Lifestyle intervention failed to sustain BMI reductions for children with obesity
Children with a high BMI who participated in a high-intensity lifestyle intervention program in New Zealand had a lower BMI standard deviation score after 1 year, but the reduction was not sustained at 5 years, according to study data.
In a randomized controlled trial, children in New Zealand aged 5 to 16 years with a BMI in the 98th percentile or greater, or the 91st percentile with weight-related comorbidities, were randomly assigned to a high-intensity intervention group, which included weekly physical activity, dietary and psychology sessions, or a minimum-intensity control group with home-based assessments and advice. In initial data, the high-intensity intervention group had a reduction in BMI standard deviation score of 0.12 and the control group had a reduction of 0.1 after 12 months. However, in follow-up data 5 years after the end of the trial, the BMI standard deviation scores for both the intervention and control groups increased.
“Both the high-intensity intervention and low-intensity control groups reverted to their baseline BMI standard deviation score, irrespective of age, ethnicity or socioeconomic status,” Yvonne C. Anderson, PhD, FRACP, MBChB, BSc, a senior lecturer in the department of pediatrics, child and youth health at the University of Auckland, New Zealand, and colleagues wrote in a study published in Obesity. “The lack of difference in terms of ethnicity and socioeconomic deprivation in the primary outcome was encouraging despite negative overall findings. Early intervention appears beneficial, which has been supported by previous international findings.”
Researchers completed 5-year follow-up assessments with trial participants at their homes or another preferred location. The assessment included measuring heart rate, blood pressure, waist-height ratio and identification weight-related comorbidities. Physical activity was measured by a questionnaire and 5 days of accelerometer wear. Cardiovascular fitness was assessed with a 550 m walk or run. The Pediatric Quality of Life questionnaire was used to assessed health-related quality of life changes.
BMI standard deviation scores revert to baseline
The 5-year follow-up data included 28 participants from the trial’s control group and 41 from the intervention group. Demographics between the two groups were similar, although there were more girls were included in the control group compared with the intervention group (79% vs. 49%; P = .012). BMI standard deviation score did not differ between the groups at follow-up, with both seeing scores return to baseline values at 5 years. Overall, 41% of participants retained a lower BMI standard deviation score at 5 years compared with baseline.
The intervention group had a mean reduction of sweet drink intake at 5 years but increases in reported screen time and fasting insulin. Both groups had increases in water intake and improvements in health-related quality of life after the trial.
In the overall cohort, girls had a 0.21 BMI standard deviation score increase at 5 years, whereas boys had a decrease in BMI standard deviation score of 0.14 (P = .013). Participants younger than 10 years at baseline also had a decrease in BMI standard deviation score of 0.15, whereas those aged 10 years or older had an increase of 0.21 (P = .008).
In subgroup analysis, participants in the high-intensity intervention group attending at least 70% of sessions maintained a reduction in BMI standard deviation score until at least 2 years after the trial. At 5 years, however, the trajectories of both the high attendance and low attendance participants converged, with no significant difference between the two groups.
Benefits still apparent in lifestyle intervention
Despite the findings, the researchers noted there were several long-term benefits stemming from the intervention.
“First, although changes in the primary outcome were not sustained long term, there are indications of wider long-term benefits from participant engagement in a nonjudgmental, non-stigmatizing approach to healthy lifestyle change,” the researchers wrote. “It has previously been argued that failing to reduce BMI should not be equated with failing to achieve healthy lifestyle change. Second, when services are designed to be accessible and appropriate for those most affected by obesity within the community, enhanced engagement can be achieved. Third, the assessment and addressing of weight-related comorbidities can be achieved within community-based programs with home-based assessments, which prevent hospital appointments and result in an efficient model of care that is participant-focused.”