Downloaded from http://journals.lww.com/jrnldbp by BhDMf5ePHKbH4TTImqenVGkodkJMcUWYi49MWVtR70fYp9bwjkxV32Ai5N2xZ4nqPF4GLk41EQY= on 05/03/2020 Original Article Physical Activity, Sleep, Body Mass Index, and Associated Risk of Behavioral and Emotional Problems in Childhood Rebecca F. Slykerman, PhD,* Christopher Budd, DClinPsyc,† John M. D. Thompson, PhD,‡ Marthinus Bekker, PhD,§ Jude Buckley, PhD,\ Clare Wall, PhD,¶ Rinki Murphy, PhD,** Edwin A. Mitchell, DSc,‡ Karen E. Waldie, PhD\ ABSTRACT: Objective: Cross-sectional data indicate that physical activity, longer sleep duration, and normal body weight are associated with better mental health in childhood. It is less clear whether these factors protect against future emotional and behavioral problems. We investigated whether physical activity, sleep duration, and body mass index (BMI) at the age of 7 years are associated with emotional and behavioral problems at the age of 11 years. Methods: Children born to European mothers enrolled in the prospective longitudinal Auckland Birthweight Collaborative Study (N 5 871) were assessed at birth and ages 7 and 11 years. Physical activity and sleep duration were measured using accelerometer. BMI was calculated from height and weight measurement. Outcome variables assessed at the age of 11 years were parent and child self-report Strengths and Difficulties Questionnaire and parent and teacher Conners’ Rating Scale scores. Results: Physical activity, sleep duration, and BMI at the age of 7 years were not significantly associated with emotional and behavioral problems at the age of 11 years. In cross-sectional analysis at the age of 11 years, there was no significant association between physical activity or sleep duration and emotional and behavioral problems. Children with a BMI in the overweight or obese range were significantly more likely to have teacher-rated behavior problems and parent-rated emotional or behavioral problems after adjustment for potential confounders. Conclusion: Although physical activity and sleep have physical health benefits, they may not be protective against future emotional and behavioral prob- lems in childhood in the general population. BMI in the obese or overweight range was significantly associated with current emotional and behavioral problems at the age of 11 years. (J Dev Behav Pediatr 41:187–194, 2020) Index terms: physical activity, sleep, body mass index, behavior. Behavioral and emotional difficulties during child- hood are common across the world, with 13.4% of young people worldwide estimated to have a mental health disorder. 1 In New Zealand, similar levels were noted, with a recent national survey using the Strengths and Difficulties Questionnaire, a measure of both in- ternalizing and externalizing difficulties, showing that 15% of young people had elevated total difficulty scores. 2 Many emotional and behavioral problems in child- hood have objective, observable behaviors that are often associated with disorders alongside subjective reported symptoms. 3 In children, many of these observable behaviors are related to the level of physical activity or sleep that the young person engages in, as is the case in hyperactivity and depression. 3 Also being related to emotional and behavioral problems, the level of physical activity and sleep duration are often a target of treat- ment 4 or prevention 5,6 strategies (e.g., behavioral acti- vation, behavioral sleep medicine, and sleep hygiene) delivered as part of intervention packages. Given the reported efficacy of these strategies, one assumption might be that healthy levels of activity and sleep may predict better future mental health. Several studies and review articles have reported a significant association between the level of physical activity and quality of life or mental health outcomes in the general population of children and adolescents. 7 However, the majority of these studies are cross- sectional, and a longitudinal prospective study design is needed to establish whether higher activity levels are protective against future emotional and behavioral problems later in childhood. Although longitudinal studies have also previously shown an inverse relation- ship between physical activity and later internalizing and externalizing problems, 8,9 a consistent limitation of many studies is the use of self-report measures of activity. It has From the *Department of Psychological Medicine, University of Auckland, Auckland, New Zealand; †Consult Liaison Team, Starship Children’s Health, Auckland, New Zealand; ‡Department of Paediatrics, Child and Youth Health, University of Auckland, Auckland, New Zealand; §Department of Psychological Medicine, University of Auckland, Auckland, New Zealand; \School of Psy- chology, University of Auckland, Auckland, New Zealand; ¶Department of Nutrition, University of Auckland, Auckland, New Zealand; **Department of Medicine, University of Auckland, Auckland, New Zealand. Received March 2019; accepted September 2019. The initial study was funded by the Health Research Council of New Zealand. The 11-year follow-up was funded by Cure Kids, New Zealand, and the National Heart Foundation. E. A. Mitchell and J. M. D. Thompson were supported by Cure Kids, New Zealand. Disclosure: The authors declare no conflicts of interest. Address for reprints: Rebecca F. Slykerman, PhD, Department of Psychological Medicine, University of Auckland, Private Bag 92019, Auckland 1142, New Zea- land; e-mail: r.slykerman@auckland.ac.nz. Copyright Ó 2020 Wolters Kluwer Health, Inc. All rights reserved. Vol. 41, No. 3, April 2020 www.jdbp.org | 187 Copyright © 2020 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.