Importance of age for 3-year continuous behavioral obesity treatment success and dropout rate.

OBJECTIVE To assess whether first year weight loss, age, and socioeconomic background correlate with the success rate of continuous long-term behavioral obesity treatment. METHODS In a 3-year longitudinal study, obese children (n = 684) were divided into three groups based on age at the start of treatment, age 6-9 years, 10-13 years, and 14-16 years. RESULTS The mean BMI standard deviation score (BMI-SDS) decline was age-dependent (p = 0.001), independently of adjustment for missing data: -1.8 BMI-SDS units in the youngest, -1.3 in the middle age group, and -0.5 in the oldest age group. SES and parental BMI status did not affect the results. 30% of the adolescents remained in treatment at year 3. There was only a weak correlation between BMI-SDS change after 1 and 3 years: r = 0.51 (p < 0.001). Among children with no BMI-SDS reduction during year 1 (n = 46), 40% had a clinically significantly reduced BMI-SDS after year 3. CONCLUSION Behavioral treatment should be initiated at an early age to increase the chance for good results. Childhood obesity treatment should be continued for at least 3 years, regardless of the initial change in BMI-SDS.