Romain Debru

Composition of the Jury

Abstract

France remains one of the European countries with the most pronounced social inequalities in health. In other words, people who are disadvantaged based on socioeconomic criteria (i.e., income, socioeconomic status, and educational attainment) are in poorer health than more affluent individuals. Among the mechanisms that may explain these inequalities are the health behaviors that individuals adopt. Regular physical activity—particularly during leisure time—coupled with limited sedentary time, are major determinants of health. However, disadvantaged adults may have activity patterns that deviate from this ideal, exposing them to adverse health effects. Consequently, addressing these behaviors in these populations represents a major public health challenge. The results of studies that have attempted to modify these behaviors among disadvantaged populations show only a slight increase in physical activity levels and a limited reduction in sedentary behaviors. In fact, the specific characteristics of these populations are not sufficiently taken into account prior to interventions. Furthermore, since these behaviors are driven by both individual and environmental factors, an ecological approach is needed to understand them. This doctoral research is structured around two main questions: 1) How do the interactions between environmental and individual factors shape physical activity and sedentary behaviors among disadvantaged populations? and 2) What levers can be mobilized to modify these physical activity and sedentary behaviors among disadvantaged populations? To answer these questions, we adopt an iterative approach that follows the key stages of the social marketing framework. In this context, we have demonstrated through a systematic literature review (Study No. 2) that adopting the principles of social marketing can be a promising avenue for changing the targeted behaviors among disadvantaged populations. Regarding the understanding of physical activity and sedentary behavior, in Essay No. 1 we demonstrate the importance of employing a theoretical framework that integrates the socio-ecological model and self-determination theory to “capture” the individual and environmental factors underlying the targeted behaviors. The results of the semi-structured interviews from our Study No. 3 highlight several contexts of practice that, under certain conditions, can trigger a compensatory process in individuals. This compensation takes the form of a reduction in the behavior in question (physical activity or sedentary behavior). Our final experiment (Experiment No. 4) shows that the environment—and in particular, the imposed nature of a behavior—can frustrate an individual’s fundamental psychological needs and trigger this compensatory process. Through an experiment, we test the effect of a communication strategy aimed at reducing frustration of fundamental psychological needs on the reduction of sedentary behaviors. This doctoral research proposes avenues for, first, better understanding physical activity and sedentary behaviors, and second, modifying these behaviors among disadvantaged populations. Despite the major public health challenge these populations represent, they remain difficult to reach and are underrepresented in research. Social marketing researchers must address this issue and implement campaigns tailored to these populations with the aim of reducing social inequalities in health.