Abstract
Objectives:
In East Asia, the incidence of gastric cancer is high, and Helicobacter pylori (HP) infection is strongly implicated. China has a high incidence rate of gastric cancer and high prevalence of HP infection. We conducted a survey on the current status of HP infection in China.
Methods:
HP antibodies were measured in 496 Chinese nationals who visited our clinic. Participants were classified into groups based on a medical questionnaire: HP infection unknown; HP non-infected; and HP infected. Results of HP antibody tests were examined for each group. A comparative analysis was also conducted among 35 Japanese examinees.
Results:
The overall HP antibody positivity rate in Chinese patients was 39.9% (age group 20s: 14.3%, 30s: 40.0%, 40s: 45.0%, 50s: 35.8%, 60s: 32.6%, 70+: 57.1%). HP antibody positivity rates in the HP infection unknown, HP non-infected, and HP-infected groups were 39.0%, 23.3%, and 62.0%, respectively. In the HP-treated group, the HP antibody positivity rate was 52.3% in the eradication-confirmed group and 69.6% in the non-confirmed group. The overall HP antibody positivity rate among Japanese examinees was 17.1%, significantly lower than that among Chinese examinees (p=0.0074).
Conclusion:
The HP antibody positivity rate in Chinese participants was higher among younger age groups, compared with Japanese participants, and tended to be higher when eradication confirmation was not performed after HP eradication therapy. Combining the group with unclear HP infection status and the group who did not undergo HP eradication confirmation, approximately half of Chinese participants had an unclear HP infection status.
Keywords: Helicobacter pylori infection, Helicobacter pylori eradication confirmation, China
Introduction
Gastric cancer is the fifth most common malignant tumor worldwide and ranks as the fifth leading cause of cancer-related deaths.1 Five East Asian countries (China, Japan, North Korea, South Korea, and Mongolia) are noted for their high incidence rates of gastric cancer.2 Among these countries, China is reported to have the highest incidence, prevalence, and mortality rates. The rate of Helicobacter pylori (HP) infection in mainland China has shown a declining trend over the past decade but remains high (42.8%) in comparison with Western countries.3 HP infection is considered the primary cause of gastric cancer, with 90% of patients who have gastric cancer being infected with HP.4 Eighty percent of patients undergoing health checkups at our clinic are Chinese nationals residing in central to coastal China. In this study, we investigated the current status of HP infection and eradication treatment in China using patient questionnaires on gastric cancer and the results from serum HP antibody tests. Furthermore, a comparative analysis was conducted among Japanese patients who visited the clinic during the same period.
Methods
Participants
A total of 750 patients visited our clinic between October 2023 and May 2025. The present analysis included 496 Chinese nationals (mean age, 50.1 years; 318 men, 178 women) who provided consent for the statistical analysis of their data. As a comparison group, we investigated 35 Japanese individuals (mean age, 58.3 years; 27 men, 8 women) who underwent examination during the same period and provided consent for the statistical analysis of their data. This study was conducted in accordance with the Declaration of Helsinki guidelines.
HP infection history
Based on questionnaires obtained from study participants prior to their clinic visit, patients were broadly categorized into three groups: a group with unknown HP infection status, a non-HP-infected group, and an HP-infected group (Figure 1). In the HP-infected group, patients were classified into those with a history of eradication therapy and those without prior therapy. The group with a history of eradication therapy was further subdivided based on the presence or absence of confirmed HP eradication. The non-HP infection and HP infection groups were classified based on self-reporting. The medical questionnaire was administered by nurses who conducted detailed interviews with each patient regarding HP infection (presence or absence of HP infection testing and its timing, history of HP eradication therapy and its duration, presence or absence of HP eradication confirmation, and the testing method used).
Figure 1 . Patient selection flowchart.
HP antibody titer
Serum antibody titers were measured using the latex agglutination turbidimetric method (H. pylori-latex Seiken, Denka Seiken Co., Ltd., Tokyo, Japan). A value of 0–9 U/mL was considered negative and ≥10 U/mL was considered positive.
Endoscopic diagnosis of HP infection
In the confirmation of HP eradication, the diagnosis of current infection was made based on the Kyoto classification. Endoscopic findings suggestive of active infection included diffuse redness, mucosal swelling, enlarged fold, sticky mucus, spotty redness, and nodularity. Regarding atrophy, this includes both current and past infections.
