Income Protects Breast Cancer Survivors From Heart Disease Unequally, National Study Finds

Higher income has long been treated as a reliable shield against chronic disease, but a sweeping new analysis of female breast cancer survivors in the United States suggests that this protection is anything but uniform. Drawing on four years of nationally representative interview data, researchers found that economic advantage dramatically lowers the odds of cardiovascular disease in some groups of survivors while offering little measurable benefit in others. The findings, published in the Journal of Cancer Survivorship, add urgent nuance to a growing body of evidence that cardiovascular disease, not cancer, is often the gravest long-term threat facing women who have survived breast cancer.

The study, led by Robina Josiah Willock of Morehouse School of Medicine together with colleagues at Wayne State University, analyzed responses from 2,745 female breast cancer survivors who participated in the National Health Interview Survey between 2019 and 2022. After excluding surveys missing more than fifteen percent of key variables, the final analytic sample comprised 2,553 women, of whom 411, or 16.1 percent, reported a physician-confirmed cardiovascular diagnosis. The conditions counted were non-fatal stroke, non-fatal myocardial infarction, and coronary artery disease, the three major cardiovascular events tracked consistently in the survey.

The central exposure of interest was the poverty-to-income ratio, or PIR, a measure calculated by dividing household income by the federal poverty threshold for a family of a given size and composition. Rather than treating income as a simple linear variable, the researchers divided it into four tiers that roughly align with policy-relevant thresholds: PIR at or below 1.49, 1.50 to 2.49, 2.50 to 3.99, and 4 or higher. These cut points approximate the income boundaries governing Medicaid expansion eligibility, Affordable Care Act Marketplace cost-sharing subsidies, and premium tax credits during the study period, making the categories directly meaningful for understanding who can and cannot afford consistent insurance coverage and care.

Methodologically, the team employed inverse probability of treatment weighting, or IPTW, in their logistic regression models, a technique that balances observed covariates across income groups more effectively than standard adjustment and reduces confounding in observational data. All estimates were weighted using the NHIS final annual sample weight, with variance estimation accounting for the survey’s complex clustering and stratification. The researchers also ran sensitivity analyses disaggregating the composite cardiovascular outcome into its individual components, and these largely confirmed a robust socioeconomic gradient: for myocardial infarction, women in the lowest income tier faced more than three times the odds of disease compared with the mid-high income tier, and for stroke more than double the odds, while the strongest protective contrast between the highest and lowest income groups yielded odds ratios of 0.26 for heart attack and 0.29 for stroke.

The headline result, however, lies in the interaction analyses. Higher income did not confer equal protection across racial and ethnic groups. The interaction between PIR and race and ethnicity was highly significant, with a p-value below 0.0001. Among Black breast cancer survivors, reaching the highest income tier reduced the odds of cardiovascular disease by 92 percent compared with the lowest tier, a striking odds ratio of 0.08. Among White survivors, the equivalent protection was a still-substantial but smaller 68 percent reduction. Among Asian survivors and those in other racial and ethnic categories, no significant association between income and cardiovascular disease emerged at any comparison, a pattern the authors attribute either to genuinely different income-health dynamics or to the instability of estimates drawn from small sample sizes in the survey.

Age told a parallel story of moderated protection. The interaction between income and age was significant at p equal to 0.017, with the strongest benefits concentrated among survivors younger than 65. In this pre-Medicare group, the highest income tier cut the odds of cardiovascular disease by 91 percent relative to the lowest tier. Among survivors aged 65 to 84, the protective gradient weakened, with only the broadest income contrasts reaching significance, and among those 85 and older the effect largely vanished except for a 56 percent reduction at the highest versus lowest income comparison. The authors suggest that Medicare and other age-linked social programs may buffer the economic circumstances of older survivors, flattening the health consequences of low income in ways that younger, uninsured, or underinsured women cannot access.

