Factors influencing participation in breast cancer screening in an urban setting A study of organised and individual screening among potentially active and retired women in the city of Nice[Facteurs déterminant la participation au dépistage du cancer du sein Etude du dépistage organisé et du dépistage individuel chez les femmes potentiellement actives et retraitées de la Ville de Nice]

Participation in breast cancer screening in urban settings is poor. Identifying factors accounting for participation and non-participation is essential to target priority areas, tackle health inequalities and suggest innovative approaches. We studied organized and individual participation in breast cancer screening within the 144 aggregated units for statistical information (Ilôts regroupés pour l'information statistique: IRIS) of the city of Nice from 2019 to 2021. The social gradient was assessed in each IRIS unit using a local human development index, among potentially active women aged 50 to 59 years and retired women aged 60 to 74 years. Modelling participation and non-participation in screening according to the IRIS units' socio-economical characteristics was performed using the SURE method (Seemingly Unrelated Regression Equations). Over a 2-year period, 24,396 breast screening tests were conducted, 11,173 as organised screening and 13,223 as individual screening. The social gradient was positively correlated with the two types of screening, respectively. Access to public transport facilitated participation. Managerial status was negatively correlated with organised screening. Single working women had a higher risk of non-participation. With regard to their socio-economic characteristics, screening rates were lower than expected in 16 IRIS units in the city of Nice. Socio-economic gradient, access to public transport, family and professional context appear to be associated with breast cancer screening in an urban setting. An innovative approach targeting these factors is called for to reduce health inequalities.