Vertebral Neural Canal Growth and Developmental Stress: A Case Study from the American Southwest

Abstract

This study aims to understand the risk of mortality in relation to vertebral canal growth disruption at the Pueblo Bonito (AD 800-1200, n=47) and Hawikku (AD 1400- 1680, n=102) sites in the pre- and protohistoric American Southwest. The vertebral neural canal encodes information from the intrauterine period until the age of 5 years for midsagittal diameter and adolescence for interpedicular diameter. Maximum midsagittal and interpedicular measurements of the neural canal were collected for all vertebrae. Age was estimated using transition analysis. An ANOVA with a Games-Howell post-hoc test found that reduced neural canal diameter was significantly associated with early adult mortality at Hawikku for several types of vertebrae (P ≤ 0.05). Significant associations with early adult mortality were also found at Pueblo Bonito (P ≤ 0.05). Additionally, survival analysis revealed decreased survivorship for Pueblo Bonito and Hawikku individuals who had smaller vertebral neural canals (P ≤ 0.05). Results from this study support an accumulative stress model in these samples, where disrupted growth in xiii skeletal structures that form over extended periods of ontogeny have the highest mortality signal. In addition, trends in mortality appear contextual. Greater mortality risk in association with VNC growth disruptions is found at Pueblo Bonito compared to Hawikku. This may reflect drought related stressors at Pueblo Bonito and epidemic mortality at Hawikku. These results are consistent with the Developmental Origins of Health and Disease framework which argues that early life stress has a contextual impact on mortality at later stages of the life cycle.