Helicobacter pylori is associated with weakened pulmonary function and reduced incidence of allergic conditions in patients with chronic cough

The present study aimed to investigate the potential association between Helicobacter pylori (a H. pylori) positive state and chronic cough. A clinical observational study with systematic analysis was performed, including 278 patients with complaints of chronic cough and 148 healthy controls. a H. pylori positive state was present in 61.2% of the patients in the chronic cough group and 68.9% in the chronic refractory cough group, as opposed to 43.9% in the control group. There was a significant improvement in 65.5% of the patients with chronic refractory cough following successful a H. pylori eradication therapy. In addition, patients with chronic cough exposed to a H. pylori exhibited decreased pulmonary function with a decrease in forced expiratory volume in 1 sec by 84 ml, a decrease in the forced vital capacity by 53 ml and a decrease in maximal vital capacity by 46 ml. The difference was even more obvious in the chronic refractory cough group. The allergy status differed significantly according to age between a H. pylori-positive and -negative cases in the cough variant asthma and allergic cough groups. Among patients aged <40 years, a H. pylori-positive cases had a lower prevalence of atopy and lower total serum immunoglobin E levels compared with a H. pylori-negative cases. However, there was no significant association between a H. pylori status and C-reactive protein levels, erythrocyte sedimentation rate or eosinophil count in the peripheral blood. In conclusion, the present study demonstrated that a H. pylori infection may be a factor associated with chronic cough and it may be associated with a decline in pulmonary function and reduced incidence of allergic conditions. Thus, a H. pylori may represent a target for the treatment of chronic cough.