title: Evidence for an intimate geochemical factor in the etiology of esophageal cancer.
abstract: Epidemiological data for esophageal cancer in the Butterworth District, Transkei, was used to calculate incidence contours which confirmed large variations within short distances (less than 5 km). High- and low-risk zones were demarcated, and a close relationship with underlying geology observed. The low-incidence zones in the study regions were underlain by dolerite intrusions, whereas higher-risk regions were on sedimentary strata. Analysis of rocks indicated that those from the higher-risk regions contain less copper, cobalt, and manganese. Soil samples were analyzed for boron, cobalt, copper, manganese, molybdenum, nickel, sodium, lead, vanadium, and zinc; the results also indicated a strong geochemical association with the disease. The concentrations of copper (P = 0.001), nickel (P = 0.001), and boron were markedly lower in the high-risk zones. Manganese, zinc, and molybdenum levels in soils also tended to be substantially lower in the high-risk zone.
mesh_terms: D000328:Adult; D004812:Epidemiologic Methods; D004938:Esophageal Neoplasms / Q000453:epidemiology / Q000209:etiology*; D055593:Geological Phenomena; D005844:Geology; D006801:Humans; D008903:Minerals / Q000032:analysis* / Q000506:poisoning; D012042:Registries; D012306:Risk; D012424:Rural Population; D012987:Soil / Q000032:analysis*; D013019:South Africa
chemical_list: D008903:Minerals; D012987:Soil