Etiology of Accelerated Weight Gain during Summer vs. School in Adolescents: What's UP (Undermining Prevention) with Summer 2

Since the early 1990s, the field of childhood obesity has known that children gain 3-5 times more weight during
their 3-month summer vacation than they do during the entire 9-month school year. Evidence shows that youth
from low-income households are especially vulnerable to accelerated BMI gain during the summer. The cohort
study we seek to extend in this renewal R01 is What’s UP (Undermining Prevention) with Summer. This is
the largest and most diverse study of elementary-age children designed to understand accelerated BMI gain
during the summer. In this R01, children are measured on key obesity-related health behaviors (i.e., activity,
sleep, screen time, time spent sedentary, and diet) during school year (April/May) and in the summer (July).
What’s UP with Summer advances the field of accelerated BMI gain during the summer by 1) measuring the
SAME children during school and again during summer over multiple years using a within-person design; 2)
measuring height/weight at the beginning and end of each summer over time to examine changes in BMI gain
during the school year and compare this to BMI gain during the summer; and 3) leveraging rich time/date
stamped 24hr accelerometry data and combining this with daily time diary recordings of where children are, what
times they are there, when and what they eat, and who they are with. Accelerated BMI gain is not a phenomenon
that occurs only in elementary-age children. Suggestive, yet limited, data suggest that middle and high school-
age youth also exhibit accelerated BMI gain during the summer. Unlike elementary-age children, important
differences in autonomy and decision making occur during these formative adolescent years. The major gaps
in the science are few studies measure key health behaviors during the school and summer in middle and high
school youth and limited information exists about the social and setting contextual influences on middle and high
school health behaviors over the summer and how they impact changes in BMI. Without information collected
as proposed in this renewal application, the ability to design effective public health interventions to address
obesity during the summer for adolescents is severely limited. In this R01 we will compare longitudinal changes
in BMI z-scores and health behaviors during school and summer and from elementary school to high school,
identify individual, peer, family/home, neighborhood, and school/community influences on BMI z-scores and
health behaviors during school and summer from elementary school to high school, and qualitatively explore
changes in adolescents’ BMI and health behaviors during the summer and school. This project is significant
because it will extend a well-established existing cohort to identify the impact of an understudied timeframe
(summer) associated with accelerated BMI gain during a developmental period for which no information exists
(adolescence). This project is innovative because it will capture information on the same youth during school
and summer, follow them over time, and collect contextually rich information to understand and identify
modifiable factors to inform the design of behavioral interventions.

Grant Number: 5R01DK116665-08
NIH Institute/Center: NIH
Principal Investigator: MICHAEL BEETS