[Thesis defense] Amalia Martinez
On November 12th, 2025, Amalia Martinez defended her thesis in public health :
‘Influence of sex and gender on colorectal cancer: incidence as a starting point for health inequalities’
Her thesis was co-directed by Sébastien Lamy and Cyrille Delpierre.
Jury:
- Guy Launoy, professeur des universités et praticien hospitalier, Université de Caen Normandie (président)
- Carole Clair, professeure, Université de Lausanne (rapporteur)
- Bernard Rachet, professeur, London school of hygiene & tropical medicine (rapporteur)
- Agnès Dumas, chargée de recherche, Inserm PACA et Corse (examinateur)
- Come Lepage, professeur des universités et praticien hospitalier, Université Bourgogne Europe (examinateur)
- Cyrille Delpierre, directeur de recherche, Inserm Occitanie Pyrénées (co-directeur de thèse)
- Sébastien Lamy, chercheur, IUCT oncopole (directeur de thèse)
Abstract:
Gender inequalities in health represent a major public health issue, influencing health behaviors and the natural history of diseases. These disparities result from complex mechanisms, partly shaped by social and structural determinants. Gender, understood as a normative system assigning roles and status based on sex assigned at birth, structures these dynamics and contributes to the observed differences between men and women in relation to disease.
Colorectal cancer (CRC), one of the most common cancers and a leading cause of mortality worldwide, clearly illustrates these issues. Although its incidence is generally higher in men, the magnitude of this gap varies according to geographical and socio-economic contexts. While numerous studies have highlighted differences in survival and management between the sexes, few have explored the influence of gender on incidence. Our scoping review confirms this gap: most studies conflate sex and gender, making it difficult to analyze the underlying mechanisms.
This thesis adopts a social epidemiology approach aimed at integrating the structural dimensions of gender. The main objective is to examine the extent to which gender mechanisms influence CRC incidence rates at different scales. The central hypothesis is that colorectal cancer is not intrinsically linked to sex assigned at birth, and that the observed differences in incidence between men and women are primarily the result of social and structural determinants related to gender.
To address this, the research is based on two complementary components: (1) an international comparative analysis between the Gender Inequality Index (GII), GDP per capita, and the CRC sex ratio; and (2) a national study analyzing gender mechanisms in the occurrence of CRC. By combining quantitative analyses with critical reflection on gender concepts in epidemiology, this thesis aims to renew the approach to inequalities in oncology. This work provides an essential framework for analyzing observed inequalities in the incidence of certain diseases, such as colorectal cancer, by examining not only living conditions but also the social mechanisms—such as gender—that structure exposure to risk.