"This is a fascinating and careful piece of research which could lead to important new avenues in treating this chronic gastric infection which is a major risk factor for stomach cancer, " said Dr Richard Sullivan, its head of clinical programmes.
Human papillomavirus (HPV) is likely to play a significant role in the development of cervical cancer, and the bacteria H. pylori in the development of gastric cancers.
Although a reduction in cancer risk was seen with all three techniques, some experts believe that gastric bypass surgery may one day be shown to be more effective than the other two.