Maternal BMI Change Linked to Child Activity Change in Family-Based Behavioral Interventions for Pediatric Weight Management

This study investigated whether change in maternal BMI was associated with change in child's moderate-to-vigorous physical activity (MVPA) and prolonged sedentary time during the course of family-based behavioral interventions (FBBIs) for pediatric weight management. Children ( = 120) ages 5-12 [mean age = 9.04 ± 1.7) years with a baseline BMI ≥85th percentile (mean BMIz = 1.8 ± 0.5) and families were enrolled in one of three similar FBBIs for pediatric weight management and followed over 6-12 months. Activity data were collected through accelerometers. Mixed effects regression models assessed the relationship of maternal change in BMI to child change in (1) minutes/d of MVPA and (2) proportion of time spent in sedentary bouts lasting ≥10 minutes (termed prolonged sedentary time), and whether the effect of maternal BMI change was moderated by child age, sex, and race/ethnicity. A decrease in maternal BMI was associated with both an increase in child MVPA,  = 2.77,  = 2.03,  = 0.048, and a decrease in proportion/d of prolonged sedentary time,  = 0.02,  = 2.40,  = 0.020, from baseline to follow-up. Child age moderated the association between maternal BMI change and change in child prolonged sedentary time ( = 0.095), whereby the association was limited to 5- to 10-year-olds and became stronger as age decreased. Improvement in maternal BMI showed important positive associations with child MVPA and prolonged sedentary time over the course of FBBIs for pediatric weight management. Targeting parent weight loss could improve child outcomes in FBBIs, particularly in younger children.