Introduction. Childhood obesity is a global epidemic that greatly effects the American population. In 2014, the prevalence of obesity and severe obesity in children and adolescents (ages 2 to 19 years) is 17% and 5.8%, respectively (1). Obesity in children is defined as a body mass index (BMI) ³ 95th percentile BMI-for-age and severe or extreme obesity in children or adolescents is defined as a BMI ³ 120% of the 95th percentile BMI-for-age. Critical periods for the development of obesity that occur during childhood have been characterized as gestation and infancy, adiposity rebound (~5-7 years of age), and adolescence (2). Bariatric surgery has been previously shown to be an effective and safe treatment for adolescents with severe obesity (3-6). There is very little research in predictors of weight loss in this population. Identifying predictors of weight loss in adolescents will provide guidance for decisions on treatment plans of obesity. The aim of this study were to examine the relationship between age of onset of obesity, preoperative weight loss, and weight loss outcomes following bariatric surgery in adolescents. We hypothesized that those who develop obesity earlier in life would have less successful weight loss outcomes, and that pre-operative weight loss would predict more successful weight loss outcomes following surgery.
Methods. We retrospectively reviewed the medical records of 50 patients (ages 9-18) who underwent vertical sleeve gastrectomy. Data extracted included reported age of onset of obesity and weight, BMI, body fat percentage (BF%), fat mass (FM), and fat free mass (FFM) at three time points (initial visit, pre-op, and 1-year post-op). Duration of obesity was calculated by subtracting age of onset of obesity with age at time of surgery. Percent of total weight loss (%TWL) and change in BMI (∆ BMI) were calculated from the extracted data. Body composition was measured by bioimpedance analysis (BIA; Body Composition Analyzer model TBF-310, Tanita, Tokyo, Japan).
Little research has examined predictors of successful weight loss in adolescents. Adult studies report that neither pre-operative weight loss not duration of obesity does not predict post-operative weight loss by 12 months following bariatric surgery (7,8). Age of onset of obesity has been shown to not predict weight loss in adults undergoing a behavioral weight loss intervention(9).
In this retrospective analysis of bariatric surgery in adolescents, we found that age of onset of obesity, duration of obesity, or weight loss during the evaluation period prior to surgery was not a significant predictor of weight loss outcomes following a sleeve gastrectomy. More research with a larger population needs to be completed to confirm our findings.