Health statistics and information systems

SAGE longitudinal multi-country study


SAGE Wave 1: 2007–2010

Implementation of SAGE Wave 1 was from 2007 to 2010 in six countries over different regions of the world (China, Ghana, India, Mexico, Russian Federation and South Africa). The study design included samples of follow-up respondents from Wave 0 in four countries (Ghana, India, Mexico and Russia) and new respondents in all countries.

SAGE Wave 1 used two target populations: a large sample of persons aged 50 years and older, which is the focus of the study, and a smaller comparative sample of persons aged 18–49 years. In all countries, households were classified into one of these two mutually exclusive categories: one or more persons aged 50 years and older are selected from households classified as “50+ households” and one person aged 18–49 years from a household classified as an “18–49 household”. In the older households, all persons aged 50 years and older (for example, spouses and siblings) were invited to participate. Proxy respondents were identified for respondents who were unable to respond for themselves (for cognitive issues, decisions based on the IQ Code (Jorm 1989)).


Sample sizes

All six countries implemented a multistage cluster sampling design resulting in nationally representative cohorts. Household-level analysis weights and person-level analysis weights, which included sample selection and a post-stratification factor, were calculated for each country. Post stratification used the most recent estimates provided by the national statistical offices of the respective countries.

In consultation with the Ministry of Health in China, China CDC and Shanghai CDC, a new sampling design was used for SAGE in China drawn from an existing national surveillance system. In India, a representative sample of six States was included, taking into consideration population size and level of development, and can be modelled to a nationally representative sample. The Russian Federation's sample was extended to the east and south (as compared to the Wave 0 sample) to include respondents from the Asian and Southern European regions of the country. The South African team chose to select a new sample based on an updated sampling frame from Wave 0.

Same sizes per country, adults aged 18 years and older


China*
14 813
Ghana
5 110
India**
11 230
Mexico
2 756
Russian Federation
4 355
South Africa*
4 223

* The China and South Africa Wave 1 samples are new, and do not include any Wave 0 follow-up respondents.
** The India sample for Wave 1 includes a large number of women aged 18-49 years as part of a nested study, subsidized by the SAGE India team.


Survey materials

The SAGE survey instruments and methods were adapted from those used by the World Health Survey (WHS) and were informed by a review of 16 surveys on ageing (including the US Health and Retirement Survey (HRS) and the English Longitudinal Study of Ageing (ELSA).

The SAGE survey instruments assessed health status and health systems from a household and individual perspective. SAGE also evaluated perceptions of well-being and more objective measures of health, including measured performance tests: 4m timed walk; spirometry; cognitive battery (verbal fluency, immediate and delayed recall, digit span forward and backward); near and distance vision; and, grip strength; and biomarkers: blood pressure and pulse rate; height and weight; hip and waist circumference; and, blood spot from finger prick.

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 (VAQ); and, 5) appendices including showcards. 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 WHS.

SAGE Wave 1 survey materials can be downloaded by clicking on the links below, including the generic household, individual and proxy questionnaires, the verbal autopsy and Survey Manual.

Download questionnaires and supporting materials:

Country-specific adaptations for SAGE questionnaires and data are available upon request by e-mail at sagesurvey@who.int.


Data access

Wave 1 meta- and micro-data, using DDI standards, are available through the online SAGE Data Archive at no cost: to access it, choose “Filter by Topic”; select “Study on Global Ageing and Adult Health (SAGE)”, click on country/data of interest, then click on "Microdata request form", and follow the online instructions to obtain data.


Support

Support for SAGE Wave 1 was provided by the U.S National Institute on Aging (NIA) Division of Behavioral and Social Research (BSR) through Interagency Agreements (OGHA 04034785; YA1323–08-CN-0020; Y1-AG-1005–01) with WHO. WHO provided salary support for members of the WHO SAGE team. The Governments of China and South Africa provided additional financial support for implementing the survey in their respective countries.

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