An investigation of the relationship between stomach cancer and cerebrovascular disease: evidence for and against the salt hypothesis.

Analysis of age-adjusted death rates in 21 countries during a 20-year period identified the presence of a strong positive association between recorded mortality from cerebrovascular disease, hypertension and stomach cancer. A study of multiple causes of death was undertaken to determine whether this association results from a unique relationship between these diseases or merely represents a secondary and fortuitous finding. The observed and expected concordances of stomach cancer, lung cancer, pancreatic cancer and cerebrovascular disease with several cardiovascular and non-cardiovascular diagnoses were calculated from tables of multiple causes of death for all persons who died in England and Wales during 1975 and 1976. Although several previously known disease associations were recognized, there was no evidence of a greater concordance between stomach cancer and hypertension or cerebrovascular disease than between lung cancer and hypertension or cerebrovascular disease. Likewise, with one exception, there was no evidence of a greater concordance between stomach cancer and hypertension or cerebrovascular disease than between pancreatic cancer and hypertension or cerebrovascular disease. These results suggest that the temporal and geographic relationships between mortality from cerebrovascular disease, hypertension and stomach cancer are not causally linked. Our findings fail to support the hypothesis that exposure to salt increases an individual's risk of both cerebrovascular disease and stomach cancer.