Results
The overall HP antibody positivity rate among Chinese study participants was 39.9% (198/496). HP antibody positivity rates by age group were as follows: 20s, 14.3% (1/7); 30s, 40.0% (32/80); 40s, 45.0% (76/169); 50s, 35.8% (44/123); 60s, 32.6% (29/89); and 70s and older, 57.1% (16/28) (Table 1). In the HP-infected group, HP antibody positivity rates were 73.1% (19/26) in the HP-untreated group and 59.5% (66/111) in the HP-treated group. The overall HP antibody positivity rate among Japanese individuals was 17.1% (6/35), significantly lower than that among Chinese patients (χ2 test, p=0.0074). HP antibody positivity rates among Chinese patients were 39.0% (73/187) in the group with HP infection unknown, 23.3% (40/172) in the HP non-infected group, and 62.0% (85/137) in the HP-infected group (Table 2). The HP-infected group displayed a significantly higher positivity rate than the HP non-infected group (χ2 test, p<0.0001). HP eradication therapy had been administered to 81.0% (111/137) of the HP-infected cohort, and 19.0% (26/137) remained untreated (Table 3). HP antibody positivity rates were 59.5% (66/111) in the HP eradication therapy group and 73.1% (19/26) in the untreated HP group, tending to be higher in the latter group (χ2 test, p=0.1978). In the group with HP eradication treatment, 58.6% (65/111) had undergone confirmation of HP eradication and 41.4% (46/111) had not. The age group ≥70 years exhibited the highest rate of eradication confirmation, at 83.3% (5/6), as compared with 0% (0/2) among participants in their 20s (Table 4). The HP antibody positivity rate was 69.6% (32/46) in the group without HP eradication confirmation and 52.3% (34/65) in the group with HP eradication confirmation, with higher positivity rate among patients without confirmed eradication of HP (χ2 test, p=0.0681). Comparing HP antibody positivity rates according to the presence or absence of HP eradication confirmation across age groups revealed that, except for those aged ≥70 years, participants without HP eradication confirmation showed higher positivity rates than those with confirmed HP eradication (Table 5). Figure 2 presents a graph in which antibody titers for the HP eradication confirmation group and HP eradication non-confirmation group are plotted. In the group without HP eradication confirmation, a certain increase in antibody titers was observed (Figure 2b). However, in the group with confirmed HP eradication, antibody titers remained largely flat up to 30 U/mL (Figure 2a). Patients with antibody titers between 10 and 30 U/mL predominantly represented cases of previous HP infection in which eradication was successful. Regarding the results of endoscopy, no findings suggestive of current infection were observed with HP antibody titers approximately 20 U/mL; however, we did observe findings suggestive of current infection with titers exceeding 30 U/mL (Table 6). Among the eight patients with HP antibody titers 30 U/mL or higher, only one was confirmed to have undergone the urea breath test as the method of confirming HP eradication (No. 65); the assessment method for the remaining seven patients was unknown.
Table 1 . HP antibody positivity rate.
| Age (years) | Chinese | Japanese | p value* |
|---|---|---|---|
| 20–29 | 14.3% (1/7) | 50% (1/2) | |
| 30–39 | 40.0% (32/80) | — | |
| 40–49 | 45.0% (76/169) | 0% (0/7) | |
| 50–59 | 35.8% (44/123) | 11.1% (1/9) | |
| 60–69 | 32.6% (29/89) | 11.1% (1/9) | |
| >69 | 57.1% (16/28) | 37.5% (3/8) | |
| Total | 39.9% (198/496) | 17.1% (6/35) | p=0.0074 |
* χ2 test
Table 2 . HP antibody positivity rate based on history of HP infection.
| HP infection history | HP antibody (+) | HP antibody (–) |
|---|---|---|
| Unknown group (n=187) | 39.0% (73/187) | 61.0% (114/187) |
| Negative group (n=172) | 23.3% (40/172) | 76.7% (132/172) |
| Positive group (n=137) | 62.0% (85/137) | 38.0% (52/137) |
Table 3 . Rate of HP eradication therapy.
| Age (years) | HP eradication therapy |
|---|---|
| 20–29 (n=2) | 100% (2/2) |
| 30–39 (n=22) | 68.2% (15/22) |
| 40–49 (n=40) | 82.5% (33/40) |
| 50–59 (n=47) | 85.1% (40/47) |
| 60–69 (n=17) | 88.2% (15/17) |
| >69 (n=9) | 66.7% (6/9) |
| Total (n=137) | 81.0% (111/137) |
Table 4 . Rate of HP eradication confirmation.
