Abstract

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. 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. 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. 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.