We read with interest the article by Bril et al. (1). We commend the authors for undertaking this comparative study between Caucasians and African Americans using histologic analysis in an attempt to elucidate racial differences in nonalcoholic fatty liver disease (NAFLD). However, we are not convinced that the authors’ conclusion that nonalcoholic steatohepatitis (NASH) “occurs as frequently, and as severe[ly]” in African Americans as it does in non-Hispanic whites is definitive.
We agree that the prevalence of hepatic steatosis (fat) is lower in African Americans than it is in Caucasians (2), yet it is unclear whether the sample size of merely 67 African Americans provides adequate power to support the conclusion by Bril et al. that NASH in a fatty liver occurs as frequently in blacks as it does in whites (1). In a very recent large systematic review of 34 studies and over 350,000 subjects, the risk of NASH in patients with steatosis was lower in blacks relative to Caucasians (relative risk 0.72 [95% CI 0.60–0.87]) (3). Furthermore, polymorphisms in the patatin-like phospholipase domain-containing 3 (PNPLA3) gene (e.g., I148M variant) are genetic determinants of liver damage and progression associated with NASH (4), and without matching for these polymorphisms in the two groups, it is unclear whether the comparators are as “well-matched” as the authors contend. Moreover, self-reported ethnicity may not reflect the presence of widespread genetic heterogeneity, which may also account for some overlap between the groups.
Finally, it is crucial to point out that hepatic fibrosis is the most important histologic feature in NAFLD; it is independently predictive of liver-related mortality (5). In Bril et al. (1), the fibrosis scores were not statistically different between the ethnic groups. However, because of the aforementioned limitations between comparators, we don’t believe the results are definitive.
We strongly agree with the authors’ closing sentiment that larger prospective studies are warranted to confirm or refute these findings.
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Duality of Interest. No potential conflicts of interest relevant to this article were reported.
