Breast cancer (BC) is the 2nd leading cause of cancer-related death in women worldwide. Increased BC mortality in diabetic patients was reported in prior studies. However, the interplay between ethnicity, race, and diabetes was not explored. This study analyzes the influence of type 2 diabetes (T2D) on BC mortality across ethnic and racial groups.
We studied a population of 2,366,551,531 by using the CDC Multiple Cause of Death database (ICD, 10th revision) between 2005 and 2020. We identified all women who died of BC, code C50, as underlying cause of death (UCD), regardless of T2D. Then we identified the same UCD among women with T2D, code E11, as multiple cause of death. Age-adjusted mortality rates (AAMR) per million persons (PMP) were calculated, standardized to 2000 US census, and stratified by ethnicity and race [Hispanic (H), non-Hispanic (NH), Black (B), and White(W)].
In the general population (GP), a total of 659738 deaths from BC were identified, with an overall AAMR of 211.5 PMP (B: 287, W: 206.6, H: 141.3, NH: 218.9). AAMR declined from 2005 to 2020 by 22% among B from 327.1 to 253.8 PMP, 20% among W from 235.3 to 187.1 PMP, 14% among H from 152.9 to 131.3 PMP, and 20% among NH from 248.8 to 198.4 PMP. In T2D population, a total of 9535 BC deaths were identified, with an overall AAMR of 3.0 PMP (B: 4.6, W: 2.8, H: 3.4, and NH: 2.9). AAMR increased from 2005 to 2020 by 37% among B from 4.1 to 5.6 PMP, 65% among W from 2.3 to 3.8 PMP, 78% among H from 2.3 PMP to 4.1 PMP, and 60% among NH from 2.5 PMP to 4.0 PMP.
Popultion Ethnicity or race Death AAMR PMP AAMR trend 98203 287 - 22% 541169 206.6 - 20% 41519 141.3 - 14% 618219 218.9 - 20% 1513 4.6 + 37% 7596 2.8 + 65% 915 3.4 + 78 8620 2.9 + 60%
This is one of the largest population based studies analyzing BC mortality. Between 2005 and 2020, BC mortality was reduced in GP and increased in T2D in all races and ethnicities included in the study. AAMR in B was higher than W in both populations. Unlike GP, T2D had a higher AAMR in H than NH. Additionally, the highest rate of mortality increase in T2D was noted in W and H. More studies are warranted to identify causes of the rise among T2D and stratigies to reduce the racial and ethnic gaps.
The authors.
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All authors have declared no conflicts of interest.