Sleep and physical activity patterns among Tanzanian, South African, and Côte d’Ivoire primary schoolchildren. Findings from the KaziAfya study
Authors: Lang Christin , Bassirou Bonfoh , Cheryl Walter , Masanja Honorati , Utzinger Jürg , Gerber Markus 
Published: February 2023

Introduction
Sleep and physical activity habits during childhood are influenced by developmental, cultural and environmental factors. Poor sleep is associated with lower immune function, physical activity levels, and psychological functioning, thus contributing to a vicious cycle of increased vulnerability during this developmental period. Regular physical activity, in turn, is associated with better sleep, improved immune function, and higher psychological well-being. There is, however, a lack of research on sleep and physical activity patterns in Sub-Saharan Africa, especially among children from marginalized areas. Therefore, the present study has two objectives: First, it aims to fill a gap in the literature by reporting sleep and physical activity patterns among primary schoolchildren aged 6-12 years from Tanzania (Ifakara: N = 845), South Africa (Gqeberha: N = 1,287), and Côte d’Ivoire (Taabo: N = 1,027). Second, to investigate the relationship between habitual physical activity (7-day actigraphy) and sleep (parental and self-reported).
Methods
Thousand three-hundred and twenty children aged 5-12 years from each country were recruited. Sleep. Parents were asked to complete a few sleep-related questions regarding their child`s bed- and rise times. To assess sleep quality, children completed questions from the Pittsburgh Sleep Quality Index (Buysse et al., 1989). To screen for sleep disturbances, children also answered three items of the Insomnia Severity Index (Morin et al., 2011), addressing difficulty falling asleep, staying asleep and waking up too early in the morning. Physical Activity. Objective physical activity was assessed with an accelerometry (Actigraph wGT3x-BT, Shalimar, FL, USA) worn around the hip. The device was worn for 7 consecutive days to assess a full weekly period, with a sampling epoch of 15 sec (Rowlands, 2007). Time per day spent in MPA (>3 MET [metabolic equivalents of task]) and VPA (>6 MET) is determined based on the raw accelerometry counts and the ActiLife computer software, with cut-off values derived from Freedson et al. (1998). The ActiGraph accelerometrys have been validated with children (Crouter et al., 2013; Hänggi et al., 2013).
Results
Children assessed in Côte d’Ivoire and Tanzania showed higher levels of daily physical activity (MVPA) than those assessed in South Africa. Yet, mean group levels still exceeded the recommended amount of 60 min MVPA/day. Across all three countries, boys generally had higher MVPA levels than their female peers, and children from the poorest wealth quintile were also more active than their peers from the least poor quintile. Composite sleep health was significantly different between countries, with the highest scores reported in Tanzania, followed by Côte d’Ivoire and South Africa. After controlling for sex, it was found that MVPA significantly predicted composite sleep health among children in Tanzania (ß = 5.83, p = .002) and Côte d’Ivoire (ß = 3.41, p = .072), but not in South Africa (ß = 0.67, p > .05).
Discussion/Conclusion
Adequate sleep and physical activity is crucial for children’s physical and mental development. Most of our understanding of the relationship between daily physical activity and sleep patterns is based on research conducted in Western high income countries. Currently, little is known about this association in children from Sub-Saharan African, specifically primary schoolchildren living in marginalized areas in Tanzania, South Africa, and Côte d’Ivoire. Results will reveal whether research from high-income countries is generalizable to low- or middle-income countries, and inform health policy makers on points for prevention and intervention in school-based settings.
References
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