HELICOBACTER PYLORI SERO-INCIDENCE IN A COHORT OF RURAL BOLIVIAN CHILDREN

58 High seroprevalence rates for Helicobacter pylori (Hp) have been reported in developing countries; however, sero-incidence studies to determine age of initial acquisition and risk factors for seroconversion are lacking. We conducted two seroprevalence studies, 15 months apart, to determine the age-specific sero-incidence rate in a cohort of rural Bolivian children. In 8/96, we conducted a survey of 1,392 children between 6 months and 9 years old, living in 17 rural Bolivian villages, to determine Hp serostatus. In 11/97, we returned to the same villages to conduct a follow-up study. The 15 month age-specific sero-incidence was determined for a cohort of 333 children, 6 months and 6 years old, who either participated in both surveys and were seronegative in the first or were born during the follow-up period. Overall, 36% of 1040 children surveyed in the follow-up study were seropositive, 52% were seronegative, and 12% had indeterminate serostatus. Of 918 children with a definitive Hp serostatus, seroprevalence increased from 4% in children aged 6-11 months to 61% in 6-year olds. In the cohort of 333 children, 64 (19%) seroconverted during the 15 month follow-up period. 15-month sero-incidence rates are summarized in the table below: The largest increase in sero-incidence occurred in children between ages 2 and 3 years old. Further analysis of risk factors for Hp seroconversion (i.e., infection acquisition) focusing on this age group is ongoing.TABLE