Helicobacter pylori infection and diabetes mellitus: the 2013 state of art

It is well-known the role of Helicobacter pylori (H. pylori) infection in the development of gastroduodenal diseases. From two decades literature has suggested the potential relationship of the bacterium with extragastric manifestations. Aim of the present review was to analyze the consistency of a potential involvement of H. pylori infection in the pathogenesis of diabetes mellitus (DM) as well as in the gastric abnormalities associated with this disease. Several studies reported a higher prevalence of H. pylori infection in diabetic patients with or without dyspeptic symptoms than in controls and a positive association with insulin resistance (IR) has been shown. However, DM has a multifactorial pathogenesis and the detection of the role of each agent is difficult. The different factors implicated in the development of DM as well as of IR include inflammation, autoimmunuty, stimulation of innate immune system, trigger to platelet activation and platelet-leukocyte aggregation, action on leptin and ghrelin regulation, alterated lipid metabolism and insulin sensitivity. Effectiveness of H. pylori eradication results significantly lower in diabetic patients than in controls, most likely because of the large use of antibiotic in DM subjects, causing selection of resistant H. pylori strains. Finally, re-infection after bacterial eradication, although rarely observed in the general population, seems to be more frequent in diabetic patients than in controls.