ArticlePediatric obesity2021
Impact of a year-round school calendar on children's BMI and fitness: Final outcomes from a natural experiment.
Article in Pediatric obesity, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 10 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
10 citing papers in PubMed, 1 synthesis or guideline pooled it, 21 citations in OpenAlex.
- Exploring the Effects of Lifestyle Disruptions on Physical Fitness in Children and Adolescents: a Systematic Scoping Review.Sports medicine - open · 2025Pooled it
- Impact of free summer day camp on physical activity behaviors and screentime of elementary-age children from low-income households: a randomized clinical trial.The international journal of behavioral nutrition and physical activity · 2025Trial
- The Cost Effectiveness of a Free Summer Day Camp Voucher Program to Prevent Summer Weight Gain Among Children From Disadvantaged Households.American journal of preventive medicine · 2025Trial
- School's Out, Rules Out: Changes in parent rules and routines over summer from the What's UP (Undermining Prevention) with Summer Observational Cohort Study.Research square · 2026Article
- Differences in children's food and beverage consumption between school and summer: three-year findings from the what's UP (Undermining Prevention) with summer observational cohort study.BMC public health · 2025Observational
- Protocol for a randomized controlled dose response trial to combat accelerated summer BMI gain in children: The Determining the Optimal amount of Structured Environments (DOSE) study.Contemporary clinical trials · 2025Article
- Children's Health, Wellbeing and Academic Outcomes over the Summer Holidays: A Scoping Review.Children (Basel, Switzerland) · 2024Article
- Feasibility and preliminary efficacy of structured programming and a parent intervention to mitigate accelerated summer BMI gain: a pilot study.Pilot and feasibility studies · 2023Article
- Seasonal variability in body mass index change among children enrolled in the Pediatric Obesity Weight Evaluation Registry: A step in the right direction.Pediatric obesity · 2023Article
- Feasibility & Preliminary Efficacy of Structured Programming and a Parent Intervention to Mitigate Accelerated Summer BMI Gain: A pilot study.Research square · 2022Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
16 authors at 4 institutions in 1 country.
Funding
Abstract
backgroundStructure may mitigate children's accelerated summer BMI gain and cardiorespiratory-fitness (CRF) loss.
objectivesExamine BMI and CRF change during school and summer for year-round and traditional calendar school children.
methodsThree schools (N = 2279, 1 year-round) participated in this natural experiment. Children's BMI z-score (zBMI) and CRF (PACER laps) were measured from 2017 to 2019 each May/August. Mixed effects regression estimated monthly zBMI and CRF change during school/summer. Secondary analyses examined differences by weight status and race. Spline regression models estimated zBMI and CRF growth from kindergarten-sixth grade.
resultsCompared to traditional school, children attending a year-round school gained more zBMI (difference = 0.015; 95CI = 0.002, 0.028) during school, and less zBMI (difference = -0.029; 95CI = -0.041, -0.018), and more CRF (difference = 0.834; 95CI = 0.575, 1.093) monthly during summer. Differences by weight status and race were observed during summer and school. Growth models demonstrated that the magnitude of overall zBMI and CRF change from kindergarten-sixth grade was similar for year-round or traditional school children.
conclusionsContrary to traditional school children zBMI increased during the traditional 9-month school calendar and zBMI decreased during the traditional summer vacation for year-round school children. Structured summer programming may mitigate accelerated summer BMI gain and CRF loss especially for overweight or obese, and/or Black children.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.