Ethnic and sex differences in fatty liver on cardiac computed tomography: The multi-ethnic study of atherosclerosis

Objective: To describe ethnic and sex differences in the prevalence and determinants of fatty liver in a multiethnic cohort. Patients and Methods: We studied participants of the Multi-Ethnic Study of Atherosclerosis who underwent baseline noncontrast cardiac computed tomography between July 17, 2000, and August 29, 2002, and had adequate hepatic and splenic imaging for fatty liver determination (n=4088). Fatty liver was defined as a liver/spleen attenuation ratio of less than 1. We compared the prevalence and severity of fatty liver, in 4 ethnicities (white, Asian, African American, and Hispanic), and the factors associated with fatty liver in each ethnicity, stratifying by obesity and metabolic syndrome. Multivariable ordinal logistic regression was used to determine the effect of cardiometabolic risk factors on the prevalence of fatty liver in different ethnicities. Results: The prevalence of fatty liver varied significantly by ethnicity (African American, 11%; white, 15%; Asian, 20%; and Hispanic, 27%; P<.001). Although African Americans had the highest prevalence of obesity, a smaller percentage of obese African Americans received a diagnosis of fatty liver than did other ethnicities (African American, 17%; white, 31%; Asian, 37%; and Hispanic 39%; P<.001). Hispanics had the highest prevalence of fatty liver, including the obese and metabolic syndrome population. An increase in insulin resistance predicted a 2-fold increased prevalence of fatty liver in all ethnicities after multivariable adjustment. Conclusion: African Americans have a lower prevalence and Hispanics have a higher prevalence of fatty liver than do other ethnicities. There are distinct ethnic variations in the prevalence of fatty liver even in patients with the metabolic syndrome or obesity, suggesting that genetic factors may play a substantial role in the phenotypic expression of fatty liver.