Introduction to Japan Gerontological Evaluation Study (JAGES)

What is JAGES?
The Japan Gerontological Evaluation Study (JAGES) project aims to build a scientific backbone from the viewpoint of preventive medicine to establish a society of healthy longevity. We have been collaborating with 40 municipalities all over Japan to investigate the living conditions of approximately 300,000 adults aged 65 and above. More than 30 researchers from colleges, universities, and national institutions in Japan are currently conducting a wide variety of studies using our data. JAGES is funded by the Japanese and the US government agencies, including the Ministry of Education, Culture, Sports, Science and Technology (Japan), the Ministry of Health, Labour and Welfare (Japan), and the National Institutes of Health (US).

History: Development from AGES to JAGES
The Aichi Gerontological Evaluation Study (AGES) project was initiated in 1999, which conducted a survey in two municipalities of Aichi Prefecture. The goal of the survey was to obtain scientific knowledge that would form the basis of the elderly care policy. We emphasized on the following three aspects:

• Promoting evidence-based, gerontological research focusing on adults aged 65 and above, from a multidisciplinary viewpoint, including physiology, psychology, and sociology;
• Promoting social epidemiological research that helps address social determinants of health (SDHs); and
• Developing a comprehensive benchmark system for the preventive care policy, as well as contributing to achieve a society of health and longevity characterized by a high level of well-being and a small level of health inequality, which would be assessed through regional interventional studies.

In 2003, we conducted a survey targeting 32,891 adults aged 65 and above who did not receive long-term care insurance in 15 municipalities of three prefectures. Moreover, we conducted another survey in 10 different municipalities of the three prefectures in 2006 as a follow-up. In 2010, our project was largely expanded to include 100,000 adults aged 65 and above in 31 municipalities across Japan, and finally, developed into the JAGES project. The JAGES project collected big data from about 140,000 adults aged 65 and above residing in 30 different municipalities throughout Japan in 2013.

Researchers from various backgrounds interested in social epidemiology have been involved in designing our questionnaire and analyzing our data. Their backgrounds include public health, epidemiology, sociology, oral and dental sciences, nutrition, psychology, social welfare, occupational therapy, economics, regional planning, political sciences, and geography.

Photograph of the fifth anniversary of CWS and the fifteenth anniversary of AGES	JAGES Summer Camp in 2015, photographed in August 2015

Research objectives of JAGES

Japan has the highest life expectancy in the world. The JAGES project aims to improve the status quo of adults aged 65 and above in Japan from a multifaceted viewpoint. In this project, we wish to shed light on the following key areas:

1. To elucidate the “social determinants of health”
   When considering the risk factors of one’s health, we need to analyze not only lifestyle such as diet, exercise, smoking, and drinking, but also one’s psychological and social factors. We aim to demonstrate the significance of social epidemiology to elucidate the “social determinants of health,” such as income and educational background.
   
   
2. To describe “health inequality”
   We have found health inequality is prevalent among Japanese adults aged 65 and above. Health inequality originates from socioeconomic factors and regional inequality in access to social services. We are also working to “visualize” and minimize health inequality among Japanese adults aged 65 and above, a national initiative for health promotion advocated in “Health Japan 21 (the second term)” by the Ministry of Health, Labour and Welfare.
   
   
3. To show the direction of renewed strategies for preventive care
   With the recent amendment of the long-term care insurance system, preventive care has increasingly been emphasized. In accordance with this movement, depression, oral care, malnutrition, the likelihood of fall, lifestyle, and social seclusion are now considered important factors for preventive care. In addition, more attention has been given to the underlying social determinants of health, such as insomnia, hobbies, abuse, household structure, participation in community organizations, social support, occupational status, and social capital. We are examining the relationship between these various factors/determinants and the socioeconomic status of adults aged 65 and above, as well as the effect of regional differences in their living conditions.
   We do not hope to choose a strategy that screens adults aged 65 and above receiving long-term care insurance or those with a high risk of mortality (high-risk approach). Instead, by paying attention to environmental factors, we intend to clarify the significance of taking measures for preventive care that targets all community residents, including those with no/low risk of death (population approach).
   Furthermore, we are currently working on interventional studies at a regional level in collaboration with municipalities across Japan.

Outline of the JAGES Project

2016 JAGES Project

Research subjects
Adults aged 65 and above who have not received long-term care insurance

Research method
We distributed questionnaire books to research subjects by mail. Respondents returned their completed forms to a designated e-mail ID.

Survey periods and “waves”
In the JAGES project, a “wave” is defined as a group of surveys that include the same basic items of questions and are conducted in several subject areas at about the same time. There have been four waves so far in the following manner:

Wave I (data from the 2003 survey): 
Survey conducted in 15 municipalities of three prefectures (12 long-term care insurers) from 2003 to 2004
Wave II (data from the 2006 survey): 
Survey conducted in 9 municipalities of three prefectures (9 long-term care insurers) from 2006 to 2007
Wave III (data from the 2010 survey):
 Survey conducted in 31 municipalities of 12 prefectures (25 long-term care insurers) from 2010 to 2011
Wave IV (data from the 2013 survey): 
Survey conducted in 30 municipalities of 14 prefectures (25 long-term care insurers) in 2013

*The preliminary survey below (i.e., data from the 2000 survey) is treated as exceptional.Wave 0: A preliminary survey done in two municipalities of one prefecture (two long-term care insurers) from 1999 to 2000

Types of data sets
We define a “data set” as a collection of information (i.e., data) obtained from research subjects in each of these surveys. There are three major types of data sets as follows:

• Cross-sectional data sets: a data set created from a wave of surveys
• Cohort data sets: a cohort data set adds the change in health status (i.e., death or receiving long-term care insurance) to cross-sectional data. It also contains the number of days until the change of health status from the baseline data.
• Panel data sets: a data set created by combining two data sets from two waves of surveys

Survey items (in the 2016 survey)
A questionnaire booklet consists of 16 pages. Each booklet has two parts: Part 1 “Core items of questions” (10 pages) and Part 2 “Thematic items of questions” (2 pages). The former part is designed for all research subjects and comprises various questions about relevant factors of preventive care and important adjustment factors, while the latter has eight different thematic topics of questions (Versions A-H), and it is intended to be used for analytical purposes. Each research subject receives, at random, one of these eight questionnaire booklets. Eight versions of booklets are assigned and distributed evenly to research subjects in each survey district.

Survey fields (in the 2013 survey)
The JAGES project conducted a nationwide survey in 30 municipalities (25 long-term care insurers) from October 1 to December 2, 2013. The research subjects were adults aged 65 and above who did not receive long-term care insurance. A total of 195,300 questionnaire booklets were distributed, and 138,300 people responded (percentage of respondents: 70.8%).