Paths to health equity: Local area variation in progress toward eliminating breast cancer mortality disparities, 1990-2009.

BACKGROUND: US breast cancer deaths have been declining since 1989, but African American women are still more likely than white women to die of breast cancer. Black/white disparities in breast cancer mortality rate ratios have actually been increasing.
METHODS: Across 762 US counties with enough deaths to generate reliable rates, county-level, age-adjusted breast cancer mortality rates were examined for women who were 35 to 74 years old during the period of 1989-2010. Twenty-two years of mortality data generated twenty 3-year rolling average data points, each centered on a specific year from 1990 to 2009. Mixed linear models were used to group each county into 1 of 4 mutually exclusive trend patterns. The most recent 3-year average black breast cancer mortality rate for each county was also categorized as being worse or not worse than the breast cancer mortality rate for the total US population.
RESULTS: More than half of the counties (54%) showed persistent, unchanging disparities. Roughly 1 in 4 (24%) had a divergent pattern of worsening black/white disparities. However, 10.5% of the counties sustained racial equality over the 20-year period, and 11.7% of the counties actually showed a converging pattern from high disparities to greater equality. Twenty-three counties had 2008-2010 black mortality rates better than the US average mortality rate.
CONCLUSIONS: Disparities are not inevitable. Four US counties have sustained both optimal and equitable black outcomes as measured by both absolute (better than the US average) and relative benchmarks (equality in the local black/white rate ratio) for decades, and 6 counties have shown a path from disparities to health equity.