Exposure to a multi-level multi-component childhood obesity prevention community-randomized controlled trial:...

Area of Science:

• Public Health
• Community-Based Interventions
• Obesity Prevention

Background:

• Effective community interventions require adequate participant exposure.
• Understanding exposure dose and intensity in low-income areas is crucial.
• This study examines exposure patterns in a multi-component obesity prevention program.

Purpose of the Study:

• To assess exposure levels to different components of the B'more Healthy Communities for Kids (BHCK) program.
• To identify factors associated with varying levels of intervention exposure among youth and caregivers.
• To inform future impact analyses by understanding exposure patterns.

Main Methods:

• A community-randomized controlled trial (BHCK) in 28 low-income Baltimore zones.
• Post-intervention interviews with 385 low-income urban youths and caregivers to assess exposure.
• Exposure scores calculated based on self-reported material viewing and activity participation; analyzed using ordered logit regression.

Main Results:

• Mean exposure scores were significantly higher in the intervention group than the comparison group for both youths and caregivers.
• Overall exposure scores were low in both groups; 10% of the comparison group showed moderate exposure.
• Older age was associated with lower odds of high exposure (OR 0.77).

Conclusions:

• Differential exposure and comparison group exposure can attenuate treatment effects in community trials.
• Measuring exposure is essential for contextualizing impact evaluations in multi-level studies.
• Future analyses should control for confounders using a treatment-on-the-treated approach, acknowledging potential biases.