Abstract
OBJECTIVES: To find the prevalence of Helicobacter pylori (Hp) infection in the population as a whole. To assess its relationship with the associated factors described in other studies. DESIGN: Transversal study of an urban population of 20,000. PARTICIPANTS: Between 14 and 80 years old. Randomised sampling of the computerised records (640 clinical histories). Necessary sample n = 384 (alpha = 0.05, prior prevalence = 50%, precision 0.05). MEASUREMENTS: Breath test with urea marked (13C), age, sex, alcohol and tobacco consumption, social class and dyspepsia and/or gastro-duodenal pathology. RESULTS: 123 exclusions. 122 losses (23%). 397 people screened, 43.6% male. Average age: 42.6. 41.6% consumed alcohol. 30.5% smoked. Prevalence of dyspepsia, gastritis, gastric ulcer and duodenal ulcer, 14%, 2.8%, 2.8% and 2.0%, respectively. Hp prevalence: 56.1% (95% CI, 51.2-60.1). There were no significant differences between prevalence of Hp+ and sex, dyspepsia, peptic ulcer history, gastritis, alcohol consumption and tobacco consumption. Greatest prevalence of Hp+ in over-70s (73%). Significant linear tendency between presence of Hp+ and age (p < 0.05) and low social class (p < 0.05). The logistic regression analysis found a statistically significant relationship only between the presence of H. pylori and age and social class. CONCLUSIONS: Prevalence was similar to that in other studies. The relationship between low social class and age and greater Hp prevalence was confirmed. Dyspepsia is not a justification for empirical treatment of Hp. Patients with and without the infection must be followed to evaluate morbidity longitudinally.