Associations of iron overload in Africa with hepatocellular carcinoma and tuberculosis: Strachan's 1929 thesis revisited

Abstract

We analyzed data from the first study of iron overload in Africans, conducted between 1925 and 1928, to determine whether this common condition is associated with death from hepatocellular carcinoma and/or tuberculosis. In the original study, necropsies were performed on 714 adult blacks from southern Africa. Hepatic and splenic iron levels were measured semiquantitatively in 604 subjects and one of five iron grades was assigned. We examined death from hepatocellular carcinoma or from tuberculosis and the variables of age, sex, the presence of cirrhosis or other diagnoses that might be influenced by iron status, and tissue iron grades. Nineteen percent of men and 16% of women had the highest grade of hepatic iron. After adjustment for the presence of cirrhosis, hepatic iron grade was the variable most significantly associated with death from hepatocellular carcinoma (P = .021). The odds of death from hepatocellular carcinoma in subjects with the highest grade of hepatic iron was 23.5 (95% confidence interval, 2.1 to 225) times the odds in subjects with the three lowest grades. Splenic iron was the variable most significantly associated with death from tuberculosis (P <.0001). The odds of death from tuberculosis with the highest grade of splenic iron was 16.9 (4.8 to 59.9) times the odds with the two lowest grades. These findings suggest that iron overload in black Africans may be a risk factor for death from hepatocellular carcinoma and for death from tuberculosis.