Ecosocial theory, first proposed by name in 1994 by Nancy Krieger of the Harvard T.H. Chan School of Public Health, is a broad and complex theory with the purpose of describing and explaining causal relationships in disease distribution. While it incorporates biological and psychosocial influences on disease occurrence, the theory is also suited to analyze the relationships between social factors and disease development in public health research. The core constructs of Ecosocial Theory are: Embodiment; Pathways to Embodiment; the cumulative interplay between exposure, resistance, and susceptibility; and agency and accountability. Further, the theory specifies that all constructs must be considered in concert, as they work together in a synergistic explanation of disease distribution. The t