Movement behaviours in Swedish 3-9-year-olds : prevalence, associations with health markers, and promotion of healthy behaviours

Background Movement behaviours are comprised of physical activity, sedentary behaviour, and sleep and are important for children's physical health. The World Health Organization (WHO) 24-hour movement guidelines integrate these behaviours into three recommendations, recognising their interdependence within the 24-hour day. However, research on the prevalence of Swedish children adhering to these guidelines is limited. Understanding how movement behaviours relate to health markers in children, and how these behaviours can be supported early on, is important for promoting long-term health. In Sweden, nearly all children attend preschool, making it a key arena for health promotion, but limited research has explored how preschools can support healthy movement behaviours. Aim The overall aim of this thesis was to investigate movement behaviours in Swedish children aged 3-9 years, in terms of adherence to movement guidelines and associations with health markers. Another aim was to explore preschool teachers' and principals' perspectives on promoting healthy lifestyle behaviours in the preschool setting, as well as their preferences for digital support. Methods Paper I: A cross-sectional study in 631 children 3-6 years of age from the Swedish arm of the International Study of Movement Behaviours in the Early Years (SUNRISE). Waist-worn accelerometers were used to measure physical activity and sedentary behaviour, whereas sleep and screen time were assessed through questionnaires. The prevalence of children adhering to the WHO 24-hour movement guidelines together and separately were investigated. Also, associations between reallocating time to either vigorous physical activity (VPA), moderate-to-vigorous physical activity (MVPA), or sedentary behaviour, at the expense of the remaining movement behaviours, with measures of physical fitness, anthropometry, and blood pressure were analysed using compositional data analysis. Paper II: A cross-sectional study in 411 children from Studies of Prospective Health Determinants in Infancy and Childhood (SPINACH) aged 9 years, investigating associations between sleep patterns, based on sleep duration and bedtime, and cardiometabolic risk factors. Sleep duration and bedtime were assessed with wrist-worn accelerometers and cardiometabolic risk factors included blood lipids, glucose, insulin, homeostatic model assessment of insulin resistance (HOMA-IR), a metabolic syndrome score, waist circumference, and blood pressure. Children were categorised into four groups depending on if they adhered to the sleep recommendation or not and if they had an early or late bedtime, based on the median bedtime of the population. Associations between sleep patterns and cardiometabolic risk factors were investigated using analysis of covariance. Paper III: A cross-sectional and longitudinal study in 411 children from SPINACH at 4 and 9 years of age. Movement behaviours were assessed with wrist-worn accelerometers and screen time with questionnaires. Cardiometabolic risk factors included the same measures as in Paper II. Longitudinal associations of increasing sedentary time (at the expense of the remaining movement behaviours) at 4 years of age with cardiometabolic risk factors at 9 years of age were examined, as well cross-sectional associations at 9 years of age, using compositional data analysis. Associations between adherence to the screen time recommendation and cardiometabolic risk factors were also examined. Paper IV: Semi-structured interviews were conducted in 15 preschool teachers and principals. Content analysis was employed to explore perceptions, needs, and prerequisites for promoting healthy lifestyle behaviours in the preschool setting, as well as preferences for potential digital support. Results Paper I: Most children met the WHO guidelines for physical activity (95%) and sleep (94%), while fewer met the screen time recommendation (44%). Only 40% adhered to all three guidelines. Increasing VPA or MVPA while evenly reducing the remaining behaviours were associated with a stronger handgrip (both P