Effects of Screen Time on Preschool Health and Development
The rapid proliferation of personal technology has provided our children with unprecedented access to screen-based devices for both educational and entertainment purposes. However, international research suggests that the excessive use of screen-based devices in children can increase the likelihood of several adverse health and behavioural outcomes, such as obesity, short attention span, emotional problems, language difficulties, and poor sleep patterns. As a consequence, the Ministry of Health has released guidelines stating that children aged 2-5 years should limit screen time to less than one hour per day, a target that was based largely on overseas evidence. It is therefore essential that the appropriateness of current guidelines for the promotion of healthy development in New Zealand preschoolers is investigated.
This research had three main aims: 1) to investigate the temporal trends in the duration and type of screen usage between 2 years and 4.5 years of age; 2) to examine the cross-sectional associations of screen time; and 3) to determine prospective associations between screen usage at 2 years of age and a range of health and behavioural outcomes at 4.5 years of age. The project utilised data collected in the Growing Up in New Zealand study – a contemporary longitudinal study that comprises data from approximately 6,000 children in the Auckland, Counties Manukau, and Waikato District Health Board regions. All screen time variables were assessed via parent-proxy report, and included television viewing time, electronic media use (eg tablets, smart phones, gaming devices, computers), and screen exposure (ie TV on in the same room as the child); a fourth measure of total screen time was also calculated. The health and behavioural outcome measures included body mass index, perceived body size, motor skills, general health, doctor visits, illnesses, accidents, emotional symptoms, hyperactivity, peer problems, and prosocial behaviour.
Results indicate that the temporal pattern of screen use tended to increase between 24 and 54 months, but varied by screen use type. NZ European ethnicity, lower socioeconomic deprivation, having household screen time rules, and fewer televisions in the household were consistently associated with meeting the screen time guidelines at each time point. Interestingly, families that had screen time rules but did not always enforce them were more likely to exceed the guidelines compared with having no rules at all. Children that did not adhere to the screen time guidelines at 24 months of age were more likely to be obese, have more illnesses, more visits to the doctor, lower physical motor skills, and exhibit hyperactivity problems at 54 months, which persisted when adjusted for ethnicity, sex, socioeconomic deprivation, and the corresponding health outcome at 24-month baseline. These findings provide insight into contemporary trends in preschooler screen use and longitudinal health and wellbeing in New Zealand, supporting the ongoing implementation of screen time guidelines.