Jim Vaupel, who died on Sunday, March 27, was an international leader in demography and aging research. He was a highly creative researcher—always with new ideas and very entrepreneurial in the development of new research environments. He inspired countless young researchers with his analytical abilities and his incredibly elegant communication both in writing and speech. There was something charismatic, almost playful, about him—a memory that will stay with us forever. But he could also be sharp, demanding the absolute best of his colleagues.

We had the great pleasure of receiving Jim as a professor at the Department of Public Health at the University of Southern Denmark (SDU) in 1991. In 1996, he was headhunted to become the head of the Max Planck Institute for Demographic Research in Rostock (Germany), while still working part-time at the University of Southern Denmark and also holding a part-time position at his former workplace, Duke University (USA). For 25 years, he regularly commuted between these three jobs. Many of his articles were written in an airport or on board a plane, so he was, in many ways, a flying researcher.

Jim was born in New York on 2 May 1945. He completed his BA in mathematical statistics and was awarded his PhD at Harvard University in 1978. He was at Duke University until 1985, after which he became professor at the University of Minnesota. In the 1980s, he had several stays at the International Institute of Applied Systems Analysis in Vienna, where he established many collaborations.

His research focused increasingly on aging and mortality. In 1979, he published his famous frailty article, which became his first classic. He began early in his career to challenge the then dominant assertion that life expectancy was close to a biological limit and the perception that mortality in older age groups was immutable. He became interested in Swedish lifetime data, which dated back to the 18th century, and in Danish twin data, which include twins born since 1870. Jim recognized that twin data could contribute to a clarification of the degree to which lifespan is genetically determined. This led to his first research collaboration with researchers in the Nordic countries.

When he came here to Odense, he had for several years been married to a Danish woman, Bodil. For many years, Bodil and Jim traveled to Europe both in connection with Jim’s research stays and during their holidays, either to the warm coasts of the Greek peninsula, where they visited all the places mentioned in Homer’s works, or to the colder “hyperborean borders” of the Nordic countries, where, according to Plinius, people in prehistoric times lived to exceptionally high ages. Whether it was this old myth that attracted him, or it was Bodil who wanted their two girls to attend Danish schools, his great interest in twin data eventually led him to Odense. He had contacted the head of the Danish twin registry, and through the Dean’s dynamic commitment, he was quickly employed as a professor at the Faculty of Health Sciences. After a few years in Odense, Bodil and Jim settled down in Kerteminde.

At this point, aging research was in rapid development worldwide, and Jim was already a leader within the field. Along with his new Danish colleagues, Jim quickly managed to acquire large grants, which contributed to the formation of a center of aging research that later developed into the present Danish Aging Research Center (DARC). Also, he propelled the computerization and new analyses of the data in the Danish Twin Registry (DTR). Jim was a true catalyst for the aging and twin research at the SDU. Not only did he promote interdisciplinary research, but he also created a very internationally oriented research environment.

At the center he established the so-called Kannisto-Thatcher database of registered deaths among 80+ year-old adults in high-income countries. This database was the basis for analyses of data on millions of the oldest adults, and it did not only lead to articles in the highest-ranking international journals, but also to several books, the Odense Monographs on Population Ageing. This work showed that mortality among old adults had declined significantly since 1950, and that this decline now contributed most to the continued increase in life expectancy. It also explained the dramatic growth in the number of nonagenarians and centenarians. Furthermore, it seemed that mortality in the highest age groups no longer rose exponentially with increasing age, but in fact stagnated. In collaboration with American biologists, Jim confirmed these findings in studies of other living organisms in biodemographic experiments: a million Mediterranean flies, various strains of Drosophila Melanogaster, and thousands of the small roundworms Caenorhabditis elegans. All these analyses led to the publication of famous articles in Science and were later summarized in a landmark article in Science in 1998 and supplemented with new results in Nature in 2010.

Together with his colleagues in Odense and Rostock and other international colleagues, Jim, in the 1990s, established an international research network for demographic studies of supercentenarians (110+ year-old adults), which resulted in much-discussed articles, and to the first demographic books on this new generation of exceptional long-livers. Along with his French colleagues and researchers at the Max Planck Institute, he established a database of these supercentenarians, The International Database on Longevity (IDL).

With his Chinese research colleagues, he contributed to the major study of 10,000 80+ year-old adults in China, who, since 1998, have been reexamined regularly. These studies were inspired by the first Danish studies of nonagenarians and centenarians. Along with his colleagues in Odense, he received several US grants to the large, continuous study of 10,000 middle-aged and older Danish twins and new studies of nonagenarians and centenarians in Denmark. Jim’s contribution to the development of aging and twin research at SDU is indeed very impressive.

He continued to contribute to research at SDU during his 20 years as head of the newly established Max Planck Institute in Rostock. Together with his Swedish co-director he attracted numerous young researchers from all over the world—generations who also became part of the European Doctoral School for Demography. In addition, he launched an online journal, Demographic Research, and he was the key driver in the founding of Population Europe—a network of European centers of population studies. Furthermore, he founded the Max Planck Research Network on Aging, where his great interest in the plasticity of aging was further developed, and many younger researchers came onboard.

A substantial part of his work was carried on at SDU when—due to the retirement rule in Germany—he had to leave the Max Planck Institute at the age of 68. He returned to a full-time professorship close to his home in Denmark. Again, he attracted young researchers from different countries with whom he continued to publish important articles in the field of formal demography—his favorite theoretical topic—as well as in areas such as evolutionary demography and forecasting. After a few years in his old department at Health Sciences at SDU, he established a new research center, The Interdisciplinary Center on Population Dynamics—CPOP, which was located at the Faculty of Social Sciences. Here, he was in the process of creating a new international research environment.

It was therefore a shock to learn that Jim had suddenly passed away at the age of 76. He had so much more in him, and he did not intend to stop working. His brain worked perfectly, and it never rested. We have lost a great researcher and a remarkable personality that will be missed for a long time.

We wish to express our deepest condolences to Bodil, Anna, Sofie and the five grandchildren.