BackgroundThe status of family-based H. pylori infection in Yunnan Province is unknown. This study is the first family-based epidemiological survey of H. pylori in the province, aiming to provide new insights into the status of family-based H. pylori infections in Yunnan Province as well as in the country as a whole.MethodsBetween 2021 and 2023, 1,176 families with 2,947 family members were tested for H. pylori in six cities in Yunnan Province with different geographic locations and economic status, to assess the status of H. pylori infection, and to clarify the related factors and modes of transmission by means of a questionnaire survey.ResultsIn Yunnan Province, the H. pylori infection rate was 31.46% (927/2947) in people and 54.59% (642/1176) in families.On the individual side, living outside of southern Yunnan (e.g., Central OR 1.41, 95% CI 1.10-1.81), having a family member living together for >= 1 year (OR 2.43, 95% CI 1.49-3.95), being >= 18 years old (e.g., 18-44 years old: OR 3.51, 95% CI 1.98-6.23), and gastrointestinal discomfort within the last 1 year (OR 1.25, 95% CI 1.04-1.50) were independent risk factors for H. pylori infection in the study population in Yunnan Province, whereas an education level of college/university and above (OR 0.62, 95% CI 0.48-0.79), and a gastroscopy within 5 years (OR 0.58, 95% CI 0.46-0.73) were independent protective factors for their H. pylori infection. In terms of family, living outside of southern Yunnan (e.g., Central OR 1.52, 95% CI 1.07-2.18), and having >= 3 people living together in the family (e.g., 3-4 people: OR 2.04, 95% CI 1.52-2.72) were independent risk factors for H. pylori infection in study families in Yunnan Province, whereas an annual household income of >= 100,000 ( OR 0.68, 95% CI 0.51-0.90), total household living area >= 60 m2 (OR 0.62, 95% CI 0.39-0.97), the use of separate meals for intra-household gatherings (OR 0.56, 95% CI 0.38-0.85), and the use of communal spoons and chopsticks (OR 0.38, 95% CI 0.28-0.52) were the independent protective factorse.ConclusionThe risk factors of Family-Based H. pylori infection in Yunnan province were closely related to demographic characteristics, personal and family living habits. Close contact with infected family members may be the main cause of transmission. Family-based control of H. pylori infection should be regarded in clinical practice.