This study examines the association between lifestyle factors, chronic disease, body-indices, and the seroprevalence of Helicobacter pylori infection in Danish adults. The relationship between age at menarche and H. pylori infection is also assessed. A random sample of 3,608 Danish adults completed a questionnaire about lifestyle factors (smoking habits, alcohol consumption, and coffee and tea intake), doctor diagnosed chronic diseases (heart conditions, diabetes, chronic bronchitis, and hypertension), menarche, and socio-demographic factors. A total of 2,913 participants were eligible for the present study. Electrocardiographs were recorded and blood pressure and serum lipid levels (HDL cholesterol, triglyceride, and cholesterol) were measured. Height and weight were determined and body mass index (BMI) calculated. Sera were analysed with an enzyme-linked immunosorbent assay for the presence of H. pylori specific IgG antibodies. The seroprevalence of H. pylori infection was associated with weekly alcohol intake ≥6 drinks (odds ratio 0.7, 95% confidence interval 0.6-0.9) due to a low rate of H. pylori infection among wine drinkers (odds ratio 0.6, 95% confidence interval 0.5- 0.7). No associations were found with smoking habits or serum lipids. People with upper quartile BMI (≥26.8 kg/m²) were more likely to be seropositive for antibodies to H. pylori (odds ratio 1.6, 95% confidence interval 1.1-2.4). Chronic bronchitis (odds ratio 1.6, 95% confidence interval 1.1-2.5) and unspecified heart condition (odds ratio 2.0, 95% confidence interval 1.1-3.3) was more often seen in IgG seropositive women than in uninfected women. The likelihood of being seropositive for IgG antibodies to H. pylori increased with age at menarche (odds ratio per year 1.10, 95% confidence interval 1.02-1.19). Previously reported associations with age and socioeconomic status were confirmed. We conclude that wine drinking is associated with lower rates of H. pylori infection in Danish adults. The seroprevalence of H. pylori infection is increased in people with high BMI. H. pylori infection may relate to a history of late menarche and chronic bronchitis in Danish women.