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Habitual Physical Activity Is Associated With Intrahepatic Fat Content in Humans

  1. Gianluca Perseghin, MD123,
  2. Guido Lattuada, PHD1,
  3. Francesco De Cobelli, MD24,
  4. Francesca Ragogna, PHD1,
  5. Georgia Ntali, MD1,
  6. Antonio Esposito, MD4,
  7. Elena Belloni, MD4,
  8. Tamara Canu4,
  9. Ileana Terruzzi, PHD1,
  10. Paola Scifo, PHD5,
  11. Alessandro Del Maschio, MD246 and
  12. Livio Luzi, MD123
  1. 1Internal Medicine, Section of Nutrition/Metabolism, San Raffaele Scientific Institute, Milan, Italy
  2. 2Unit of Clinical Spectroscopy, San Raffaele Scientific Institute, Milan, Italy
  3. 3Center “Physical Exercise for Health and Wellness,” Faculty of Exercise Sciences, Università degli Studi di Milano, Milan, Italy
  4. 4Diagnostic Radiology, San Raffaele Scientific Institute, Milan, Italy
  5. 5Nuclear Medicine, San Raffaele Scientific Institute, Milan, Italy
  6. 6Università Vita e Salute San Raffaele, Milan, Italy
  1. Address correspondence and reprint requests to Gianluca Perseghin, MD, Faculty of Exercise Sciences, Università degli Studi di Milano and San Raffaele Scientific Institute, Internal Medicine, via Olgettina 60, 20132, Milan, Italy. E-mail: perseghin.gianluca{at}hsr.it

Abstract

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/m2). IHF content was assessed in a quantitative fashion and noninvasively as a continuous variable by means of 1H magnetic resonance spectroscopy (MRS), and habitual physical activity was assessed by means of a questionnaire. Fatty liver was defined as IHF content of >5% 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; χ2 = 15.63; P = 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 = −0.27; P < 0.000). This association was not attenuated when adjusted for age, sex, BMI, HOMA-2, and adiponectin (partial correlation r = −0.25; P < 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.

Footnotes

  • A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.

    The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C Section 1734 solely to indicate this fact.

    • Accepted November 30, 2006.
    • Received October 2, 2006.
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