Dr. Nieca Goldberg, director of the New York University Langone Medical Center Women's Heart Program, said many factors could be at play. "Breast-feeding really mobilizes fat stores and has an impact on cholesterol. It also increases levels of [the hormone] oxytocin, which can relax blood vessels."
However, she cautioned that the study only showed an association, not a cause-and-effect relationship. It could be that women who choose to breast-feed are women who are healthier in general, she noted.
But, Goldberg added, the issue still warrants further study. She said it's important for researchers to look specifically at things women do when they're young and how they might affect heart health.
To learn more about the benefits of breast-feeding, visit the U.S. National Women's Health Information Center.
SOURCES: Eleanor Bimla Schwarz, M.D., assistant professor, medicine, epidemiology, obstetrics, gynecology and reproductive sciences, University of Pittsburgh Center for Research on Health Care, Pittsburgh; Nieca Goldberg, M.D. director, women's heart program, New York University Langone Medical Center, and associate professor, New York University School of Medicine, New York City; May 2009, Obstetrics & Gynecology