Helicobacter pylori infection, anti-cagA antibodies and peptic ulcer: a case-control study in Italy.
OBJECTIVE
To evaluate the association between infection with specific strains of Helicobacter pylori and peptic ulcer in patients referred for upper gastrointestinal endoscopy.


METHODS
One thousand, six hundred and twenty-six consecutive dyspeptic patients, referred to one Endoscopy Unit in Bologna, Italy, were enrolled. For each participant, a blood sample was obtained for the measurement of distinct immunoglobulin G antibodies against H. pylori lysate and cytotoxin associated gene A (cagA). A case-control study included the whole series: patients diagnosed with duodenal (n=275) or gastric (n=71) ulcer were identified and independently compared with controls with non-ulcer dyspepsia (n=1280).


RESULTS
H. pylori seroprevalence (at least one positive marker) was associated with increasing age, male sex and a diagnosis of peptic ulcer. This association was stronger with duodenal ulcer (multivariate odds ratio (OR), 5.2; 95% confidence interval (CI), 3.5-7.9) than with gastric ulcer (OR, 2.3; 95% CI, 1.2-4.4). Further analyses showed that H. pylori lysate+/cagA- subjects had a moderately increased risk of duodenal (OR, 3.2), but not gastric (OR, 1.1), ulcer. When cagA+ subjects were separately compared with seronegative patients, there was a six-fold increased risk for duodenal ulcer and a three-fold increased risk for gastric ulcer.


CONCLUSIONS
A strong positive association between infection with a cagA+ H. pylori strain and the presence of peptic disease was found. The seroprevalence of anti-cagA antibodies among patients with non-ulcer dyspepsia is so high (41%) to preclude its use as a pre-endoscopic screening test.
Palli
D
D
Epidemiology Unit, CSPO, Florence, Italy.
Menegatti
M
M
Masala
G
G
Ricci
C
C
Saieva
C
C
Holton
J
J
Gatta
L
L
Miglioli
M
M
Vaira
D
D
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000302:isolation & purification*; D016022:Case-Control Studies; D004381:Duodenal Ulcer / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D005773:Gastroscopy; D016481:Helicobacter Infections / Q000453:epidemiology*; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010437:Peptic Ulcer / Q000453:epidemiology* / Q000382:microbiology; D016036:Seroepidemiologic Studies
D000907:Antibodies, Bacterial; D007074:Immunoglobulin G