Family-based prevention of childhood obesity : long-term outcomes, challenges and implications for future research

Background: Childhood obesity is considered to be one of the most serious health challenges of the 21st century. There have been indications that the prevalence has reached a plateau in high-income countries, yet the prevalence is increasing in poorer parts of the world. The same tendencies are seen within richer countries, with higher prevalence in more disadvantaged groups. Despite many ambitious attempts, an effective solution has not yet been found. Family-based early prevention interventions targeting the whole population has been called for, as well as more studies aiming at understanding factors that predispose for childhood obesity or moderate the outcomes of interventions. The cluster-randomized PRIMROSE trial had the aim of primary prevention of childhood obesity. It was based on Motivational Interviewing (MI) and cognitive behavioral principles, and delivered to parents within Swedish child health care services.

Aims: The overall aim of this thesis was to investigate the long-term results of the PRIMROSE trial in terms of intervention nurses’ MI proficiency and children’s weight status at follow-up, and to gain further understanding of the results by exploring the experiences of nurses and study coordinators who had worked in the trial, as well as investigating parental risk factors for children’s weight status.

Methods: In Study I the MI proficiency level among nurses who had participated in the PRIMROSE trial was explored after the nurses had received the full training package of workshop and supervision. Proficiency at follow-up and potential predictors were also analyzed. In Study II the effect of the PRIMROSE intervention in terms of children’s weight status was investigated, as well as potential moderators of the effect. Study III had a qualitative approach and intervention nurses and study coordinators who had worked in the trial were interviewed. In Study IV we explored parental self-efficacy, health behaviors and weight status as potential risk factors for children’s weight status.

Results: The nurses’ proficiency levels after completing the training was generally low, and the results did not change at follow-up. There were no long-term effects of the PRIMROSE intervention on children’s weight status, and no significant moderators. The analyses of potential predictors of children’s weight status yielded no significant results except for strong associations between parents and children’s anthropometry. The interviews with the nurses and study coordinators revealed two overarching themes: “The nurses felt it was rewarding to participate in the trial, but challenging to combine working with the intervention with regular work at the child health care center”; and “The study coordinators felt they were in a difficult position handling the conflicting needs of the research group and the nurses’ commitment to usual child health care services”. The importance of support, encouragement and clear communication was emphasized, as was adaptation of the training in MI to the setting and target group. Stress and lack of time seem to have been major barriers to delivering the intervention as it was intended.

Conclusions: The results of the PRIMROSE trial are in line with previous prevention trials targeting individuals’ diet and PA, indicating that we need to shift our focus. Tackling obesity demands a system approach including upstream interventions also targeting the policy level. In addition, the multifactorial etiology of childhood obesity points to the importance of multifactorial solutions, and there’s a need for more high-quality research aiming to increase our knowledge about modifiable predisposing factors and moderators. In addition, the often reported challenges in regards to practitioners’ stress levels and difficulties combining regular work duties with working in clinical trials indicates the importance of organizational support.

List of scientific papers

I. Proficiency in Motivational Interviewing among Nurses in Child Health Services Following Workshop and Supervision with Systematic Feedback. Enö Persson J, Bohman B, Forsberg L, Beckman M, Tynelius P, Rasmussen F, Ghaderi A. Plos One. 2016;11(9):e0163624.
https://doi.org/10.1371/journal.pone.0163624

II. Prevention of Childhood Obesity in Child Health Services: Follow-Up of the PRIMROSE Trial. Enö Persson J, Bohman B, Tynelius P, Rasmussen F, Ghaderi A. Childhood Obesity. 2018;14(2):99-105.
https://doi.org/10.1089/chi.2017.0117

III. Experiences of Nurses and Study Coordinators in a Childhood Obesity Prevention Trial Based on Motivational Interviewing within Swedish Child Health Services. Enö Persson J, Leo Swenne C, von Essen L, Bohman B, Rasmussen F, Ghaderi A. [Submitted]

IV. Parental Self-efficacy, Health Behaviors and Body Size in Relation to Childhood BMI, Overweight and Obesity at 5 years of age - Prospective Findings from the Control Cohort of the PRIMROSE Trial. Enö Persson J, Tynelius P, Bohman B, Rasmussen F, Ghaderi A. [Submitted]