| Age (years) | Judgment (+) |
|---|---|
| 20–29 (n=2) | 0% (0/2) |
| 30–39 (n=15) | 46.7% (7/15) |
| 40–49 (n=33) | 69.7% (23/33) |
| 50–59 (n=40) | 57.5% (23/40) |
| 60–69 (n=15) | 46.7% (7/15) |
| >69 (n=6) | 83.3% (5/6) |
| Total (n=111) | 58.6% (65/111) |
Table 5 . HP antibody positivity rate between presence or absence of HP eradication confirmation.
| Age (years) | Confirmation (+) | Confirmation (–) | p value* |
|---|---|---|---|
| 20–29 (n=2) | 0% (0/0) | 50.0% (1/2) | 1 |
| 30–39 (n=15) | 57.1% (4/7) | 100% (8/8) | 0.077 |
| 40–49 (n=33) | 52.2% (12/23) | 70.0% (7/10) | 0.025 |
| 50–59 (n=40) | 47.8% (11/23) | 58.8% (10/17) | 0.538 |
| 60–69 (n=15) | 28.6% (2/7) | 75.0% (6/8) | 0.132 |
| >69 (n=6) | 100% (5/5) | 0% (0/1) | 0.167 |
| Total (n=111) | 52.3% (34/65) | 69.6% (32/46) | 0.08 |
* Fisher’s exact test
Figure 2 . HP antibody titer trends based on eradication confirmation status.
a: Graph showing antibody titers for the HP eradication confirmation group. b: Graph showing antibody titers for the HP eradication non-confirmation group.
Table 6 . HP antibody titers and endoscopic findings in the HP eradication confirmation group.
| Patient Number | Age | Sex | HP antibody titer | Endoscopic findings* |
|---|---|---|---|---|
| 1 | 32 | M | <3 | A |
| 2 | 40 | M | 3 | A |
| 3 | 41 | M | 3 | None |
| 4 | 42 | M | 3 | A |
| 5 | 44 | M | 3 | A |
| 6 | 44 | M | 3 | A |
| 7 | 44 | M | 3 | none |
| 8 | 46 | M | 3 | No endoscopy |
| 9 | 50 | M | 3 | A |
| 10 | 50 | M | 3 | A |
| 11 | 53 | M | 3 | A |
| 12 | 54 | M | 3 | A |
| 13 | 62 | F | 3 | A |
| 14 | 43 | M | 4 | A |
| 15 | 57 | M | 4 | A |
| 16 | 63 | M | 4 | A |
| 17 | 37 | M | 5 | A |
| 18 | 53 | M | 5 | A |
| 19 | 55 | M | 5 | A |
| 20 | 68 | F | 5 | A |
| 21 | 36 | M | 6 | A |
| 22 | 44 | F | 6 | A |
| 23 | 52 | M | 6 | No endoscopy |
| 24 | 53 | F | 6 | A |
| 25 | 52 | M | 7 | A |
| 26 | 54 | M | 7 | A |
| 27 | 45 | M | 8 | A |
| 28 | 64 | M | 8 | No endoscopy |
| 29 | 49 | F | 9 | A |
| 30 | 52 | F | 9 | A |
| 31 | 69 | M | 9 | A |
| 32 | 46 | F | 10 | A |
| 33 | 49 | M | 10 | A |
| 34 | 51 | M | 10 | No endoscopy |
| 35 | 51 | F | 10 | A |
| 36 | 56 | F | 10 | A |
| 37 | 35 | F | 11 | A |
| 38 | 56 | M | 11 | A |
| 39 | 65 | F | 11 | A |
| 40 | 46 | F | 12 | A |
| 41 | 71 | M | 12 | A |
| 42 | 47 | M | 13 | A |
| 43 | 72 | M | 13 | A |
| 44 | 73 | M | 13 | A |
| 45 | 53 | M | 16 | A |
| 46 | 59 | F | 16 | A |
| 47 | 70 | F | 16 | A |
| 48 | 47 | M | 18 | A |
| 49 | 39 | M | 19 | A |
| 50 | 65 | F | 20 | A |
| 51 | 34 | F | 21 | A |
| 52 | 44 | F | 21 | A |
| 53 | 53 | F | 21 | A |
| 54 | 54 | M | 22 | A |
| 55 | 46 | F | 23 | A |
| 56 | 40 | M | 24 | A |
| 57 | 47 | M | 25 | A |
| 58 | 42 | F | 31 | M |
| 59 | 48 | F | 53 | N |
| 60 | 45 | M | 64 | M |
| 61 | 74 | F | 85 | S, A |
| 62 | 53 | M | 97 | S, E, A |
| 63 | 39 | F | 101 | M, A |
| 64 | 50 | M | 101 | S, E, A |
| 65 | 50 | M | 101 | N, S, A |
* A; atrophy, M; mucosal swelling, N; nodularity, S; spotty redness, E; enlarged fold
The fact that 37.7% (187/496) of study participants had unknown HP infection status and 41.4% (46/111) had not undergone HP eradication confirmation despite receiving eradication therapy indicates that approximately half of our Chinese participants (47.0%; 233/496) had an unclear HP infection status.
