title: Obesity and the clinical use of serum GGT activity as a marker of heavy drinking.
abstract: OBJECTIVE
  Gamma-glutamyl transferase (GGT) is a widely used clinical marker of alcohol abuse. However, although obesity may also elevate serum GGT activities, the effects of overweight on the interpretation of GGT testing have remained poorly defined.
  
  
  METHODS
  GGT activities from 1147 moderate drinkers and 449 abstainers who were classified according to body mass index (BMI) were compared with those of 208 heavy drinkers admitted for detoxification.
  
  
  RESULTS
  GGT upper normal limits, defined based on normal weight abstainers (men 53 U/L; women 45 U/L) were lower than those based on moderate drinkers (men 68 U/L; women 50 U/L). The relative increases in GGT activities in male moderate drinkers with overweight (54%) or obesity (125%) exceeded the corresponding changes found in women (25% and 75%, respectively). The BMI-dependent variation on the sensitivity of GGT for correctly classifying heavy drinkers ranged from 29% to 67%. The rates of false-positive values in the subgroups from low to high BMI varied from 0% to 27%, respectively.
  
  
  CONCLUSIONS
  The data indicate that the diagnostic value of serum GGT testing could be improved by using reference data derived from databases of abstainers with normal weight or BMI-based categorization of reference ranges.
authors.affiliation: Department of Laboratory Medicine and Medical Research Unit, Seinäjoki Central Hospital, Seinäjoki, Finland.
authors.forename: K
authors.initials: K
authors.lastname: Puukka
authors.forename: J
authors.initials: J
authors.lastname: Hietala
authors.forename: H
authors.initials: H
authors.lastname: Koivisto
authors.forename: P
authors.initials: P
authors.lastname: Anttila
authors.forename: R
authors.initials: R
authors.lastname: Bloigu
authors.forename: O
authors.initials: O
authors.lastname: Niemelä
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000428:Alcohol Drinking / Q000097:blood* / Q000453:epidemiology; D000437:Alcoholism / Q000097:blood* / Q000150:complications / Q000453:epidemiology; D015415:Biomarkers / Q000097:blood*; D015992:Body Mass Index; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000150:complications / Q000453:epidemiology; D012016:Reference Values; D012537:Scandinavian and Nordic Countries / Q000453:epidemiology; D013695:Temperance; D005723:gamma-Glutamyltransferase / Q000097:blood*
chemical_list: D015415:Biomarkers; D005723:gamma-Glutamyltransferase