title: An inverse and independent association between Helicobacter pylori infection and the incidence of shigellosis and other diarrheal diseases.
abstract: OBJECTIVE
  We examined the association between Helicobacter pylori infection and the incidence of diarrheal diseases.
  
  
  METHODS
  In a nested case-control study participants were sampled from cohorts of male Israeli soldiers aged 18-21 years, serving in field units and followed up for diarrheal diseases. Case patients (n = 177) were subjects who visited the base clinic because diarrhea and were positive for Shigella sonnei (n = 66), enterotoxigenic Escherichia coli (ETEC) (n = 31) or negative for bacterial pathogens (n = 80; diarrhea of unknown etiology). Controls (n = 418) were subjects who did not suffer from a diarrheal disease during the follow-up. They were matched to case patients by training unit and period. Serum samples were obtained from participants at the beginning of their field training and were tested for anti-H. pylori immunoglobulin (Ig) G and preexisting Shigella sonnei lipopolysaccharide IgG and IgA antibodies using enzyme-linked immunosorbent assay.
  
  
  RESULTS
  The proportion of H. pylori-infected subjects was significantly lower among case patients with infection of unknown etiology (36.3%) than among controls (56.0%) (adjusted odds ratio [OR], 0.43; 95% confidence interval [CI], .24-.77; P = .005). The proportion of H. pylori-infected subjects among case patients with S. sonnei shigellosis was also significantly lower than in the control group: 36.3% versus 56.0%. The association persisted after adjusting for sociodemographic variables and preexisting S. sonnei serum IgA antibodies (adjusted OR, 0.37; 95% CI, .14-.95; P = .03) and IgG antibodies (adjusted OR, 0.38; 95% CI, .14-.99; P = .04). The direction of the association between H. pylori infection and ETEC diarrhea was similar, albeit not statistically significant.
  
  
  CONCLUSIONS
  Our findings suggest an active role of H. pylori in protection against diarrheal diseases.
authors.affiliation: Department of Epidemiology and Preventive Medicine, School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Israel. dancohen@post.tau.ac.il
authors.forename: Dani
authors.initials: D
authors.lastname: Cohen
authors.forename: Ofra
authors.initials: O
authors.lastname: Shoham
authors.forename: Nadav
authors.initials: N
authors.lastname: Orr
authors.forename: Khitam
authors.initials: K
authors.lastname: Muhsen
mesh_terms: D000293:Adolescent; D000907:Antibodies, Bacterial / Q000097:blood; D016022:Case-Control Studies; D003967:Diarrhea / Q000453:epidemiology*; D004405:Dysentery, Bacillary / Q000453:epidemiology*; D004926:Escherichia coli / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology; D016481:Helicobacter Infections / Q000453:epidemiology*; D016480:Helicobacter pylori / Q000302:isolation & purification; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D015994:Incidence; D007557:Israel; D008297:Male; D008889:Military Personnel; D012764:Shigella sonnei / Q000302:isolation & purification; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D007070:Immunoglobulin A; D007074:Immunoglobulin G