The Study on global AGEing and adult health (SAGE) is run by the World Health Organization. An objective for SAGE is to compile comprehensive longitudinal data on the health and well-being of adult populations and the ageing process across different countries, through primary data collection, secondary data analysis and cross-study collaborations. SAGE baseline data (Wave 0, 2002–04) was collected as part of WHO's World Health Survey (WHS). A second round of data collection (Wave 1, 2007–10) is completed, expanding the sample sizes in each participating country (China, Ghana, India, Mexico, the Russian Federation and South Africa). Wave 2 (2014/15) data collection was completed in 2015. Wave 3 has been implemented in 2017/19.
SAGE Wave 0 (2002/04) A baseline cohort for the six participating countries was created as part of the larger World Health Survey effort and contains data on the situation of 65,964 adults aged 18 years and older, including over 20,000 persons aged 50 years and older. Samples of these respondents were followed-up as a part of SAGE Wave 1 (2007–10) data collection in four of the six SAGE countries (Ghana, India, Mexico and the Russian Federation). Meta- and micro-data are in the public domain through WHO at http://apps.who.int/healthinfo/systems/surveydata/index.php/catalog/whs.
SAGE Wave 1 (2007/10) Weighted data for China, Ghana, India, Mexico, Russian Federation and South Africa are in the public domain (see Study on global AGEing and Adult Health). SAGE's first full round of data collection included both follow-up and new respondents in four participating countries. The goal of the sampling design was to obtain a nationally representative cohort of persons aged 50 years and older, with a smaller cohort of persons aged 18 to 49 for comparison purposes. The target sample size was 5000 households with at least one person aged 50+ years and 1000 households with an 18- to 49-year-old respondent. In the older households, all persons aged 50+ years (for example, spouses and siblings) were invited to participate. Proxy respondents were identified for respondents who were unable to respond for themselves. The pooled data set will include over 43,000 respondents (see table below).
Data collected, Wave 1 Standardized SAGE survey instruments were used in all countries consisting of five main parts: 1) household questionnaire; 2) individual questionnaire; 3) proxy questionnaire; 4) verbal autopsy questionnaire; and, 5) appendices including showcards. A question by question guide (Survey Manual) is available. A VAQ was completed for deaths in the household over the last 24 months. The procedures for including country-specific adaptations to the standardized questionnaire and translations into local languages from English follow those developed by and used for the World Health Survey.
Descriptive results from SAGE Wave 1 are available through a US Census Bureau/WHO report Shades of Gray: A Cross-Country Study of Health and Well-Being of the Older Populations in SAGE Countries, 2007-2010. Background information on SAGE is also available through: Kowal P, Chatterji S, Naidoo N, Biritwum R, Wu Fan, Lopez Ridaura R, Maximova T, Arokiasamy P, Phaswana-Mafuya N, Peltzer K, Williams S, Snodgrass JJ, Minicuci N, D'Este C, Boerma JT and the SAGE Collaborators. Data Resource Profile: The WHO Study on global AGEing and adult health (SAGE). Int J Epidemiol. 2012;41(6):1639-49.
SAGE Wave 2 (2014/15) Data collection for SAGE Wave 2 was completed in 2015 in all SAGE countries. The Russian Federation hold Wave 2 data. Data can be requested through the WHO data archive at https://apps.who.int/healthinfo/systems/surveydata/index.php/catalog/whs/?page=1&ps=15&repo=whs
SAGE Wave 3 (2017/19) Data for SAGE Wave 3 in China, Ghana, India, Mexico and South Africa will be available through the WHO multi-country studies data archive https://apps.who.int/healthinfo/systems/surveydata/index.php/catalog/whs/?page=1&ps=15&repo=whs.
Links to other studies SAGE adapted methods and instruments used by the WHS and/or from 16 surveys on ageing (including the US Health and Retirement Survey (HRS) and the UK English Longitudinal Study of Ageing (ELSA) to collect household data on persons aged 50 years and older in over 20 countries, as well as fostering links to other data collection efforts such as the Study on Health, Ageing and Retirement in Europe (SHARE), the Chinese Health and Retirement Survey (CHARLs), the Longitudinal Ageing Study in India (LASI). An R21-funded effort, SAGE+ Wave 1 - which harmonized data from SAGE, HRS, ELSA and SHARE, resulted in a first publication in 2016. Minicuci N, Naidoo N, Chatterji S, Kowal P. Data Resource Profile: Cross-national and cross-study sociodemographic and health-related harmonized domains from SAGE plus ELSA, HRS and SHARE (SAGE+), Wave 1 Int J Epidemiol. 2016. (NIA grant R21AG034263) SAGE-like surveys have been conducted as the World Health Survey Plus (WHS+) in the Gulf Cooperation Council countries, as a short version of SAGE in eight demographic surveillance fieldsites INDEPTH; as a full SAGE in three INDEPTH fieldsites; and, as COURAGE in Europe in three European countries.
SAGE Tunisia was completed in 2016. (see, Wisniewski A, DeLouize AM, Walker T, et al. Sustained metabolic dysregulation and the emergence of diabetes: associations between HbA1c and metabolic syndrome components in Tunisian diabetic and nondiabetic groups. J Physiol Anthropol 43, 18 (2024). https://doi.org/10.1186/s40101-024-00365-4.) SAGE Al-Ain (UAE) started interviews in April 2017. SAGE Mongolia was completed in 2018 (see for example, Yiengprugsawan V, Dorj G, Drackis JG, et al. Disparities in outpatient and inpatient utilization by rural-urban areas among older Mongolians based on a modified WHO-SAGE instrument. BMC Health Serv Res. 2021;21(1):1183. https://pubmed.ncbi.nlm.nih.gov/34717613/ )
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