Weight loss in obese African American and Caucasian adolescents - Secondary analysis of a randomized clinical trial of behavioral therapy plus sibutramine

Background: Obesity, a major risk factor for cardiovascular disease, is more prevalent in African American adolescents than in their Caucasian counterparts. Effective weight loss treatment options are required to aid in the reduction of this health disparity. The purpose of this study, a secondary analysis of data collected as part of a double-blind, randomized clinical trial of behavioral and pharmacologic weight loss, was to examine and compare changes in weight loss and cardiometabolic risk factors in African American and Caucasian adolescents. Methods: Analysis included 34 African American and 45 Caucasian obese boys and postmenarcheal girls. The participants were randomized to family-based behavioral therapy plus placebo or family-based behavioral therapy plus sibutramine. Changes in weight, body mass index, % body mass index, fasting glucose, insulin, homeostatically assessed insulin resistance, and lipid levels were measured at baseline and month 6. Results: Mean age was 14.1 years (range 13-17 years). Average body mass index was 37.8 kg/m(2) (32-44). Retention was 88.2% for African American adolescents and 91 % for Caucasian adolescents. At baseline, African American adolescents had lower waist circumferences, triglycerides, serum glucose, and higher high-density lipoprotein cholesterol levels. At month 6, percent change in body mass index and weight loss was significantly greater in the Caucasian drug group than in placebo, whereas the weight loss for African Americans in the drug group versus those in the placebo group was not significant but had a medium effect size (Cohen d = 0.64). Irrespective of treatment group, those losing > 5% of initial BMI had significant reductions in waist circumference. Caucasians had significant reductions in triglycerides, high-density lipoprotein cholesterol, glucose, insulin, and homeostatically assessed insulin resistance levels; African American responders had significant reductions in triglycerides, insulin, and homeostatically assessed insulin resistance. Conclusion: Sibutramine impacted reductions in weight loss in both African American and Caucasian teens. Weight loss, whether by behavioral therapy alone or in combination with pharmacotherapy, produced beneficial changes in cardiometabolic risk factors in adolescents from both racial groups. Limitations included a small sample size. Longer-term obesity intervention studies addressing retention, acceptability, safety, and treatment effect on cardiometabolic risk are critical to reducing health disparities.