EXPLAINING THE RELATION BETWEEN EDUCATION AND POSTMENOPAUSAL BREAST-CANCER

The authors examined the relation between socioeconomic status, as def ined by education level, and postmenopausal breast cancer incidence us ing data from the National Health and Nutrition Examination Survey I E pidemiologic Followup Study. Female participants in the study were fol lowed from 1971-1974 to 1992-1993. Cox proportional hazards modeling w as used to determine the relation between breast cancer incidence and education level. There was a direct dose-response association between education level and postmenopausal breast cancer risk. Several breast cancer risk factors, including height and reproductive-related risks s uch as nulliparity, were found to mediate this relation. Adjustment fo r these factors reduced, but did not eliminate, the positive relation between education level and risk of postmenopausal breast cancer; howe ver, the association was no longer statistically significant, The asso ciation between higher education and increased risk of breast cancer a ppears to be largely explained by differences in the known risk factor s for breast cancer.