People ageing with Down syndrome are at much higher risk of developing dementia compared to the general population. The Lancet Model of brain health (Livingston et al., 2020) has not yet been tested for its applicability in this population. The aim of this study is to explore the relative influence of identified risk factors on dementia outcomes in a representative sample of an Irish population ageing with Down syndrome. Data gathered from the four waves of IDS-TILDA were used for longitudinal risk modelling. IDS-TILDA is an Irish nationally representative longitudinal study that collects information on a variety of biopsychosocial indicators in people ageing with intellectual disability. Binomial logistic regression analysis was used to investigate the predictive relationship between biopsychosocial risk factors and dementia outcomes over a period of 15 years. Dementia prevalence in the sample of 150 people with Down syndrome increased from 10.7% in Wave 1 to 44% by Wave 4. Longitudinal changes in cognitive functioning are associated with type of living situation and social isolation, with physical inactivity another variable of potential interest. General population risk factors such as hypertension, smoking, frequent alcohol use are not as relevant for this population. Findings from this exploratory modelling provide an initial framework to assess the relative influence of various biopsychosocial indicators on dementia outcomes in people ageing with Down syndrome. Development of an evidence-based framework of risk factors will support targeted interventions to improve the brain health of those with Down syndrome across the life span.

P.59 2.6.5 Alcohol & Smoking Alcohol abuse is recognised as one of the leading influences on morbidity and mortality worldwide, with projections of a continuing increase until 2030 and beyond (Manthey et al., 2019; Shield et al., 2020; Wiegmann et al., 2020). A high level of alcohol consumption appears to increase the risk of dementia (Wiegmann et al., 2020). Brain autopsies of those who have died from alcoholism have shown atrophy and reduced brain volume, mainly white matter loss, with some MRI studies showing increasing loss of cerebral brain volume with increase in alcohol consumption (Wiegmann et al., 2020). High levels of alcohol consumption promote increased inflammatory processes in the central nervous system, increased thiamine deficiency and impact on cardiovascular health (Wiegmann et al., 2020). Alcohol may also reduce the ability of microglial cells to remove beta amyloid depositions in the brain, thereby promoting the progression of AD (Kalinin et al., 2018). Drinking more than 21 units of alcohol per week from middle age is associated with increased dementia risk, related to reduced brain volume (grey matter) (Livingston et al., 2020; Rehm et al., 2019). Excess alcohol consumption in midlife is estimated to increase dementia risk across the lifespan by 1% (Livingston et al., 2020).....