gastric bypass

A long-term follow-up study shows some potential for modest sustainable weight loss in severely obese adolescents following gastric bypass, but recommends close monitoring for nutritional deficiencies.


Severe childhood obesity – defined as having a body mass index (BMI) at least 120% higher than the 95th percentile for age and sex – is a growing concern in western nations. Currently, it is estimated that 4.6 million children and adolescents in the United States fall into this category. In addition to posing health risks not normally encountered in childhood, this condition also has a serious impact on quality of life and life expectancy for affected children.

Treatment of severe obesity in children typically focuses on non-operative interventions, which unfortunately tend to be of limited effectiveness.  While surgical interventions – in particular, gastric by-pass – have been used on obese adults with relative success for many years, they have only sparingly been performed on children.  An important concern inhibiting greater use of surgery on younger patients is the lack of knowledge about potential long-term risks and benefits, and whether weight loss from surgery is likely to be sustainable over time.

A study recently published in The Lancet has attempted to address that gap in knowledge. The study involved 57 obese adolescent patients between 13 and 21 years of age who underwent Roux-en-Y gastric bypass surgery.  Patients were then followed for varying periods of time ranging from 5 to 12 years (mean follow-up of 8 years) after the surgery to evaluate for durability of surgical outcomes (reduced BMI) as well as health indicators such as prevalence of diabetes, hypertension and dyslipidaemia (elevated lipids), changes in micronutrient levels, and other clinical events.

At the start of the study, all participants were severely obese and had a BMI over 40 kg/m2. The mean BMI of the group was 58.5 kg/m2. In the first year after surgery, the mean BMI of the group decreased by 22.8 kg/m2, indicating noteworthy benefits from the procedure.  Over the longer-term, some of those benefits were lost; the decrease in mean BMI over baseline declined to 16.9 kg/m2 at long-term follow-up. Overall, however, there was a mean sustained weight loss across the group of 49.9 kg at long-term follow-up.

Other benefits from the procedure were also noted. For example, participants showed significantly reduced rates of high blood pressure (from 47% of participants at baseline to 16% at long-term follow-up), dyslipidemia (from 86% at baseline to 38% at long-term follow-up) and type 2 diabetes (from 16% at baseline to 2% at long-term follow-up).

On the other hand, 46% of the participants were found to have mild anemia (not requiring intervention) at long-term follow-up; 45% had hyperparathyroidism; and 16% had low amounts of vitamin B12 (below the normal cutpoint).

Overall, participants did demonstrate improvements in weight reduction that were sustained to some extent over the follow-up period. At long-term follow-up, 48 of the 57 participants had a 10% or greater reduction in BMI compared with baseline.

Even with these improvements, however, most participants remained obese. At the time of long-term follow-up, one participant had achieved a healthy body weight (BMI 18.5 kg/m2 to <25 kg/m2).  Ten were overweight (BMI 25 kg/m2 to <30 kg/m2), and ten had class one obese status (BMI 30 kg/m2 to <35 kg/m2). Thirty-six of the 57 participants had a BMI of 35 kg/m2 or higher at long-term, even though significant weight loss had initially occurred in the post-operative period.

Based on these results, the authors of the study consider that Roux-en-Y gastric bypass surgery offers some potential for sustainable benefits in adolescents and young adults, in terms of both bodyweight reduction and cardiometabolic indicators. However, they caution that long-term sustainability of benefits requires adherence to dietary regimes and vigilance in monitoring for micronutrient deficiencies.


Written By: Linda Jensen

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