Descriptive epidemiology of objectively-measured, free-living sleep parameters in a rural African setting.

Females had more nocturnal sleep than males (7.2 vs. 6.8 h/night, p = 0.0464) while males recorded more diurnal sleep time (p = 0.0290). Wake after sleep onset and number of awakenings were higher in females, and sleep efficiency was higher in males (p ≤ 0.0225). Sleep indices were generally similar between weekdays and weekends, except for sleep fragmentation index (p = 0.0458). Sleep quantity, but not sleep quality was independently and inversely associated with adiposity (p = 0.0453). Physical activity and morbidity measures were significantly and consistently associated with sleep and adiposity measures (p < 0.0458). The preliminary qualitative data suggests that future studies should include more detailed data around contextual issues of sleep (social, cultural, economic, environment).