Self-reported sleep duration in relation to incident stroke symptoms: Nuances by body mass and race from the REGARDS study

Background To determine, among employed persons with low risk for obstructive sleep apnea (OSA), if sleep duration is associated with incident stroke symptoms, independent of body mass index (BMI), and if sleep duration mediates racial differences in stroke symptoms. Methods In 2008, 5666 employed participants (US blacks and whites, ≥45 years) from the longitudinal and nationally representative Reasons for Geographic And Racial Differences in Stroke study self-reported their average sleep duration. Participants had no history of stroke, transient ischemic attack, or stroke symptoms and were at low risk for OSA. After the sleep assessment, self-reported stroke symptoms were collected at 6-month intervals, up to 3 years (M = 751 days). Interval-censored, parametric survival models were conducted to estimate hazard ratios predicting time from sleep duration measurement (<6, 6-6.9, 7-7.9 [reference], 8-8.9, ≥9 hours) to first stroke symptom. Adjusted models included demographics, stroke risk factors, psychological symptoms, health behaviors, and diet. Results During follow-up, 224 participants reported 1 or more stroke symptoms. In the unadjusted model, short sleep (<6 hours) significantly predicted increased risk of stroke symptoms but not in adjusted models. Stratification by BMI revealed a significant association between short sleep duration and stroke symptoms only for normal BMI persons in unadjusted (hazard ratio: 2.93, 95% confidence interval: 1.38-6.22) and fully adjusted models (hazard ratio: 4.19, 95% confidence interval: 1.62-10.84). The mediating effect of sleep duration on the relationship between race and stroke symptoms was borderline significant in normal weight participants. Conclusions Among middle-aged to older employed individuals of normal weight and low risk of OSA, self-reported short sleep duration is prospectively associated with increased risk of stroke symptoms.