Dose-Response Relationship in a Healthy Habits Study for Head Start Preschoolers

Background Understanding the dose-response relationship in behavioral interventions is critical to guide future research efforts. However, only few studies have fully examined the dose-response relationship especially among children. Objective The aim of the study was to examine the relationships between level of participation and intervention effects. Methods The study used data from 39 Head Start parent-preschooler dyads participating in a 10-week lifestyle intervention. The intervention included daily center-based preschooler program, preschooler weekly letters to parents, parent meetings, and weekly Facebook-based program. Height, weight, waist circumference (WC), moderate-to-vigorous physical activity (MVPA), screen time, and fruit/vegetable intake were assessed. Results Preschooler program average daily attendance was 79%, and Facebook-based program average completion rate was 80%. About 49% attended all three parent meetings. Parent meeting attendance was significantly and positively related to preschoolers' vegetable intake (p = .023) and MVPA (p < .001) and parents' MVPA (p = .016). Preschooler letters were significantly and negatively related to preschoolers' screen time (p = .002) and parents' WC (p = .027) and positively correlated with parents' MVPA (p = .01). Preschooler program attendance was not significantly correlated with their body mass index (rho = -.31) or WC (rho = -.16). Discussion The study provides important information for designing effective interventions among low-income families. The findings imply that (a) parent-only interventions and parent-child interventions may result in similar effects, (b) future behavioral interventions should focus on the bidirectional parent-child relationship, and (c) it is important to include face-to-face contacts in lifestyle interventions. In addition, it highlights the need to examine the dose-response relationship in multicomponent lifestyle interventions.