Role of Helicobacter pylori infection and lifestyle habits in the development of gastroduodenal diseases in a population from the Brazilian Amazon.

CONTEXT Although more than half of the world's population is colonized with Helicobacter pylori, it remains unknown why this organism is able to produce severe disease in some hosts and be innocuous in others. The clinical outcome of infection is determined by several factors, including differences in the host response to bacterial stimulation, specific virulence factors of the organism and environmental influences, or a combination of these factors. OBJECTIVES This study compared the prevalence of H. pylori infection and risk factors (infection with CagA+ strains, excessive alcohol consumption, smoking, and inadequate eating habits) between patients with different gastrointestinal disorders and associated these risk factors with the histopathological findings. METHODS In a prospective study, samples were collected from 442 patients and a standardized questionnaire regarding lifestyle habits (excessive alcohol consumption, smoking, and eating habits) was applied. The presence of H. pylori and of the cagA gene was investigated by polymerase chain reaction (PCR). Gastric biopsies were obtained for histological assessment. RESULTS The frequency of alcohol consumption, smoking, inadequate diet and infection with CagA+ H. pylori was higher among patients with peptic ulcer and adenocarcinoma when compared to those with gastritis. Gastric inflammation was more pronounced in patients infected with CagA+ strains. CONCLUSION We conclude that infection with CagA+ H. pylori strains, excessive alcohol consumption, smoking and inadequate eating habits increase the risk of developing peptic ulcer and gastric carcinoma.