Diminishing educational differences in breast cancer mortality among Finnish women: a register-based 25-year follow-up.

ABSTRACT

OBJECTIVES: This study examined trends in breast cancer mortality by education, age, and birth cohort. METHODS: Census records of Finnish women 35 years and older were linked with death records for 1971 through 1995. RESULTS: Excess breast cancer mortality of more-educated women has declined rapidly, mainly because of increasing mortality among less-educated women and stable or decreasing mortality among more-educated 35- to 64-year-old women. During the 1990s, mortality among more-educated 50- to 64-year-old women declined particularly fast. CONCLUSIONS: The causes of declining differences by education in breast cancer mortality are difficult to verify, but they may be due in part to narrowing differences in reproductive behavior among the younger birth cohorts and to a period effect possibly associated with the introduction of breast cancer screening in the late 1980s.