In a cohort of 29 584 residents of Linxian, China, followed from 1985 to 2001, we conducted a case -cohort study of the magnitude of the association of Helicobacter pylori seropositivity with cancer risk in a random sample of 300 oesophageal squamous cell carcinomas, 600 gastric cardia adenocarcinomas, all 363 diagnosed gastric non-cardia adenocarcinomas, and a random sample of the entire cohort (N ¼ 1050). Baseline serum was evaluated for IgG antibodies to whole-cell and CagA H. pylori antigens by enzymelinked immunosorbent assay. Risks of both gastric cardia and non-cardia cancers were increased in individuals exposed to H. pylori (Hazard ratios (HRs) and 95% confidence intervals ¼ 1.64; 1.26 -2.14, and 1.60; 1.15 -2.21, respectively), whereas risk of oesophageal squamous cell cancer was not affected (1.17; 0.88 -1.57). For both cardia and non-cardia cancers, HRs were higher in younger individuals. With longer time between serum collection to cancer diagnosis, associations became stronger for cardia cancers but weaker for non-cardia cancers. CagA positivity did not modify these associations. The associations between H. pylori exposure and gastric cardia and non-cardia adenocarcinoma development were equally strong, in contrast to Western countries, perhaps due to the absence of Barrett's oesophagus and oesophageal adenocarcinomas in Linxian, making all cardia tumours of gastric origin, rather than a mixture of gastric and oesophageal malignancies.

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We analyzed serum samples obtained from 100 heart transplant recipients before and after transplantation for the presence of IgG antibodies to Helicobacter pylori. Enzyme-linked immunosorbent assay revealed that 35 patients were seropositive before the procedure. Seropositive patients were older than seronegative patients, but the two groups did not differ in terms of cardiac diagnosis, gender, survival, or the number of admissions or rejection episodes. In addition, seropositive patients did not have more-frequent episodes of gastritis, ulcer disease, or gastrointestinal bleeding. Over a mean serological follow-up of 3.4 years, only one of 65 seronegative patients seroconverted. Of the 35 seropositive patients, 14 became seronegative for H. pylori a median of 194 days (range, 47-2,657 days) after transplantation. Seroreverters, as compared with serofast patients, had received more intravenous and total antibiotics during follow-up (P = .01), were more likely to have received a combination of antibiotics active against H. pylori (P < .025), and had received more antirejection treatment (P = .01). The incidence of H. pylori infection is not increased after heart transplantation, and many seropositive patients serorevert after transplantation when antibacterial and immunosuppressive agents are administered.

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