Breast arterial calcifications: a systematic review and meta-analysis of their determinants and their association with cardiovascular events.

Objective: Breast arterial calcifications (BAC), regularly observed at mammography, are medial calcifications and as such an expression of arteriosclerosis. Our objective was to evaluate and summarize the available evidence on the associations of BAC with cardiovascular risk factors and cardiovascular risk.

Methods: A systematic literature review and meta-analysis were conducted. Embase and PubMed databases were searched. After critical appraisal, odds ratios were extracted from studies of moderate or good quality that examined risk factors for BAC or associations of BAC with cardiovascular disease. Random effects model meta-analyses were used to calculate pooled odds ratios and 95% confidence intervals (95%CIs).

Results: BAC prevalence is around 12.7% among women in breast cancer screening programs. Increasing age (pooled OR 2.98 [95%CI 2.31-3.85] for every 10 years), diabetes (pooled OR: 1.88 [95%CI 1.36-2.59]) and parity as opposed to nulliparity (pooled OR 3.43 [95%CI 2.23-5.27]) are associated with higher BAC prevalence. Smoking is associated with lower BAC prevalence (pooled OR 0.48 [95%CI 0.39-0.60]). No associations were found with hypertension, obesity or dyslipidemia. Although longitudinal studies (n = 3) were scarce, BAC appear to be associated with an increased risk of cardiovascular disease events (adjusted hazard ratios for coronary heart disease ranging from 1.32 [95%CI 1.08-1.60] to 1.44 [95%CI1.02-2.05]).

Conclusion: BAC appear to be associated with an increased risk of cardiovascular disease events, while only being associated with some of the known cardiovascular risk factors, illustrating that medial arterial calcification might contribute to cardiovascular disease through a pathway distinct from the intimal atherosclerotic process.