The National Research Council in 2001, recognizing the need for multi-disciplinary research and longitudinal studies on aging, emphasized that cross-national studies can provide substantially more useful evidence for policy than can single country studies. The Council also stressed the need for harmonizing and standardizing data collection across countries. The National Institute on Aging has recently reiterated the need to understand international differences in health and longevity on older adults. A prerequisite for this is comparable measurement and data. It is with this intent that WHO's Study on Global Ageing and Adult Health (SAGE) has been designed using a set of methods to provide comparable cross-national data. Though SAGE is focused on Low and Middle Income (LAMI) countries, comparative analysis of data from similar studies in high income countries is likely to provide useful insights that will be mutually beneficial. The creation of a common harmonized data set where great deal of attention has been paid to ex ante and ex post harmonization strategies and the validity of the indicators from such a harmonized data set has been demonstrated for further in-depth analysis is the foundation for comparative analysis. The current proposal sets out an agenda to further align the measurement of health, quality of life and well-being in SAGE with other cross-national studies such as the Health and Retirement Study (HRS) in the US and the Study of Health And Retirement in Europe (SHARE) in 11 European countries (in its first wave and in 13 countries in the European Union in the second round), and other national studies such as the English Longitudinal Study of Ageing (ELSA) in the UK, the Longitudinal Aging Study in India (LASI) and the China Health and Retirement Longitudinal Study (CHARLS). The proposed study aims to harmonize SAGE methods and data with HRS, SHARE, ELSA, LASI and CHARLS for self-reported health and well- being, adjusting for known biases in self-report across two waves of the surveys. Besides harmonizing measurement of self-reports it also intends to create derived variables using data from health examinations and biomarkers where available. The proposed study will prepare a combined data set for the three main outcomes (health state, quality of life and well-being) across these surveys and record the psychometric properties of the different instruments with regard to their internal consistency, factor structure, IRT properties, sensitivity to change and construct and predictive validity. Redundancies across surveys will be identified and a parsimonious set of items that measure the constructs in the most reliable and valid manner will be identified. The ability of the measures to predict future health outcomes will be compared across these surveys where longitudinal data is available from multiple waves (in SAGE, HRS, ELSA and SHARE). The study will thus provide a harmonized data set across these surveys with a methodology to measure these outcomes in a robust manner.
With the rapid demographic and epidemiological transition occurring globally, including in low and middle income countries, there is an urgent need to generate data with regard to the dynamics of health, quality of life and well-being in the older adult segment of the population that is comparable across populations and over time. Insights obtained from such studies will help shape current and future health and social policy. Important strategies to prevent the burden of ill-health and disability in older age groups, as well as to extend health care for chronic diseases, can be identified to promote well-being and improve quality of life.
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|Gildner, Theresa E; Liebert, Melissa A; Kowal, Paul et al. (2014) Sleep duration, sleep quality, and obesity risk among older adults from six middle-income countries: findings from the study on global AGEing and adult health (SAGE). Am J Hum Biol 26:803-12|