Effects of gender and socio-environmental factors on health-care access in oncology: a comprehensive, nationwide study in France

Background: Gender-based disparities in health-care are common and can affect access to care. We aimed to investigate the impact of gender and socio-environmental indicators on health-care access in oncology in France. Methods: Using the national health insurance system database in France, we identified patients (aged ≥18 years) who were diagnosed with solid invasive cancers between the 1st of January 2018 and the 31st of December 2019. We ensured that only incident cases were identified by excluding patients with an existing cancer diagnosis in 2016 and 2017; skin cancers other than melanoma were also excluded. We extracted 71 socio-environmental variables related to patients' living environment and divided these into eight categories: inaccessibility to public transport, economic deprivation, unemployment, gender-related wage disparities, social isolation, educational barriers, familial hardship, and insecurity. We employed a mixed linear regression model to assess the influence of age, comorbidities, and all eight socio-environmental indices on health-care access, while evaluating the interaction with gender. Health-care access was measured using absolute and relative cancer care expertise indexes. Findings: In total, 594,372 patients were included: 290,658 (49%) women and 303,714 (51%) men. With the exception of unemployment, all socio-environmental indices, age, and comorbidities were inversely correlated with health-care access. However, notable interactions with gender were observed, with a stronger association between socio-environmental factors and health-care access in women than in men. In particular, inaccessibility to public transport (coefficient for absolute cancer care expertise index = −1.10 [−1.22, −0.99], p