Sleep, 24-hour activity rhythms, and brain structure: A population-based study

In this thesis, Chapter 2 focuses on sleep, 24-hour activity rhythms and health. Chapter 2.1 describes the influence of demographics, lifestyle and sleep on 24-hour activity rhythms. In Chapter 2.2 sleep and 24-hour activity rhythms are used to predict mortality. This chapter is extended with Chapter 2.2a in which the addition of information on circadian misalignment (the difference between the timing of sleep on workdays and weekend days) was discussed. In Chapter 2.3 I present a study on the differential effects of clinical heart failure and echocardiographic indicators of cardiac dysfunction on sleep quality. Chapter 3 focusses on sleep, 24-hour activity rhythms and structural brain parameters. In Chapter 3.1 I present our research on the relation of cerebral small vessel disease with disturbed 24-hour activity rhythms. In Chapter 3.2 I investigated different aspects of sleep apnea in relation with brain structure. Chapter 3.3 describes the associations between brain structure and sleep parameters, measured both subjectively and objectively with PSG. In Chapter 3.4 differences in brain morphology between insomnia cases and good sleepers were explored. Finally, in Chapter 4 I discuss the main findings of this thesis, together with methodological considerations, clinical implications and suggestions for future research