Objectives and background Social demands of the school-year and summer environment may affect children’s sleep patterns and circadian rhythms during these periods. The current study examined differences in children’s sleep and circadian-related behaviors during the school-year and summer and explored the association between sleep and circadian parameters and change in body mass index (BMI) during these time periods. Methods This was a prospective observational study with 119 children ages 5 to 8 years with three sequential BMI assessments: early school-year (fall), late school-year (spring), and beginning of the following school-year in Houston, Texas, USA. Sleep midpoint, sleep duration, variability of sleep midpoint, physical activity, and light exposure were estimated using wrist-worn accelerometry during the school-year (fall) and summer. To examine the effect of sleep parameters, physical activity level, and light exposure on change in BMI, growth curve modeling was conducted controlling for age, race, sex, and chronotype. Results Children’s sleep midpoint shifted later by an average of 1.5 h during summer compared to the school-year. After controlling for covariates, later sleep midpoints predicted larger increases in BMI during summer, (γ = .0004, p = .03), but not during the school-year. Sleep duration, sleep midpoint variability, physical activity levels, and sedentary behavior were not associated with change in BMI during the school-year or summer. Females tended to increase their BMI at a faster rate during summer compared to males, γ = .06, p = .049. Greater amounts of outdoor light exposure (γ = −.01, p = .02) predicted smaller increases in school-year BMI. Conclusions Obesity prevention interventions may need to target different behaviors depending on whether children are in or out of school. Promotion of outdoor time during the school-year and earlier sleep times during the summer may be effective obesity prevention strategies during these respective times.

This study examined the effects of food insecurity and housing instability experiences during early childhood on adolescent anxiety and depressive symptoms through maternal depression and parenting stress. This longitudinal study included 4 waves of data from the Fragile Families and Child Well-Being Study (n ϭ 2,626). Food insecurity was measured when the child was 5 years of age using the U.S. Department of Agriculture's 18-item Food Security Scale. Housing instability was also measured when the child was 5 years of age based on an affirmative response to 6 housing adversity items. Maternal depression and parenting stress were measured when the child was 9 years of age. Anxiety and depressive symptoms were assessed when the child (now adolescent) was 15 years of age using 6 items of the Brief Symptom Inventory 18 anxiety subscale and 5 items of the Centers for Epidemiologic Studies Depression Scale, respectively. Two structural equation models assessed the associations between food insecurity and housing instability on adolescent anxiety (Model 1) and depressive symptoms (Model 2) through maternal depression and parenting stress simultaneously, controlling for sociodemographic characteristics. Results suggest that experiencing both food insecurity and housing instability during early childhood increases the risk of long-term adolescent depressive (indirect: B ϭ 0.008, 95% CI [0.002, 0.016]) and anxiety (indirect: B ϭ 0.012, 95% CI [0.002, 0.026]) symptoms through maternal depression to parenting stress. Screening for food insecurity and housing instability during early childhood could potentially identify both mothers who are at risk for depression and parenting stress and children who are at increased risk for anxiety or depressive symptoms during adolescence.

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Objective: To determine the temporal directionality of the association between food insecurity and maternal depression. Design: Food insecurity was measured at two time points using the 18-item USDA Food Security Scale. Maternal depression was measured at two time points using the 15-item Composite International Diagnostic Interview-Short Form. Two structural equation models were utilized to evaluate the impact of food insecurity on maternal depression (model 1) and the impact of maternal depression on food insecurity (model 2). Both models controlled for socio-demographic and parenting characteristics and child behavior problems, along with prior measures of the dependent variable, concurrent measures of the independent variable. Setting: Fragile Families and Child Wellbeing (FFCW) study, 20 cities across the United States Participants: 4,897 mothers who participated in two waves of the FFCW study. Results: On average, 17% (time 1) and 15% (time 2) of mothers experienced food insecurity and 21% (time 1) and 17% (time 2) of mothers experienced depression over time. Maternal depression at time 1 was associated with 53% increased odds (OR=1.53; B=0.43; p <.001) of food insecurity at time 2, controlling for time 1 food insecurity, concurrent depression, and covariates. Food insecurity at time 1 was associated with 36% increased odds (OR=1.36; B=0.31; p <.001) of maternal depression at time 2, controlling for time 1 depression, concurrent food insecurity, and covariates. Conclusions: We found a bidirectional relationship between food insecurity and maternal depression. A holistic approach that combines food assistance and mental health services may be an efficacious approach to reducing both depressive symptoms food insecurity among low-income mothers.

Background Excessive screen time is associated with poor health and behavioral outcomes in children. However, research on screen time use has been hindered by methodological limitations, including retrospective reports of usual screen time and lack of momentary etiologic processes occurring within each day. Objective This study is designed to assess the feasibility and utility of a comprehensive multibehavior protocol to measure the digital media use and screen time context among a racially and economically diverse sample of preschoolers and their families. This paper describes the recruitment, data collection, and analytical protocols for the Tots and Tech study. Methods The Tots and Tech study is a longitudinal, observational study of 100 dyads: caregivers and their preschool-age children (aged 3-5 years). Both caregivers and children will wear an Axivity AX3 accelerometer (Axivity Ltd) for 30 days to assess their physical activity, sedentary behavior, and sleep. Caregivers will complete ecological momentary assessments (EMAs) for 1 week to measure child behavioral problems, caregiver stress, and child screen time. Results The Tots and Tech study was funded in March 2020. This study maintains rolling recruitment, with each dyad on their own assessment schedule, depending on the time of enrollment. Enrollment was scheduled to take place between September 2020 and May 2022. We aim to enroll 100 caregiver-child dyads. The Tots and Tech outcome paper is expected to be published in 2022. Conclusions The Tots and Tech study attempts to overcome previous methodological limitations by using objective measures of screen time, physical activity, sedentary behavior, and sleep behaviors with contextual factors measured by EMA. The results will be used to evaluate the feasibility and utility of a comprehensive multibehavior protocol using objective measures of mobile screen time and accelerometry in conjunction with EMA among caregiver-child dyads. Future observational and intervention studies will be able to use this study protocol to better measure screen time and its context. International Registered Report Identifier (IRRID) DERR1-10.2196/36240