title: Serum pepsinogen levels and their influencing factors: a population-based study in 6990 Chinese from North China.
abstract: OBJECTIVE
  To explore the essential characteristics of serum pepsinogen (PG) levels in Chinese people, by analyzing the population-based data on the serum levels of PG I and II and the PG I/II ratio, and their influencing factors in Chinese from North China.
  
  
  METHODS
  A total of 6990 subjects, who underwent a gastric cancer screening in North China from 1997 to 2002, were collected in this study. Serum pepsinogen levels were measured by enzyme-linked immunosorbent assay (ELISA). H pylori status was determined by histological examination and H pylori-IgG ELISA. The cut-off point was calculated by using receiving operator characteristics (ROC) curves. Factors linked to serum PG I/II ratio were identified using a multivariate logistic regression.
  
  
  RESULTS
  The serum PG I and PG II levels were significantly higher in males than in females (95.2 microg/L vs 79.7 microg/L, P < 0.01; 12.1 microg/L vs 9.4 microg/L, P < 0.01), PG I/II ratio was significantly lower in males than in females (7.9 vs 8.3, P < 0.01). The PG I/II ratio decreased significantly in the aged groups following the progression of gastric mucosa from normal to non-atrophic and atrophic lesions (10.4, 8.8, and 6.6, respectively). The serum PG I and II levels were significantly higher in patients with H pylori infection than in those without H pylori infection (88.7 microg/L vs 81.4 microg/L, P < 0.01; 11.4 microg/L vs 8.4 microg/L, P < 0.01), while the PG I/II ratio was significantly lower in patients with H pylori infection than in those without H pylori infection (7.7 vs 9.6, P < 0.01). For patients with atrophic lesions, the area under the PG I/II ROC curve was 0.622. The best cut-off point for PG I/II was 6.9, with a sensitivity of 53.2%, and a specificity of 67.5%. Factors linked to PG I/II were sensitive to identified PG using a multinomial logistic regression relying on the following inputs: males (OR: 1.151, 95% CI: 1.042-1.272, P = 0.006), age > or = 61 years (OR: 1.358, 95% CI: 1.188-1.553, P = 0.000), atrophic lesion (OR: 2.075, 95% CI: 1.870-2.302, P = 0.000), and H pylori infection (OR: 1.546, 95% CI: 1.368-1.748, P = 0.000).
  
  
  CONCLUSIONS
  The essential characteristics of serum PG levels in Chinese are significantly skewed from the normal distribution, and influenced by age, sex, gastric mucosa lesions and H pylori infection. PG I/II ratio is more suitable for identifying subgroups with different influence factors compared with PG I or PG II alone.
authors.affiliation: Cancer Institute, First Affiliated Hospital, China Medical University, 155 Nanjing North Street, Shenyang 110001, Liaoning Province, China.
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Sun
authors.forename: Yue-Hua
authors.initials: YH
authors.lastname: Gong
authors.forename: Lan
authors.initials: L
authors.lastname: Wang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yuan
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002648:Child; D002681:China; D005260:Female; D016481:Helicobacter Infections / Q000097:blood* / Q000175:diagnosis / Q000208:ethnology; D016480:Helicobacter pylori / Q000472:pathogenicity; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D020116:Pepsinogen A / Q000097:blood*; D020115:Pepsinogen C / Q000097:blood*; D012372:ROC Curve; D012680:Sensitivity and Specificity; D012737:Sex Factors; D013270:Stomach / Q000382:microbiology; D013274:Stomach Neoplasms / Q000097:blood* / Q000175:diagnosis / Q000208:ethnology
chemical_list: D015415:Biomarkers; D020115:Pepsinogen C; D020116:Pepsinogen A