Premenopausal breast cancer mortality in the United States, 1999-2003: Temporal trends of racial and urbanization status disparities

Background: Few studies have addressed variation of premenopausal breast cancer mortality between metropolitan and non-metropolitan areas. Objective: We characterized recent temporal trends of racial and urbanization status disparities for premenopausal breast cancer mortality in the United States (US). Methods: We queried CDC WONDER to obtain breast cancer mortality data for women ages 20-44 years for 1999 and 2003 from the 1999-2003 Compressed Mortality File (CMF). The CMF classified underlying cause of death according to International Classification of Diseases 10 criteria (breast cancer: C50) from all 50 states and Washington, DC. Data were stratified by race (Non-Hispanic Black or Non-Hispanic White) and urbanization status (large central metropolitan or non-metropolitan [micropolitan]). Mortality rate ratios (MRRs) were used for comparisons. Results: The premenopausal breast cancer MRR between Black and White females in the US declined from 1999-2003 (1999 MRR=2.42, 2003 MRR=2.07). Stratified data indicated that the MRR between Black and White females declined for US metropolitan areas (1999 MRR=2.52, 2003 MRR=2.15) and US non-metropolitan areas (1999 MRR=2.05, 2003 MRR=1.73). The MRR between metropolitan and non-metropolitan areas (Black and White combined) increased slightly from 1999-2003 (1999 MRR=1.08, 2003 MRR=1.18). Conclusion: Our data suggest that racial disparities for premenopausal breast cancer mortality in the US have collectively improved from 1999-2003, but urbanization status disparities increased. The results should be interpreted cautiously because of the brief period of investigation. More importantly, our data suggest that the interaction of race and urbanization status may be a consideration for future epidemiologic studies of premenopausal breast cancer.