This study compared the effects of a real-world multidisciplinary intervention with additional exercise or nutritional elements and investigated the effectiveness of a booster intervention after weight regain. A total of 242 children and adolescents (age- and sex-specific body mass index [BMI] ≥ 85th percentile, mean age: 10.82 years, 60% male) were allocated to three groups: usual care, exercise, or nutrition. Six-month active treatment with 1:1 session and a maintenance stage with group activities were repeated twice to comprise a 24-month intervention. The primary outcome was change % of the BMI z-score (zBMI). A total of 110 (45.4%) participants completed the 24-month intervention. A mixed-effects model analysis indicated no significant interaction effect of the intervention group and treatment phase on the zBMI change % (p = 0.976). However, there was a significant main effect of the treatment phase on zBMI change % at 6 months (β = -2.98, [95% CI, -5.69-0.27]), 18 months (β = -3.99, [95% CI, -6.76-1.22]), and 24 months (β = -3.23, [95% CI, -5.94-0.52]; p = 0.042). The improvements in zBMI, body fat %, and cardiometabolic markers were observed only among males. Whereas the additive effect of intensive exercise or nutritional feedback was not detected in the long term, a booster intervention with 1:1 counseling was effective even after weight regain during the maintenance period. It may be useful to combine individualized counseling with a less intensive form of group care for long-term maintenance in a real-world setting.
Keywords: BMI z-score; body composition; booster intervention; cardiometabolic risk markers; lifestyle intervention; maintenance therapy; pediatric obesity.