A case-control study of diet and social factors in cancer of the esophagus in Transkei.

A study of 100 patients with cancer of the esophagus and 100 controls matched for sex, age, and educational level was done in Transkei, with extensive inquiries into diet and social habits. The significant risk factors found were use of Solanum nigrum as a food (relative risk, 3.6), smoking (relative risk, 2.6), and use of traditional medicines (relative risk, 2.1). Consumption of traditional beer was not a risk factor.