistency assessed by Cronbach's alpha is high (0.81 to 0.95). We find that bathing is the first activity that both older Americans and Chinese have difficulty with, while eating is the last activity. There are, however, differences in the rank order for toileting (ranked more challenging in the Chinese sample) and dressing (ranked more challenging in the U.S. sample). Item orderings are stable over time. Conclusions: The results highlight the relative importance of bathing in the functional loss sequence for older adults, regardless of socio-cultural context. Health interventions are needed to address deficits in the bathroom environment, especially in developing countries like China.