Survivorship duration and care-seeking behavior added further texture. Although the overall interaction between income and years since diagnosis was not statistically significant, strong patterns appeared at both ends of the trajectory: among women one to four years past diagnosis, the highest income tier reduced cardiovascular odds by roughly 80 percent, and among long-term survivors more than ten years out, significant protections of 38 to 61 percent persisted. Notably, the persistence of cardiovascular risk and income gradients more than a decade after diagnosis challenges the conventional survivorship model, in which surveillance typically tapers after the five-year mark. Meanwhile, the interaction between income and delayed medical care approached significance at p equal to 0.058, with women who reported no delays in follow-up showing consistent income protection across all tiers, while among those who delayed care only the very highest income group showed a significant benefit.

The biological and structural backdrop makes these findings consequential. Breast cancer therapies, particularly radiotherapy and anthracycline chemotherapy, are known to cause acute cardiotoxicity and to seed subclinical cardiac injury that manifests years later; one landmark 25-year follow-up study cited in the paper reported a 1.7-fold increase in cardiovascular mortality among irradiated patients. As survival rates climb, with the current five-year breast cancer survival standing at 91 percent and more than 4.9 million survivors projected in the United States by 2030, cardiovascular disease has become a predominant non-cancer cause of death in this population. Women of lower socioeconomic status enter survivorship with higher burdens of hypertension, diabetes, obesity, and smoking, are more often diagnosed at advanced stages requiring more cardiotoxic regimens, and are more exposed to financial toxicity, the economic fallout of diagnosis that disproportionately harms racial and ethnic minority women even after adjusting for baseline income and education.

The authors are candid about the limitations inherent in their design. All diagnoses were self-reported, introducing potential recall bias, and validation studies suggest self-reported stroke and heart attack are reasonably accurate while angina and coronary artery disease are less so. The cross-sectional design precludes any inference of causality or temporality, breast cancer stage and treatment details were unavailable for adjustment, and the predominantly non-Hispanic White sample limits generalizability, potentially underrepresenting women with advanced disease who died early. Nonetheless, the consistency of the income gradient across composite and individual outcomes, and the strength of the moderation by race and age, lend weight to the central claim: economic status functions as an independent and modifiable risk marker for cardiovascular disease in breast cancer survivors.

The practical implications are pointed. The authors argue that clinical cardiovascular risk models for breast cancer patients remain underspecified when they omit economic status, and they call for embedding longitudinal economic screening into survivorship care plans alongside traditional cardiovascular surveillance. They further propose extending cardiovascular prevention guidance beyond the current five-year threshold, expanding means-tested supports such as Medicaid expansion, subsidized supplemental coverage, and caps on out-of-pocket cardio-oncology costs toward younger survivors, and testing through comparative effectiveness trials whether routine screening of lower-income survivors improves outcomes. As the survivor population swells, the study suggests that protecting their hearts will require protecting their finances first, and that the size of that protection depends profoundly on who the survivor is.

Subject of Research: Socioeconomic and racial disparities in cardiovascular disease risk among female breast cancer survivors in the United States.

Article Title: Income, race, and cardiovascular disease in female breast cancer survivors: evidence of moderated socioeconomic protection in the National Health Interview Survey (NHIS) 2019–2022

Article References: Josiah Willock, R., Parks, D., Nabi, S., Rivers, B., Rivers, D., Li, C., & Levy, P. (2026). Income, race, and cardiovascular disease in female breast cancer survivors: evidence of moderated socioeconomic protection in the National Health Interview Survey (NHIS) 2019–2022. Journal of Cancer Survivorship. https://doi.org/10.1007/s11764-026-02112-3

Image Credits: AI Generated

DOI: 10.1007/s11764-026-02112-3

Keywords: breast cancer survivors, cardiovascular disease, poverty-to-income ratio, health disparities, social determinants of health, National Health Interview Survey, financial toxicity, cardiotoxicity, cancer survivorship, racial disparities, Medicare, survivorship care