Despite national initiatives to address health disparities, African Americans (AAs) suffer higher rates of cardiovascular disease (CVD), especially stroke, than European Americans (EAs). The Jackson Heart Study (JHS) was established in 2000 with the aim of generating data that would support public health recommendations for reducing CVD disparities in AAs. This landmark study has reported a higher prevalence of diabetes and uncontrolled hypertension in this entirely AA cohort compared to other U.S. mostly EA cohorts. Increased risk factor prevalence is not explained by obesity or other traditional risk factors, suggesting a potential role for additional unmeasured factors in influencing adverse cardio- metabolic outcomes. Although JHS has comprehensively assessed a wide variety of CVD risk factors, a notable gap has been the absences of objective assessment of sleep disordered breathing (SDB) and sleep patterns. The importance of rectifying this gap is underscored by recent research from predominantly EA samples that have demonstrated that SDB and insufficient sleep each are associated with increased incidence of coronary heart disease, diabetes, and stroke. Our preliminary data also indicate that SDB may be more prevalent in the entirely AA JHS cohort than in predominantly white cohorts. Our long-range goal is to ameliorate CVD disparities by identifying ethnicity-specific modifiable risk factors. The proposed study will examine relationships among SDB, insufficient sleep, obesity, psycho- socio-cultural variables, and CVD risk factors in 1,200 members of the JHS cohort. Sleep apnea and sleep patterns will be objectively assessed using low burden but reliable in-home sleep apnea monitoring and wrist actigraphy. To assess intermediate measurements of CVD, particularly related to stroke and diabetes, intimal media thickness (IMT), blood pressure, and biochemical indices of glucose control and inflammation will be obtained using rigorous protocols. These data will be used to achieve three specific aims: (1) Identify risk factors for SDB and insufficient sleep in AAs, including novel measurements of major and minor stress and negative emotions relevant to minority populations;(2) Elucidate relationships between SDB severity, insufficient sleep, and risk for uncontrolled hypertension, stroke and diabetes;and (3) Quantify the extent to which SDB may statistically mediate relationships between obesity and traditional CVD risk factors. Our study will identify the role of sleep disorders as novel modifiabe risk factors for CVD in AAs, provide a basis for promoting better screening for SDB, and enhance scientific understanding of how disparities in stroke and intermediate CVD outcomes such as diabetes, hypertension, and dyslipidemia are impacted by sleep disorders. Finally, the results of our study will serve as the foundation for prospective analyses linking SDB to incident CVD events, morbidity, and mortality in AAs.
The proposed study will help us better understand how sleep disorders and too little sleep contribute to the risk for stroke, diabetes, and cardiovascular disease in African Americans. The data gathered by this study will help researchers develop future targeted health interventions to reduce the public health burden of cardiovascular disease and racial disparities in diabetes, hypertension and stroke.