Protecting children's mental health is important and studies have shown that diet and exercise can have a positive impact. There are limited data available, however, from representative populations of children on the relationship between regular healthy lifestyle behaviours and psychological health. Data were obtained from the New South Wales Child Population Health Survey, 2013-2014. Parents were asked about diet, physical activity and screen time behaviours and completed the Strengths and Difficulties Questionnaire (SDQ) for one child aged 5-15. Higher SDQ scores indicate poorer psychological health and risk for mental health problems. Multivariable linear and logistic regression examined the relationships among dietary consumption, physical activity, screen time and SDQ scores, adjusting for potential confounding. Meeting screen time recommendations was most strongly associated with a lower SDQ total difficulties score (5-10 years: -1.56 (-2.68, -0.44); 11-15 years: -2.12 (-3.11, -1.12)). Children and adolescents who met screen time recommendations were also significantly less likely to have any score in the at-risk range. Children and adolescents meeting vegetable intake guidelines had significantly lower total difficulties scores (5-10 years: -1.54 (-3.03, -0.05); 11-15 years: -1.19 (-3.60, -0.39)), as did adolescents meeting discretionary food guidelines (-1.16 (-2.14, -0.18)) and children consuming the recommended fruit intake (-1.26 (-2.42, -0.10)). Our findings indicate that more effective interventions to increase the proportion of young Australians who meet the guidelines for diet and screen time would contribute to protecting their mental health.
Keywords: adolescents; children; diet; mental health; physical activity; psychological factors; screen time.