1Anthropology, University of California, Santa Barbara, 2Center for Evolution and Medicine, Arizona State University, 3Economic Science Institute, Chapman University, 4Institute for Advanced Study in Toulouse
April 16, 2020 2, Platinum Ballroom
Physiological aging describes the somatic, cellular, endocrine, immune, and other physical changes that underlie age-related increases in mortality and declines in fertility. Understanding the dynamics of physiological aging is essential for elucidating how and why senescence occurs across species and human populations. However, much of what is known about physiological aging in humans is restricted to industrialized populations with high burdens of chronic “diseases of civilization.” Little is known about physiological aging in varied environments, and local selective pressures have been under-appreciated as a source of variation. To better characterize human diversity in aging patterns, we examined physiological age trajectories among Tsimane horticulturalist-foragers from the Bolivian Amazon using longitudinal data (n=21,543) on 61 biomarkers that are combined into a statistical index (mahalanobis distance) of “biological age.” Although few individual biomarkers showed a significant decline with age, a combined index revealed significant increases in “dysregulation” (β = 0.15, p < 0.001). Compared to relatively rapid increases in cardiovascular dysregulation with age (p < 0.001), dysregulation in the immune system remained constant (p > 0.05). Finally, we compared Tsimane aging profiles with those of Americans/Italians under the expectation that differences could arise due to higher lifetime exposure to pathogens, minimal sedentism, lean diet, and higher fertility, but found that rates of increase in standardized dysregulation were nearly identical (β = 0.15 vs. 0.14). Our results provide the first large-scale evidence of physiological aging in a subsistence context and highlight the diversity of physical aging profiles across different body systems and human populations.