OBJECTIVE -Fatty liver may be involved in the pathogenesis of type 2 diabetes. Physical exercise is a tool to improve insulin sensitivity, but little is known about its effect on intrahepatic fat (IHF) content. The purpose of this study was to examine the association of habitual physical activity, insulin resistance, and adiponectin with IHF content.RESEARCH DESIGN AND METHODS -Participants were 191 (77 female and 114 male) apparently healthy, nonalcoholic individuals (aged 19 -62 years; BMI 17.0 -35.5 kg/m 2 ). IHF content was assessed in a quantitative fashion and noninvasively as a continuous variable by means of 1 H magnetic resonance spectroscopy (MRS), and habitual physical activity was assessed by means of a questionnaire. Fatty liver was defined as IHF content of Ͼ5% wet weight, and insulin sensitivity was estimated using the computer homeostasis model assessment (HOMA)-2 indexes.RESULTS -A reduced prevalence of fatty liver in the quartile of the most physically active individuals (25,11,25, and 2% in quartile 1, 2, 3, and 4, respectively; 2 ϭ 15.63; P ϭ 0.001) was found along with an inverse correlation between the physical activity index and the IHF content when plotted as continuous variables (Pearson's r ϭ Ϫ0.27; P Ͻ 0.000). This association was not attenuated when adjusted for age, sex, BMI, HOMA-2, and adiponectin (partial correlation r ϭ Ϫ0.25; P Ͻ 0.001).CONCLUSIONS -This study demonstrated that a higher level of habitual physical activity is associated with a lower IHF content and suggested that this relationship may be due to the effect of exercise per se. Diabetes Care 30:683-688, 2007A lanine aminotransferase and ␥-glutamyltransferase are associated with type 2 diabetes risk (1-3), and it is thought that the link is represented by the intrahepatic fat (IHF) content. Ectopic fat accumulation within the liver, in fact, has been reported in association with impairment of insulin-stimulated glucose metabolism, of suppression of endogenous glucose production, and of whole-body lipolysis in nondiabetic individuals with nonalcoholic fatty liver disease (NAFLD) (4,5). Additional results also demonstrated that decreased levels of circulating adiponectin in NAFLD are related to hepatic insulin sensitivity and to the IHF content, suggesting that hypoadiponectinemia may be involved in excessive hepatic fat accumulation (6).Physical exercise was found to be associated with a reduced risk of development of type 2 diabetes (7,8) and is a wellrecognized tool to improve insulin sensitivity at the level of the skeletal muscle (9). However, whether physical exercise may affect insulin sensitivity and diabetes risk via an effect on the IHF content and adiponectin remains unknown.The IHF content may be assessed as a continuous variable by means of 1 H magnetic resonance spectroscopy (MRS) (10), and recently this technique was found to be a sensitive, quantitative, and noninvasive method also when applied to a large population (11) without the need for the use of a more invasive approach such as liver biopsy. The ...

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Fatty liver is characterized by metabolic abnormalities at the liver, but also at skeletal muscle and adipose tissue sites. It is hypothesized that the heart may be suffering metabolic alterations, and this study was undertaken to ascertain whether individuals with fatty liver have left ventricular (LV) alterations of energy metabolism, structure, and function and abnormal amounts of epicardial fat as a specific marker of visceral fat accumulation. To this end we studied young, nondiabetic men matched for anthropometric features with (n ‫؍‬ 21) or without (n ‫؍‬ 21) fatty liver by means of (1) cardiac magnetic resonance imaging (MRI); (2) cardiac 31 P-MR spectroscopy (MRS); and (3) hepatic 1 H-MRS to assess quantitatively the intrahepatic fat (IHF) content. Insulin sensitivity was determined by the updated HOMA-2 computer model. Individuals with fatty liver showed reduced insulin sensitivity, increased serum free fatty acid (FFA), and Eselectin, abnormal adipokine concentrations, and higher blood pressure. LV morphology and systolic and diastolic functions were not different; however, in the scanned intrathoracic region, the intrapericardial (7.8 ؎ 3.1 versus 5.9 ؎ 2.5 cm 2 ; P < 0.05) and extrapericardial (11.7 ؎ 6.1 versus 7.8 ؎ 3.2 cm 2 ; P < 0.03) fat was increased in men with fatty liver compared with those without fatty liver. N onalcoholic fatty liver (NAFL) is a feature of the insulin resistance syndrome 1,2 and a typical aspect of body composition related to visceral adiposity. 3 Multiple metabolic abnormalities in organs and tissues under the influence of insulin were reported: impaired insulin-mediated inhibition of hepatic glucose production was reported at the liver site, 1,4 impaired insulin-stimulated glucose metabolism was shown at the level of the skeletal muscle, 1,5,6 and impaired insulin-dependent control on lipolysis was detected at the level of the adipose tissue. 1,4 The heart is another organ whose metabolism may be influenced by insulin resistance. Few insights are available about cardiac metabolism in patients with NAFL because of the difficulties of studying nonin-

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