Prospective, longitudinal assessment is critical as cross-sectional studies lack the ability to infer the direction of the relationship between food insecurity and type 2 diabetes. For example, the 'health selection' hypothesis has been studied, positing that a decline in health status may precede and ultimately cause downward social mobility and a decrease in income leading to food insecurity. Consequently, this theory presents evidence for reverse causation, by which poor health may precede financial difficulties, especially in cases where early age of diagnosis, and thus longer duration of disease, might predispose individuals to being in a food insecure household.