Helicobacter pylori infection in subjects negative for high titer serum antibody

Table 1 Characteristics of enrolled subjects

	Total	H. pylori infected1	H. pylori uninfected	P value3
n (%)	136	23 (17)	113 (83)
Demographic characteristics
Age median (IQR), yr	45 (37-56)	53 (44-68)	42 (35-53)	0.0057
Male sex (%)	53 (39)	7 (30)	46 (41)	0.48
Body mass index median (IQR), kg/m2	21.2 (19.6-23.7)	22.7 (20.4-25.6)	21.2 (19.5-23.3)	0.028
Family history of gastric cancer, present/absent	12/124	3/20	9/104	0.43
Smoking, present/absent	4/132	0/23	4/109	1.0
Drinking, present/absent	25/111	4/19	21/92	1.0
Laboratory data
Anti-H. pylori antibody median (IQR), U/mL	4.7 (3.7-6.6)	5.4 (4.2-7.9)	4.7 (3.7-6.4)	0.048
13C-urea breath test result median (IQR), per mil	0.3 (0.1-0.8)	19.3 (9.3-26.3)	0.3 (0.1-0.4)	3.6 × 10-14
Endoscopic findings
Kyoto classification of gastritis4, 5/4/3/2/1/0	1/3/14/9/13/96	1/3/8/6/2/3	0/0/6/3/11/93	3.8 × 10-13
Atrophy, 2/1/0	15/20/101	10/4/2009	6/10/97	5.8 × 10-12
Intestinal metaplasia, 1/0	14/122	9/14	5/108	2.9 × 10-5
Enlarged folds, 1/0	5/131	4/19	1/112	0.0029
Nodularity, 1/0	2/134	2/21	0/113	0.028
Redness, 1/0	19/117	12/11	7/106	7.3 × 10-7
Gastric sticky mucus, present/absent	22/114	8/15	14/99	0.013
Gastric ulcer, present/absent	1/135	1/22	0/113	0.17
Duodenal ulcer, present/absent	3/133	1/22	2/111	0.43
Gastroesophageal reflux disease, present/absent	20/116	2/21	18/95	0.53
Hiatal hernia, present/absent	18/118	2/21	16/97	0.74
Fundic gland polyp, present/absent	41/95	1/22	40/73	0.0022
Histological findings5
H. pylori density, present/absent	18/118	18/5	0/113	2.8 × 10-18
Chronic inflammation, present/absent	46/90	21/2	25/88	4.5 × 10-10
Neutrophil activity, present/absent	15/121	15/8	0/113	1.4 × 10-14
Intestinal metaplasia, present/absent	4/132	1/22	3/110	0.53
Glandular atrophy, present/absent	4/132	1/22	3/110	0.53

^{1 13}C-urea breath test-positive subjects were defined as H. pylori-infected patients;

³Fisher’s exact test, Cochran-Armitage test, or Mann-Whitney U test was used as appropriate;

⁴Kyoto classification of gastritis was estimated by gastric atrophy, intestinal metaplasia, enlarged folds, nodularity, and redness[13];

⁵We defined one or more score classified by the updated Sydney system in either the great curvature of the corpus or the antrum as present. H. pylori: Helicobacter pylori; IQR: Interquartile range.