Atrophic gastritis, but not antibody to Helicobacter pylori, is associated with body mass index in a Japanese population

Background: The relationship between Helicobacter pylori (HP) infection and body mass index (BMI) is controversial. Several reports have indicated that eradication of HP infection induces an increase in BMI. In contrast, epidemiological case-control studies have failed to show an association between HP infection and BMI. Therefore, we investigated whether HP and atrophic gastritis (AG) were associated with BMI. Methods: A total of 617 individuals were recruited for the measurements of BMI, serum leptin, pepsinogens (PGs) I and II, and IgG antibody to HP (HP-IgG). BMI and leptin of the subjects were compared when the subjects were stratified by HP-IgG and PGs. Results: The subjects were divided into AG-positive and AG-negative groups according to PGs (AG-positive: PG I ≤ 70 ng/ml and PG I/II ratio ≤ 3.0). BMI after adjusting for sex and age was significantly lower in the AG-positive group than in the AG-negative group (23.47 ± 3.05 vs. 24.18 ± 3.25, P = 0.010). When the subjects were divided into two groups according to HP-IgG, BMI tended to be lower in the HP-IgG-positive group, though the difference was not large. When the subjects were divided into four groups for different combinations of AG and HP-IgG, BMI was the lowest in the AG-positive and HP-IgG-negative group. Conclusions: BMI was associated with AG, as diagnosed by PGs, but not with HP infection status. These results mean that HP infection affects BMI via atrophic gastritis.