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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #318146
Title: Seasonal variability in weight change during elementary school

Author
item MORENO, JENNETTE - Children'S Nutrition Research Center (CNRC)
item JOHNSTON, CRAIG - Children'S Nutrition Research Center (CNRC)
item CHEN, TZU - Children'S Nutrition Research Center (CNRC)
item O'CONNOR, TERESIA - Children'S Nutrition Research Center (CNRC)
item HUGHES, SHERYL - Children'S Nutrition Research Center (CNRC)
item BARANOWSKI, JANICE - Children'S Nutrition Research Center (CNRC)
item WOEHLER, DEBORAH - The Cluthe And William B Oliver Foundation
item BARANOWSKI, TOM - Children'S Nutrition Research Center (CNRC)

Submitted to: Obesity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/26/2014
Publication Date: 2/1/2015
Citation: Moreno, J.P., Johnston, C.A., Chen, T.A., O'Connor, T.M., Hughes, S.O., Baranowski, J., Woehler, D., Baranowski, T. 2015. Seasonal variability in weight change during elementary school. Obesity. 23(2):422-428.

Interpretive Summary: Schools have often been criticized for contributing to the child obesity epidemic due to what has been perceived as offering less healthy food options and inadequate levels of physical activity. Some studies, however, have indicated that major increases in adiposity among elementary school children occurred during the summer break. To test this hypothesis, height and weight were collected in the fall and spring on all children initially in the kindergarten cohort through the beginning of 5th grade. Mean changes in standardized body mass index (zBMI) (an indicator of body composition) were calculated between each pair of assessments. Our analyses revealed that except for the kindergarten year, these elementary school children tended to remain stable or even lose zBMI during the school year, and increase zBMI during the summer vacation. Research is needed to identify which behaviors (diet, physical activity, screen media use, sleep) are the primary causes of the summer adiposity increases, and how what is happening at home (e.g. parenting practices, family routines) can explain the summer increases.

Technical Abstract: Seasonal variation in weight gain across elementary school (kindergarten-5th grade) was examined among children who were healthy weight, overweight, or obese and from different racial and ethnic groups. The sample included 7,599 ethnically diverse students ages 5-7 years at baseline (Caucasian: 21.1%, Black: 36.2%, Hispanic: 26.0%, Asian 16.7%). Heights and weights were measured by school nurses at the beginning and end of each school year from kindergarten through the beginning of 5th grade. Beginning the summer after 1st grade, all children demonstrated a pattern of standardized BMI (zBMI) increases during the summer (0.04 to 0.09) and zBMI decreases across the school years (-0.06 to 0.00; P<0.0001). Hispanic children and children who were overweight and obese exhibited this pattern in kindergarten while children of other ethnicities and with a healthy weight did not (P<0.0001). Beginning the summer after 1st grade, a consistent pattern of relative weight gain during the summer months (change in BMI percentile=1.04) and weight loss during the school year (change in BMI percentile=-0.34) emerged. This pattern appeared earlier for children who were overweight, obese, or Hispanic. These findings suggest a need to better understand the causes of the problematic increases in weight during the summer.