Nonalcoholic Fatty Liver Disease in Nonobese Subjects of African Origin Has Atypical Metabolic Characteristics

Nonobese nonalcoholic fatty liver disease is reported in several populations. However, because persons of African origin display unique fat accumulation, insulin resistance, and lipid profiles, we investigated fatty liver in nonobese persons of African origin.

We recruited 78 urban Jamaican volunteers. CT was used to estimate liver and abdominal fat and dual-energy X-ray absorptiometry to measure body composition. Fasting blood was collected for lipids, alanine aminotransferase (ALT), adiponectin, and fetuin-A. Homeostatic model assessment of insulin resistance (HOMA-IR), whole-body insulin sensitivity index (WBISI), insulinogenic index (IGI), and oral disposition index (oDI) were calculated after a 75-g oral glucose tolerance test.

Fifty-two percent of participants were male; mean (±SD) age was 28.5 ± 7.8 years, and body mass index was 22.4 ± 3.0 kg/m². Mean liver attenuation (MLA) and liver/spleen (LS) ratio, both inversely correlated to liver fat, were 62.8 ± 4.3 HU and 1.2 ± 0.1, respectively; 3.8% of participants had liver fat >30% (LS ratio < 1). In age, sex, and BMI-adjusted correlations, MLA was negatively associated with weight (r = -0.30; P = 0.009) and height (r = -0.28; P = 0.017) and was associated with fasting glucose (r = 0.23; P = 0.05), fasting insulin (r = 0.42; P ≤ 0.001) and HOMA-IR (r = 0.35; P = 0.004). Serum lipids, ALT, adiponectin, fetuin-A, WBISI, IGI, and oDI were not associated with liver fat.

In nonobese Afro-Caribbean participants, greater liver fat was associated with weight and height and lower fasting insulin and hyperinsulinemia appears to be influential in the reduction of NAFLD. These findings may be influenced by ethnicity, body size, and method of estimating liver fat.