P202 Examining Shifts in School-Time Physical Activity Patterns From Elementary to Middle School Among Lower-Income Schoolchildren

Background The elementary-to-middle school transition likely impacts the decline in school-time physical activity (PA) and may exacerbate disparities in these behaviors that exist for girls and overweight/obese children. Objective To assess changes in school-time moderate-to-vigorous physical activity (sMVPA) and school sedentary time (ST) from elementary to middle school among children and whether there are disparities by sex and weight status. Study Design, Settings, Participants Lower-income children who participated in the FLEX Study during grades 4 and 5 were re-recruited into this supplementary prospective cohort study, FLEX+ during middle school (grade 6). Measurable Outcome/Analysis Demographic data were collected via parent questionnaire. Child assessments included height, weight, and 7-day accelerometry (Actigraph GT3X+) in 4th, 5th, and 6th grade. The association between grade and changes in sMVPA and ST were examined using mixed effects models adjusting for sex, race, BMI status, free/reduced price lunch eligibility (FPRL), and mean weekly ambient temperature. Individual-level clustering was adjusted for as a random intercept. Interactions were tested to examine disparities by sex and BMI status. Results Eighty eight children (grade 4: 9.2 ± 0.5 years, 42% male, 38% non-white, 39% FRPL, 33% overweight/obese, sMVPA = 19.9 ± 8.5 min/day) had valid accelerometer wear-time (> 3 days, >10 hrs/day). There was a decline in children meeting the 30-minute sMVPA recommendation from grades 4 to 6 (14.8%, 7.5%, and 3.5%, respectively; P P > .05). Notably, the change in ST reflects an increase in grade 5 (β = 16.5 mins/day; 95% CI: 8.4, 24.6; P P P > .05). Conclusion Policies and programs that promote movement time during school hours are urgently needed to counteract the steep increase in sedentary behaviors that occur in middle school. Funding NIH.