The Health and Retirement Study (HRS) began in 1992 as the first study to collect longitudinal information about both the health and economic conditions of older adults. It became nationally representative of individuals over age 50 and their partners living in the United States in 1998. The publicly provided data of the HRS has been highly utilized by the research community with more than 3,300 citations in peer-reviewed journal articles as of July 2020. Due to the innovations and success of the study, the HRS has served as a model for sister studies around the world. As of 2017, the HRS and its international sister studies have conducted nearly 1.1 million interviews in 44 countries.

The first study designed to be comparable with the HRS was the Mexican Health and Aging Study (MHAS), a nationally and urban-rural representative study of people aged 50 and older and their partners that started in 2001. Expanding the comparability with the HRS to outside of North America, the English Longitudinal Study of Ageing (ELSA) began in 2002 as a nationally representative study of individuals aged 50 and older and their partners living in England. In 2004, the Survey of Health, Ageing and Retirement in Europe became the first cross-national member of the HRS family of surveys, being administered to people aged 50 and older and their partners living in Austria, Belgium, Denmark, France, Germany, Greece, Israel, Italy, Netherlands, Spain, Sweden, and Switzerland. Since its baseline wave, Bulgaria, Croatia, Cyprus, Czech Republic, Estonia, Finland, Hungary, Ireland, Latvia, Lithuania, Luxembourg, Malta, Poland, Portugal, Romania, Slovakia and Slovenia have also joined SHARE. The Costa Rican Longevity and Healthy Aging Study (CRELES) began by studying a nationally representative sample of adults aged 60 and older in 2005 but then starting in 2010 shifted to focus on adults between the ages of 55 and 65 and their partners.

The first Health and Retirement study in Asia was the Korean Longitudinal Study of Ageing (KLoSA), a nationally representative study of people aged 45 and older and their partners living in the Republic of Korea (South Korea) that began in 2006. While the Indonesian Family Life Study (IFLS) initially started in 1993 as a longitudinal study of the Indonesian population, the survey was changed beginning in 2007 to provide more comparability with the HRS. Japanese Study of Aging and Retirement (JSTAR) began in 2007 as a panel study of individuals between the ages of 50 and 75. In 2007, the World Health Organization launched the Study on Global Ageing and Adult Health (SAGE), focusing on the health of older adults in low and middle-income countries. SAGE interviewed people aged 50 and older living in China, Ghana, India, Mexico, Russia and South Africa. While Ireland joined SHARE in 2007, the Irish Longitudinal Study on Ageing (TILDA) began in 2010 as a standalone nationally representative study of individuals aged 50 and older and their partners living in the Republic of Ireland.

Expanding the HRS family of surveys to include the country with the largest aging population, the China Health and Retirement Longitudinal Study (CHARLS) began in 2011 as a nationally representative study of people aged 45 and older and their partners. The Northern Ireland Cohort for the Longitudinal Study of Ageing (NICOLA) started in 2014 as a nationally representative study of individuals aged 50 and older and their partners living in Northern Ireland. Also in 2014, Health and Ageing in Africa: A Longitudinal Study of an INDEPTH Community in South Africa (HAALSI) was launched as a longitudinal study of individuals aged 40 and older living in a surveillance site in Mpumalanga Province, South Africa. The Brazilian Longitudinal Study of Aging (ELSI-Brazil), a nationally representative study of people aged 50 and older, joined the HRS family of surveys in 2015. Also in 2015, Health, Aging and Retirement in Thailand (HART) started as a panel study of individuals aged 45 and older. In 2016, the Longitudinal Aging Study in India (LASI), a nationally representative study of people aged 45 and older and their partners, became the largest single-country Health and Retirement study, with an initial sample size of over 72,000 adults. A pilot study of Healthy Ageing in Scotland (HAGIS) was conducted among a sample of individuals aged 50 and older in 2017. The Malaysia Ageing and Retirement Survey (MARS) started in 2018 as a nationally representative study of people aged 40 and older.

To date, the Gateway has produced harmonized datasets for the HRS, MHAS, ELSA, SHARE, CRELES, KLoSA, JSTAR, TILDA and CHARLS. All harmonized datasets are made publicly available to researchers. Users can access the data either from the originating study or from the Gateway website. Remember to check back often for updates to the harmonized data and the addition of new studies!