Dr. Luiz Pezo-Lanfranco and his colleagues have made significant strides in understanding child mortality in the Central Andes through their research published in the International Journal of Osteoarchaeology. This study focused on the child mortality rates at the Quebrada Chupacigarro Cemetery (QCC), offering a rare glimpse into the health and living conditions of children during a pivotal time in Andean history, spanning from the Middle Formative to the Late Formative Period (circa 500–400 BCE).
The research team discovered that the individuals buried at the QCC showed high levels of health-disease markers, likely linked to poor living conditions, including high population density, insufficient sanitation, and widespread nutritional deficiencies. These factors were particularly prominent during the transitional period when societal structures in the region underwent significant changes.
In this era, the established theocratic governments and large ceremonial centers were gradually abandoned in favor of secular governments. Populations relocated from large urban centers to clustered, often defensively situated settlements on hilltops and fortresses. The QCC, located on the slopes of Cerro Mulato near the Supe River, was one such burial site that emerged during this time. It was discovered and excavated in 2011 and provided a treasure trove of archaeological data, with the human remains of 67 individuals, 47 of whom were children under the age of eight.
The QCC offered a unique opportunity to delve into the bioarchaeology of children from the Formative Period—a period not commonly studied due to the inherent challenges of preserving juvenile skeletons. According to Pezo-Lanfranco, this collection was rare in that it represented one of the few fully excavated cemeteries from this specific period in Andean prehistory. Moreover, children have historically been marginalized in bioarchaeological research, often overlooked due to fragility in their skeletal remains and differential burial practices when compared to adults. Pezo-Lanfranco emphasized the importance of understanding the health conditions of these children, noting that little was known about the paleopathology of preadults in prehistoric Peru prior to this study.
The analysis of the QCC skeletal remains revealed numerous bone markers indicative of health-related issues. These markers included cribra orbitalia (CO), a lesion in the eye sockets commonly linked to anemia, and porotic hyperostosis (PH), which causes bone porosity in the skull and is often associated with chronic anemia. In addition, many of the remains displayed periosteal reactions (PR), indicating new bone formation as a result of infections or inflammation. Linear enamel hypoplasia (LEH) was also observed in a number of the teeth, a sign of arrested tooth growth linked to periods of severe stress or malnutrition.
What the researchers found was particularly troubling: anemia, which was widespread in prehistoric Peru and continues to affect modern populations, appeared to be endemic in these children. The presence of anemia, coupled with other stressors like infection and malnutrition, may have contributed significantly to the high infant mortality rates observed at the QCC. Pezo-Lanfranco offered an insightful interpretation of these findings, explaining that those individuals who survived into adulthood typically exhibited fewer signs of anemia or had healed lesions. However, those who survived past early childhood—around 3.5 years, as estimated by LEH—tended to show less evidence of these chronic conditions.
The study revealed some alarming statistics: around 85% of the bones from individuals below eight years of age exhibited periosteal reactions, and nearly half of the children who survived into childhood (up to the age of 25) had signs of linear enamel hypoplasia. These findings indicated that these children were exposed to chronic and severe inflammatory conditions, anemia, and stress—factors that likely contributed to the high levels of mortality observed in the cemetery.
Pezo-Lanfranco pointed to several factors that likely contributed to these health issues, including malnutrition, poor sanitation, and high population density. During the period in question, communities were already under significant stress, likely exacerbated by inter-community conflicts. The migration of people to clustered settlements with limited resources would have placed enormous strain on families, especially those with young children. Malnourished children, in particular, would have been more vulnerable to infections and disease, especially in the absence of proper sanitation. Pezo-Lanfranco further speculated that the environmental conditions at the time, including the unpredictable water flow of the Supe River, may have contributed to the deteriorating health conditions. The river’s irregular flow could have led to contaminated water supplies, which would have been a breeding ground for gastrointestinal parasites and waterborne diseases. Previous studies had already detected parasites in the area linked to crop irrigation using contaminated water, suggesting that these children were exposed to diseases such as diarrhea, which could prove fatal if untreated.
Pezo-Lanfranco and his colleagues also hypothesized that environmental factors such as those associated with the El Niño-Southern Oscillation (ENSO) could have played a role in exacerbating these conditions. ENSO events can lead to floods, landslides, and disruptions in the availability of water and food resources, which in turn may have led to population migrations to areas where resources were more accessible. Such disruptions would have intensified the existing health vulnerabilities in already strained communities.
Although the QCC study provided significant insights into the health and mortality patterns of children in this region, Pezo-Lanfranco emphasized that many questions remain unanswered. One key issue the team is seeking to address is whether the health conditions observed at QCC were unique to this site and its transitional period, or if similar patterns can be observed across the broader Andean region throughout time. Did these high childhood mortality rates and health conditions emerge as early as during the flourishing of the Caral Civilization (3000–1800 BCE), a contemporaneous culture in the Supe Valley? Or did they occur later, during the rise of the Chavín cult, which dominated the Middle Formative Period?
Pezo-Lanfranco and his team are also interested in whether these health issues were specific to marginalized or rural populations like those at QCC or if they affected the elites and urban centers as well, particularly during the early stages of Andean civilization. This would help paint a more complete picture of the socio-economic disparities in health and mortality during the Formative Period.
While the study provides valuable new insights into child health during the Formative Period of the Central Andes, it also raises important questions about the broader patterns of health and social inequality across Andean cultures. With continued research, Pezo-Lanfranco hopes to expand on these findings, contributing to a deeper understanding of the factors that shaped the lives and deaths of children in prehistoric Peru and shedding light on the broader social and environmental conditions that influenced health outcomes in ancient populations.
More information: Luis Pezo‐Lanfranco et al, Preadult Living Conditions During Sociopolitical Transition in Quebrada Chupacigarro Cemetery (500–400 bc), Supe Valley, Peru: Childhood Morbidity and Sociopolitical Change in Prehistoric Central Andes, International Journal of Osteoarchaeology (2025). DOI: 10.1002/oa.3386