Biologic sex as a risk factor for Helicobacter pylori infection in healthy young adults.

Diseases associated with Helicobacter pylori infection, such as peptic ulcer disease and gastric cancer, afflict men more frequently than women. No study, however, has demonstrated any difference in sex-specific rates of H. pylori infection. In a healthy population undergoing multiphasic health evaluations in 1992-1993 as members of the Kaiser Permanente Medical Care Program of Northern California, adults aged 20-39 years were screened for antibodies to H. pylori infection using a serum enzyme-linked immunosorbent assay and were surveyed with regard to their demographic characteristics and health practices. Among 556 African-American, Hispanic, and white men and women, male sex was a significant risk factor for infection. Other risk factors included African-American race and Hispanic ethnicity, increasing age, living with children, birth in a developing country, and lower levels of income and education. Men consistently had a higher prevalence of antibodies across all strata of race/ethnicity, age, education, and income, and in multivariate analysis male sex remained significantly associated with infection (odds ratio = 2.0, 95% confidence interval 1.2-3.1). African-American race, Hispanic ethnicity, increasing age, lower levels of education, and birth in a developing country were also associated with infection in multivariate analysis. Data from previously reported seroprevalence studies support a tendency for men to have a higher risk of infection. The higher prevalence of infection among young males as observed in Northern California may account in part for the increased incidence of H. pylori-related diseases among men in later decades of life.