Opportunities for Dementia Prevention: Modifiable Dementia Risk Factors in Ireland

Abstract Background Dementia is preventable and deferrable yet remains a major cause of disability and dependency and the seventh leading cause of death worldwide. The Lancet Commission on dementia published a report in July 2024, identifying 14 modifiable dementia risk factors and estimating a 45% reduction in dementia cases with risk factor elimination. The aim of this study is to assess the prevalence of modifiable dementia risk factors, providing crucial context for the delivery of dementia prevention in Ireland. Methods This is a longitudinal study using data from three waves of the Irish Longitudinal Study on Ageing (TILDA) to quantify the prevalence of modifiable dementia risk factors in Ireland over a 10·93 (±0·37) year follow-up. TILDA is a population-based prospective cohort study, representative of community-dwelling adults aged 50 years and older, living in Ireland. Data were analysed using Stata 15·1 applying inverse probability weighting. Results 8,171, 6,615 and 4,318 participants were included in wave one, three and six analyses. 70·6%, 61·1% and 54·2% of the population had 4 or more modifiable risk factors for dementia at consecutive waves amounting to over 500,000 people with 4 or more modifiable risk factors for dementia on weighted population analysis at wave six.77% of those with severe decline in cognitive performance during follow-up had 4 or more risk factors at baseline. An estimated 32,480 cases of severe decline in cognitive performance during follow-up were potentially preventable if risk factors were eliminated. Conclusion This study identifies a high prevalence of modifiable dementia risk factors in Ireland and highlights the need for public education on the concept of brain health and the development of a clinical framework focused on delivering on the opportunity of dementia prevention. Preventing and delaying dementia onset has the potential to compress morbidity and increase healthy lifespan in older age.