Association of Helicobacter Pylori Infection with Iron Deficiency in Asians and Pacific Islanders but not in Caucasians, African Americans, or Hispanics
Authors: McLaren Gordon D. , Murray Joseph A. , McLachlan Stela , Adams Paul C. , Eckfeldt John H. , Vulpe Chris D. , Gordeuk Victor R. , Brantner Tricia , Leiendecker-Foster Catherine , Chen Wen-Pin , Killeen Anthony A. , Acton Ronald T. , Barcellos Lisa F. , Nickerson Deborah A. , Beckman Kenneth B. , McLaren Christine E. 
Published: October 2019

Abstract
It is well-recognized that Helicobacter pylori infection causes gastrointestinal blood loss and iron deficiency. H. pylori gastritis has also been implicated in iron deficiency refractory to oral iron replacement therapy. Although H. pylori infection is common in multiple populations, less is known about the extent to which H. pylori contributes to iron deficiency in different racial/ethnic groups. To address this question, we tested the serum collected from men aged ≥ 25 y and women ≥ 50 y in the Hemochromatosis and Iron Overload Screening (HEIRS) Study to identify those with iron deficiency (defined as serum ferritin ≤ 12 mg/L [cases]) and iron-replete controls (serum ferritin > 100 mg/L in men, serum ferritin > 50 mg/L in women).
All samples were tested for H. pylori IgG antibodies and for antibodies to CagA (cytotoxin-associated gene-bearing strain). We tested 571 cases and 1142 controls. Participants were considered to have evidence of H. pylori infection if they had positive results for both antibodies or for either antibody alone. Participants who did not have a result for either test were excluded. We examined the association between the presence of H. pylori in cases and controls among Caucasians, Asian/Pacific Islanders, African Americans, and Hispanics.
Among Caucasians, evidence of H. pylori infection was comparable in cases and controls; 170 of 735 controls (23.1%) and 97 of 363 cases (26.7%), respectively, were positive. Similar results were found in African Americans (56.3% of 144 controls; 55.8% of 77 cases) and Hispanics (66.7% of 159 controls; 59.5% of 79 cases). However, in Asian/Pacific Islanders, the prevalence of H. pylori was higher among cases (62.8% of 51) than controls (44.1% of 102), p=0.029 by the likelihood ratio Chi-Square test. The relative risk (RR) of iron deficiency among those with H. pylori-positivity was significantly greater than in those without (RR, 1.66; 95% CI [1.04, 2.66]). A comparison of subgroups by positivity for IgG or CagA showed that the relative risk of iron deficiency was increased among those with IgG positivity, with or without Cag A positivity (RR, 1.80 and 1.90, respectively), but not among those with CagA positivity alone (RR, 1.00).
H. pylori infection is a frequent contributor to iron deficiency but is also common in the general population. Our results indicate that among HEIRS Study Asian/Pacific Islander participants, H. pylori infection is more prevalent in cases with iron deficiency than in controls. In contrast, there was no difference in the prevalence of H. pylori infection between cases and controls among Caucasians, African Americans, and Hispanics. These results have implications for the investigation of iron deficiency in Asians and Pacific Islanders.

Disclosures
No relevant conflicts of interest to declare.