17 June 2021
We probably cannot slow the rate at which we get older because of biological constraints, an unprecedented study of lifespan statistics in human and non-human primates has confirmed.
The study set out to test the ‘invariant rate of ageing’ hypothesis, which says that a species has a relatively fixed rate of ageing from adulthood. An international collaboration of scientists from 14 different countries, including José Manuel Aburto from Oxford’s Leverhulme Centre for Demographic Science, analysed age-specific birth and death data spanning centuries and continents. Led by Fernando Colchero, University of Southern Denmark and Susan Alberts, Duke University, North Carolina, the study was a huge endeavour requiring monitoring wild populations of primates over several decades.
Jose Manuel Aburto says, ‘Our findings support the theory that, rather than slowing down death, more people are living much longer due to a reduction in mortality at younger ages. We compared birth and death data from humans and non-human primates and found this general pattern of mortality was the same in all of them. This suggests that biological, rather than environmental factors, ultimately control longevity.
‘The statistics confirmed, individuals live longer as health and living conditions improve which leads to increasing longevity across an entire population. Nevertheless, a steep rise in death rates, as years advance into old age, is clear to see in all species.’
He continues: ‘The debate over how long we can live has divided the academic community for decades. Some scholars argue human lifespan has no limit, while others say the opposite. But what has been missing is research comparing lifespans of multiple animal populations with humans, to work out what is driving mortality. Our study plugs that gap. This extraordinarily diverse collection of data enabled us to compare mortality differences both within and between species.’
The team analysed data from primates, since they are our closest genetic relatives, and therefore most likely to shed light on our biology. The research team analysed information from 30 primate species, 17 in the wild and 13 in zoos, including gorillas, baboons, chimpanzees and guenons. And it examined birth and death records from nine diverse human populations in 17th to 20th century Europe, the Caribbean and Ukraine, and two hunter gatherer groups between 1900 and 2000.
All the datasets examined by the team revealed the same general pattern of mortality: A high risk of death in infancy which rapidly declines in the immature and teenage years, remains low until early adulthood, and then continually rises in advancing age.
José Manuel Aburto says: ‘Our findings confirm that, in historical populations, life expectancy was low because many people died young. But as medical, social, and environmental improvements continued, life expectancy increased. More and more people get to live much longer now. However, the trajectory towards death in old age has not changed. This study suggests evolutionally biology trumps everything and, so far, medical advances have been unable to beat these biological constraints.’
The team hopes its findings will lead to greater understanding of the ecology and evolution of a wide range of animal species worldwide, and their conservation.
Notes to Editors:
For copies of the report, The Long Lives of Primates and the ‘Invariant Rate of Ageing’ Hypothesis, or for interviews, please contact firstname.lastname@example.org
Authors: Fernando Colchero, José Manuel Aburto, Elizabeth A. Archie, Christophe, Boesch, Thomas Breuer, Fernando A. Campos, Anthony Collins, Dalia A. Conde, Marina Cords, Catherine Crockford, Melissa Emery Thompson, Linda M. Fedigan, Claudia Fichtel, Milou Groenenberg, Catherine Hobaiter, Peter M. Kappeler, Richard R. Lawler, Rebecca J. Lewis, Zarin P. Machanda, Marie L. Manguette, Martin N. Muller, Craig Packer, Richard J. Parnell, Susan Perry, Anne E. Pusey, Martha M. Robbins, Robert M. Seyfarth, Joan B. Silk, Johanna Staerk, Tara S. Stoinski, Emma J. Stokes, Karen B. Strier, Shirley C. Strum, Jenny Tung, Francisco Villavicencio, Roman M. Wittig, Richard W. Wrangham, Klaus Zuberbühler, James W. Vaupel, Susan C. Alberts
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Leverhulme Centre for Demographic Science:
Societies and economies face unprecedented global demographic challenges, including radical shifts in age structures, global aging, rapid population growth in some areas but decline in others, substantial sudden flows of migrants and refugees, diverse families and fertility patterns and population-related environmental threats. The Leverhulme Centre for Demographic Science (LCDS) was set up in 2019 to build an internationally recognized and interdisciplinary centre of demographic science that will disrupt, realign and raise the value of demography in science and society. The Leverhulme Trust was established by the Will of William Hesketh Lever, the founder of Lever Brothers. Since 1925 the Trust has provided grants and scholarships for research and education. Today, it is one of the largest all-subject providers of research funding in the UK, distributing approximately £100m a year. For more information about the Trust, please visit www.leverhulme.ac.uk and follow the Trust on Twitter @LeverhulmeTrust