Introduction: Short and long sleep durations are associated with incident stroke. Few studies have investigated these associations by race despite prevalent inequities in stroke between non-Hispanic black and white adults. The aim of this study was to investigate the relationship between sleep duration and incident stroke in a US cohort of blacks and whites.
Methods: Within the REasons for Geographic And Racial Differences in Stroke study, 15,941 black and white adults (≥45yrs) with no history of stroke or sleep apnea were studied. Participants self-reported their habitual sleep duration. Suspected stroke events were identified every 6 months, and associated medical records were retrieved and physician adjudicated. Proportional hazards analysis was used to estimate hazard ratios for incident stroke associated with sleep duration (<6, 6.0-6.9, 7.0-7.9, 8.0-8.9[reference group], 9+hrs) controlling for sociodemographics, stroke risk factors, and depressive symptoms.
Results: At baseline, 11.2% of the sample was very short sleepers (<6hrs) and 6.7% were long sleepers (9+hrs). Over an average follow-up of 4.7 ± 1.4 years, 321 stroke events occurred (blacks=114; whites=207). After adjustment, shorter sleep duration was associated with increased risk for incident stroke (6.0-6.9hr: OR=1.41, 95%CI 1.02-1.94; 7.0-7.9hr: OR=1.36, 95%CI 1.01-1.83). The interaction between sleep duration and race was significant (p=0.02). In stratified analyses, shorter sleep duration was associated with increased risk for stroke in whites but not blacks (see table).
Discussion: Among middle-aged to older, white adults with no history of stroke or sleep apnea, shorter sleep duration was associated with increased risk for stroke. There was no association among blacks. Resilience to insufficient sleep as a risk factor for stroke may differ for blacks and whites.
Adjusted for age, sex, education, income, depressive symptoms, hypertension, diabetes, atrial fibrillation, left ventricular hypertrophy, heart disease, and smoking status