Cancer Diagnosis and Cancer‐Related Mortality in Adults With Intellectual Disability: Evidence From Two Irish Cohort Studies

ABSTRACT Cancer is a major public health concern and is now the leading cause of death in many countries. Despite this, little is known about cancer in underserved groups, particularly adults with intellectual disability. The aim of this study was to explore cancer diagnosis and mortality from cancer in adults with intellectual disability and those who are ageing in the general population, and adults with a physical disability. We analysed five waves of longitudinal data from IDS‐TILDA and TILDA, two Irish longitudinal studies. Two TILDA cohorts (adults aged ≥ 65 years and adults with physical disability) were used as contextual reference points to aid the interpretation of findings. Cancer deaths for those with intellectual disability were identified from death certificates across the study period. Self‐reported cancer prevalence in IDS‐TILDA was 4%–8% across Waves 1–3. This was 15.5%–17.5% in the two TILDA cohorts. Among 241 deaths in IDS‐TILDA, 38 people with intellectual disability had cancer recorded on death certificates although 26 (68%) had never self‐reported cancer. Overall, adults with intellectual disability reported low cancer prevalence and incidence across five waves of longitudinal data. A gap exists in terms of the proportion of cancer deaths among people in this group who never reported having a cancer diagnosis at any point across the wave. While data limitations mean this cannot be interpreted as direct evidence of under‐diagnosis, the finding raises important questions about cancer recognition, reporting and diagnostic pathways for adults with intellectual disability. Overall, the findings suggest that there appears to be systemic gaps in cancer detection, and there is a need for improved policy and diagnostic pathways for this population.