Body composition among adults at a healthy body mass index and association with undetected non-alcoholic fatty liver

Abstract

Background: Adults with a healthy Body Mass Index but elevated body fat are at risk for a variety of undetected metabolic problems. It is unclear whether non-alcoholic fatty liver is associated with this body type.

Participants/methods: Associations between elevated body fat and non-alcoholic fatty liver disease (NAFLD) among adults with a healthy Body Mass Index (18.5-24.9) were assessed. A cohort of healthy BMI, non-pregnant, adults without history of liver disease or recent heavy drinking was constructed from the NHANES 2017-2018 survey. Body fat percentages were determined from whole-body DXA scans. Liver ultrasound transient elastography indicated the presence of hepatic steatosis.

Results: A significantly larger proportion of adults with an elevated body fat % (46.2%) than those with a healthy body fat % (25.1%) (p = 0.002) had undiagnosed NAFLD. In a logistic regression adjusted for age, sex, race/ethnicity, and exercise, hepatic steatosis was associated with an elevated body fat percentage within the cohort of adults with a healthy BMI (OR 3.51; 95% CI 2.11-5.86).

Conclusion: The usefulness of alternative body composition measures should be considered when screening for NAFLD.