Biocultural and evolutionary approaches to the study of human diseases: Integrative perspectives from biological anthropology.

In this special issue of the American Journal of Biological Anthropology, co-editors Andrew Kim and Sabrina Agarwal have brought together a diverse group of prominent authors whose research showcases the important role that biological anthropologists play in understanding the origins, nature, and long-term consequences of the burden of disease on human health and well-being. Biological anthropology is distinct from other fields of biomedicine and the health sciences in explicitly drawing on both comparative/evolutionary and biocultural approaches to explore how social and ecological forces shape variation in the exposure to and impact of infectious and chronic diseases. Indeed, the rich temporal and cross-cultural dimensions of research in bioanthropology provide a unique framework for understanding the dynamic interplay between disease ecology and human biology through space and time. This collection includes papers from researchers across the sub-fields of biological anthropology, including paleoanthropology, bioarcheology, primatology, anthropological genetics, demography, and human biology. Papers by Houldcroft and Underdown (2023), Joseph and Lindo (2023), Zuckerman et al. (2023), Honap et al. (2023), and van Doren and Kelmelis (2023) examine the impact of infectious and non-communicable diseases on human health in the historic and pre-historic past. Houldcroft and Underdown (2023) revisit the question of when in our evolutionary history infectious diseases became a major health burden and selective force. Traditional views have held that infectious diseases emerged as a significant force relatively recently, with the origins of agriculture and increased human population density; however, Houldcroft and Underdown argue persuasively that insights from ancient DNA analyses suggest an earlier rise of infectious disease burden, during the Pleistocene. They further highlight the important role that ancient infectious diseases have played in shaping variation in immune function and disease susceptibility in modern human populations. The papers by Joseph and Lindo (2023) and Honap et al. (2023) examine the health of indigenous populations of the Americas before and after European contact. Joseph and Lindo note that a rich diversity of endemic pathogens existed before colonial contact in the Americas, and call for a re-examination of the “unidirectional” model of European introduction of infectious diseases post-contact. Honap and colleagues offer parallel conclusions with their analyses of the oral microbiomes from pre-contact skeletal remains of Wichita Ancestors from Oklahoma. These authors document distinct oral microbiomes, some associated with periodontal disease, in these pre-contact individuals. Together, these papers provide us with a more complex and nuanced view of the mechanisms through which colonialism and migration have shaped disease spread and health outcomes among indigenous populations of the Americas. Papers by Zuckerman et al. (2023) and van Doren and Kelmelis (2023) both consider the biosocial dimensions of variation in mortality patterns associated with the 1918 influenza pandemic. Zuckerman and colleagues draw on mortality data from a patient population of the Mississippi State Asylum, whereas van Doren and Kelmelis utilize death records from the Canadian province of Newfoundland, drawn from the digital archives at Memorial University of Newfoundland. In both studies, mortality rates varied strongly by social class, ethnicity/race, and region, just as has been seen with the COVID-19 pandemic (e.g., Rubino et al., 2020; Van Dorn et al., 2020; Wang & Tang, 2020; Yancy, 2020). These findings highlight the importance of explicitly drawing on biocultural and syndemic frameworks for better understanding the pathways through which conditions of systemic racism and social distress promote disparities in health outcomes (e.g., see Gravlee, 2020; Mendenhall & Singer, 2020; Singer, 2009). Contributions by Radhakrishna (2023) and Werner et al. (2023) articulate how research with non-human primates can provide important insights into patterns of disease transmission and exposure. Radhakrishna uses the example of the Kyansaur Forest Disease (KFD), a tick-borne viral hemorrhagic fever endemic to southwestern India, to develop a model that explores the social, biological, and ecological correlates of its spread. Macaques are common hosts for the KFD virus. With agricultural expansion and shifting land-use patterns in India, more intensive interactions between human and macaque populations have promoted the spread of KFD. Radhakrishna's model offers to provide regional planners and public health officials with a tool that could be used to identify communities at greatest risk for KFD outbreaks. Werner and colleagues address the need to better understand and identify the origins of future zoonotic disease risks, particularly in areas where humans are in close contact with non-human primate populations. The authors draw on novel phylogenetic approaches to make predictions about what primate parasites are likely candidates to infect human populations in the future. Their model identifies 54 parasites likely to infect humans that are not currently reported in the global database! These findings highlight the power and relevance of comparative and evolutionary approaches for identifying emerging human diseases and “at risk” populations. Papers by Cepon-Robins et al. (2023b) and Kim et al. (2023) examine the biocultural determinants of diverse health outcomes among contemporary populations living in marginal circumstances in rural Mississippi and urban South Africa, respectively. Cepon and colleagues specifically consider how economic resources and parasite exposure influence intestinal inflammation and physical nutritional status among children of low-income families of Mississippi. In this sample, persistent helminth infections were associated with increased intestinal inflammation, which in turn contributed to lower body mass indexes (BMI z scores) in these children. These findings are consistent with previous research that has shown how conditions of poverty and poor sanitation contribute to increased risks of intestinal parasites and inflammation, compromising childhood growth and nutritional status (e.g., Cepon-Robins et al., 2019; Tanner et al., 2009). Further, these results offer insights into the possible developmental origins of racial/ethnic disparities in health outcomes in the U.S. (see also Cepon-Robins et al., 2023a). Kim and colleagues explore the influences of both childhood trauma and stress from the COVID-19 pandemic on the mental health of adults from Soweto, South Africa. The data were derived from an ongoing longitudinal birth cohort study (the “Birth to 30” Study) initiated in the early 1990s to explore the impacts of urbanization on the health and well-being of South African children. Kim and colleagues find that over half of their sample of 88 adults have marked symptoms of PTSD, and that the severity of those symptoms are independently associated with greater childhood trauma and higher COVID-19 stress levels. This study is a part of a growing body of literature that is addressing an long under-studied area of global health, the social and developmental influences on mental health and cognitive function (Kieling et al., 2011; Kim, 2020; Lund et al., 2011; Patel et al., 2018). Overall, this collection of papers elegantly demonstrates how current research in biological anthropology is providing critical new insights into the origins of human health disparities and the complex web of social and ecological forces that shape variation in disease exposure. Equally impressive are the diverse range of novel methodologies and data sources that these authors are using to investigate the dynamics of human disease patterns. It is these broad, integrative approaches to the study of human diversity and health that are the hallmarks of our discipline, providing us with a more complete picture of human adaptations to ever-changing disease landscapes. William R. Leonard: Conceptualization (equal); writing – original draft (equal); writing – review and editing (equal).