Gastric bypass surgery helps severely obese teenagers lose weight and keep it off, according to the first long-term follow-up studies of teenagers who had undergone the procedure 5-12 years earlier. However, the two studies, published in The Lancet Diabetes & Endocrinology, show some patients will likely need further surgery to deal with the complications of rapid weight loss or may develop vitamin deficiencies later in life.
Severe obesity is classified as having a BMI of 40 or over (around 100 pounds overweight) and affects around 4.6 million children and teenagers in the USA. Obesity causes ill health, poor quality of life and cuts life expectancy.
The studies are the first to look at long-term effects of gastric bypass surgery in teenagers. Until now, it has been unclear how successful the surgery is in the long-term and whether it can lead to complications. Despite this thousands of teenagers are offered the surgical treatment each year.
Both papers showed that gastric bypass dramatically reduced the teenagers’ weight and helped them maintain weight loss over more than five years of follow-up. However, the surgery was associated with the development of vitamin D and B12 deficiencies and mild anaemia, and some of those who had a bypass needed further surgery to deal with complications. While the surgery resulted in dramatic weight loss and BMI reductions, many of the teenagers remained obese, meaning that earlier intervention may be needed coupled with lifestyle changes such as diet and exercise.
In the first paper, researchers studied 58 American teenagers aged between 13 and 21 who were severely obese and had a gastric bypass.
Average BMI was reduced from 59 before surgery to 36 a year after surgery. Eight years later, average BMI was 42, equivalent to a loss of 50 kilos per person or a 30% weight reduction. Although the weight loss was significant, almost two-thirds of cases (63%, 36/57) remained very obese (BMI over 35) and only one person became a normal weight (BMI 18.5-25) at follow-up.
The number of teenagers with diabetes dropped from 16% to 2%, those with high cholesterol reduced from 86% to 38%, while the number with high blood pressure decreased from 47% to 16% as a result of the surgery. However, some had low levels of vitamin D (78%, 39/50), B12 (16%, 8/50) and mild anaemia (46%, 25/54), which could be a result of lower food consumption or impaired gut absorption.
Given the long-term weight loss and health benefits that result from the surgery, the researchers note that these benefits outweigh the small and manageable risk of nutritional deficiencies.
“Weight loss is crucial for severely obese patients who face poor health and shorter lifespans,” said lead author Dr Thomas Inge, Cincinnati Children’s Hospital Medical Center, USA. “These two manuscripts clearly document long-term benefits of adolescent bariatric treatment, but also highlight several nutritional risks. Now it is important to focus on delivery of the substantial health advantages of surgery while minimizing these risks. Since there are currently two effective bariatric procedures, namely gastric bypass and vertical sleeve gastrectomy, we are currently examining the outcomes of both procedures to determine what is best for adolescents.”