Ethnicity and Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disorder in the U.S.; however, few data are available about racial and ethnic variation. We investigated relationships between ethnicity, NAFLD severity, metabolic derangements and socio-demographic characteristics in a well-characterized cohort of adults with biopsy-proven NAFLD. Data were analyzed from 1026 adults (≥18 years) in the Nonalcoholic Steatohepatitis Clinical Research Network (NASH CRN) from 2004–2008 for whom liver histology data were available within 6-months of enrollment. Associations between ethnicity (Latino versus Non-Latino White) and NAFLD severity (NASH versus Non-NASH histology; and mild versus advanced fibrosis) were explored with multiple logistic regression analysis. We also investigated effect modification of ethnicity on metabolic derangements for NAFLD severity. Within the NASH CRN, 77% (N=785) were Non-Latino White and 12% (N=118) Latino. Sixty-one percent (N=668) had NASH histology and 29% (N=291) had advanced fibrosis. Latinos with NASH were younger, performed less physical activity and had higher carbohydrate intake compared to Non-Latino Whites with NASH. Gender, diabetes, hypertension, hypertriglyceridemia, aspartate aminotransferase (AST), platelets, and the homeostasis model assessment of insulin resistance (HOMA-IR) were significantly associated with NASH. Age, gender, AST, alanine aminotransferase, alkaline phosphatase, platelets, total cholesterol, hypertension and HOMA-IR, but not ethnicity, were significantly associated with advanced fibrosis. The effect of HOMA-IR on risk of NASH was modified by ethnicity: HOMA-IR was not a significant risk factor for NASH among Latinos (Odds Ratio, OR=0.93 [95% Confidence Interval, CI, 0.85–1.02]), but was significant among Non-Latino Whites (OR 1.06, [95%CI 1.01–1.11]). Conclusion Metabolic risk factors and socio-demographic characteristics associated with NASH differ by ethnicity. Additional insights into NASH pathogenesis may come from further studies focused on understanding ethnic differences in this disease.