Seroepidemiology of Helicobacter pylori infection and hepatitis A in a rural area: evidence against a common mode of transmission.
OBJECTIVE
Recent studies have shown that the age-specific seroprevalence of H pylori infection parallels hepatitis A (HAV), suggesting similar modes of transmission. The aim of this study was to investigate the seroepidemiology of H pylori and HAV in the same setting.


METHODS
A sample of 705 resident subjects (273 men, age range 1-87 years, median 50) who attended the outpatient medical centre of the rural town of Cirò, Southern Italy (11,000 inhabitants) for blood testing were recruited.


METHODS
All subjects completed a structured questionnaire. A serum sample was drawn from each subject and assayed for H pylori IgG by a validated in house enzyme linked immunosorbent assay. Antibodies to HAV were determined in 466 subjects (163 men, age range 1-87 years, median 49). A measure of agreement between H pylori and HAV seropositivity, the kappa statistic, was used.


RESULTS
Overall, 446 (63%) subjects were seropositive for H pylori. Of the 466 subjects screened for both H pylori and HAV, 291 (62%) were seropositive for H pylori and 407 (87%) for HAV. Cross-tabulation of these data showed that 275 (59%) were seropositive and 43 (9%) seronegative for both H pylori and HAV, 16 (3%) were seropositive for H pylori, and 132 (28%) were seropositive for HAV (OR = 5.6, CI 3 to 10). There was a parallel, weakly correlated (r = 0.287) rise in the seroprevalence of the two infections with increasing age. However, the agreement between H pylori and HAV seropositivity was little better than chance (kappa = 0.21) and in those aged less than 20 years it was worse than chance (kappa = -0.064). Furthermore, multiple logistic regression analysis did not show any risk factor shared by both infections.


CONCLUSIONS
The correlation between H pylori and HAV reflects the age-specific seroprevalence of both infections rather than a true association. This study provides evidence against a common mode of transmission of H pylori and HAV.
Luzza
F
F
Dipartimento di Medicina Sperimentale, Università di R Calabria, Catanzaro, Italy.
Imeneo
M
M
Maletta
M
M
Paluccio
G
G
Giancotti
A
A
Perticone
F
F
Focà
A
A
Pallone
F
F
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D002648:Child; D002675:Child, Preschool; D005260:Female; D016481:Helicobacter Infections / Q000453:epidemiology* / Q000276:immunology / Q000635:transmission; D016480:Helicobacter pylori / Q000276:immunology; D006506:Hepatitis A / Q000453:epidemiology* / Q000276:immunology / Q000635:transmission; D017957:Hepatitis A Virus, Human / Q000276:immunology; D006801:Humans; D007223:Infant; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D012424:Rural Population; D016036:Seroepidemiologic Studies; D012959:Socioeconomic Factors
D000907:Antibodies, Bacterial; D000914:Antibodies, Viral