The scans can give clinically meaningful indications of heart risk, addressing a gender gap without adding patient burden, experts say.
Breast arterial calcification could be a strong predictor of future cardiovascular disease, according to a large multi-centre cohort study from Emory University in the United States.
Compared with women without BAC, those with mild calcification were about 30% more likely to experience serious cardiovascular disease, those with moderate calcification had roughly 70% higher risk and women with severe calcification had more than double the risk.
Additionally, each 1mm² increase in BAC area was associated with a 1–2% increase in cardiovascular risk. Doubling the BAC area increased major adverse cardiac event (MACE) risk by up to 19%.
“This is about using information we already have to better identify risk earlier, particularly in women who might otherwise be missed,” Professor Garry Jennings, Heart Foundation Chief Medical Advisor, told Oncology Republic.
“There is a real opportunity for improved use of existing health data to close long‑standing gaps in women’s heart health,” he said.
“Breast screening is one of several routine investigations performed for reasons other than cardiovascular risk assessment and increasingly supported by artificial intelligence. These developments create opportunities to improve risk detection without adding extra tests or burden on patients.”
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The study used mammograms from 123,762 women aged 40–79 years who had participated in breast screening and had no known cardiovascular disease at baseline, including 74,124 women from the Emory Breast Imaging Dataset (EMBED) and 49,638 women from the Mayo Clinic Enterprise.
An AI model, which was trained, validated and tested using a set of 1000 mammograms annotated by an expert radiologist, was used to split participants into four categories of BAC severity: zero BAC, mild (>0–10 mm²), moderate (>10–25 mm²) and severe (>25 mm²).
The model was highly accurate, with a coefficient of determination (R²) of 0.91. A score of 1.0 is indicative of perfect prediction.
BAC was detected in 16.1% of women in the EMBED cohort and 26.0% in the Mayo Clinic cohort; a difference likely due to an older patient population in the latter, researchers noted. However, both cohorts fell within the 12.3%–29.4% prevalence range reported in previous studies.
Participants were followed for a median of seven years, until the first occurrence of MACE or the study cut-off date of 1 September 2024. Cardiovascular outcomes included acute myocardial infarction (AMI), stroke, heart failure and all-cause mortality.
Across both cohorts, increasing BAC severity was associated with progressively higher rates of all cardiovascular events. In multivariable Cox regression models adjusting for age, severe BAC was linked with a twofold increase in mortality risk (HR 2.0) and more than double the risk of heart failure (HR 2.13).
When the researchers accounted for death as a competing event using a Fine–Gray model, the relationship became even stronger, and the hazard ratio for heart failure among women with severe BAC in the EMBED cohort reached 4.65.
BAC severity also correlated strongly with age, with a mean age difference of about 13 years between women with no calcification and those with severe BAC.
Higher BAC severity was also associated with several established cardiovascular risk factors, including diabetes, antihypertensive medication and statin use, higher systolic blood pressure, higher BMI and lower estimated glomerular filtration rate.
Interestingly, smoking was not associated with BAC severity in either cohort.
“This is a substantial and well conducted study, and the findings are compelling,” said Professor Jennings.
“Importantly, it shows that arterial calcification identified on routine breast screening provides incremental information about cardiovascular risk beyond standard risk prediction tools, and may help identify risk in younger women, where traditional assessment is often less reliable.
“However, these findings will need to be confirmed in different populations, including Australian women. It’s also important to be clear that arterial calcification seen on mammograms is a marker of cardiovascular risk, not necessarily a direct cause.
“From a clinical perspective, the appropriate response is not alarm, but action. When this marker is identified, clinicians should intensify management of cardiovascular risk factors and engage women in long term prevention strategies.”
The Heart Foundation is currently funding similar research.
