title: Gamma-glutamyltransferase and cancer incidence: the Ohsaki cohort study.
abstract: BACKGROUND
  Although experimental studies have shown that gamma-glutamyltransferase (GGT) has a role in tumor progression, epidemiologic evidence for a relationship between GGT and cancer incidence is limited. The present study investigated the association between GGT and cancer incidence and assessed the role of alcohol consumption in this association.
  
  
  METHODS
  We examined a cohort of 15 031 Japanese adults aged 40 to 79 years who attended a health checkup in 1995 and were free of cancer at that time. GGT was measured using the Szasz method. The participants were then followed from 1 January 1996 until 31 December 2005, and cancer incidence was recorded by using the Miyagi Regional Cancer Registry. Hazard ratios (HRs) and 95% confidence intervals (CIs) were computed for each quartile of GGT and compared. The lowest quartile (GGT <13.0 IU/ml) was used as the reference category.
  
  
  RESULTS
  We documented 1505 cancers. Among participants in the highest quartile (GGT ≥31.0 IU/ml), the multivariate HR for any cancer was 1.28 (95% CI, 1.08-1.53; P for trend, <0.001), the HR for colorectal cancer was significantly greater than unity, and the HRs for esophageal, pancreatic, and breast cancers were greater than unity but not significantly so. This positive trend was observed only in current drinkers.
  
  
  CONCLUSIONS
  Our findings suggest that there is a positive relationship between GGT and cancer incidence only for alcohol-related cancers in current drinkers and that the positive association of GGT with cancer incidence largely reflects alcohol consumption.
authors.affiliation: Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan. tsubo828@med.tohoku.ac.jp
authors.forename: Toru
authors.initials: T
authors.lastname: Tsuboya
authors.forename: Shinichi
authors.initials: S
authors.lastname: Kuriyama
authors.forename: Masato
authors.initials: M
authors.lastname: Nagai
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hozawa
authors.forename: Yumi
authors.initials: Y
authors.lastname: Sugawara
authors.forename: Yasutake
authors.initials: Y
authors.lastname: Tomata
authors.forename: Masako
authors.initials: M
authors.lastname: Kakizaki
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Nishino
authors.forename: Ichiro
authors.initials: I
authors.lastname: Tsuji
mesh_terms: D000328:Adult; D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects* / Q000453:epidemiology; D014408:Biomarkers, Tumor / Q000097:blood*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000201:enzymology* / Q000453:epidemiology*; D011446:Prospective Studies; D005723:gamma-Glutamyltransferase / Q000097:blood*
chemical_list: D014408:Biomarkers, Tumor; D005723:gamma-Glutamyltransferase