title: Age impacts ability of aspartate-alanine aminotransferase ratio to predict advanced fibrosis in nonalcoholic Fatty liver disease.
abstract: OBJECTIVE
  While histological differences have been reported between pediatric and adult nonalcoholic fatty liver disease (NAFLD), potential age-related changes in serum transaminases and liver histology remain largely unexplored. Our study sought to investigate the clinical and histological characteristics of NAFLD across age.
  
  
  METHODS
  This was a prospective cross-sectional study of 502 biopsy-proven NAFLD patients. Clinical data were evaluated and compared among different age groups; group A (ages 18-44), B (ages 45-64), and C (≥ ages 65).
  
  
  RESULTS
  34.9, 56.0, and 9.1 % of the cohort were distributed among group A, B, and C, respectively. While the prevalence of nonalcoholic steatohepatitis (NASH) was comparable across age groups, the prevalence of advanced fibrosis increased with age (p = 0.000). Although the mean ALT progressively decreased with age; 87, 64, 56 U/L in group A, B, and C, respectively (p = 0.000), there was no difference in mean AST (p = 0.939) across age. The AST:ALT ratio (AAR) progressively increased from 0.7, 0.9, and 1.1 in group A, B, and C, respectively (p = 0.000). In group C, an AAR ≥ 1 was found in 74 and 40 % of patients with and without advanced fibrosis.
  
  
  CONCLUSIONS
  With advancing age, ALT levels progressively declined while AST levels remained stable, leading to a higher AAR. Although higher AAR is often used as a surrogate measure of advanced fibrosis, advancing age can also contribute to increased AAR. In fact, an AAR ≥ 1 was found in significant number of elderly patients without advanced fibrosis. Consequently, an increased AAR may be a function of decreasing ALT with age in addition to progressive fibrosis.
authors.affiliation: Department of Gastroenterology, Cleveland Clinic Foundation, 9500 Euclid Avenue/A30, Cleveland, OH, 44195, USA, george.goh.b.b@sgh.com.sg.
authors.forename: George Boon-Bee
authors.initials: GB
authors.lastname: Goh
authors.forename: Mangesh R
authors.initials: MR
authors.lastname: Pagadala
authors.forename: Jaividhya
authors.initials: J
authors.lastname: Dasarathy
authors.forename: Aynur
authors.initials: A
authors.lastname: Unalp-Arida
authors.forename: Rish K
authors.initials: RK
authors.lastname: Pai
authors.forename: Lisa
authors.initials: L
authors.lastname: Yerian
authors.forename: Amer
authors.initials: A
authors.lastname: Khiyami
authors.forename: Achuthan
authors.initials: A
authors.lastname: Sourianarayanane
authors.forename: Ruth
authors.initials: R
authors.lastname: Sargent
authors.forename: Carol
authors.initials: C
authors.lastname: Hawkins
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Dasarathy
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: McCullough
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000410:Alanine Transaminase / Q000097:blood*; D001219:Aspartate Aminotransferases / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D001706:Biopsy; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008103:Liver Cirrhosis / Q000453:epidemiology / Q000209:etiology* / Q000473:pathology*; D008111:Liver Function Tests; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease / Q000150:complications* / Q000473:pathology*; D011237:Predictive Value of Tests; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors
chemical_list: D015415:Biomarkers; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase