Research indicates that rates of severe obesity among adolescents are increasing around the world, with no signs of slowing. Although the first recommended intervention for severely obese adolescents remains lifestyle modification, according to Stavra Xanthakos, MD, MS, the majority of patients in this population do not experience significant sustained weight loss with this approach. Evidence suggests that, in an attempt to resolve this issue, the rate of bariatric surgeries conducted on adolescents has increased in recent years. Bariatric surgery can lead to increased quality of life and sustained weight loss, and resolve serious comorbidities in adolescents but comes with the major long-term risk of developing nutritional deficiencies. With research lacking on how this affects adolescents who have received the intervention, Dr. Xanthakos and colleagues conducted a 5-year study, published in Clinical Gastroenterology and Hepatology, to better understand the nutritional risks in adolescents after bariatric surgery.

For the study, the researchers sought to determine the prevalence of nutritional deficiencies after more than 200 adolescents had undergone roux-en-y gastric bypass or sleeve gastrectomy from 2007-2012. The study team measured serum levels of ferritin; red blood cell folate; vitamins A, D, B1, B12; and parathyroid hormone at baseline and annually. “We broke our analysis into two phases,” explains Dr. Xanthakos: “changes in the first year of rapid weight loss and then changes from 1 to 5 years, after weight had generally stabilized.” The team also sought to better understand risk factors associated with developing nutritional deficiencies, in the hope of identifying modifiable factors and ultimately being able to reduce nutritional risk.

Both procedures resulted in similar weight loss, with a mean body mass decrease of 23%. However, sleeve gastrectomy resulted in a lower risk of nutritional deficiencies. The primary risk for sleeve gastrectomy in adolescent patients was iron deficiency, which was increased in patients who did not adhere to recommended dietary supplements. Ferritin levels significantly decreased in both groups at the 5-year mark, with hypo-ferritinemia prevalence of 71% after roux-en-y gastric bypass and 45% following sleeve gastrectomy. At 5 years post operation, the prevalence of two or more deficiencies was 59% in those who underwent roux-en-y gastric bypass, compared with 27% among those who received sleeve gastrectomy. “Beyond surgery type, other risk factors associated with increased nutritional risk after the first year included female sex (iron), interval weight regain after the first year (iron, vitamin D, parathyroid hormone) and black race (vitamin A, vitamin D and parathyroid hormone),” explains Dr. Xanthakos.