This study intends to investigate the prevalence and risk factors of Helicobacter pylori (H. pylori) infection in the population of physical examination centers and communities. The physical examination population from the health management center of the Third Xiangya Hospital and the family-based community residents in Changsha were randomly selected. The H. pylori infection was detected by carbon-13 urea breath test (13C-UBT), and the related factors of H. pylori infection were investigated by questionnaire survey. The study provides supporting evidences to implement family-base H. pylori management to curb its intrafamilial spread. The results have important clinical implications in refinement of eradication strategies and impact on public health policy formulation for related disease prevention.

Inclusion Criteria:

1. population aged 4-90 years, no requirement for gender;
2. the physical examination population from the health management center of the Third Xiangya Hospital;
3. the family-based community residents in Changsha City [families containing two or more family members (living together for more than 10 consecutive months per year) and the family members aged 3 years and above];

Exclusion Criteria:

1. people with use of antibiotics, bismuth or Chinese traditional medicines with antibacterial effects in the previous 4 weeks of 13C-UBT, or H2 receptor antagonists, PPIs, P-CAB or other drugs affecting H. pylori activity within the previous 2 weeks of 13C-UBT;
2. people with H. pylori treatment within the past 3 months;
3. People who fasted less than 3 hours before 13C-UBT;
4. people with other contraindications to performing 13C-UBT;
5. people living alone in a family;
6. people with incomplete questionnaire information;
7. people with serious diseases or clinical conditions that may interfere with the evaluation of the results of the study, such as severe heart, liver, lung, and renal insufficiency, low immunity, and so on;
8. people with mental illness and communication disorders;
9. people deemed unsuitable by the researchers to participate in this project;

1. the physical examination population from all over the country was randomly selected from the Health Management Center of the Third Xiangya Hospital;
2. the family-based community residents were randomly selected in Changsha. [families containing two or more family members (living together for more than 10 consecutive months per year) and the family members aged 3 years and above];