Age-Specific Diagnostic Panorama Among People With Intellectual Disabilities in Comparison With the General Population: A Longitudinal Register Study (IDcare).

BackgroundPeople with intellectual disabilities (ID) are known to have a higher risk for a wide range of health conditions compared to the general population. However, there is little research comparing a more comprehensive range of diseases and conditions at different ages. Therefore, the aim of this study was to explore the overall age-specific diagnostic pattern among people with ID compared to the general population.MethodOf all people living in Skåne, the southernmost part of Sweden (n = 1 274 727), those with a diagnosis indicating ID (F70-F79 or Q90 according to ICD-10) and/or service and support for people with ID/Autism spectrum disorders (ASD) constituted the ID cohort (n = 14 716). After excluding those in the same family/household as someone in the ID cohort, the remaining people comprised the general population cohort (gPop; n = 1 226 955). The main outcome was diagnoses by body system (i.e., ICD-10 chapters) during 2014-2021. Differences between the cohorts were investigated using Poisson regression, thereby estimating relative risks for the ID cohort vs. the gPop cohort.ResultsFour different diagnostic patterns among people with ID compared to the general population were identified: (1) increased risks with an age-related decline (ICD-10 Chapters III, IV, V, VI, VII, VIII, IX, XI, XII and XIV), (2) increased risk for higher ages but overall similar risks at younger ages (Chapters I and X) and (3) similar or decreased risk across age groups (Chapters II and XIII).ConclusionsFor most body systems, there was an increased risk of diagnosis for people with ID, although in some cases, it declined with age. Although there are some potential explanations for this age-related decline, further investigations are needed to understand the pathways behind this phenomenon. Cancer diagnoses stood out in that a decreased risk was found for the ID cohort. This needs further attention. One reason may be due to lower rates of cancer screening in this group. The need for screening interventions tailored for people with ID has been highlighted for at least two decades, but few seem to have been developed, tested or implemented, which means that such interventions are still urgently warranted.