Physical Activity, Sleep, Body Mass Index, and Associated Risk of Behavioral and Emotional Problems in Childhood.

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 = 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 problems 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.