Does physical activity and BMI mediate the association between DCD and internalizing problems in early childhood? A partial test of the Environmental Stress Hypothesis

BACKGROUND AND PURPOSE: Young children with Developmental Coordination Disorder (DCD) are more likely to experience internalizing problems, such as depression and anxiety, than typically developing (TD) children. Currently, the underlying mechanisms resulting in increased internalizing problems in DCD remains unknown; however, a previous study based on the Environmental Stress Hypothesis (ESH) indicated that physical inactivity and obesity may mediate the relationship between DCD and internalizing problems. The purpose of this study is to investigate the relationships among DCD, internalizing problems, physical activity, and BMI, and the role of sex in these relationships in preschool children, a population for which we currently have very limited data. METHODS: Young children between the ages of 4 and 5 years enrolled in the Coordination and Activity Tracking in CHildren (CATCH) study comprised the sample (n = 589). Of these, 288 (193 boys, 67.0%) were classified as at risk for DCD (rDCD), based on scoring at or below 16th percentile on the Movement Assessment Battery for Children - Second Edition. Physical activity was measured using accelerometers and height and weight were measured by trained research assistants, while parents completed the Child Behavior Checklist to rate internalizing problems. The mediating effects of physical activity and BMI were tested on the relationship between rDCD and internalizing problems. RESULTS: Children with rDCD reported more internalizing problems than TD children. While there was a direct effect of rDCD on internalizing problems, neither physical activity nor BMI were found to mediate this relationship. CONCLUSION: The findings from this study support co-occurring internalizing problems in preschool children with DCD, and extend these findings to demonstrate that this relationship is not explained by physical activity or BMI in early childhood. Further research should be directed toward other psychosocial factors identified in the ESH to better understand the underlying mechanisms between DCD and co-occurring internalizing problems.