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The Aftermath of Bariatric Surgery in Adolescents

Jul 9, 2016

The benefits of weight loss surgery for younger patients may persist for years.

Adolescent obesity is becoming an epidemic, with numbers doubling from 800 to 1,600 from 2003 to 2009. Bariatric surgery is one of the feasible therapies for seriously obese adolescents. It includes a variety of procedures: reducing the size of a stomach with a gastric band, or removal of a portion, or resecting or rerouting to a small stomach pouch. To date there have been limited prospective studies analyzing BMI and other outcomes of currently used procedures. The purpose of this study is to examine the efficacy and safety of bariatric surgery in adolescents, even years after treatment.


For this prospective, multicenter, observational study, adolescents who were less than ≤19 years, obese and undergoing bariatric surgery were recruited. The Committee of the study was made up of a Principal Investigator, a Data Coordinator, and a project scientist; this took place from March 2007 to February 2012. Data was collected at 6 months, 1, 2 and 3 years postoperative, with most research visits taking place at clinical centers or the subjects’ homes. Outcomes measured were weight loss, quality of life, coexisting conditions and micronutrient outcomes, using linear mixed and separate models. Poisson regression was also used to calculate unadjusted rates and 95% confidence interval.

Of the 242 adolescents recruited, 161 (67%) did Roux-en-Y gastric bypass and 67 (28%) did sleeve gastrectomy. 98% of participants had a BMI of more than 40, with the majority from a low income household. 99% of the cohort participated and completed 88% of all postoperative visits through the 3-year study endpoint. 90% completed all visits at 1 year, 89% at 2 years and 85% at 3 years. The mean weight reduction at 3 years was 41 kg, with a mean percentage weight loss of 27% (95% confidence interval, P<0.001).

At baseline, all participants were obese with a BMI>30, but by 3 years 26% were no longer obese. 96 participants had an elevated blood pressure at baseline, but normalized by 3 years after their surgery with 74% of them having 95% confidence interval. For 171 participants with dyslipidemia at baseline, 66% were at a normalized value at 3 years (95% confidence interval, P<0.001) without lipid-lowering therapy drugs. For participants with abnormal kidney function, 86% of them had a normalized kidney function (95% confidence interval). For diabetes, there was no improvement in patients with type 1 after 3 years, but type 2 had a confidence interval of 95%, median glycated hemoglobin of 5.3%, a median fasting glucose of 88 mg/dl and median insulin of 12 IU/ml. The mean quality of life score was 63 (95% CI) at baseline, but increased to 83 by 3 years with a P<0.001 after the surgery.

For nutritional measures, patients had low levels of ferritin at the end of 3 years from baseline with 57% (95% confidence interval) and P<0.001. For vitamin B12 only 8% had a deficiency at the end of 3 years as compared to a baseline of 35%. 16% of participants who went through this surgery had vitamin A deficiency at the end of 3 years. One participant died from complications of hypoglycemia 3 years after surgery. Of the intra-abdominal procedures related to bariatric surgery 24% were performed within the first year, 55% within the second year and 21% within third year.

In conclusion, there was a significant reduction of weight, obesity, and coexisting conditions, and increase in their quality of life. However, there were specific deficiencies in micronutrients; therefore multivitamin and mineral supplementation is needed.  Abdominal procedures show an increased risk with bariatric surgery in the adolescent population. A study of 53 younger adolescents with a mean age of 14 years had a mean BMI decrease of 20, and an increase of 5 cm in mean height  3 years after sleeve gastrectomy. This indicates that adolescents can lose a clinically significant amount of weight after bariatric surgery, and the majority of patients were able to maintain meaningful weight loss for at least 3 years. The weakness of this study includes the use of a small population size, especially the diabetes sample size, also the observational nature of the study introduces heterogeneity into the data. Additionally, the lack of a control group made it difficult to place the postoperative changes in weight and health status completely into perspective since behavioral treatment can result in modest improvement in weight and cardio-metabolic health.

Practice Pearls:        

  • Adolescents can lose a drastic amount of weight after bariatric surgery, and most of them are able to maintain their weight loss for at least 3 years or more.
  • In addition to the weight loss, there are improvements in glycemic control, blood pressure, and dyslipidemia. This could alleviate the advancement of adverse anatomical and cardiovascular changes which are less reversible after additional weight gain later in life.
  • 3 years after sleeve gastrectomy, they had a BMI decrease of 20 and an increase of 5 cm in mean height.


Inge, Thomas H. et al. “ Weight loss and Health Status 3 Years after Bariatric Surgery in Adolescents” The New England Journal of Medicine  374(2).(2016) Web June 8 2016

Paul J. Samuels, Matthew D. Sjoblom. (2016) Anesthetic considerations for pediatric obesity and adolescent bariatric surgery. Current Opinion in Anaesthesiology 29:3, 327-336 Web June 8 2016

Skinner AC, et al. “Prevalence and Trends in Obesity in Children and Adolescents”: identification, associated health risks, and treatment approaches: American Heart Association.128:1689-712 (2013) Web June 8 2016

Daniels SR, et al. “Pediatric severe obesity: time to establish serious treatment for a serious disease. Child Obes10:283-4 (2014) Web June 8 2016

Van Baan-Slootweg D. et al. Inpatient treatment of children and adolescents with severe obesity in the Netherlands: JAMA Pediatric 168:807-14 (2014) Web June 8 2016