It is with profound sadness that we announce the passing of Professor Yasuhiko Saito, Research Project Professor at the College of Economics, Nihon University. He died on April 11, 2026, in Tokyo, following a courageous battle with cancer.
Born in 1955, Professor Saito was a distinguished scholar whose academic journey began at Nihon University, where he graduated from the Department of Economics in 1979. He later moved to the United States to pursue further studies, earning his Ph.D. in Sociology from the University of Southern California (USC) in 1993. He began his research career at USC under the mentorship of demographer Eileen Crimmins and economist Richard Easterlin. In 1995, he returned to his alma mater in Tokyo, where he dedicated over two decades to research and teaching.
Professor Saito was a leading figure in demography, gerontology, and population health. His work focused on active and healthy life expectancy, centenarian research, and the social determinants of health among older populations in both developed and developing countries. He promoted data collection for the study of ageing and health in Asian countries. He led a six-wave national longitudinal survey on ageing and health in Japan—the Nihon University Japanese Longitudinal Study of Ageing—which remains a cornerstone of gerontological research. He also worked on a five-country comparative study of centenarians (5-COOP), involving Denmark, France, Japan, Sweden, and Switzerland.
Professor Saito was also affiliated with Duke-NUS Medical School in Singapore, where he contributed to research on ageing and health, particularly through longitudinal studies. At the time of his death, he was serving as Senior Research Fellow and Senior Advisor to the President on Population Ageing at the Economic Research Institute for ASEAN and East Asia (ERIA) and was overseeing the conduct of a groundbreaking longitudinal survey on ageing and health in the Philippines and Viet Nam.
Professor Saito’s research contributed significantly to advancing population studies in Japan, Asia, and globally, with an emphasis on improving population health and standardizing the measurement of healthy life expectancy. He was an internationally recognized scholar who dedicated himself to advancing and standardizing the healthy life expectancy calculation methods, including the Sullivan method, IMaCh, and SPACE. He collaborated closely with the REVES international network as one of its most experienced and longest-serving members, helping to improve how the world understands the quality of life in ageing societies. In 1997, he hosted and organized the annual REVES meeting at Nihon University in Tokyo. He also led the Asia-REVES subnetwork in the 1990s, actively promoting the use of healthy life expectancy across the region. In recent years, he established a workshop dedicated to these methods of healthy life expectancy, held prior to the network's annual meeting.
Professor Saito had an extensive network across regions and institutions. He served as a council member of the International Union for the Scientific Study of Population (IUSSP) from 2006 to 2009 and as an executive committee member of the International Social Science Council (ISSC), representing IUSSP, from 2010 to 2018. In addition, he served as a member of the 2025 IUSSP Nomination Committee. He was also a member of the 4th Council of the Asian Population Association from 2016 to 2018.
Beyond his technical achievements, Professor Saito was deeply committed to the growth of the academic community. He was a passionate mentor who dedicated himself to developing the capacity of young researchers throughout the Asia-Pacific region. He served as a crucial academic bridge between Japan and the international community, leaving behind a wealth of knowledge and a generation of scholars inspired by his dedication.
Professor Saito is survived by his wife, Tomoko Saito, and their only child, Kazuki.
Written by Reiko Hayashi, Chi-Tsun Chiu and Grace Cruz.