Statistical methods for bioarchaeology: applications of age-adjustment and logistic regression to comparisons of skeletal populations with differing age-structures

Previous studies of patterns of osteoarthritis involvement in prehistoric skeletal populations have been used to suggest differences in lifestyle or subsistence patterns. In spite of the intriguing nature of such studies, inadequate controls for the potential confounding effects of age have made results less secure than they appear. While researchers remain unable to control for the inherent limitations imposed by preservation bias, meaningful advancement could be made in the analysis of these data. Here we propose two methods from epidemiology that would allow more robust comparisons between populations with differing age-structures: age-adjustment and logistic regression. We apply these two methods to previously published data from prehistoric populations of the American Great Basin. In doing so, we are able to discern sex differences in risk for osteoarthritis at the shoulder (beta = −1.82, SE = 0.74, OR = 0.16, 95% CI = 0.04–0.69, p = 0.013), elbow (beta = −2.07, SE = 0.82, OR = 0.13, 95% CI = 0.03–0.63, p = 0.011), and in the foot (beta = −3.11, SE = 1.57, OR = 0.04, 95% CI = 0.00–0.97, p = 0.048), that were not noted in previous analyses of these data. These findings suggest that greater clarity of results and more precise comparisons of risk may be achieved by using these methods. We conclude that further application of these methods to bioarchaeological studies would potentially improve what can be said about prehistoric health patterns and lifeways.     

The US Government’s Role in Deepwater Archaeology: The Deep Gulf Wrecks Project

The deepwater part of the Gulf of Mexico has shown a remarkable increase in oil and gas exploration, development, and production. In part, this is because of the development of new technologies reducing operational costs and risks, as well as the finding of reservoirs with high-production wells. With expanding development in deep water come increasing challenges in managing our nation’s Submerged Cultural Heritage on the Outer Continental Shelf and Slope. To fulfill obligations under Section 106 of the Historic Preservation Act of 1966 (36 CFR 800), managers need a clearer understanding of the size of debris fields expected around deepwater shipwrecks, as well as their state of preservation and future research potential—both cultural and biological. With this in mind, the Minerals Management Service, in partnership with the National Oceanographic Partnership Program and the National Oceanographic and Atmospheric Administration’s Office of Ocean Explorations, launched the Deep Gulf Wrecks Project.