Collaborative Research: Obesity as a Natural Experiment to Investigate Bone Functional Adaptation

Johns Hopkins University, Baltimore MD

Investigators

Abstract

While it is understood that bone is a dynamic, living tissue that responds to changes in the forces applied to it, researchers do not yet have a complete and detailed understanding of this response in humans. This project will compare the skeletons of individuals who were overweight and healthy-weight during life to determine the effects of increased loading and altered walking mechanics on bone microstructure. Results will help clarify the role mechanical force plays in determining bone microstructure and assess the sensitivity of bone to load alteration. Understanding changes in bone microstructure as a function of loading may help anthropologists reconstruct past behaviors from bone form and may also inform clinical understanding of conditions such as osteoporosis and osteoarthritis. Elucidating the relationship between body weight and bone microstructure may also provide forensic anthropologists new insights for identifying decedents from skeletal material. As part of this project, three female graduate students will receive diverse and intense hands-on research training in high-resolution computed tomography, image analysis, and bone microstructure analysis. In addition, the project will foster public science outreach, specifically engaging students traditionally underrepresented in STEM fields. The theoretical basis behind the scientific understanding of bone functional adaptation is that bone tissue that experiences high levels of mechanical strain will adapt by adding bone material, while low strain levels will lead to bone resorption or reduction. The goal of this project is to test bone functional adaptation ("Wolff's Law") in humans using obesity as a natural experiment in load alteration. Results will establish if and how variation in locomotor motion (kinematics) and applied forces (kinetics) associated with obesity manifest in the trabecular structure of the human skeleton. The researchers will collect high-resolution computed tomography image stacks of bones that are part of an extremely well-documented human skeletal collection. Using novel analytical techniques and leveraging well-established image analysis, this project will quantify the patterns of trabecular bone distribution in obese and healthy-weight individuals across the human skeleton. Results will advance knowledge about trabecular bone structure in the human skeleton and its relationship to mechanical loading, produce guidelines for data collection and analysis, and generate data and software for future research. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.