By Serena Gordon
The research found that women who breastfeed have a 23 percent lower risk of stroke after menopause. The link was even stronger among black women, who had a 48 percent lower risk of postmenopausal stroke.
The study also found that the longer women breastfed, the lower their stroke risk.
"Breastfeeding is one of many factors that could help protect against stroke," said study author Lisette Jacobson. She's an assistant professor at the University of Kansas School of Medicine-Wichita.
Stroke is the fourth leading cause of death among U.S. women aged 65 and older, the researchers said. It's the third leading cause of death among older Hispanic and black women in the United States.
Known ways to prevent stroke include eating a healthy diet, maintaining a healthy weight, getting regular exercise, not smoking, limiting the amount of alcohol you drink, and controlling chronic medical conditions such as high blood pressure and diabetes, according to the U.S. Centers for Disease Control and Prevention.
The new study looked at more than 80,000 women who participated in the Women's Health Initiative observational study. Their average age was nearly 64, and all had given birth to one or more children.
Fifty-eight percent reported ever breastfeeding. Fifty-one percent of those women breastfed from one to six months, and 22 percent did so for seven to 12 months. Twenty-seven percent of women breastfed for more than a year.
Among the entire study group, 2,700 women had a stroke during nearly 13 years of follow-up, the findings showed.
After adjusting the data to account for other stroke risk factors, such as age and family history, the researchers found that women who breastfed for any length of time had a 23 percent lower risk of stroke. Women who breastfed for one to six months had a reduced risk of 19 percent, while women who breastfed for more than six months had a reduced risk of about one-quarter.
The association between breastfeeding and a reduced risk of stroke was strongest in black women. Hispanic women also appeared to benefit significantly -- reducing their risk of stroke by 32 percent. However, Jacobson said there weren't enough Hispanic women in the group to know if the association held up for Hispanic women over a longer duration of breastfeeding.
Jacobson was also quick to point out that this study wasn't designed to tease out a cause-and-effect relationship.
She did add that previous studies have suggested that women who breastfeed have better heart health later in life, with reduced risks of high blood pressure, abnormal cholesterol and metabolic syndrome.
Dr. Larry Goldstein, a spokesperson for the American Stroke Association, said the study was well-conducted, but also noted that it was unable to show an underlying biological mechanism that could account for the decreased stroke risk.
"Although it is premature to conclude that breastfeeding directly leads to a reduction in later-life stroke risk, this study should not dissuade women from breastfeeding, and if anything, [should] further encourage them to do so," he said.
"There are a large variety of benefits of breastfeeding for the child, and likely for the mother, supporting evidence-based guidelines from the American Academy of Pediatrics and the World Health Organization," Goldstein added.
The findings were published online Aug. 22 in the Journal of the American Heart Association.