Endemic goitre in whites and negroes: racial or social effect?

A sample of 2688 individuals, about half of them showing endemic goitre, has been studied in a hyper-endemic area of the state of Mato Grosso, Brazil. The codified data were processed in computers. Analyses through contrasts among multinominal proportions showed Negroes and Mulattoes with higher frequencies of goitre than Whites, thus agreeing with results from the literature. A number of multiple regression models, including 21 independent variables, showed no evidence of any intrinsic racial effect on the occurrence of goitre. The authors conclude that the higher prevalence of goitre among Malattoes and Negroes probably reflects the influence of their poorer socio-economic conditions. Although genetic factors are generally assumed to play some role in the development of goitre, it is to environmental causes that the most important role is ascribed.