Routine mammograms often reveal calcifications in the breast: bright white lines snaking through the tissue. While not a sign of cancer, new research suggests they may provide clues to risk of cardiovascular disease.

The white lines are indicators of calcium buildup in the breast’s arterial wall, which is different from coronary artery calcification, already known as a cardiovascular risk. In a study of more than 5,000 postmenopausal women, those with breast arterial calcification (BAC) were 51 percent more likely to develop heart disease or have a stroke compared with women who didn’t have the condition.

Researchers don’t have an explanation yet — and women without this calcification still face cardiovascular risks — but BAC may prove to be another indicator of poor cardiovascular health and add another benefit to routine mammographies.