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NAFLD prevalent in adolescents undergoing bariatric surgery

In the Teen-Longitudinal Assessment of Bariatric Surgery study, researchers found that more than half of obese adolescents undergoing bariatric surgery had nonalcoholic fatty liver disease, according to published findings in Gastroenterology.

“Severe obesity is highly prevalent among children and adolescents with nonalcoholic fatty liver disease in the United States. … The Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) study, a prospective observational longitudinal cohort study of 242 adolescents undergoing bariatric surgery at five tertiary care centers in the United States, offers the opportunity to determine the biopsy-confirmed prevalence and determinants of NAFLD in a larger multicenter cohort of severely obese adolescents,” the researchers wrote.

Researchers enrolled the patients who were undergoing bariatric surgery between March 2007 and February 2012 and were able to collect intraoperative core liver biopsies from 165 of them to include for analysis. Seventeen of these patients were ultimately excluded because of insufficient liver tissue or use of hepatotoxic medications. Therefore, a total of 148 adolescents were included in the final analysis cohort (mean age, 16.8 ± 1.6 years; median BMI = 52 kg/m²). The researchers also conducted hepatic gene expression analyses in 67 liver biopsy samples to “elucidate biological pathways underlying NAFLD phenotypes,” according to the study.

Overall, 59% of patients had NAFLD, of which 24% had borderline nonalcoholic steatohepatitis and 10% had definite NASH. Among the examined liver biopsies, stage 2 or lower fibrosis was found in 18% and stage 3 fibrosis was found in 0.7%. Cirrhosis was not observed in any of the patients. In addition, dyslipidemia was found in 78%, hypertension was found in 44% and diabetes in 14% of patients.

Multivariate analysis showed that more severe NAFLD was associated with increasing levels of alanine aminotransferase, fasting glucose level, hypertension (P < .01 for all) and white blood cell count (P = .04). Further analysis showed only diabetes was associated with detection of fibrosis (OR = 3.56; 95% CI, 1.93-6.56).

The gene expression analysis showed that the presence of NASH was associated with altered expression of genes that regulate macrophage chemotaxis, cholesterol absorption and fatty acid binding.

“We found that although NAFLD was common, advanced NASH was rare in this multicenter cohort of severely obese adolescents undergoing bariatric surgery. … Whether there are potential protective biological factors unique to severe obesity, [it] requires further study,” the researchers concluded. “We are following a subset of adolescent participants in Teen-LABS longitudinally to determine long-term ALT change and histologic outcome of NASH, but it will also be critical to conduct prospective controlled studies in severely obese adolescents with more advanced NASH to guide practitioners and patients on optimal treatment for NASH in the most severely obese.” – by Melinda Stevens

Disclosures: The researchers report no relevant financial disclosures.