title: Effect of exercise on the development of new fatty liver and the resolution of existing fatty liver.
abstract: Guidelines about recommendations for amounts of exercise/physical activity are variable in non-alcoholic fatty liver disease. Our aim was to determine the amount of exercise that was associated with two outcomes: a) development of incident liver fat and b) resolution of baseline liver fat, at five-year follow-up.
  
  
  
  In an occupational health screening program, weekly frequency of exercise was assessed using the validated Korean version of the International Physical Activity Questionnaire Short Form (IPAQ-SF). Liver fat was identified by ultrasonography (3.5MHz probe) at baseline and at five-year follow-up. Fully adjusted Cox proportional hazards models were used to estimate hazard ratios (HRs and 95% confidence intervals [CI]) for incident fatty liver and resolution of fatty liver at follow-up.
  
  
  
  233,676 men and women were studied between 2002 and 2014. 126,811 individuals were identified without fatty liver, and of these subjects, 29,014 subjects developed incident fatty liver during follow-up. At baseline, there were 42,536 individuals with liver fat and of these individuals, fatty liver resolved in 14,514, during follow-up. After full adjustment, compared to no exercise, exercise was associated with benefit for both outcomes; for exercise ⩾5times per week for incident fatty liver: HR 0.86 (95% CI 0.80,0.92), p<0.001, and for resolution of fatty liver HR 1.40 (95% CI 1.25,1.55), p<0.001.
  
  
  
  Moderate to vigorous exercise is beneficial in decreasing risk of development of new fatty liver or improving resolution of existing fatty liver during 5years of follow-up.
  
  
  
  The amount of exercise/physical activity to benefit fatty liver disease in non-alcoholic fatty liver disease is not known. In a large study of free-living people, our aim was to determine the amount of exercise that was linked with a decrease in new fatty liver and also improvement of existing fatty liver over 5years of follow-up. Compared to no exercise, exercise ⩾5times per week (lasting at least 10min on each occasion) was linked to a highly significantly benefit for both a decrease in new fatty liver and also improvement of existing fatty liver.
authors.affiliation: Division of Cardiology, Department of Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. Electronic address: kcmd.sung@samsung.com.
authors.forename: Ki-Chul
authors.initials: KC
authors.lastname: Sung
authors.affiliation: Department of Occupational and Environmental Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University, School of Medicine, Seoul, Republic of Korea.
authors.forename: Seungho
authors.initials: S
authors.lastname: Ryu
authors.affiliation: Division of Cardiology, Department of Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Jong-Young
authors.initials: JY
authors.lastname: Lee
authors.affiliation: Department of Cardiology, Yonsei University Wonju College of Medicine, Republic of Korea.
authors.forename: Jang-Young
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Centre for Population Health Sciences, Lothian Place University of Edinburgh, UK.
authors.forename: Sarah H
authors.initials: SH
authors.lastname: Wild
authors.affiliation: Endocrinology and Metabolism Unit, IDS Building, Southampton General Hospital, (University of Southampton), MP 887 Southampton, UK. Electronic address: c.d.byrne@soton.ac.uk.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Byrne
mesh_terms: D015444:Exercise; D005234:Fatty Liver; D005260:Female; D006801:Humans; D008297:Male; D016016:Proportional Hazards Models; D012307:Risk Factors
keywords: Exercise; Insulin resistance; Metabolic syndrome; Non-alcoholic fatty liver disease; Obesity; Type 2 diabetes