Cognitive Impairment and Dementia in Older Australians: Risk Factors and Adverse Health Outcomes

Cognitive Impairment and Dementia in Older Australians: Risk Factors and Adverse Health Outcomes

Dementia is a progressive neurodegenerative disorder characterised by a sustained decline in memory, thinking, and functional abilities, severely impacting daily life. It is often preceded by a prolonged preclinical phase, potentially spanning up to two decades, during which cognitive impairment may emerge. Cognitive impairment refers to a measurable decline in cognitive function that does not yet meet the diagnostic criteria for dementia. These conditions not only reduce the quality of life for affected individuals but also impose considerable emotional and financial burdens on families and society. Despite rising awareness, the existing literature lacks comprehensive exploration of the multifaceted risk factors and adverse health outcomes associated with dementia and cognitive impairment. This thesis addresses these gaps by investigating three critical aspects: (i) the prevalence and risk factors of dementia; (ii) the adverse health outcomes, including self-care limitations, various health outcomes, and socio-economic inequalities in health-related quality of life (HRQoL); and (iii) potential pathways for improving the HRQoL of people living with cognitive impairment. The thesis is divided into three themes comprising six chapters. Utilising data from two sources—the Survey of Disability, Ageing, and Carers (SDAC) and the Household, Income and Labour Dynamics in Australia (HILDA) survey—this research applies various econometric methods, including multivariable logistic regression, pooled ordinary least squares (OLS), pooled ordered logit, random effects models, generalised estimating equations, and the Wagstaff-Doorslaer-Watanabe standard concentration index to assess the relationships rigorously. Key findings reveal that older adults in major cities had higher odds of dementia than those in regional and remote areas, and that chronic pain significantly increased the odds of developing dementia. Furthermore, the co-occurrence of dementia and chronic pain demonstrated a synergistic negative impact on self-care abilities. The analysis of health-related quality of life (HRQoL) indicated significant pro-rich inequalities, and cognitive impairment was associated with lower self-assessed health and health satisfaction. Importantly, engaging in physical activity 1-3 times weekly was linked to significant improvements in physical and mental health components, as well as overall health utility, among individuals with cognitive impairment. This research offers vital evidence to inform Australian policymakers and guide the development of more effective health interventions to reduce the impact of dementia and enhance health outcomes for those living with cognitive impairment.

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