ClinicalTrials.gg
CompletedNCT03397940Updated May 5, 2022

Role of Structured Days on Weight Gain

An observational study in Body Weight, Cardio-respiratory Fitness and Sleep, sponsored by University of South Carolina. Completed at 1 site in United States. Open to participants aged 5 Years to 9 Years. Per ClinicalTrials.gov, last updated 2022-05-05.

Primary conditionBody Weight(the registry's first term)UnverifiedIs this wrong?Body Weight is a broad heading, used only when no more specific condition is named. No better condition is named, so the registry's term is kept.

Sponsored by University of South Carolina · Observational

Study type
Observational
Model
Cohort
Time perspective
Prospective
Enrollment
2,279
Ages
5 Years to 9 Years
Sex
All
01

Study summary

Summer vacation is a 3-month window of vulnerability for children from low-income households when health behaviors and academic learning decay. The goal of this project is to collect information on where low-income children go during summer, what they do when they get there, and how their behaviors (physical activity, sedentary, sleep, and diet) differ between the summer (unstructured days) and school year (structured days). This study is 1) significant because it will provide evidence on potential points of intervention that can reduce or reverse the excessive unhealthy weight gains that occur during summer and 2) innovative because it will be the first to identify changes in activity, sedentary, sleep, and dietary behaviors during prolonged and shorter periodic breaks from school and link these behaviors to changes in zBMI over time.

Read the detailed description

For children (5-12yrs) from low-income households, summer vacation is a "window of vulnerability" and represents an extended period of time (typically 9-10 weeks) in which declines in academic performance occur. For 30 years, empirical evidence has indicated that children from low-income households experience greater declines in reading and math skills during the summer vacation than their middle-to-upper income peers. Additionally, a growing body of evidence demonstrates that the amount of weight gained during summer vacation is 3-5 times greater than the amount of weight gained during the school year. Moreover, this excessive weight gain during summer is more pronounced for low-income, minority children, the same children experiencing the greatest summer learning loss. What children eat and drink, the types of physical activity opportunities, and the amount of screen-time and sleep (two important correlates of weight gain) they engage in during summer vacation is unknown. However, a substantial body of literature indicates that children engage in a greater number of obesogenic behaviors during less-structured times (e.g., weekend days) compared to more-structured times (e.g., week/school days). This phenomenon is refered to as the Structured Days Hypothesis. These behaviors include 1) increased time spent sedentary, 2) reduced engagement in physical activity, 3) displaced sleep patterns, and 4) unhealthy dietary patterns. This study hypothesizes that summer vacation is simply one long weekend where the effect of children's obesogenic behaviors on weight are compounded over a three month time period. However, should children be involved in a structured program over the summer they would not engage in obesogenic behaviors and they would not experience unhealthy weight gains and fitness loss. Recently, one school district in the Columbia, SC area adopted a year-round calendar for an elementary school. This provides a unique opportunity to conduct a natural experiment examining the effects of shorter periodic breaks vs. one prolonged break from structured days (i.e., school days) on the obesogenic behaviors, weight gain, and fitness. This study will use a two arm accelerated longitudinal cohort design to complete the following specific aims: Aim 1: Compare changes in BMI z-scores and fitness during the traditional 3-month summer and 9-month school year between children attending a school that follows a year-round school calendar to children attending match-paired schools that follow a traditional school calendar. Aim 2: Compare changes in sleep, physical activity, sedentary behaviors, and diet during the traditional 3-month summer and 9-month school year between children attending a school that follows a year-round school calendar to children attending match-paired schools that follow a traditional school calendar. This study is significant because the reason for children's weight gain and fitness loss during the summer is unknown. This study is innovative because no studies have examined the effects of prolonged (9 weeks all at once) vs. periodic breaks (3 week breaks distributed throughout the year) from a structured environment on children's weight and fitness.

02

Conditions studied

  • Body Weight
  • Cardio-respiratory Fitness
  • Sleep
  • Nutrition Poor
  • Physical Activity
  • Screen Time

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03

In context

Body Weight Unverified

657 studies on the registry are indexed under Body Weight; 76 are open to participants now.

This study's enrollment of 2,279 is above the median of 147 across 141 observational studies indexed under Body Weight.

Browse Body Weight studies →

Lead sponsor

University of South Carolina is the lead sponsor of 197 studies on the registry; 42 are open to participants now.

Compared within Body Weight, the registry's first condition term, which may not be this study's main condition. Counted across the registry records on this site, refreshed daily. How we classify →

04

Who can participate

Ages eligible
5 Years to 9 Years
Sexes eligible
All
Sampling method
Probability sample

Study population

Three schools (2 traditional and 1 year-round) enrolling 1,279 students have agreed to participate. 85.0% of children in these schools qualify for free and/or reduced price lunch, and 67.5% of children attending these schools are black, 28.5% are white, and 3.6% are Hispanic. The first school was selected to participate because it operates on a year-round calendar. The second and third schools were selected because their enrollment size and student demographics closely match the enrollment and student demographics of the first school. All children in the participating schools will have their height/weight and cardiovascular fitness measured.

