Elevated breast cancer mortality among highly educated Asian American women.

backgroundPostmenopausal breast cancer (PMBC) is the most commonly diagnosed and the second leading cause of cancer death among women in the US. Research examining the association between PMBC and education level has been inconsistent; no study in the US has examined how educational level impacts PMBC mortality in Asian American women, a largely immigrant population with above-average educational attainment.

methodsCalifornia Vital Statistics data from 2012-2017 were analyzed to derive age-adjusted mortality rate ratios (MRRs) by education level (associates degree or above referred to as "higher education", high school, less than high school) and race [Non-Hispanic White (NHW), Asian/Pacific Islander (Asian), and its two largest subpopulations: Chinese and Filipino] from negative binomial regression models.

resultsPMBC mortality for both NHWs and Asians was greater among women with higher education compared to those who did not complete high school: NHWs had 22% higher PMBC mortality (MRR 1.22; 95% CI: 1.14-1.31) and Asians had 2.6 times greater PMBC mortality (MRR 2.64; 95% CI: 2.32-3.00) than their counterparts who did not complete high school. Asians in the lowest education level had 70% lower mortality than NHWs (MRR 0.30; 95% CI: 0.27-0.34). This mortality advantage among Asians was greatly reduced to only 27% lower among the highest educated (MRR 0.73; 95% CI: 0.68-0.78). For higher educated Filipina women, no mortality advantage was evident compared to NHWs (MRR 0.96; 95% CI: 0.88-1.05).

conclusionPMBC mortality for higher educated Asian women is elevated in comparison to their counterparts with less education. Given that PMBC survival is greater among those with higher education, our findings strongly suggest an excess in the incidence of PMBC (more than double) among higher educated Asian women; this warrants more research into potentially modifiable causes of PMBC in this burgeoning population.