How Often Do Children with Obesity Have a Fatty Liver?

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According to a recent study (EL Yu et al. J Pediatr 2019; 207: 64-70), about one-third of boys and one-fourth of girls with obesity have nonalcoholic fatty liver disease (NAFLD).

This study from San Diego with 408 children aged 9-17 years (mean 13.2 years) with obesity evaluated for NAFLD with laboratories (to exclude other etiologies) and with liver MRI proton density fat fraction (PDFF), with ≥5% considered the threshold for NAFLD.

Key findings:

  • Prevalence of NAFLD was 26% in this population, with 29.4% in males and 22.6% in females
  • The optimal cut offs of ALT for detecting NAFLD in this study were ≥30 U/L for females and ≥42 U/L for males. These are much lower than NASPGHAN guidelines which proposed ≥80 U/L or twice the ULN as thresholds for further investigation.  (The NASPGHAN recommendations are likely to have higher specificity in identifying children at greater risk for nonalcoholic steatohepatitis (NASH).)

Limitations:

  • 77% of this cohort were hispanic, thus prevalence may vary significantly in other populations.
  • MRI-PDFF -the exact cut off is unclear.  The authors note that if 3.5% were chosen, the NAFLD prevalence jumped to 49.3% (according to Table II –though the discussion stated 53.2%)

My take: Understanding the likelihood of NAFLD in children at risk is a helpful first step.  This study points to the growing use of non-invasive diagnosis with MRI.

On a related topic, briefly noted: “Obesity in Adolescents and Youth: The Case for and against Bariatric Surgery” (A Khattab, MA Sperling. J Pediatr 2019; 207: 18-22). In this review, the authors refer frequently to endocrine society guidelines (J Clin Endocrinol Metab 2017; 102: 709-57).    These guidelines generally recommend bariatric surgery only under specific conditions (eg. completion of Tanner 4 or 5 along with a BMI of 40 kg/m-squared or BMI of 35 with significant extreme comorbidities after failure of lifestyle modifications & without untreated psychiatric illness).  This review predicts increasing use of bariatric surgery in adolescents “as more data on long-term outcomes in larger cohorts become known.”

Related blog posts on fatty liver disease:

Related blog posts on bariatric surgery: