Target Audience and Goal Statement: Bariatric surgeons, endocrinologists, pediatricians, primary care physicians, family medicine specialists
The goal of this 5-year prospective cohort study was to determine the prevalence of, and risk factors for, nutritional deficiencies in adolescents who underwent bariatric surgery.
Question Addressed:
- What is the prevalence of, and risk factors for, nutritional deficiencies in adolescents who underwent bariatric surgery at 5-year follow-up?
Study Synopsis and Perspective:
Adolescents who underwent bariatric surgery, particularly Roux-en-Y gastric bypass (RYGB), had an elevated risk for nutritional deficiencies at 5 years, according to results from a study by the Teen Longitudinal Assessment of Bariatric Surgery (Teen-LABS) consortium.
Action Points
- Adolescents who underwent bariatric surgery — particularly Roux-en-Y gastric bypass, but also vertical gastric sleeve — had an elevated risk for nutritional deficiencies at 5 years, according to results from a study by the Teen Longitudinal Assessment of Bariatric Surgery consortium.
- Understand that because adolescents have an anticipated longer lifespan, it is recommended that they be closely monitored for nutrient deficiencies in an ongoing manner and given supplements to treat these deficiencies.
Five years after surgery, 59% of RYGB recipients and 27% of vertical sleeve gastrectomy (VSG) recipients had two or more nutritional deficiencies, according to Stavra Xanthakos, MD, MS, of Cincinnati Children’s Hospital Medical Center, and colleagues.
Researchers enrolled; 161 patients had undergone RYGB and 65 had undergone VSG. The participants were 75% female and 72% white, with a mean age of 16.5 years and a mean body mass index (BMI) of 52.7 kg/m2 at the time of surgery. Mean BMI decreased by 23% at 5 years in both groups.
Following RYGB surgeries, serum concentrations of vitamin B12 significantly decreased, while serum levels of transferrin and parathyroid hormone increased. Ferritin levels decreased significantly after both RYGB and VSG: hypoferritinemia was diagnosed in 2.5% of patients before RYGB and in 71% at 5 years (P<0.0001), and in 11% of patients before VSG and in 45% at 5 years (P=0.002), the authors reported in Clinical Gastroenterology and Hepatology.
At baseline and once yearly for 5 years, researchers measured serum levels of vitamins A, D, B1, and B12; ferritin; red blood cell folate; and parathyroid hormone. General linear mixed models were used to examine changes over time and identify factors associated with nutritional deficiencies.
Higher multivitamin intake was associated with higher ferritin, vitamin B12, folate, vitamin A, and 25-hydroxyvitamin D levels and reduced odds of vitamin D deficiency. Vitamin D and calcium supplementation were not associated with parathyroid hormone levels or abnormality.
There were no significant changes in serum folate or vitamins A, B1, or D between baseline and 5 years after either procedure.
For both groups, risk factors associated with specific deficiencies included surgery type, female sex, black race, supplementation intake, weight regain, and pregnancy.
The authors noted that while bariatric surgery is an increasingly accepted treatment for severe obesity in young people, post-surgical nutritional deficiencies have been estimated largely from adult cohorts. “Yet, lower adherence to supplementation and anticipated longer lifespan with altered gastrointestinal physiology may increase risk of adverse nutritional outcomes in these youth,” they wrote.
The differential nutritional risk profiles associated with the two surgical procedures point to a need to monitor patients undergoing bariatric surgery, as the numbers of these procedures are likely to increase as the prevalence of childhood and adolescent obesity and associated morbidities grow. VSG is now the predominant bariatric surgery in adolescents and adults due to its limited anatomical alteration, lower operative risk, and presumed lower risk of nutritional deficits.
“Our results now provide critical evidence that VSG does in fact carry significantly lower nutritional risk than RYGB, but can still worsen iron status,” the authors wrote.
Study limitations included some missing data and the limited number of nutritional measures available, which prevented full characterization of iron and vitamin B12 nutriture. In addition, copper, zinc, and vitamin E were not assessed, and the self-reported supplement intake by participants was likely to entail appreciable error, possibly biasing findings towards the null. Data on dietary intake and non-recommended supplements were also lacking, the authors noted.
