Selenium and other mineral elements in populations at risk for esophageal cancer.

The current study tested the hypothesis that deficiencies of certain mineral elements are risk factors for esophageal cancer (EC). In rural blacks living in areas with moderate to high EC incidence rates in southern Africa, the whole blood selenium (Se) levels were found to be significantly (P less than 0.0005) lower (58 to 71 ng/ml) than those of rural and urban populations living in low EC rate areas (114 to 177 ng/ml). No significant differences were found in the plasma levels of the other mineral elements examined, including zinc, copper, and magnesium. Within a high EC rate area occupants of households with previously recorded EC cases had significantly (P less than 0.0025) lower levels of Se (64 ng/ml), but not of other mineral elements, than subjects from households without known cases (77 ng/ml). Mean Se levels of subjects with premalignant or malignant esophageal cytological changes (54 ng/ml) were significantly (P less than 0.0025) lower than those of subjects without such lesions (68 ng/ml). An inverse relationship was found between Se status and the degree of cytologic abnormality. These findings suggest that Se deficiency may play a role in the development of EC. The potential value of whole blood Se determinations and esophageal cytologic examinations in the early detection and of Se supplementation in the prevention of EC merits further investigation.