The role of sleep in ethnic inequalities in health: Cardiovascular disease and risk factors

Background: Cardiovascular disease (CVD) is the leading cause of death. The prevalence is higher among ethnic minority groups compared to host population in high income countries. Efforts to reduce increased prevalence of CVD by focusing on conventional CVD risk factors have not yielded much expected results. This thesis focused on sleep as a novelty modifiable CVD risk factor and investigates the role of sleep in ethnic inequalities in health specifically on CVD and risk factors. Objectives: To assess inequalities in sleep duration in the Netherlands between ethnic groups in both adults and preschool children, and to explore possible factors that explain these inequalities. Methods: Healthy Life in an Urban Setting (HELIUS) (2011-2015) study and Amsterdam Born Children and their Development (ABCD) (2003-2008) study were used for this thesis. Results: Prevalence of short sleep was higher in all ethnic minority groups than in Dutch in both adult and preschoolers. Short sleep was associated with obesity and diabetes, but the association with hypertension and dyslipidaemia was inconsistent across ethnic groups. Short sleep was associated with CVD and contributed 10-15% to ethnic differences in CVD. Conclusion: Ethnic minority groups sleep shorter than native Dutch. Short sleep was associated with CVD and risk factors, and accounted significantly for ethnic inequalities in CVD. This suggests that sleep may be a new modifiable risk factor of CVD and could play a significant role in reducing ethnic inequalities in health.