The Bloom Study - a Safe and Healthy Start in Life

Childhood overweight and obesity are major public health challenges. In Denmark, 14% of children have overweight or obesity at school entry, rising to 19% by school leaving, with higher prevalence levels among children from low socio-economic positions and ethnic minority backgrounds.

Early intervention is crucial since childhood obesity is hard to reverse, and infancy presents an opportunity to address modifiable risk factors. It is well-documented that both genetic, behavioral, psychosocial, and environmental factors play key roles. Modifiable risk factors include feeding practices, physical activity, screen use, and sleep. Additionally, growing evidence suggests that psychological stress in early life due to unmet socio-emotional needs may lead to disrupted energy balance homeostasis, resulting in weight gain.

The Bloom Study is designed to address food and meals, motor skills and movement, screen use, sleep, and sense of security in the family. The intervention targets first-time families, with a special focus on reaching all families across varying socio-economic positions and ethnic backgrounds. Also, the Bloom intervention has a strong focus on involving fathers/partners. It is delivered through the established and highly accepted system of community health nurses in Denmark.

The intervention is initiated during pregnancy and continues until the child reaches 30 months of age. The main intervention components include: 1) an extra home visit during pregnancy, 2) an extra home visit when the child ais 18 months, 3) an extra home visit when the child is 30 months, 3) telephone consultations, 4) parent groups, and 5) a video library for parents.

An important element of the implementation strategy is to ensure that the intervention design and implementation are compatible with the existing practices, priorities, and values within the system of Danish community health nurses. Additionally, the implementation of the Bloom Study will be supported by five main activity components: 1) training of community health nurses including a five-day training course, supervision, and a comprehensive implementation manual containing instructions for standardized delivery of the intervention, 2) selection of local program ambassadors among community health nurses in the municipalities, 3) regular contact with the research group including assignment of one main contact person, 4) meeting activities including start-up meetings, network meetings across municipalities, and local staff meetings, and 5) partial economic compensation.

The Bloom Study is evaluated within a cluster-randomized controlled trial (cluster-RCT) with 22 municipalities randomly allocated to intervention (11 municipalities) and control (11 municipalities). The intervention is initiated during pregnancy and continues until the child reaches 30 months of age. Follow-up data are collected at child age of 36 months. Primary outcome is Body Mass Index (BMI) z-score at child age of 36 months.

• Weight status [Time frame: 36 months]
• BMI z-score [Time frame: Few days after birth, Within first week after returning to home, Within first months, 2 months, 4-6 months, 8-10 months, 18 months, 30 months]
• Fat mass (kg) [Time frame: 36 months]
• Fat free mass (kg) [Time frame: 36 months]
• Fat mass index in kg/m2 [Time frame: 36 months]
• Fat free mass index (kg/m2) [Time frame: 36 months]
• % Fat mass [Time frame: 36 months]
• % Fat free mass [Time frame: 36 months]