['To determine the prevalence of chronic infection with Helicobacter pylori (HP) in patients with established coronary artery disease (CAD) and in healthy controls. Furthermore, to investigate whether HP infection is associated with inflammatory parameters, lipid concentrations and degree and progression of CAD.', 'A case-control study combined with a prospective angiographic study.', 'Stockholm Metropolitan Area, Sweden.', 'A material consisting of 92 young men aged 40.9 +/- 3.2 (mean +/- SD) years, with previous myocardial infarction and documented coronary atherosclerosis, and 95 healthy sex-matched controls, aged 43.2 +/- 3.0 (mean +/- SD) years, with similar socio-economic status and ethnic background was analysed for the prevalence of HP seropositivity, plasma concentrations of the inflammatory parameters fibrinogen, tumour necrosis factor alpha and orosomucoid, and serum concentrations of lipids. The impact of HP seropositivity on degree and progression of CAD, as assessed by quantitative coronary angiography, was also determined.', 'The study population of mainly Scandinavian origin had a low prevalence of HP seropositivity in comparison with previously published European populations. No significant increase in HP seropositivity was found in patients compared with controls (42.2 vs. 32.6%). Furthermore, HP infection was not associated with increased levels of inflammatory parameters, lipid concentrations or with degree of angiographically determined CAD at baseline, or progression of CAD and clinical events over 5 years.'] Is helicobacter pylori seropositivity associated with inflammatory parameters , lipid concentrations and degree of coronary artery disease?