title: Association of cardiorespiratory fitness, body mass index, and waist circumference to nonalcoholic fatty liver disease.
abstract: OBJECTIVE
  There is a need for more work examining the potential of physical activity and/or weight control as a preventive and/or therapeutic option in the treatment of fatty liver diseases. The purpose of this study was to examine the association between cardiorespiratory fitness, body mass index (BMI), and waist circumference with markers of nonalcoholic fatty liver disease (NAFLD).
  
  
  METHODS
  Participants consisted of 218 apparently healthy nonsmoking, nonalcoholic men aged 33-73 years. Cardiorespiratory fitness was assessed by a maximal treadmill test. Liver and spleen density were measured using a computed tomography scan. We defined the presence of NAFLD as the following 3 conditions being met: (1) liver to spleen density of 1.0 or less, (2) serum alanine transaminase level greater than 30 U/L, and (3) serum aspartate transaminase/alanine transaminase level less than 1.0.
  
  
  RESULTS
  Twenty-four (11%) of the participants met the NAFLD definition. There was an inverse association between fitness categories, and a positive association for BMI categories (and waist circumference categories) with the prevalence of NAFLD (P for trend <.001 for all). Fitness and BMI were independent of each other in their associations with the prevalence of NAFLD. The addition of waist circumference to the regression model attenuated the association with prevalence of NAFLD for both fitness (P value changed from <.0001 to .06) and BMI (P value changed from <.001 to .22).
  
  
  CONCLUSIONS
  Fitness (inversely) and BMI (directly) were associated with the prevalence of NAFLD. However, these associations were attenuated when abdominal obesity was included in the statistical model.
authors.affiliation: The Cooper Institute, Dallas, Texas, USA.
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Church
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Kuk
authors.forename: Robert
authors.initials: R
authors.lastname: Ross
authors.forename: Elisa L
authors.initials: EL
authors.lastname: Priest
authors.forename: Emily
authors.initials: E
authors.lastname: Biltoft
authors.forename: Emily
authors.initials: E
authors.lastname: Biltoff
authors.forename: Steven N
authors.initials: SN
authors.lastname: Blair
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D001824:Body Constitution; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000453:epidemiology*; D015331:Cohort Studies; D005234:Fatty Liver / Q000175:diagnosis* / Q000453:epidemiology*; D006801:Humans; D008111:Liver Function Tests; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010809:Physical Fitness / Q000502:physiology*; D015995:Prevalence; D011379:Prognosis; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D049629:Waist-Hip Ratio