Source Reference: Clinical Gastroenterology and Hepatology 2019; DOI: 10.1016/j.cgh.2019.10.048
Study Highlights and Explanation of Findings:
The study authors noted that nutritional deficiencies associated with bariatric surgeries are “a significant concern” and may lead to morbidities including chronic anemia, osteoporosis, and/or permanent neurological problems if not diagnosed and managed. They noted that deficiencies found in the first year after surgery may not reflect what is found at 5 years.
“Lifelong micronutrient supplementation is therefore recommended,” the authors wrote. Nutritional deficiencies are an especially pressing concern for adolescents, given their anticipated longer lifespan and lower likelihood of adhering to supplementation regimens.
Because more is known about adult nutritional deficiencies, the authors designed this prospective study to determine what deficiencies exist among adolescents who have undergone RYGB or VSG procedures. Previous trials had been retrospective single-center studies, they noted.
This is the first study to evaluate nutritional deficiencies in adolescents after both types of bariatric surgery, examining longitudinal changes in iron status and vitamins A, B12, B1, D, albumin, folate, and calcium. The authors hypothesized that nutritional deficiencies would increase with time, particularly after RYGB.
The most widespread abnormality was hypoferritinemia, which affected nearly twice as many patients who had undergone RYGB compared with VSG at 5 years. Similarly, vitamin B12 status worsened disproportionately after RYGB.
Overall, RYGB was associated with a five-fold increase in two or more deficiencies, and a six-fold increase in three or more deficiencies by 5 years after surgery. VSG produced a four-fold — but not significant — increase in two or more deficiencies, “supporting a lower, but not negligible, nutritional risk,” the authors noted.
The iron and B12 deficiencies seen after RYGB mirror results from a 5-year Swedish cohort study of 81 teens who underwent RYGB surgeries, and also align with deficiencies found in adults undergoing this procedure, the authors wrote.
Adolescents and adults have high rates of vitamin D deficiency both pre- and postoperatively, which raises a red flag for fracture risk.
“Our findings underscore the importance of long-term nutritional monitoring in adolescents after bariatric surgery and the need to examine impact on health outcomes and quality of life as these youth advance into adulthood, including systematic assessment of anemia and bone health,” the researchers said.
The authors recommended that patients be monitored for nutrient deficiencies in an ongoing manner and given supplements to treat deficiencies.
Earlier this year, the Teen-LABS researchers reported that while weight loss was similar in teens to that in adults, at 26% and 29%, respectively, adolescents had a significantly higher rate of intra-abdominal reoperations within 5 years of initial surgery.
Asked for her perspective, Elizabeth Parks Prout, MD, MSCE, of Children’s Hospital of Philadelphia, who was not involved with the research, called the study “a wonderful follow-up, as the group’s prior publication on nutrition deficiencies after surgery did not include VSG.”
She added that while both procedures are safe and effective for treating obesity and serious comorbidities such as type 2 diabetes, obstructive sleep apnea, and high blood pressure, both surgeries do have complications.
“And it is a natural tendency for adolescents to decrease medication use during adolescence, so this study emphasizes the need for life-long follow-up,” Prout said. “After the 2-year visit, patients should have vitamin and mineral levels checked at least yearly. Adolescents with deficiencies prior to surgery are more likely to continue to have those deficiencies.”
She added that, surprisingly, the study did not find B1 deficiencies, which have been noted in adults after both surgeries. For example, a 2018 study by Tang and colleagues found a “troubling” higher risk of B1 deficiency in African Americans in the first 3 years.
“This study reinforces the pediatric follow-up and nutrition recommendations of the American Society for Metabolic and Bariatric Surgery published in 2018,” Prout said.
Reviewed by Henry A. Solomon, MD, FACP, FACC Clinical Associate Professor, Weill Cornell Medical College
Primary Source
Clinical Gastroenterology and Hepatology
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