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

K, 1st, 2nd, and 3rd grade students without any physical and/or medical conditions that would limit their ability to take part in measurements.

Exclusion criteria

Exclusion Criteria:

Children in the 4th and 5th grade will be excluded from participation in the obesogenic behavior assessments because they will move out of elementary school over the two-year study.

05

Study design

Observational model
Cohort
Time perspective
Prospective
Enrollment
2,279 participants (actual)
Patient registry
No

Groups and cohorts

  • Year Round School

    Children attending year round school

  • Traditional School

    Children attending a traditional school with a traditional calendar school year

06

What researchers measure

Primary outcomes

  1. Change in Body Mass Index

    All students enrolled in the partnering schools will have their height and weight measured using standard procedures, as part of their routine PE class. Height and weight will be collected prior to and following every break lasting 3 weeks or longer. These measures will be collected with the help of trained research staff during regularly scheduled PE classes to ensure data quality. This information will be used to compare the BMI (translated into age/sex z-scores \[zBMI\] for analytical modeling) over time and between students attending a year-round school and traditional schools. These tests are valid and reliable for this age group.

    Time frame: Baseline and will follow up at 4 months, 12 months, 16 months, and 24 months

  2. Change in Cardiorespiratory Fitness:

    All students enrolled in the partnering schools will take part in the cardiovascular fitness (CVF) test (i.e., PACER) as part of their routine PE class. These tests are administered to this age group and occur as part of regular PE class as part of a South Carolina statewide assessment system.This information will be used to compare the CVF over time and between students attending a year-round school and traditional schools. These tests are valid and reliable for this age group.

    Time frame: Baseline and will follow up at 4 months, 12 months, 16 months, and 24 months

Secondary outcomes

  1. Change in Sleep

    Children's sleep will be assessed via wrist-placed Actigraph Links.

    Time frame: Baseline and follow up at 3 months, 12 months, and 15 months

  2. Change in Dietary Behavior

    Dietary patterns rather than individual foods will be assessed. For the current study, the intent is to estimate less healthful/more healthful foods and beverages consumed and compare these between summer and school. The study will assess child dietary patterns using two approaches. First, a modified dietary screener questionnaire will be completed by a parent/guardian at each measurement (traditional school and summer vacation) each year. Screener items were selected from multiple screeners developed for use in this age group and have been widely used in research. The screeners are the 26-item Dietary Screener Questionnaire,16 items from the National Youth Physical Activity and Nutrition Study, and items from several additional food/beverage validated screeners. These dietary screeners provide accurate estimates of food groups and dietary patterns, to allow for examination of relationships between diet and other variables in this study. These screeners have been tested for validity

    Time frame: Baseline and follow up at 3 months, 12 months, and 15 months

  3. Change in Physical Activity

    Time (minutes per day) spent sedentary, and in light, moderate, and vigorous physical activity will be collected using a non-dominant wrist-placed ActiGraph Link for 9-days (common timeframe to collect physical activity data). Non-dominant wrist-placement provides an advantage over waist placement by improving compliance and the ability to collect information regarding sleep. The device is water-proof, allowing us to capture water activities during summer. A calibration/validation study was recently published to establish methodology to distill activity-intensities from wrist-placed ActiGraph in children. The widely accepted protocols for a valid day of data will be used. Each parent with receive a logbook to complete each night to report non-wear time. Logs will be cross-referenced with the accelerometer data for quality assurance.

    Time frame: Baseline and follow up at 3 months, 12 months, and 15 months

07

Study locations

1 site
  • University of South Carolina
    Columbia, South Carolina 29205, United States
08

References and documents

Publications

  • Weaver RG, Armstrong B, Hunt E, Beets MW, Brazendale K, Dugger R, Turner-McGrievy G, Pate RR, Maydeu-Olivares A, Saelens B, Youngstedt SD. The impact of summer vacation on children's obesogenic behaviors and body mass index: a natural experiment. Int J Behav Nutr Phys Act. 2020 Nov 26;17(1):153. doi: 10.1186/s12966-020-01052-0. PubMed 33243252 ↗
09

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Ran from Mar 2018 to primary completion in Oct 2021, 43 months.

Of 40 non-industry observational studies under Body Weight, half reached primary completion within 34 months of starting (the median), counting those still running; a quarter within 21 and three quarters within 72. This study's 43 months is above that.

Counting every sponsor, half of 41 studies reached it within 31 months; a quarter within 20 and three quarters within 71.

How these figures are worked out, and which studies are left out of them.

Registered
Nov 10, 2017
First posted
Jan 12, 2018
StartActual
Mar 1, 2018
Primary completionActual
Oct 1, 2021
CompletionActual
Oct 1, 2021
Last update
May 5, 2022
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on May 5, 2022, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT03397940
Responsible party
R. Glenn Weaver (Assistant Professor, University of South Carolina) — Principal investigator
First posted
Jan 12, 2018
Start date
Mar 1, 2018
Primary completion
Oct 1, 2021
Completion
Oct 1, 2021
Last update
May 5, 2022

Oversight

FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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This study is completed, as verified in May 2022. You cannot join it, but the record below documents what was studied.

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