Resumo

Helicobacter pylori infects more than 50% of the world’s population, with higher prevalence in developing countries. This bacterium is linked to chronic gastritis, peptic ulcer and gastric cancer. The aim of this study was to determine the frequency of H. pylori infection and the associated factors. For this, a cross-sectional study was conducted including 256 patients submitted to upper gastrointestinal endoscopy. Biopsy specimens were obtained from gastric antrum and body for histology and PCR. Data on age, gender, marital status, number of people living in the house, type of consumed water, sanitary, educational level, monthly family income and smoking status were collected using questionnaires. Of the 256 patients included in this study,69.1% (177) were H. pylori positive. No significant difference was detected between the sex and the H. pylori presence (female: 55.9% (99), male: 44.1% (78); p > 0.05). However, a statistically significant relation was detected between the presence of H. pylori and the patient’s age (p = 0.040). The frequencies of H. pylori according the different ages groups were: 4.5% (20-29), 15.3% (30-39), 22.6% (40-49), 31.6% (50-59), 18.1% (60-69), 5.6% (70-79) and 2.3% (80-88). As observed, the increase in the frequency of infection with age may be due a birth cohort effect (i.e. a changing in the rate of infection in childhood). It has been suggested that the H. pylori infection occurs mainly during childhood. Hence, the living conditions in the childhood seem to play a significant role in the risk of infection. The decrease in the frequency of infection among more recent generations of the study can be due to improved in hygiene and in the socio-economic condition of the population. On the other hand, a decrease in the frequency of H. pylori observed from the age group of 60-69 years can be explained due to a reduction in the specific serological response among older individuals and/or to a decreased number of microorganisms as result of gastric mucosa atrophy. Based on the questionnaires applied to the patients, marital status, smoking, number of persons per household, type of consumed water, toilet, education level and monthly family income had no significant effect on the H. pylori infection (p > 0.05). These results suggest a birth cohort effect. The high frequency of H. pylori infection/colonization found in this study may be due the acquisition of bacterium during childhood.