Chronic Health Condition Trajectories and Multimorbidity in Older Adults With Intellectual Disability: A Brief Report of 15 years of Longitudinal Evidence From IDS‐TILDA

BACKGROUND: Adults with intellectual disability experience significant health issues that increase with age. Longitudinal analyses offer important evidence on how the trajectories of these conditions' develop and change. METHODS: Data were drawn from five waves of IDS-TILDA, with a nationally representative sample of over 700 adults with intellectual disability aged 40 and over in Ireland from 2009 to 2023. Twelve chronic conditions and multimorbidity (≥ 2 chronic conditions) were explored. Generalised linear mixed models assessed associations with demographic and clinical characteristics. RESULTS: Three in four ageing adults with intellectual disability were multimorbid. Those aged 65 + had sevenfold higher odds of multimorbidity than those under 50. Gastrointestinal, mental health and neurological conditions were the most common conditions, affecting 41.65%, 41.31% and 29.40% of the cohort, respectively. Women, those with more severe intellectual disability and those living in residential care were particularly at risk of having more health conditions while those with Down syndrome had increased risks of eye, endocrine and heart disease. CONCLUSION: As people with intellectual disability age, the trajectory and burden of disease increase in tandem. Longitudinal evidence from this study points to the urgent need for earlier prevention and upstream action to reduce the widening inequality gap with the general population.