PROSPECTIVE RELATIONS BETWEEN HELICOBACTER-PYLORI INFECTION, CORONARYHEART-DISEASE, AND STROKE IN MIDDLE-AGED MEN

Objective-To determine whether Helicobacter pylori, a chronic bacteria l infection often acquired in childhood, is associated with increased risk of coronary heart disease and stroke later in life. Design-Nested case-control study. Setting-Prospective study of cardiovascular disea se in men aged 40-59 years at entry (1978-1980) in 24 British towns. S ubjects-135 cases of myocardial infarction and 137 cases of stroke occ urring before December 1991; 136 controls were identified, frequency m atched to cases by town and age group. Methods-Serum samples stored at entry were analysed by an enzyme linked immunosorbent assay for the p resence of H pylori specific IgG antibodies. Results-95 of the myocard ial infarction cases (70%) and 93 (68%) of the stroke cases were serop ositive for H pylori compared with 78 (57%) of the controls (odds rati o for myocardial infarction 1.77, 95% confidence interval (CI) 1.06 to 2.95, P = 0.03; odds ratio for stroke 1.57, 95% CI 0.95 to 2.60, P = 0.07). Helicobacter pylori infection was associated with manual social class, residence in Northern England or Scotland, cigarette smoking, higher systolic pressure and blood glucose, and a lower height-standar dised forced expiratory volume in one second. Adjustment for these fac tors attenuated the relation between H pylori and myocardial infarctio n (odds ratio = 1.31, 95% CI 0.70 to 2.43, P = 0.40) and effectively a bolished the relation with stroke (odds ratio = 0.96, 0.46 to 2.02, P 0.92). The relation between helicobacter infection and fatal myocardia l infarction was slightly stronger (odds ratio 2.41, 95% CI 1.13 to 5. 12) but was also markedly attenuated after adjustment (1.56, 95% CI 0. 68 to 3.61). Conclusion-In this prospective study the association betw een Helicobacter pylori infection and increased risk of myocardial inf arction and stroke was substantially confounded by the relation betwee n this infection, adult social class, and major cardiovascular risk fa ctors.