OBJECTIVE There has been a widespread misconception among physicians that African Americans are protected from developing nonalcoholic steatohepatitis (NASH). However, a formal histologic and metabolic comparison against well-matched Caucasians has never been performed.

RESEARCH DESIGN AND METHODS Sixty-seven African American patients were matched 2:1 to Caucasians (n = 134) for age, sex, BMI, hemoglobin A_1c, and prevalence of type 2 diabetes mellitus (T2DM). Screening for NASH included measurement of intrahepatic triglyceride content by proton MRS (¹H-MRS), followed by a liver biopsy if patients had hepatic steatosis. Insulin resistance was estimated during an oral glucose tolerance test using the Matsuda Index.

RESULTS Compared with Caucasians, African American patients had a lower intrahepatic triglyceride content (mean ± SD 6.1 ± 6.8% vs. 9.4 ± 7.5%, P = 0.007) and the presence of nonalcoholic fatty liver disease (NAFLD) was less common (25.0% vs. 51.9%, P = 0.003). However, prevalence of NASH was not different between ethnicities in patients with NAFLD (57.1% vs. 73.3%, P = 0.12). Moreover, they showed similar severity in each of the individual histologic parameters (inflammation, ballooning, and fibrosis). Among patients with NAFLD, insulin resistance was similar between both ethnic groups (Matsuda Index: 3.3 ± 1.8 vs. 3.1 ± 1.9, P = 0.61; adipose tissue insulin resistance [Adipo-IR] index: 5.7 ± 4.6 vs. 6.4 ± 4.7 mmol/L ⋅ µU/mL, P = 0.53) but appeared to be worse in African American versus Caucasian patients without NAFLD (Matsuda Index: 4.9 ± 3.6 vs. 7.0 ± 4.9, P = 0.11; Adipo-IR: 3.9 ± 2.8 vs. 2.7 ± 2.3 mmol/L ⋅ µU/mL, P = 0.06). African American patients also had lower plasma triglycerides and higher HDL cholesterol, independent of the severity of intrahepatic triglyceride.

CONCLUSIONS Although African Americans have lower intrahepatic triglyceride accumulation, once NAFLD develops, NASH occurs as frequently, and as severe, as in Caucasian patients. Therefore, African Americans with NAFLD should be screened for NASH with the same degree of clinical resolve as in Caucasian patients.

目的在医生中普遍存在一种误解，即非洲裔美国人受到保护免于发展为非酒精性脂肪性肝炎（NASH）。但是，从未进行过针对匹配的高加索人的正式组织学和代谢比较。

研究设计与方法在年龄，性别，BMI，血红蛋白A _1c和2型糖尿病（T2DM）患病率方面，有67名非裔美国人与高加索人（n = 134）2：1配对。NASH的筛查包括通过质子MRS（¹ H-MRS）测量肝内甘油三酸酯含量，如果患者患有肝脂肪变性，则进行肝活检。使用Matsuda指数在口服葡萄糖耐量试验期间评估胰岛素抵抗。

结果与高加索人相比，非洲裔美国人肝内甘油三酸酯含量较低（平均值±SD 6.1±6.8％与9.4±7.5％，P = 0.007），非酒精性脂肪肝病（NAFLD）的发生率较低（25.0％） vs. 51.9％，P = 0.003）。但是，NAFLD患者中不同种族的NASH患病率无差异（57.1％对73.3％，P = 0.12）。此外，他们在每个单独的组织学参数（发炎，膨胀和纤维化）中表现出相似的严重程度。在患有NAFLD的患者中，两个族裔的胰岛素抵抗相似（松田指数：3.3±1.8与3.1±1.9，P= 0.61; 脂肪组织胰岛素抵抗[Adipo-IR]指数：5.7±4.6 vs. 6.4±4.7 mmol / L⋅µU / mL，P = 0.53），但在非洲裔美国人中，与没有NAFLD的白人患者相比，情况更糟（Matsuda指数：4.9± 3.6 vs. 7.0±4.9，P = 0.11； Adipo-IR：3.9±2.8 vs. 2.7±2.3 mmol / L⋅µU / mL，P = 0.06）。非裔美国人患者的血浆甘油三酸酯含量较低，而HDL胆固醇较高，与肝内甘油三酸酯的严重程度无关。

结论尽管非裔美国人的肝内甘油三酸酯蓄积量较低，但一旦发展为NAFLD，NASH的发生频率与白种人患者一样频繁且严重。因此，应以与白种人患者相同的临床决心对具有NAFLD的非洲裔美国人进行NASH筛查。