Age distribution of H pylori infection. The rate (%) of H pylori infection according to age (≥ 20 years) found in patients with ITP and in 7465 healthy adults in the United States.¹⁴  Although the methods of diagnosis used in the 2 groups were different (ie, breath test in the ITP group and serology in the study from Everhart et al¹⁴ ), the likelihood of H pylori infection increased with age in both cases.