Protective effect of black relative to white race against non-alcoholic fatty liver disease in patients with severe obesity, independent of type 2 diabetes

Abstract

Severe obesity (body mass index ⩾35 kg m) and type 2 diabetes (T2D) are potent and additive risk factors for non-alcoholic fatty liver disease (NAFLD), including non-alcoholic steatohepatitis (NASH). Scant available evidence indicates that black relative to white patients with severe obesity are less susceptible to NAFLD, but it is unclear if T2D abolishes this apparent racial disparity. Therefore, we compared biopsy-proven NAFLD and its progression between black (n=71) and white (n=155) patients with severe obesity stratified by presence or absence of T2D. Although prevalence of T2D was similar between races (37%, P>0.9), whites were significantly more likely than blacks to have NAFLD, NASH and advanced fibrosis (defined as bridging fibrosis and/or cirrhosis). Importantly, T2D was associated with increased odds of NAFLD, NASH and advanced fibrosis (defined as bridging fibrosis or cirrhosis) in whites only (P<0.05). In turn, a higher proportion of blacks than whites with T2D were free of NAFLD (58 versus 22%, P<0.01). These preliminary findings question translation of the powerful interconnection between T2D and NAFLD in whites with severe obesity to blacks and point to an important role of race in the pathophysiology and treatment of these diseases.

Ethnic influence on nonalcoholic fatty liver disease prevalence and lack of disease awareness in the United States, 2011–2016

“…Although, we must keep in mind that we used the NFS to determine fibrosis which has not been validated in African Americans. Thus, we may have overestimated the number of non‐Hispanic Blacks with fibrosis so caution must be used when interpreting these findings, but also, our findings do suggest that more research is needed to better understand NAFLD within the non‐Hispanic Black population .…”

Racial Disparities in Diagnosis and Prognosis of Nonalcoholic Fatty Liver Disease

“…1. T2D was shown to increase risk for NAFLD and NASH in whites compared with blacks 12 . Distribution of metabolic factors and susceptibility to metabolic factors varies between races.…”

“…However, despite similar prevalence of T2D and obesity among blacks compared with whites, the latter group has significantly higher risk for NAFLD 13,14 . Browning et al 12 compared biopsy‐proved NAFLD and its progression between black and white patients with severe obesity stratified by the presence or absence of T2D. Whites were significantly more likely than blacks to have NAFLD, NASH, and advanced fibrosis.…”

Prevalence and long-term outcomes of non-alcoholic fatty liver disease among elderly individuals from the United States

“…Most individuals with NAFLD have components of metabolic syndrome (MS) such as type 2 diabetes (T2D), dyslipidemia, hypertension and visceral obesity [3–8]. Additionally, NAFLD seems to be more common in Hispanics and less common in African Americans [9–11]. Although gender-specific differences in the prevalence of NAFLD have been debated, increasing age does seem to have an influence by increasing the prevalence of NAFLD [1, 12, 13].…”