title: Efficacy of the Omega-3 Index in predicting non-alcoholic fatty liver disease in overweight and obese adults: a pilot study.
abstract: Non-alcoholic fatty liver disease (NAFLD) is an independent predictor of CVD in otherwise healthy individuals. Low n-3 PUFA intake has been associated with the presence of NAFLD; however, the relationship between a biomarker of n-3 status - the Omega-3 Index - and liver fat is yet to be elucidated. A total of eighty overweight adults (fifty-six men) completed the anthropometric and biochemical measurements, including the Omega-3 Index, and underwent proton magnetic resonance spectroscopy assessment of liver fat. Bivariate correlations and multiple regression analyses were performed with reference to prediction of liver fat percentage. The mean Omega-3 Index was high in both NAFLD (intrahepatic lipid concentration≥5·5 %) and non-NAFLD groups. The Omega-3 Index, BMI, waist circumference, glucose, insulin, TAG, high-sensitive C-reactive protein (hsCRP) and alanine aminotransferase (ALT) were positively correlated, and HDL and erythrocyte n-6:n-3 ratio negatively correlated with liver fat concentration. Regression analysis found that simple anthropometric and demographic variables (waist, age) accounted for 31 % of the variance in liver fat and the addition of traditional cardiometabolic blood markers (TAG, HDL, hsCRP and ALT) increased the predictive power to 43 %. The addition of the novel erythrocyte fatty acid variable (Omega-3 Index) to the model only accounted for a further 3 % of the variance (P=0·049). In conclusion, the Omega-3 Index was associated with liver fat concentration but did not improve the overall capacity of demographic, anthropometric and blood markers to predict NAFLD.
authors.affiliation: 1Faculty of Health Sciences,University of Sydney,NSW 2141,Australia.
authors.forename: Helen M
authors.initials: HM
authors.lastname: Parker
authors.affiliation: 1Faculty of Health Sciences,University of Sydney,NSW 2141,Australia.
authors.forename: Helen T
authors.initials: HT
authors.lastname: O'Connor
authors.affiliation: 1Faculty of Health Sciences,University of Sydney,NSW 2141,Australia.
authors.forename: Shelley E
authors.initials: SE
authors.lastname: Keating
authors.affiliation: 3Nutrition and Metabolism Group,Heart Research Institute,NSW 2042,Australia.
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Cohn
authors.affiliation: 4School of Biomedical Sciences and Pharmacy,University of Newcastle,NSW 2308,Australia.
authors.forename: Manohar L
authors.initials: ML
authors.lastname: Garg
authors.affiliation: 5Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders,University of Sydney,NSW 2006,Australia.
authors.forename: Ian D
authors.initials: ID
authors.lastname: Caterson
authors.affiliation: 6Storr Liver Unit,Westmead Millennium Institute,University of Sydney,NSW 2145,Australia.
authors.forename: Jacob
authors.initials: J
authors.lastname: George
authors.affiliation: 1Faculty of Health Sciences,University of Sydney,NSW 2141,Australia.
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Johnson
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D004910:Erythrocyte Membrane / Q000378:metabolism*; D015525:Fatty Acids, Omega-3 / Q000097:blood*; D005260:Female; D006801:Humans; D050356:Lipid Metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease / Q000097:blood / Q000209:etiology / Q000378:metabolism*; D009752:Nutritional Status; D009765:Obesity / Q000097:blood / Q000150:complications / Q000378:metabolism*; D010865:Pilot Projects; D055815:Young Adult
chemical_list: D015415:Biomarkers; D015525:Fatty Acids, Omega-3
keywords:     n-3 PUFA; 1H-MRS proton magnetic resonance spectroscopy; Biomarkers; IHL intrahepatic lipid; NAFLD non-alcoholic fatty liver disease; Non-alcoholic fatty liver; Omega-3 Index; hsCRP high-sensitive C-reactive protein