GoalsTo determine whether serum vitamin B12levels in non-vitamin B12deficient healthy adults correlate with serological evidence ofH. pyloriinfection.BackgroundAn association betweenH. pyloriinfection and vitamin B12deficiency has been recently reported.Study133 adults, presenting to a community based primary care clinic who met the following exclusion criteria; history ofH. pylorieradication or antacid use, liver disease, inflammatory bowel disease, previous gastrointestinal surgery, a vegetarian diet or multivitamin supplementation were studied. Blood was drawn for a complete blood count, serum vitamin B12, gastrin, folic acid andH. pyloriIgG antibodies. Subjects with vitamin B12≤ 145 ng/mL (deficient range) were excluded.ResultsOf 133 subjects 96 (72.2%) were seropositive forH. pyloriIgG antibodies (HP+). Age of HP(+) subjects did not differ from that of seronegative subjects (HP−); 52.8 ± 1.6 mean ± SE versus 49.2 ± 2.9 (p= NS). Prevalence of HP seropositivity was significantly higher among subjects with borderline (>145–180 pg/mL) or low normal (>180–250 pg/mL) vitamin B12levels than among those with vitamin B12>250 pg/mL; among 25 subjects with vitamin B12>145–180 pg/mL 92% were seropositive and among 47 subjects with vitamin B12>180–250 pg/mL 89% were seropositive as compared with 31/61 (51%) of subjects with B12>250 pg/mL, Fisher exact testp< 0.0001. Vitamin B12levels did not correlate with age (r = −0.07). Gastrin levels (pg/mL) did not differ significantly between groups; 70.2 ± 5.8 in HP(+) versus 56.0 ± 12.4 in HP(−).ConclusionsThe higher prevalence ofH. pyloriinfection among subjects with serum vitamin B12levels that are within the lower end of the normal range suggests a causal relationship betweenH. pyloriinfection and vitamin B12levels in healthy adults.