Subject(s): Primary health care | Helicobacter pylori -- pathogenicity | Helicobacter pylori -- immunology | Chlamydophila pneumoniae -- pathogenicity | Chlamydia pneumoniae -- immunology | Helicobacter infections -- complications | Chlamydophila infections -- complications | Cardiovascular diseases -- etiology | Gastrointestinal diseases -- etiology | Antibodies, bacterial -- analysis