Lack of consensus on an aging biology paradigm? A global survey reveals an agreement to disagree, and the need for an interdisciplinary framework
Introduction
The authors were all participants at the Biology of Aging Symposium: Understanding Aging to Better Intervene, held November 9–11, 2019 in Montreal, Quebec. The symposium featured 44 speakers with a diversity of expertise related to aging, including basic aging biology, translational geroscience, geriatric medicine, nutrition, immunosenescence, evolutionary ecology, demography, statistics, systems biology, epidemiology, and complex systems theory. During the course of the symposium, a debate was held on the question, “Do we know what aging is?” with Brian Kennedy ostensibly arguing the “Yes” side and Alan Cohen ostensibly arguing the “No” side. There was dynamic audience participation. Most participants agreed that the debate and the subsequent extensive discussion involving many participants were striking in how they highlighted the lack of a clear consensus paradigm (Kuhn, 1970) in the field, and collectively we agreed it would be important to describe this for the research community in our field.
Accordingly, we designed a survey that was sent to participants of the symposium, both invited speakers and students/other participants. The survey was meant to capture the opinions on both the key points of disagreement and basic features of aging in general. All participants who responded to the survey are co-authors. We use the term “aging” to refer to “aging biology,” though, as will be shown, some but not all participants felt that aging biology cannot be understood in isolation from psychological, social, and cultural factors.
Philosophers of science generally believe that at least some aspects of a shared paradigm or worldview are often critical in helping a field advance, though the precise nature and role of such paradigms is debated (Kuhn, 1970; Lakatos, 2014). Beyond the biology of aging that is our focus here, it has been argued that there is a broad gerontological paradigm spanning from biology to the social sciences (Ferraro, 2018), with six key features: causality, life course analysis, multifaceted change, heterogeneity, accumulation processes, and ageism. Our discussions at the symposium showed no consensus on questions relating to ageism and causality, but generally supported the other four proposed features. Nonetheless, the broad areas of disagreement shown below will pose challenges for the field, and the nature of a paradigm is likely to be quite different for aging biology than in gerontology more broadly. If we cannot agree on what aging is (definitions and mechanisms), how can we identify it, measure it, or know if we are measuring it (Belsky et al., 2015; Calimport et al., 2019; Horvath, 2013; Levine, 2013)? How can we evaluate potential anti-aging interventions (Justice et al., 2018)? How relevant are findings from other species in terms of understanding human aging (Austad, 2010; Jones et al., 2014)? We do not believe it is possible at this point to propose a paradigm that would be broadly accepted in the field; accordingly, the best we can do is to note the important differences and try to propose a roadmap for what would be needed to achieve consensus on key questions.
Section snippets
Survey
We used the tool Google Forms to distribute a survey to all participants at the symposium (44 invited speakers, 2 organizers, 14 students, and 11 others). The survey collected the following information: (1) name; (2) demographic data (sex, country of origin, career stage) (3) domains of expertise (multiple responses permitted); (4) Likert-scale and other limited response questions (see below); and (5) a single open-ended question, “In no more than three sentences or 1000 characters, please
Results
Thirty-seven researchers/students responded to the survey (the authors of this paper). Demographically, 27 of 37 respondents were male, with origins in 18 different countries. No country had more than 3 respondents except Canada, which had 14, though it is worth noting that some respondents marked their current country of residence, some marked their country of origin, some marked both, and some left the field blank. Respondents were at a variety of career stages as early as post-bachelor’s,
Discussion
The results of our survey undeniably confirm the impression at the symposium: there is no clear consensus in the field of aging biology, even on the most fundamental questions. There was a near-consensus (but not complete) that aging is heterogeneous, reflected in a clear preponderance of respondents considering that aging does not proceed uniformly across tissues and that aging cannot be measured with a single, unidimensional metric. The only other question with such a clear preponderance of
Acknowledgements
A.A.C. is supported by a Canadian Institutes of Health Research (CIHR) New Investigator Salary Award and is a member of the <GS2>Fonds de recherche du Québec - Santé (FRQ‐S)<GS2> funded Centre de recherche du CHUS and Centre de recherche sur le vieillissement, as well as by a CIHR project grant (153011). A.M.S. is supported by a DECRA fellowship from the Australian Research Council (DE180101520). VG and VNG are supported by grants from US National Institutes of Health. D.F. is supported by NIH
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