Association of breast cancer and cervical cancer incidence with income and education among whites and blacks.

Data from the 1969-71 Third National Cancer Survey were used to study the association of cancer incidence with income and education as indicated by census tract of residence. Also considered was the effect of adjustment for differences in socioeconomic distribution on the observed excess risk of cervial cancer and lower risk of breast cancer among black women compared to white women. Strong positive associations with both income and education were found, with the rates based on 19,344 breast cancer cases among white women. These observations were noted in most geographic areas studied. The relative risk showed little apparent relationship to age. The rates based on 1,570 cases among black women indicated a strong positive association with education but not with income. Socioeconomic adjustment reduced by almost one-half the black-white difference in breast cancer rates, and education had a stronger effect than did income. White women continued to have a significantly higher rate after such adjustment. Conversely, the incidence of cancer of the cervix showed strong negative associations with each of the two variables among both the 3,802 cases in white women and 954 cases in black women. The negative gradient decreased with age and was apparent in almost all the areas. The excess risk among black women was reduced by two-thirds with socioeconomic adjustment, though the rates remained significantly different. Income had a stronger association than did education with cervical cancer incidence.