Aetiology of dementia and depression:untangling the role of biomarkers and sociodemographic factors

Dementia and depression are major causes of disability with diverse underlying disease pathologies. Therefore, this thesis investigated sociodemographic and biological factors that potentially contribute to the development of depression and cognitive impairment in dementia. In part I of this thesis, the relationship between social network characteristics or blood glucose levels and depression was explored. In part II, the influence of sociodemographic factors on test performance on the semantic fluency test, a widely used test to measure cognitive impairment, was investigated. In part III, links between biomarkers of damage to the small blood vessels and biomarkers related to Alzheimer’s disease with MRI-based brain imaging outcomes and cognition were explored. In the final chapter, this thesis discusses the main findings and talks about how to determine causality in cohort studies. It also suggests areas for further research.