Objective: Leptin resistance is discussed to be involved in the genesis of obesity. Therefore, we hypothesized that leptin levels were negatively associated with degree of weight loss in obese children participating in a lifestyle intervention.
Methods: We studied 248 obese children aged 8-14 years attending the "Obeldicks" lifestyle intervention (mean age 10.6+/-0.2 years, 53% female, 48% pubertal, mean body mass index (BMI) 27.8+/-0.3 kg/m2, and mean standard deviation score [SDS]-BMI 2.43+/-0.03). Baseline leptin concentrations were correlated with change of weight status, waist circumference, and percentage body fat, as calculated from skinfold measurements in the one-year intervention by Pearson correlation and multiple linear regression analyses. Furthermore, the relationship between leptin and cardiovascular risk factors (insulin, insulin resistance index HOMA, blood pressure, lipids, and glucose) were analyzed.
Results: A total of 212 children (85%) reduced their overweight, 9 children (4%) dropped out, and 27 children (11%) did not reduce their overweight in the lifestyle intervention "Obeldicks". The mean reduction of SDS-BMI was 0.34+/-0.02. The reduction of SDS-BMI (r=- 0.27), waist circumference (r=- 0.64), and percentage body fat (r=- 0.26) were significantly negatively associated with baseline leptin levels both in univariate analyses and in multiple regression analyses, adjusted to baseline age, BMI, gender and pubertal stage. Baseline leptin concentrations were significantly associated with BMI, pubertal stage, gender, waist circumference, and insulin, but not to any other cardiovascular risk factors in multiple regression analyses.
Conclusions: The finding that baseline leptin concentrations were significantly negatively correlated with the degree of weight loss in a lifestyle intervention supports the hypothesis of leptin resistance in obesity. This study is registered at clinicaltrials.gov (NCT00435734).