Studies in the epidemiology and preventability of rheumatic fever-II. Socio-economic factors and the incidence of acute attacks

Incidence rates of hospitalized rheumatic fever from 1960 to 1964 have been calculated for socio-economic fifths of the Baltimore white and non-white populations. The incidence rates for non-whites are consistently higher than those for whites in each socio-economic fifth. With improving socio-economic status the incidence rate of rheumatic fever declines in the white population but in the non-white population there is no clear pattern of declining incidence. A comparison of white and non-white socio-economic fifths, in terms of housing characteristics, indicates that extent of crowding is the variable which relates most closely to incidence of rheumatic fever. When degree of crowding is held constant, incidence rates among non-whites are no higher than those calculated for whites. The data suggest that the higher incidence of rheumatic fever among non-whites is not a result of any particular susceptibility of non-whites to rheumatic fever, but relates to the crowded conditions in which most of this ethnic group live in Baltimore. The findings in this study suggest that socio-economic factors should be an important consideration in programs designed to prevent and control rheumatic fever.