Evaluation of a Multicomponent Early Intervention for Childhood Obesity Prevention in Vulnerable Families

The BMI z-scored will be measured using the WHO Child Growth Standards. "At risk for overweight," "overweight," and "childhood obesity" for children under five are defined as BMI z-scores >1 and ≤2, >2 and ≤3, or >3 standard deviations above the median established by WHO growth standards, respectively.

Child dietary intake will be measured using the multiple-pass 24-hour recall, which is a brief interview that will be conducted by healthcare professionals who participate in the project.

The Feeding Practices and Structure Questionnaire is a self-administered questionnaire that measures parental feeding practices, specifically maternal responsiveness to children's hunger/satiety signals facilitated by routine and structure in feeding.

Age- and feeding-stage-appropriate versions of the questionnaire will be administered: (a) the specific FPSQ-28 version for children aged ≥2 years; and (b) the FPSQ version for children aged <2 years, either the FPSQ milk-feeding version (for caregivers predominantly feeding their child with milk) or the FPSQ (semi-)solids version (for caregivers predominantly feeding their child with solid food.

Each subscale is scored separately (range 1-5). No overall total score is calculated. Higher scores indicate greater endorsement of the feeding practice represented by the subscale.

The Movement Behavior Questionnaire is a self-administered questionnaire that measures physical activity, screen time and sleep in infants, toddlers and preschoolers.

The two age-specific versions of the questionnaire will be used: the MBQ-Baby (MBQ-B) for infants who have not yet reached the walking milestone, and the MBQ-Child (MBQ-C) for children who are able to walk. The closed-ended versions of the MBQ will be used.

The questionnaire does not produce a total score. It assesses individual movement behaviours (e.g., tummy time, physical activity, screen time, restrained time, sleep duration). Interpretation depends on the behaviour measured and its alignment with age-specific movement guidelines.

The Brief Physical Activity Assessment Tool is a self-administered 2-item questionnaire to identify "inactive" patients in primary care settings. Responses to the two items are combined into a total score ranging from 0 to 8. Higher scores indicate a better outcome, reflecting higher levels of physical activity and adherence to recommended activity guidelines.

Parents' eating patterns will be measured with the self-administered Dutch Eating Behavior Questionnaire.

The questionnaire comprises three subscales (Restrained Eating, Emotional Eating, and External Eating), each scored separately by averaging item responses (range 1-5). No overall total score is calculated. Higher scores indicate greater endorsement of the eating behaviour measured by each subscale; the interpretation of whether this represents a more or less desirable outcome depends on the subscale.

Selected items (applicable to the whole children's age range included in the study) from the Brief Infant Sleep Questionnaire (BISQ) will be used to measure child sleep.

The complete BISQ will not be administered because the original questionnaire is not appropriate for the full age range of the study population. Sleep parameters derived from selected BISQ items will be analyzed individually. No total sleep score will be calculated; therefore, there is no overall minimum or maximum score. The direction of interpretation depends on the specific sleep parameter assessed (e.g., longer sleep duration is generally considered favorable, whereas more frequent night awakenings or longer nocturnal wakefulness may indicate poorer sleep).

Parents' attendance will be recorded after each session using attendance sheets. These data will be used to calculate overall compliance and engagement across the full intervention period.

Parents' acceptability and satisfaction with the program will be assessed with a Final Participant Satisfaction Questionnaire. Data will be collected after the last session of the intervention.

Higher scores indicate greater acceptability and satisfaction with the intervention.

Fidelity with the program will be assessed after each session using the Leader Checklist completed by group leaders. Fidelity will be summarized across all sessions to evaluate adherence to the intervention protocol.

Semi-structured individual interviews and focus groups will be conducted with parents and group leaders during the intervention and after the final session to explore barriers and facilitators, as well as acceptability, adoption, appropriateness, feasibility, penetration, and sustainability of the intervention.