The Impact of Summer Vacation on Children’s Obesogenic Behaviors and Body Mass Index: A natural experiment.

Abstract

Background: Children’s BMI gain accelerates during summer. The Structured Days Hypothesis posits that the lack of the school day during summer vacation negatively impacts children’s obesogenic behaviors (i.e., physical activity, screen time, diet, sleep). This natural experiment examined the impact of summer vacation on children’s obesogenic behaviors and body mass index (BMI). Methods: Elementary-aged children (n=285, grade=1-5, 48.7% male, 57.4% African American) attending a year-round (n=97) and two match-paired traditional schools (n=188) participated in this study. Obesogenic behaviors were collected during three conditions: Condition 1) all children attend school, Condition 2) year-round children attend school while traditional children were on summer vacation, and Condition 3) summer vacation for all children. Changes in BMI z-score were collected for the corresponding school years and summers. Multi-level mixed effects regressions estimated obesogenic behaviors and monthly zBMI changes. It was hypothesized that children would experience unhealthy changes in obesogenic behaviors when entering summer vacation because the absence of the school day (i.e., Condition 1 vs. 2 for traditional school children and 2 vs. 3 for year-round school children). Results: From Condition 1 to 2 traditional school children experienced statistically significantly greater unhealthy changes in daily minutes sedentary (∆=24.2, 95CI=10.2, 38.2), screen time minutes (∆=33.7, 95CI=17.2, 50.3), sleep midpoint time (∆=73:43, 95CI=65:33, 81:53), and sleep efficiency percentage (-∆=0.7, 95CI=-1.1, -0.3) when compared to year-round school children. Alternatively, from Condition 2 to 3 traditional school children experienced statistically significantly smaller unhealthy changes in daily minutes sedentary (∆=-54.5, 95CI=-70.9, -38.0), MVPA minutes (∆=11.4, 95CI=3.7, 19.1), screen time minutes (∆=-46.5, 95CI=-63.0, -30.0), sleep midpoint time (∆=-95:54, 95CI=-106:22, -85:26), and sleep efficiency percentage (-∆=0.7, 95CI=-1.1, -0.3) when compared to year-round school children. Monthly zBMI gain accelerated during summer for traditional (∆=0.033 95CI=0.019, 0.047) but not year-round school children (∆=0.004, 95CI=-0.014, 0.023).Conclusions: This study suggests that the lack of the school day during summer vacation negatively impacts sedentary behaviors, sleep timing, and screen time. Changes in sedentary behaviors, screen time, and sleep midpoint may contribute to accelerated summer BMI gain. Providing structured programming during summer vacation may positively impact these behaviors, and in turn, mitigate accelerated summer BMI gain.

Impact of theCOVID‐19 pandemic on elementary schoolers' physical activity, sleep, screen time and diet: A quasi‐experimental interrupted time series study

“…In a natural experiment examining children's obesogenic behaviours during structured and unstructured periods, children's sedentary behaviour, screen time, and sleep timing worsened during a traditional 12‐week summer vacation compared to those who remained in more structured settings (i.e., children attending year‐round school with a shorter 5‐week summer vacation). These behavioural changes corresponded to a statistically significant acceleration in z BMI gain in children during the traditional 12‐week summer vacation suggesting that structured environments have a protective effect on children's health outcomes 24 …”

Differences in ​the proportion of children meeting behavior guidelines ​between summer ​and school by socioeconomic status and race

“…20,28,33,[42][43][44][45] Given that children who are Black and children from low-income households experience more dramatic accelerations in BMI during the summer than their White and middle-to-highincome counterparts, 31 days and during the summer when compared to the school year. 21,33,48,49 However, these same studies show that children's bedtimes and wake times shift later and become more variable during the summer. While meeting sleep duration guidelines is protective against developing obesity, 50,51 sleep timing (i.e., late to bed, late to wake) and stability (i.e., keeping bed and wake time constant) have also been shown to be independent risk factors for obesity.…”

“…For instance, a growing number of studies demonstrate that children engage in less physical activity, spend more time sedentary, and spend more time on screens during the summer than during the school year. 19 , 20 , 21 Studies are also emerging that show children engage in healthier amounts of sleep and less variable sleep on nights prior to school days, compared to extended breaks from school, like summer. 20 , 21 , 22 The degradation of health behaviors during summer vacation likely leads to decreased rates of meeting activity, 23 sleep, 24 and screen‐time guidelines.…”

“…19 , 20 , 21 Studies are also emerging that show children engage in healthier amounts of sleep and less variable sleep on nights prior to school days, compared to extended breaks from school, like summer. 20 , 21 , 22 The degradation of health behaviors during summer vacation likely leads to decreased rates of meeting activity, 23 sleep, 24 and screen‐time guidelines. 25 , 26 Failing to meet these guidelines has been associated with increased risk for obesity, insulin resistance, cardiovascular and other diseases.…”

Biopsychosocial exposure to the COVID-19 pandemic and the relative risk of schizophrenia: Interrupted time-series analysis of a nationally representative sample

“…We use the qualifier "biopsychosocial capture" to capture the experiences of the Covid-19 pandemic. These experiences include the biological exposure to the Covid-19 infection and the social and psychological experiences of the Covid-19 attenuation policies, which include lockdown, social distancing, loneliness, financial loss, unemployment [8], secondary health effects (e.g., weight gain) [9], and crime [10]. Many of these biopsychosocial pandemic adversities may be risk factors for psychosis, e.g., loneliness [11] and social defeat [12].…”