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Prolonged Exposure to H. pylori (Hp) in Developing Countries

Is There an Increased Risk of Infection?


Go, Mae F.; Clark, Holly; Christison, Bona Bona Shell; Hatton-Ward, Stephanie; Sonnenberg, Amnon

American Journal of Gastroenterology: September 2005 - Volume 100 - Issue - p S54–S55
Supplement Abstracts Submitted for the 70th Annual Scientific Meeting of the American College of Gastroenterology: STOMACH

Medicine / Gastroenterology, VA SLC Health Care System, Salt Lake City, UT and Medicine / Gastroenterology, Portland VA Medical Center, Portland, OR.

Purpose: It has been speculated that prolonged exposure to Hp infection increases risk for infection, especially in developing countries with a high prevalence of the infection.

We asked whether Hp seropositivity was more frequent among young men from the Church of Latter Day Saints who had recently returned from two-year missions in developing countries compared with the seropositivity among missionaries to areas in the US and developed countries.

Methods: 456 subjects were recruited into the study: 149 who served in developing countries, 177 who served in the US or developed countries; 130 male subjects who had not yet done their mission served as controls. Age range was 19–27 years of age. Women were excluded because of a variable duration of their missionary service, which may have confounded the analyses. Hp QuickVue test was used to determine presence of Hp antibodies in serum. Each subject completed the validated GSRS questionnaire on GI symptoms. Statistical analyses included chi-square tests for comparison of categorical variables, t-tests and ANOVA for comparison of continuous variables, and multivariate logistic regression for overall prediction of Hp seropositivity. The study was approved by the University of Utah IRB Committee.

Results: Hp antibodies were detected in 5.4% (95% CI, 3.9–11.9%) of missionaries to developing countries, 7.9% (95% CI, 3.9–11.9%) of missionaries to developed countries, and 8.5% (95% CI, 3.7–13.2%) of those prior to their missions. The average birth order was later among subjects who tested positive vs. those who tested negative for Hp antibodies: 3.9 vs. 3.0, p = 0.01. Subjects who served in developing countries had higher GSRS scores (more severe symptoms) than missionaries who had served in a developed country or those who had not yet completed a mission: 22.9 vs. 21.8 and 19.8, respectively, F-ratio = 15.2437, p < 0.0001. In a multivariate logistic regression analysis, only birth order was a significant predictive factor for a positive Hp test.

Conclusions: The similar rates of Hp seropositivity in the three groups suggests that risk of Hp infection in young healthy adults is low even after prolonged exposure in developing countries with high frequencies of Hp infection. Our study detected an increased likelihood of Hp infection in children of later birth order while family size was not a predictor of Hp seropositivity.

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