Early Elective Delivery Disparities between Non-Hispanic Black and White Women after Statewide Policy Implementation

e12599 Background: Higher prevalence of triple negative breast cancer (TNBC) in black women with associated poor outcomes due to various disparities is well documented within a single state. We examine multiple states to better understand the state effect on such differences in incidence and prevalence of TNBC in black women. Methods: Female patients of ages 19 years old and above with breast cancer from the Surveillance, Epidemiology and End Results (SEER) Program across 13 states (608 counties) from 2015 (n = 66,444) and 2016 (n = 66,122) were examined. The relationships between the proportion of black and white women and the rate of patients with different tumor subtypes (luminal A, luminal B, HR-HER2+, and triple negative) were examined at the county level using ordinary least-square regression models. In parallel, due to consideration of various state-specific healthcare policies, socio-cultural norms, and socio-economic disparities, multi-level regression models were applied to examine the nested, random effect of each state on TNBC prevalence in each county. Bonferroni correction was applied to reduce the Type I error caused by repeated use of the same variables in multiple tests. Results: The baseline breast cancer rates between black and white women were similar in the population (0.171% for black and 0.168% for white). Consistent to previous studies, we demonstrate a significant positive correlation (p < 0.001) in TNBC in black females in both years. Surprisingly, when accounted for the random effects on states, 38.2% (2015) and 34.3% (2016) increase in incidence of TNBC in black females were seen, suggestive of state-specific disparity affecting race-specific health. In 2015, other subtypes of breast cancer in both black and white females did not result in significant relationship. Interestingly, in 2016, there was a significant relationship seen between the TNBC rate in white females and the white female population rate only after adjusting for the state effect (p = 0.026). This indicates the impact of non-biological factors such as state-wide health policies. Additionally, HR-HER2+ black females had a significant relationship against respective population rate only after adjusting for the state effect as well (p = 0.0394). For luminal A white females, a 15% decrease in incidence was seen after adjusting for state effect (p = 0.0424). Conclusions: This is the first known across-state examination of breast cancer subtypes by race with random effects on state. This study shows the role of state-specific factors affecting incidence in black and white females and potentially indicates the importance of state-level management for breast cancer on health disparities in addition to race-driven effects. Further studies are needed to elucidate comparable differences between states affecting the rates of various subtypes of breast cancer and thus health outcomes.

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Abstract MP008: Racial Differences in Total, Free, and Bioavailable 25(OH)D and PTH Levels and CVD Risk Among Postmenopausal Women

Circulation ◽

10.1161/circ.135.suppl_1.mp008 ◽

2017 ◽

Vol 135 (suppl_1) ◽

Author(s):

Xi Zhang ◽

Wanzhu Tu ◽

Lesley Tinker ◽

JoAnn E Manson ◽

Simin Liu ◽

...

Keyword(s):

Vitamin D ◽

Cohort Study ◽

Black Women ◽

Postmenopausal Women ◽

Racial Differences ◽

White Women ◽

Sitting Time ◽

Cvd Risk ◽

Black And White ◽

Circulating Levels

Background: Recent evidence suggests that racial differences in circulating levels of free or bioavailable 25(OH)D rather than total 25(OH)D may explain the apparent racial disparities in cardiovascular disease(CVD).However, few prospective studies have directly tested this hypothesis. Objective: Our study prospectively examined black white differences in the associations of total, free, and bioavailable 25(OH)D, vitamin D binding protein (VDBP), and parathyroid hormone (PTH) levels at baseline with incident CVD in a large, multi-ethnic, geographically diverse cohort of postmenopausal women. Method: We conducted a case-cohort study among 79,705 black and non-Hispanic white postmenopausal women aged 50 to 79 years and free of CVD at baseline in the Women’s Health Initiative Observational Study (WHI-OS). We included a randomly chosen subcohort of 1,300 black and 1,500 white noncases at baseline and a total of 550 black and 1,500 white women who developed incident CVD during the follow up. We directly measured circulating levels of total 25(OH)D, VDBP (monoclonal antibody assay), albumin, and PTH and calculated free and bioavailable vitamin D levels. Weighted Cox proportional hazards models were used while adjusting for known CVD risk factors. Results: At baseline, white women had higher mean levels of total 25(OH)D and VDBP and lower mean levels of free and bioavailable 25(OH)D and PTH than black women (all P values < 0.0001). White cases had lower levels of total 25(OH)D and VDBP and higher levels of PTH than white noncases, while black cases had higher levels of PTH than black noncases (all P values < 0.05). There was a trend toward an increased CVD risk associated with low total 25(OH)D and VDBP levels or elevated PTH levels in both US black and white women. In the multivariable analyses, the total, free, and bioavailable 25(OH)D, and VDBP were not significantly associated with CVD risk in black or white women. A statistically significant association between higher PTH levels and increased CVD risk persisted in white women, however. The multivariate-adjusted hazard ratios [HRs] comparing the extreme quartiles of PTH were 1.37 (95% CI: 1.06-1.77; P-trend=0.02) for white women and 1.12 (95% CI: 0.79-1.58; P-trend=0.37) for black women. This positive association among white women was also independent of total, free, and bioavailable 25(OH)D or VDBP. There were no significant interactions with other pre-specified factors, including BMI, season of blood draw, sunlight exposure, recreational physical activity, sitting time, or renal function. Interpretation: Findings from a large multiethnic case-cohort study of US black and white postmenopausal women do not support the notion that circulating levels of vitamin D biomarkers may explain black-white disparities in CVD but indicate that PTH excess may be an independent risk factor for CVD in white women.

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