Discussion
Since the International Agency for Research on Cancer classified HP as a Group 1 carcinogenic pathogen in 1994, HP eradication therapy has been performed worldwide.5 The infection rate for HP is reported to be 50% worldwide, but this rate varies widely by country.6 A meta-analysis reported the annual trends in HP infection rates across mainland China from 1983 to 2019, showing a decline from 58.3% to 40.0%,7 which closely matched our infection rate of 39.9%.
In Japan, HP infection exhibits a birth cohort effect, with infection rates steadily declining as birth cohorts advance.8 Reports have indicated a decrease from 59.1% in 1950 to 15.6% in 1990. For the Japanese population born after 1998, the multivariable-adjusted infection rate has been less than 10%. In this analysis of Chinese participants, the HP positivity rate exceeding 40% among those in their 30s and 40s suggests that infection is spreading among relatively younger age groups in China, as compared with Japan. HP infection rates generally increase with age; however, in our statistical analysis, rates exceeded 40% among those in their 30s and 40s, declining to approximately 30% among those in their 50s and 60s. Reasons for this decline may include the following: 1) the rate of HP eradication therapy administration is 68.2% among patients in their 30s but exceeds 80% among those in their 40s to 60s; 2) the rate of HP eradication confirmation is 46.7% among individuals in their 30s but ranges from 57.5% to 69.7% among those in their 40s to 50s; 3) the status of oral eradication medication intake is unknown, as patients are not regularly undergoing HP eradication confirmation.
HP transmission is thought to occur via oral infection, with reports of transmission within families, particularly between mothers and infants or among siblings.9 HP reinfection is considered rare,10 and appropriate eradication therapy can prevent outbreaks. However, antibiotic resistance rates in China are reported to be approximately 20%–40% for clarithromycin and levofloxacin and 60%–90% for metronidazole.11 In one review, only 58.6% of patients had undergone HP eradication confirmation despite having a history of HP eradication therapy. Using the Kyoto Classification12 for endoscopic diagnosis of HP infection, findings suggestive of active HP infection were observed in patients with anti-HP antibody titers 30 U/mL or higher; titers in the range of 10–20 U/mL were almost exclusively associated with findings of gastric mucosal atrophy due to past infection. Regarding anti-HP antibody titers, values within the range of 3–9.9 U/mL are classified as negative-high titer and have been reported to indicate a high-risk group for gastric cancer development.13 In this study, 38.5% (25/65) of cases within the 10–20 U/mL range after infection were considered potential false positives, suggesting that further investigation is needed regarding the reference range for anti-HP antibody titers. In the group undergoing HP eradication confirmation, even in cases of successful treatment, false positives were present, with antibody titers in the range of 10–30 U/mL. This finding indicates that relying solely on anti-HP antibodies for diagnosing active as well as past HP infection has limitations, and a clear medical history regarding eradication treatment is considered important. Inadequate administration of HP eradication therapy or persistent infection in cases of failed HP eradication contributes to the spread of HP infection. Therefore, concurrently with prescribing HP eradication medication, our hospital schedules follow-up appointments to confirm the eradication of HP.
Limitations
This study focused on patients visiting a single facility and included patients from specific regions within mainland China; therefore, the study findings do not represent the Chinese population as a whole. Furthermore, because HP infection was evaluated using serum anti-HP antibodies, it was not possible to accurately distinguish between current and past infections.
Conclusions
Our study population included a group with unknown HP infection status comprising 37.7% (187/496) of participants, and 41.4% (46/111) of participants had no confirmation of HP eradication, despite receiving HP eradication therapy. Consequently, approximately half of Chinese participants (47.0%; 233/496) had unclear HP infection status.
