Abstract
BACKGROUND: Risk factors for cardiovascular disease (CVD) and sleep health are well-known to be sex- and race-specific. To build on the established relationship between sleep duration and CVD risk, this cross-sectional study aimed to describe sex-specific associations between CVD risk and other sleep characteristics (sleep quality, sleep timing and sleep onset latency) in low-income adults of African descent. METHODS: Self-reported sleep (Pittsburgh Sleep Quality Index [PSQI], Epworth Sleepiness Scale [ESS], Insomnia Severity Index [ISI]), demographic and lifestyle data were collected in 412 adults (56 % women, 35.0 ± 7.6y, 40 % employed) living in an informal settlement in South Africa. CVD risk was determined using the BMI-modified Framingham 10-year CVD risk formula. RESULTS: Logistic regression analyses, adjusted for employment, alcohol use and physical activity, indicated that men reporting poor sleep quality (OR: 1.95[95 %CI: 1.07-3.51], p=0.025) and earlier bedtimes (0.54[0.39-0.74], p<0.001) were more likely to belong to a higher 10-year CVD risk score quintile. Women reporting earlier bedtimes (0.72[0.55-0.95], p=0.020) and wake-up times (0.30[0.13-0.73], p=0.007), longer sleep-onset latency (1.47[1.43-1.88], p=0.003), shorter total sleep times (0.84[0.72-0.98], p=0.029), higher PSQI global scores (1.93[1.29-2.90], p=0.001) and more moderate to severe symptoms of insomnia (ISI≥15)(3.24[1.04-10.04], p=0.016) were more likely to belong to higher 10-year CVD risk score quintile. CONCLUSION: In addition to sleep duration, we found that sleep quality, sleep timing and sleep onset latency are additional risk factors for CVD in adults of African descent. Sex-specific differences in the sleep-CVD-risk relationship observed suggests that future studies and recommendations about sleep health in relation to CVD should take sex into account.