A multinational exploratory assessment of cancer knowledge among people with intellectual disabilities across European countries

Background People with intellectual disabilities (ID) experience significant health inequalities, including limited access to cancer-related information and poor cancer outcomes. Cancer knowledge is a key determinant of early detection and prevention; however, evidence from European countries remains limited. This study aimed to assess cancer knowledge among people with (ID) across European countries and to examine associated sociodemographic factors. Methods A cross-sectional, multinational exploratory study was conducted between January 2025 and January 2026 across multiple European countries using a collaborative research network. A total of 896 adults with mild-to-moderate (ID) participated in this study. Cancer knowledge was assessed using an adapted, easy-to-read Cancer Awareness Measure covering three domains: warning signs (9 items), risk factors (11 items), and prevention (7 items). Data were analyzed using descriptive statistics, Spearman’s rank correlation, Mann–Whitney U test, Kruskal–Wallis test, and multiple linear regression. Results All three knowledge domains demonstrated good internal consistency (Cronbach’s α = 0.802–0.929). Significant positive correlations were observed among knowledge of warning signs, risk factors, and prevention (ρ = 0.503–0.772, p < 0.001). Female participants had higher warning sign knowledge than male participants ( p = 0.039). Participants living with their families had higher knowledge of warning signs and risk factors, whereas those in nursing homes showed higher prevention knowledge ( p < 0.05). Significant differences were also observed across education, employment, and marital status (all p < 0.001), with higher education consistently associated with better knowledge. Conclusions Cancer knowledge among people with (ID)varies across sociodemographic factors and is strongly interrelated across domains. The findings highlight the influence of structural and social determinants on health literacy in this population group. Targeted, accessible cancer education and inclusive health communication strategies are essential for reducing inequalities and improving cancer prevention across participating European settings.