Acknowledgment
We wish to thank the patients and healthcare staff at Fujita Health University Haneda Clinic.
Ethical Approval
Ethics Committee Approval Number: CI25-575, Fujita Health University Certified Review Board
Conflict of Interest
The authors have no conflicts of interest to declare in relation to this study. This report has been prepared with the consent of the patient and has received approval from the ethics committee.
References
- 1.Bray F, Laversanne M, Sung H, Ferlay J, Siegel RL, Soerjomataram I, Jemal A. Global cancer statistics 2022: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin 2024; 74: 229–263. [DOI] [PubMed] [Google Scholar]
- 2.Guo T, Zhou T, Zhu W, Yuan Y, Hui Y, Zhu W, Shen W, Li L, Wei W, Cheng H, Wu X. Burden and future trends of gastric cancer in 5 East Asian countries from 1990 to 2036: epidemiological study analysis using the Global Burden of Diseases Study 2021. JMIR Cancer 2025; 11: e74389. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Xie L, Liu GW, Liu YN, Li PY, Hu XN, He XY, Huan RB, Zhao TL, Guo HJ. Prevalence of Helicobacter pylori infection in China from 2014–2023: a systematic review and meta-analysis. World J Gastroenterol 2024; 30: 4636–4656. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.de Martel C, Ferlay J, Franceschi S, Vignat J, Bray F, Forman D, Plummer M. Global burden of cancers attributable to infections in 2008: a review and synthetic analysis. Lancet Oncol 2012; 13: 607–615. [DOI] [PubMed] [Google Scholar]
- 5.Schistosomes, liver flukes and Helicobacter pylori. In: IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. No. 61. Lyon: Agency for Research on Cancer; 1994: 1–241. [PMC free article] [PubMed] [Google Scholar]
- 6.Hooi JKY, Lai WY, Ng WK, Suen MMY, Underwood FE, Tanyingoh D, Malfertheiner P, Graham DY, Wong VWS, Wu JCY, Chan FKL, Sung JJY, Kaplan GG, Ng SC. Global prevalence of Helicobacter pylori infection: systematic review and meta-analysis. Gastroenterology 2017; 153: 420–429. [DOI] [PubMed] [Google Scholar]
- 7.Ren S, Cai P, Liu Y, Wang T, Zhang Y, Li Q, Gu Y, Wei L, Yan C, Jin G. Prevalence of Helicobacter pylori infection in China: a systematic review and meta-analysis. J Gastroenterol Hepatol 2022; 37: 464–470. [DOI] [PubMed] [Google Scholar]
- 8.Wang C, Nishiyama T, Kikuchi S, Inoue M, Sawada N, Tsugane S, Lin Y. Changing trends in the prevalence of H. pylori infection in Japan (1908–2003): a systematic review and meta-regression analysis of 170,752 individuals. Sci Rep 2017; 7: 15491. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Yokota S, Konno M, Fujiwara S, Toita N, Takahashi M, Yamamoto S, Ogasawara N, Shiraishi T. Intrafamilial, preferentially mother-to-child and intraspousal, Helicobacter pylori infection in Japan determined by mutilocus sequence typing and random amplified polymorphic DNA fingerprinting. Helicobacter 2015; 20: 334–342. [DOI] [PubMed] [Google Scholar]
- 10.Take S, Mizuno M, Ishiki K, Imada T, Okuno T, Yoshida T, Yokota K, Oguma K, Kita M, Okada H, Yamamoto K. Reinfection rate of Helicobacter pylori after eradication treatment: a long-term prospective study in Japan. J Gastroenterol 2012; 47: 641–646. [DOI] [PubMed] [Google Scholar]
- 11.Zhou L, Lu H, Song Z, Lyu B, Chen Y, Wang J, Xia J, Zhao Z. 2022 Chinese national clinical practice guideline on Helicobacter pylori eradication treatment. Chin Med J (Engl) 2022; 135: 2899–2910. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Kamada T, Haruma K, Inoue K, Shiotani A. Helicobacter pylori infection and endoscopic gastritis -Kyoto classification of gastritis-. Nihon Shokakibyo Gakkai Zasshi 2015; 112: 982–993 (in Japanese). [DOI] [PubMed] [Google Scholar]
- 13.Kishikawa H, Kimura K, Takarabe S, Kaida S, Nishida J. Helicobacter pylori antibody titer and gastric cancer screening. Dis Markers 2015; 2015: 156719. [DOI] [PMC free article] [PubMed] [Google Scholar]