Objective. We aimed to examine the independent contributions of physical health and cognitive function to disability among Chinese older adults living in two Asian metropolises and explore the potential influences of environment. Design and Participants. Cross-sectional analysis based on data from two population-based studies: the Shanghai Survey of Alzheimer's Disease and Dementia ( ) and the Singapore Longitudinal Ageing Study ( ). Disability was defined as needing help in at least one activity of daily living. Results. The prevalence of functional disability was higher in Shanghai sample (5%) than that in Singapore sample (1.8%). Number of chronic diseases, self-rated health status, cognitive function (measured by the Mini-Mental State Examination), and environment (Singapore versus Shanghai) significantly contributed to functional disability independent of each other. The adjusted Odds Ratio was 1.35 (95%CI 1.22–1.50), 2.85 (95% CI 2.36–3.43), 0.89 (95% CI 0.85–0.94), and 0.68 (95% CI 0.48–0.96), respectively. The strength of associations between health variables and disability appeared to be influenced by environment. Conclusion. Physical health and cognitive function independently contributed to functional disability. The associations are modulated by environmental factors. 1. Introduction Disability prevalence increases with advanced age [1], and disability in the elderly population is a major public health problem [2]. This is especially crucial for Chinese: there are 88 million persons aged 65 and above in China alone, and the number is projected to increase to 341 million in 2050 [1]; importantly, disability prevalence in Chinese elderly population has been increasing [3–5] in contrast to a declining trend in the developed countries [6, 7]. There is a big gap between the scale of the problem and the quantity and quality of available information. The first population-based report from China was published 16 years ago [8], and countable number of publications [3–5, 8–12] exist in the literature. In this study, with large population-based data from Shanghai (the biggest city in China) and Singapore (a city country in Southeast Asia, with majority of the residents being descendents of immigrants from South China), we aimed to examine the independent contributions of physical and cognitive health to disability in Chinese older adults and explore the potential influences of environment. 2. Methods 2.1. Participants Participants of the present study were identified from two big population-based studies: the Shanghai Survey of Alzheimer's Disease and
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