[Prevalence of Helicobacter pylori infection in primary health care]

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.

Transversal study of an urban population of 20,000.

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).

Breath test with urea marked (13C), age, sex, alcohol and tobacco consumption, social class and dyspepsia and/or gastro-duodenal pathology.

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.

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.