Association between cardiometabolic health and objectively-measured, free-living sleep parameters: a pilot study in a rural African setting

Abstract

Objectives To investigate the relationship between objectively-measured, free-living sleep quantity and quality, and cardiometabolic health, in a rural African setting in 139 adults (≥40 years, female: n = 99, male: n = 40). Wrist-mounted, tri-axial accelerometry data was collected over 9 days. Measures of sleep quantity and quality, and physical activity were extracted from valid minute-by-minute data. Self-reported data included behavioural, health and socio-demographic variables. Biological data included body composition, resting blood pressure and fasting blood glucose, insulin and lipids. Logistic regression models were constructed with insulin resistance (IR) and cardiometabolic (CM) risk, as dependent variables, adjusting for socio-demographic, behavioural and biological factors. Results Nocturnal sleep time was longer in females (p = 0.054) and sleep quality was better in males (p ≤ 0.017). Few participants slept > 9 h/night (4–5%), and 46–50% slept < 7 h/night. IR and CM risk was higher in females (p ≤ 0.006). In adjusted models, sleep variables were independently associated with IR (p < 0.05). Sleep quantity was non-linearly associated with CM risk (p ≤ 0.0398), and linearly associated with IR (p ≤ 0.0444). Sleep quality was linearly related with CM risk and IR (p ≤ 0.0201). In several models, sleep quantity and sleep quality measures were concurrently and significantly associated with IR (p ≤ 0.044).

Impact of objectively-measured sleep duration on cardiometabolic health: A systematic review of recent evidence

“…For example, in a demographic surveillance study done in South Africa using actigraphy sleep measures, it was found that insufficient and fragmented sleep were significantly associated with poor cardiometabolic health outcomes ( 14 ) ( Table 1 ). Another pilot study in a rural setting in South Africa using the same sleep measurements found that objectively measured short sleep duration was significantly associated with HOMA-IR and showed a linear relationship with type-2 diabetes mellitus ( 16 ).…”

“…On the other hand, Cook et al. found a significant non-linear (U-shaped) association between short sleep duration and JIS-MetS risk (p = 0.0308) ( Table 1 ) ( 16 ). The findings of this study are consistent with the study conducted by Rae et al.…”