Investigation of early life factors associated with physical activity and screen-time of young children

Children's physical activity and screen-time are important risk factors associated with the early onset of childhood overweight and obesity. However, it is not clear what early life factors are associated with physical activity and screen-time of children aged 2 to 5 years. Studies that have examined correlates of physical activity and screen-time in preschool children were mainly cross-sectional design with mixed findings. To address this knowledge gap this thesis will investigate early life factors associated with physical activity and screen-time among children aged 2-5 years uning longitudinal data from the Healthy Beginnings Trial funded by NHMRC 393112 (Phase 1: 2007-2010) and NHMRC 1003780 (Phase 2: 2011-2014). The trial was an international first, home-based randomised controlled trial to determine whether a home-based early intervention program is effective in improving infant feeding practices and physical activity, decreasing sedentary behaviours especially screen-time (i.e., TV, computer), enhancing parent-child interaction, and hence reducing overweight and obesity among children at 2 and 5 years of age. A total of 667 first-time mothers at 24-34 weeks of gestation were recruited to the trial from antenatal clinics at Liverpool and Campbelltown Hospitals, located in south-western Sydney, Australia. Participating mothers were randomly allocated to intervention and control groups. The intervention comprised eight home visits over child's first two years of life. The participanting mothers and their children allocated to the control group received usual care (i.e. current standard practice is one home visit within a month of birth pls possible baby clinic visits) plus home safety promotion materials. Longitudinal data on mothers and children were collected at baseline (30-36 weeks of pregnancy) and when the children were aged 6 months, 1, 2, 3.5, and 5 years. The data included family demographics, BMI, self-reported outdoor play time (a proxy of physical activity time) and screen-time, as well as general information regarding social support, family functioning, parenting style, parent-child interaction, neighborhood environment, child-care arrangement, and children's sleep time. Secondary data analysis will be conducted. A number of statistical models will be built to determine factors predicting children's physical activity and screen-time. In addition, a systematic review on the associations of parental influences with physical activity and screen time among young children will be conducted. Physical activity and screen-time are modifiable risk factors contributing to childhood overweight and obesity. The research findings will have public health significance and can lead to potential health promotion interventions to be developed in tackling childhood overweight and obesity