Epidemiological study of oesophageal and gastric cancer in south-east England

Background: This epidemiological study was carried out to establish the magnitude of the changing incidence of gastric and oesophageal cancer. Methods: Time-trend analyses of subsite-specific cancers of the oesophagus and stomach were performed using data from the Thames Cancer Registry database (1960-1996) for the South Thames Region. The changes in sex ratio and peak age of incidence are reported. Results: In the upper two-thirds of the oesophagus there was no significant change in the incidence rate, but the lower third of the oesophagus showed a marked rise for both sexes (average annual change + 0.05 for men, + 0.009 for women). For the gastric cardia, the incidence in males increased (average annual change + 0.025), while in females it remained unchanged. Cancers of the oesophagogastric junction showed a clear increase for both sexes (average annual change + 0.07 for men, + 0.009 for women). There were changes in the sex ratio and peak age of incidence for all subsite cancers for both sexes. Conclusion: Over a 37-year period the incidence of cancer of the oesophagogastric junction increased threefold, while the incidence of cancers of the other subsites of the stomach decreased. Further studies are needed to investigate the aetiology of these changes.

Review paper: role of aluminum in glass-ionomer dental cements and its biological effects

The role of aluminum in glass-ionomers and resin-modified glass-ionomers for dentistry is reviewed. Aluminum is included in the glass component of these materials in the form of Al(2)O(3) to confer basicity on the glass and enable the glass to take part in the acid-base setting reactions. Results of studies of these reactions by FTIR and magic-angle spinning (MAS)-NMR spectroscopy are reported and the role of aluminum is discussed in detail. Aluminum has been shown to be present in the glasses in predominantly 4-coordination, as well as 5- and 6-coordination, and during setting a proportion of this is converted to 6-coordinate species within the matrix of the cement. Despite this, mature cements may contain detectable amounts of both 4- and 5-coordinate aluminum. Aluminum has been found to be leached from glass-ionomer cements, with greater amounts being released under acidic conditions. It may be associated with fluoride, with which it is known to complex strongly. Aluminum that enters the body via the gastro-intestinal tract is mainly excreted, and only about 1% ingested aluminum crosses the gut wall. Calculation shows that, if a glass-ionomer filling dissolved completely over 5 years, it would add only an extra 0.5% of the recommended maximum intake of aluminum to an adult patient. This leads to the conclusion that the release of aluminum from either type of glass-ionomer cement in the mouth poses a negligible health hazard.