Smoking, high cholesterol, hypertension and family history are among the most well-known risk factors for heart disease, the leading cause of death in the U.S. But in a study published today in Circulation: Journal of the American Heart Association, Dutch scientists suggest a new risk factor for postmenopausal womenone that can be detected by a routine urine test.

The scientists measured levels of albumin, a protein common in blood, in urine samples donated by 1,118 healthy, postmenopausal women participating in a breast cancer screening study in the late 1970s. The researchers then compared urinary albumin levels of two groups of women: one whose members had since died of cardiovascular disease and a control group of women who had not. Women with the highest levels of albumin in their urine had a cardiovascular death rate 4.4 times that of women with the lowest albumin levels.

According to Jan Dirk Banga, one of the co-authors of the report, the presence of albumin in the urine suggests that blood vessels in the kidneys, lined by endothelial cells, are leaking. "The endothelial cells may already be damaged and malfunctioning at the early stage of heart disease when there are no symptoms," Banga says. "Our finding supports the hypothesis that albumin in the urine is a reflection of vascular damage and a marker of early disease."

Limitations of the studynamely the size and homogeneity of its samplemean the findings might not apply to men or even to women who have not yet gone through menopause. Future studies, the researchers say, need to address different populations, the link between albumin in urine and cardiovascular disease, and whether lowering urinary albumin levels reduces cardiovascular risk. Banga cautions that a routine urinary analysis will never be able to predict a person's cardiac-related death. But, he says, it may help predict an increased risk of it.