Epidemiological studies on ingested mineral fibres: gastric and other cancers.

The epidemiological studies of ingested asbestos fibres conducted world-wide are reviewed and evaluated. Most of the studies have been done in the United States and Canada and have involved community exposures via natural contamination of drinking-water supplies. One or more studies found associations between asbestos fibres in drinking-water supplies and cancer incidence or mortality associated with many body sites, including oesophagus, stomach, small intestine, colon, rectum, gall-bladder, lungs, pancreas, peritoneum, pleura, prostate, kidneys, brain and thyroid. Each study has methodological limitations or weaknesses that limit the ability to assess risk from ingested asbestos. There is no agreement between the results of the various studies, but an association between ingested asbestos fibres and cancer of the stomach and pancreas has been found with some degree of consistency.