Breast arterial calcifications are correlated with subsequent development of coronary artery calcifications, but their aetiology is predominantly different

Abstract

Objective

To study whether calcifications in breast arteries, as seen on mammograms, predict future development of coronary artery calcifications.

Methods

We studied 499 women, aged 49–70 years, participating in a breast cancer screening program and investigated whether arterial calcifications in the breast (BAC) are associated with coronary arterial calcifications (CAC) after 9 years follow-up. Mammograms were reviewed for the presence of BAC. CAC was assessed by multi slice computed tomography (MSCT). With logistic regression analysis the independent effect of various risk factors on BAC and CAC was measured.

Results

BAC was present in 58 of 499 women (12%) and CAC score > 0 was present in 262 of 499 women (53%). BAC was strongly associated with CAC (OR 3.2, 95% CI 1.71–6.04) and this remained significant after adjustment for age at baseline and the duration of follow-up (OR 2.1, 95% CI 1.10–4.23). Most CV risk factors were associated with CAC but not with BAC. Only parity was significantly associated with both increased CAC (OR 2.1, 95% CI 1.21–3.60) and increased BAC (OR 5.3, 95% CI 1.23–22.43). Breastfeeding was associated with BAC (OR 3.4, 95% CI 1.40–8.23) but not with CAC (OR 1.3, 95% CI 0.84–1.93).

Conclusion

Breast arterial calcifications are predictive of subsequent development of calcifications in the coronary arteries.

Introduction

Calcium in the coronary vascular wall is a known marker of the presence of atherosclerotic disease in the coronary arteries. The amount of calcium, detected by electron beam computed tomography (EBCT) or multi slice computed tomography scanning (MSCT), is a promising method to measure the risk of coronary heart disease (CHD) events [1], [2]. Disadvantages of using these new radiology techniques in risk assessment are the costs and feasibility for its widespread application, the impaired additional diagnostic value in low-risk and high-risk patients and the risks involved in radiation exposure [3], [4], [5]. Calcium deposits are also present in other parts of the vascular tree as a sign of subclinical atherosclerosis. Imaging of calcifications in the thoracic and abdominal aorta on conventional X-rays for example has also been associated with an increased CHD event risk, but its clinical application for screening purposes has not been established [6], [7], [8].

Calcifications in the arteries of the breasts can be seen in 3–29% of women undergoing mammography, with the advantage that mammograms are often obtained in already running breast cancer screening programs [9], [10], [11], [12]. The simultaneous use of mammograms for screening purposes of breast cancer and CHD could be very cost effective. The clinical significance of breast arterial calcifications however is controversial and thus far has merely been associated with aging, diabetes, parity and lactation [13], [14], [15], [16]. It is yet undetermined whether breast arterial calcifications (BAC) and coronary artery calcifications (CAC) are related. Furthermore, it is not known whether both types of vascular calcifications share common CHD risk factors. Moreover, to our knowledge it has not been studied whether women with BAC are at greater risk to develop CAC as a sign of atherosclerotic disease. In the current study we investigated the relation between the prevalence of BAC at baseline and CAC scores at 6–11 years follow-up in 499 women participating in a breast-cancer screening program.