Associations between mother's and children's moderate-to-vigorous physical activity and sedentary time in the family context

The manner in which mothers' and children's moderate-to-vigorous physical activity (MVPA) and sedentary time (ST) are associated across different settings (i.e., at home versus outside of the home, on weekdays versus weekends) is not well understood. The purposes of this study were to: (Strong et al., 2005) describe associations between mothers' and children's levels of MVPA and ST, and (U.S. Department of Health and Human Services, 2008) determine how setting and mothers' and children's characteristics moderate the associations. We used baseline data from the University of Michigan Healthy Families baseline data (2013-2015) from 55 mothers who have children in two age groups (3-5.99 years [n = 25] and 10-12.99 years [n = 30]) for the analysis. MVPA and ST data were collected using accelerometry over a seven day period. Proportion of time spent in MVPA and ST between 08:00 am and 08:59 pm was calculated. Mixed-effects models were used to examine associations. After controlling for selected mother and child characteristics and setting variables, MVPA and ST levels were positively associated in mothers and their children (P < 0.001). The mother-child associations for MVPA and ST were 1.7 times (β = 0.365 versus β = 0.216) and 2.2 times (β = 0.255 versus β = 0.117) stronger, respectively, when both were at home together. The association did not differ by day of the week. The variations by setting underline the importance of developing home-based, family-centered interventions to increase PA and decrease ST.