Barrett, The Honors College Thesis/Creative Project Collection

This study sought to determine if perceived neighborhood danger impacted children's sleep. The current study asks: how does perceived neighborhood danger impact children’s sleep both quantity and quality (duration and efficiency), could children’s physical activity mediate these associations, and how do genetic and environmental factors play into these relationships? Questionnaires, biological measurements, and actigraphy watch data were collected from 709 8-year-old Arizonan twins and their parents in order to calculate neighborhood safety, sedentary physical activity, moderate to vigorous physical activity, sleep duration, and sleep efficiency as well as covariates. It was concluded that perceived neighborhood danger does not directly impact children’s sleep duration and efficiency, children’s physical activity does not mediate the relation of perceived neighborhood danger and children’s sleep, but rather, perceived neighborhood danger indirectly impacts children’s sleep duration and efficiency through moderate to vigorous activity, and finally, that both sedentary and moderate to vigorous activity are heavily influenced by genetics.

Attention-deficit hyperactivity disorder (ADHD) is a developmental disorder categorized by symptoms of inattention, impulsivity, and/or hyperactivity. The onset of ADHD symptoms begin to appear in childhood, tend to be persistent into adulthood, and are associated with adverse physical and mental health outcomes (Caye et al., 2016; Yoshimasu et al., 2018). The current study examined the effects of health-promoting behavior (i.e., diet and physical activity) on ADHD symptoms in middle childhood. The sample consisted of 670 twins (30.1% monozygotic, 36.5% same-sex dizygotic, 32.3% opposite-sex dizygotic) from the ongoing longitudinal study, the Arizona Twin Project. The twin’s (51% female) diet, physical activity, and ADHD symptoms were assessed at age 8 (M = 8.45, SD = 0.69) and ADHD symptoms were assessed again at age 9 (M = 9.70, SD = 0.92). Mixed model regression analyses revealed that aspects of diet (i.e., protein, carbohydrates, and fiber) at age 8 negatively predicted ADHD symptoms at age 9. Similarly, sedentary behavior at age 8 negatively predicted ADHD symptoms at age 9, whereas moderate-to-vigorous activity at age 8 positively predicted ADHD symptoms at age 9. Univariate twin analyses revealed that certain aspects of diet (i.e., sugar, vegetable, and fruit consumption) were influenced by environmental factors whereas other aspects of diet (i.e., protein, carbohydrates, calories, fat, and fiber consumption) were influenced by both genetic and environmental factors. Both children’s sedentary behavior and moderate-to-vigorous activity were influenced primarily by genetic factors, with the remaining variance being attributed to non-shared environmental factors. Additive genetic influences explained the majority of the variance in ADHD symptoms. Future research should examine bidirectional effects of activity and diet on ADHD symptoms across childhood.