Study On Global AGEing & Adult Health (SAGE)

http://www.who.int/healthinfo/sage/en/

Overview
The World Health Organization's Study on Global Ageing and Adult Health (SAGE) is a longitudinal household survey study that includes respondents 50 years and older with a smaller, comparative cohort of adults aged 18-49 years. Currently, the survey is comprised of nationally representative samples in China, Ghana, India, Mexico, Russia and South Africa with a sample size of over 40,000 respondents. In addition, SAGE functions as a research platform for collecting data and for improving survey methodology and measurement approaches to address comparability of data across population groups. Partners from eight health and demographic surveillance sites in Bangladesh, Ghana, India, Indonesia, Kenya, South Africa, Tanzania and Viet Nam as part of a research collaboration with the International Network for the continuous Demographic Evaluation of Populations and Their Health in developing countries (INDEPTH), with a combined sample size of over 45,000 respondents. These partners implemented a shorter version of the instrument in their routine surveillance to allow comparisons with national data and enable closer monitor of ageing- related transitions. A SAGE sub-study on the direct and indirect impacts of HIV and ART in older persons, in collaboration with partners in Uganda and South Africa, includes a cohort of around 1000 persons. A number of sub-studies have also been completed: in India assessing different short forms of the Day Reconstruction Method against the full instrument; in India and Uganda comparing self-reported and measured physical activity using an accelerometer; and, in Mexico, South Africa and India comparing matched venous blood samples to DBS. Another current multi-country study has used SAGE methods and instruments in its first wave of data collection in Finland, Poland and Spain. 

SAGE has focused on health and health-related outcomes, including examination of the determinants and impacts of health and well-being. The goals of SAGE are to: 1) promote a better understanding of the effects of ageing on well-being; 2) examine the health status of individuals aged 50+ years and changes, trends and patterns that occur over time; and, 3) improve the capacity of researchers to analyze the effects of social, economic, health care and policy changes on current and future health. The objective of SAGE is to improve the empirical understanding of the health and well-being of older adults through provision of reliable, valid and cross-nationally comparable data.

Data Collection
Wave 0 was completed in 2004 (as part of the World Health Survey) with Wave 2 finalized in 2014 - Wave 3 of SAGE is planned for later in 2017. Further details are available from: http://www.who.int/healthinfo/sage/en/

Biomarkers
The biomarker component of SAGE includes performance tests and the collection of dried blood spots (DBS) in Wave 1. The performance tests included visual acuity (near and distant vision), cognition (verbal fluency, word recall and digit span), mobility (timed walk), grip strength, blood pressure, anthropometry (height, weight, waist and hip circumferences) and spirometry. The DBS samples have been collected from approximately 40,000 respondents and stored at -20° Celsius in central laboratories in each country. The assays for hemoglobin, glycosylated hemoglobin (HbA1c), high sensitivity C-reactive protein (hsCRP), Epstein Barr Virus (EBV) and HIV, have been standardized and validated against venous blood samples (only three countries agreed to run the HIV assay). Results from China, Ghana, India and South Africa are currently under review, with the Mexico and Russia to complete their analyses this year. DBS assays for apolipoproteins A1 and B and high density lipoprotein (HDL) are ready for validation. Work is ongoing to developed and validate tests for total cholesterol and triglycerides; and to standardize tests for interleukin-6 (Am J Human Biol. 2012;24(6):863-5), telomerase (hTERT, Nucleic Acids Res. 2011 Nov 1;39(20):e134)and/or telomere length (PLoS One. 2012;8(2):e57787), and to standardize assays for cytomegalovirus (Immun Ageing. 2011; 8: 3.), and T-cell receptor excision cycles (TREC, J Immunol Methods. 2012;384(1-2):118-27. and J Immunol Methods. 2013;389(1-2):1-8.) in our samples in the future. Standardization across laboratories is being carried out by the exchange of standard sample/protocols generated by collaborators in a reference laboratory in the United States, with a more extensive calibration process being rolled out (N=200 standard samples). Training of all lab personnel was carried out in preparation for the study - with additional quality control processes in place and ongoing. Future waves of SAGE will consider the collection of DNA samples from saliva.

Publications
http://www.who.int/healthinfo/sage/en/

Data and Codebook
http://apps.who.int/healthinfo/systems/surveydata/index.php/catalog/sage 

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