Factors that determine disease severity in nonalcoholic fatty liver disease (NAFLD) are unclear, but exercise is a recommended treatment. We evaluated the association between physical activity intensity and histological severity of NAFLD.
We conducted a retrospective analysis of adults with biopsy-proven NAFLD enrolled in the NASH CRN (Nonalcoholic Steatohepatitis Clinical Research Network). Using self-reported time spent in physical activity, we classified participants as inactive or as meeting the US guidelines for either moderate or vigorous exercise. Histology was reviewed by a central pathology committee. Frequency and odds of steatohepatitis (NASH) and advanced fibrosis were compared between subjects who either met or did not meet exercise recommendations, and by the total amount of exercise per week.
A total of 813 adults (males=302, females=511) with NAFLD were included, with a mean age of 48 years. Neither moderate-intensity exercise nor total exercise per week was associated with NASH or stage of fibrosis. Meeting vigorous recommendations was associated with a decreased adjusted odds of having NASH (odds ratio (OR): 0.65 (0.43–0.98)). Doubling the recommended time spent in vigorous exercise, as is suggested for achieving additional health benefits, was associated with a decreased adjusted odds of advanced fibrosis (OR: 0.53 (0.29–0.97)).
These data support an association of vigorous but not moderate or total exercise with the severity of NAFLD. Optimal doses of exercise by duration and intensity for the prevention or treatment of NASH have not been established; however, intensity may be more important than duration or total volume.
1Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, University of California, San Diego, California, USA
2Joint Doctoral Program in Public Health, San Diego State University and University of California San Diego, San Diego, California, USA
3Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, Missouri, USA
4School of Medicine and Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
5Department of Medicine, Duke University, Durham, North Carolina, USA
6Department of Psychology, San Diego State University, San Diego, California, USA
7Department of Gastroenterology, Rady Children's Hospital, San Diego, California, USA
Correspondence: Jeffrey B. Schwimmer, MD, Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, University of California, San Diego, 200 West Arbor Drive, MC 8450, San Diego, California 92103, USA. E-mail: firstname.lastname@example.org
8See Supplementary Appendix online.
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Article Title: Physical Activity Recommendations, Exercise Intensity, and Histological Severity of Nonalcoholic Fatty Liver Disease
SUPPLEMENTARY MATERIAL accompanies this paper at http://links.lww.com/AJG/A688
Received 9 June 2010; accepted 9 August 2010